design calculation cover sheet, 000-00c-mgr0-05400-000 …las vegas, nevada: bechtel saic company....
TRANSCRIPT
BSC
ENG200812100012
Design Calculation or Analysis Cover Sheet Complete only applicable items
3 System
Monitored Geologic Repository
1 QA Q
2 Page 1
4 Document Identifier
000-00C-MGRO-05400-000-00A 5 Title
Dose Reduction Factors Between Different Source Terms in a Cask 6 Group
Discipline EngineeringNuclear and Radiological Engineering 7 Document Status Designation
Preliminary Committed Confirmed Cancelled [7 Superseded 8 NotesComments
Attachments
Attachment I List of electronic files on Attachment I1 Attachment I1 Compact Disc (electronic attachment)
Total Number of Pages
1 NA
RECORD OF REVISIONS 16
ApprovedIAccepted (PrintISignIDate) David Darling
9 No
OOA
10 Reason For Revision
Initial Issue
11 Total of Pgs
50
12 Last Pg
1-3
13 Originator
(PrintISignIDate) Jabo S Tang
14 Checker
(PrintISignlDate) John HC Wang
15 EGS
(PrintISignlDate) Norman Kahler
ENG200812100012
BSC Complete only applicable items
1 QA QA
2 Page 1
Design Calculation or Analysis Cover Sheet
3 System 14 Document Identifier Monitored Geologic Repository OOO-OOC-MGRO-05400-000-00A 5 Title Dose Reduction Factors Between Different Source Terms in a Cask 6 Group Discipline EngineeringlNuc1ear and Radiological Engineering 7 Document Status Designation
D Preliminary I8J Committed D Confirmed D Cancelled o Superseded B NoteslComments
Attachments Total Number of Pages
Attachment I List of electronic files on Attachment II 1
Attachment II Compact Disc (electronic attachment) NA
RECORD OF REVISIONS
9 10 11 12 13 14 15 16
No Reason For Revision Total Last Originator Checker EGS Approvedl Accepted of Pgs Pg (PrinUSignDate) (PrinUSignDate) (PrinUSignDate) (PrinUSignDate)
OOA Initial Issue 50 1-3 Jabo S Tang John H C Wang Norman Kahler David Darling
~
t~ ~ 40( ~ ( yenrlJpgf gt7(~ ()ri j 210 075
ENG200812100012
BSC Complete only applicable items
1 QA QA
2 Page 1
Design Calculation or Analysis Cover Sheet
3 System 14 Document Identifier
Monitored Geologic Repository OOO-OOC-MGRO-05400-000-00A 5 Title
Dose Reduction Factors Between Different Source Terms in a Cask 6 Group
Discipline EngineeringlNuc1ear and Radiological Engineering
7 Document Status Designation
D Preliminary I8J Committed D Confirmed D Cancelled o Superseded
B NoteslComments
Attachments Total Number of Pages
Attachment I List of electronic files on Attachment II 1
Attachment II Compact Disc (electronic attachment) NA
RECORD OF REVISIONS
9 10 11 12 13 14 15 16
No Reason For Revision Total Last Originator Checker EGS Approvedl Accepted of Pgs Pg (PrinUSignDate) (PrinUSignDate) (PrinUSignDate) (PrinUSignDate)
OOA Initial Issue 50 1-3 Jabo S Tang John H C Wang Norman Kahler David Darling
~
t~ ~ 40( ~ (
yenrlJpgf gt7(~ ()ri j 210 075
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
DISCLAIMER
The calculations contained in this docum ent were developed by Bechtel SAIC Company LLC and are intended solely for the use of Bechtel SAIC Com pany LLC in its work for the Yucca Mountain Project
2
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
CONTENTS
Page
1 PURPOSE 9
2 REFERENCES 10 21 PROJECT PROCEDURESDIRECTIVES 10 22 DESIGN INPUTS10 23 DESIGN CONSTRAINTS 12 24 DESIGN OUTPUTS13
3 ASSUMPTIONS 14 31 ASSUMPTIONS REQUIRING VERIFICATION14 32 ASSUMPTIONS NOT REQUIRING VERIFICATION14
321 Material and Wall Thickness of TAD Canister 14 322 Material and Thickness of TAD Shield Plug 14 323 Geometry and Materials of Conceptual TAD Transportation Casks 15 324 Usage of Unirradiated Fuel for Commercial SNF 16 325 Homogenization of Radiation Source Regions 16 326 Ignoring Internal Fuel Basket Materials 17
4 METHODOLOGY 18 41 QUALITY ASSURANCE18 42 USE OF COMPUTER SOFTWARE18
421 Baseline Software 18 422 Commercial off the Shelf Software 18
43 CALCULATION APPROACH19 431 MCNP5 Program 19
5 LIST OF ATTACHMENTS 20
6 CALCULATIONS 21 61 DESCRIPTION OF CALCULATIONS21 62 CALCULATION INPUT 24
621 TAD Canister 24 622 Conceptual TAD Transportation Casks 24 623 Fuel Assembly Selection 25 624 BampW 15x15 Mark B PWR Fuel Assembly 25 625 Material Compositions 27 626 Homogenization Assembly Materials 28 627 PWR Source Terms 30
63 MCNP SPECIFIC INPUT 35 631 Source Probability 35 632 Dose Rate and Flux Tallies 35 633 Variance Reduction Techniques 35
64 DOSE CONVERSION FACTORS 36
3
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION 37
7 RESULTS AND CONCLUSIONS 38 71 RESULTS 38
711 Dose Rates of Conceptual Cask A 38 712 Dose Rates of Conceptual Cask B 41 713 Comparison of Dose-Rate Reduction Factors 44
72 CONCLUSIONS46 ATTACHMENT I ELECTRONIC FILES ON COMPACT DISCI-1
4
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
FIGURES
Page
Figure 1 Geometry and Tally Scheme for the TAD Transportation Cask 23
5
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
TABLES
Page
Table 1 Geometry and Materials of Conceptual TAD Transportation Cask A 15 Table 2 Geometry and Materials of Conceptual TAD Transportation Cask B 16 Table 3 Dimensions of TAD Canister 24 Table 4 BampW 15x15 Mark B Fuel Assembly Description 26 Table 5 PWR Fuel Assembly Regions 27 Table 6 Chemical Compositions of Materials 28 Table 7 Isotopic Compositions of Homogenized PWR Assembly Regions 29 Table 8 Gamma and Neutron Sources for the Maximum PWR SNF Assembly 31 Table 9 Gamma and Neutron Sources for the Design Basis PWR SNF Assembly 32 Table 10 Gamma and Neutron Sources for the Average PWR SNF Assembly 33 Table 11 Gamma and Neutron Axial Source Profiles for a PWR Assembly 34 Table 12 Gamma and Neutron Flux to Dose Conversion Factors 36 Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources 39 Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources 39 Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources 39 Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources 40 Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources 40 Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources 40 Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources 42 Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources 42 Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources 42 Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources 43 Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources 43 Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources 43 Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources 44 Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources 45 Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources 45 Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources 45 Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources 45 Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial
Sources 46 Table 31 Recommended Average Radial Dose-Rate Reduction Factors 46 Table 32 Recommended Average Top Dose-Rate Reduction Factors 46 Table 33 Recommended Average Bottom Dose-Rate Reduction Factors 46 Table I-1 Listing of Electronic Files on Compact DiscI-1
6
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ACRONYMS AND ABBREVIATIONS
ACRONYMS
ANS American Nuclear Society
ANSI American National Standards Institute
ASTM American Society for Testing and Materials
BSC Bechtel SAIC Company LLC
BWR Boiling Water Reactor
CD Compact disc
CSNF Commercial Spent Nuclear Fuel
DB Design Basis
DOE U S Department of Energy
DPC Dual Purpose Canister
NRC U S Nuclear Regulatory Commission
PCSA Preclosure Safety Analysis
PWR Pressurized Water Reactor
RPM Repository Project Management
SNF Spent Nuclear Fuel
SS 316 Stainless Steel 316
TAD Transportation Aging and Disposal
WP Waste Package
YMP Yucca Mountain Project
ABBREVIATIONS and UNITS
b barn
cm centimeter
7
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
g gram
GWd gigawatt-day
hr hour
in inch
kg kilogram
m meter
mrem millirem
MeV million electron volt
MTU metric ton uranium
s second
8
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
1 PURPOSE
The purpose of this calculation is to calcu late th e dose ra tes of two conceptua l tr ansportation casks each carrying a Transportation Aging and Disposal (TAD) canister separately loaded with the average design basis (DB) and m aximum comm ercial spent nuc lear fuel (CSNF) assemblies Then the dose-ra te reduction f actors between the m aximum and the design basis fuels the d esign bas is and the average fuels and the m aximum and the averag e fuels are computed
The results of this calculation may be used to substantiate the dose-rate reduction factors such as those in the engineering study Repository ALARA Goal Compliance (Reference 227) which is cited as a reference in a Preclosure Safety Analyses (PCSA) calculation that supports the License Application
The calculations contained in this docum ent are developed by Nuclear and Radiological Engineering of the Repository Project Mana gement (RPM) organization Yucca Mountain Project (YMP) personnel from Nuclear and Radiological Engineering should be consulted before use of the calculations for purposes other than those stated herein or use by individuals other than personnel in Nuclear and Radiological Engineering
9
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
2 REFERENCES
21 PROJECT PROCEDURESDIRECTIVES
211 IT-PRO-0011 Rev 0010 Software Management Las Vegas Nevada Bechtel SAIC Company
212 EG-PRO-3DP-G04B-00037 Rev 14 Calculations and Analyses Las Vegas Nevada Bechtel SAIC Company
213 IT-PRO-0012 Rev 007 Qualification of Software Las Vegas Nevada Bechtel SAIC Company
22 DESIGN INPUTS
221 ANSIANS-611-1977 Neutron and Gamma-Ray Flux-to-Dose-Rate Factors La Grange Park Illinois American Nuclear Society TIC 239401
222 ASME (American Society of Mechanical Engineers) 2004 2004 ASME Boiler and Pressure Vessel Code 2004 Edition New York New York American Society of Mechanical Engineers TIC 256479 ISBN 0-7918-2899-9
223 ASM International 1990 Properties and Selection Nonferrous Alloys and Special-Purpose Materials Specific Metals and Alloys Volume 2 of Metals Handbook 10th Edition Page 666 [Materials Park Ohio] American Society for Metals TIC 239807
224 ASTM (American Society for Testing and Materials) B 811-90 1991 Standard Specification for Wrought Zirconium Alloy Seamless Tubes for Nuclear Reactor Fuel Cladding Philadelphia Pennsylvania American Society for Testing and Materials TIC 239780
225 ASTM G 1-90 (Reapproved 1999) 1999 Standard Practice for Preparing Cleaning and Evaluating Corrosion Test Specimens West Conshohocken Pennsylvania American Society for Testing and Materials TIC 238771
226 Bowman SM Hermann OW and Brady MC 1995 Sequoyah Unit 2 Cycle 3 Volume 2 of Scale-4 Analysis of Pressurized Water Reactor Critical Configurations ORNLTM-12294V2 Oak Ridge Tennessee Oak Ridge National Laboratory TIC 244397 [DIRS 123796]
227 BSC (Bechtel SAIC Company LLC) 2008 Repository ALARA Goal Compliance 000-30R-MGR0-04000-000 REV 000 Las Vegas Nevada Bechtel SAIC Company ACC ENG200802050014 [DIRS 184957]
228 BSC 2002 Subsurface Shielding Source Term Specification Calculation 000-00C-WER0-00100-000-00A Las Vegas Nevada Bechtel SAIC Company ACC MOL200212160076 ENG200508150022
10
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
229 BSC 2004 PWR Source Term Generation and Evaluation 000-00C-MGR0-00100-000-00B Las Vegas Nevada Bechtel SAIC Company ACC ENG200405240007
2210 BSC 2008 Basis of Design for the TAD Canister-Based Repository Design Concept 000-3DR-MGR0-00300-000-003 Las Vegas Nevada Bechtel SAIC Company ACC ENG200810060001
2211 BSC 2007 Project Design Criteria Document 000-3DR-MGR0-00100-000-007 Las Vegas Nevada Bechtel SAIC Company ACC ENG200710160005 ENG200711080001 ENG200712200003 ENG200801070001 ENG200801070002 ENG200801070016 ENG200801070017 ENG200801310006 ENG200803050002 ENG200803050011 ENG200803050012 ENG200803060009 ENG200803130004 ENG200807100001 ENG200811120006 ENG200811140004
2212 BSC 2004 PWR and BWR Source Term Sensitivity Study 000-00C-MGR0-00300-000-00A Las Vegas Nevada Bechtel SAIC Company ACC ENG200401140003 ENG200508150023
2213 BSC 2007 Dose Rate Calculation for Exhaust Main Drifts 800-00C-SS00-00700-000-00B Las Vegas Nevada Bechtel SAIC Company ACC ENG200711050017 ENG200803060001
2214 BSC 2006 Dual Purpose Canister Opening Study 050-30R-WHS0-00600-000-000 Las Vegas Nevada Bechtel SAIC Company ACC ENG200612200023
2215 BSC 2007 GROA Shielding Requirements Calculation 000-00C-MGR0-03300-000-00B Las Vegas Nevada Bechtel SAIC Company ACC ENG200705290037
2216 BSC 2002 Concrete Shielding Calculation for Dry Facility 1 110-00C-CS10-00100-000-00A Las Vegas Nevada Bechtel SAIC Company ACC MOL200301140075
2217 BSC 2003 Shielding Design Calculations for Dry Facility 1 110-00C-CS10-00200-000-00A Las Vegas Nevada Bechtel SAIC Company ACC ENG200306020003
2218 CRWMS MampO 1998 Calculation of the Effect of Source Geometry on the 21-PWR WP Dose Rates BBAC00000-01717-0210-00004 REV 00 Las Vegas Nevada CRWMS MampO ACC MOL199902220059 [DIRS 102134]
2219 CRWMS MampO 2000 Users Manual for SCALE-44A 10129-UM-44A-00 Las Vegas Nevada CRWMS MampO ACC MOL200011300136 MOL200108220084 MOL200108220085 MOL200108220086 MOL200108220087 [DIRS 153872]
2220 DOE (US Department of Energy) 1987 Appendix 2A Physical Descriptions of LWR Fuel Assemblies Volume 3 of Characteristics of Spent Fuel High-Level Waste and Other Radioactive Wastes Which May Require Long-Term Isolation DOERW-0184 Washington DC US Department of Energy Office of Civilian Radioactive Waste Management ACC HQX198804050024 [DIRS 132333]
11
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
2221 DOE 2007 Software Validation Report for MCNP5 v140 Document ID 11199-SVR-140-00-WINXP Las Vegas Nevada US Department of Energy Office of Repository Development ACC MOL200702280252 [DIRS 180516]
2222 DOE 2008 Transportation Aging and Disposal Canister System Performance Specification WMO-TADCS-000001 Rev 1 ICN 1 Washington DC US Department of Energy Office of Civilian Radioactive Waste Management ACC DOC200803310001 [DIRS 185304]
2223 Harmon CD II Busch RD Briesmeister JF and Forster RA 1994 Criticality Calculations with MCNPtrade A Primer LA-12827-M Los Alamos New Mexico Los Alamos National Laboratory TIC 234014 [DIRS 154532]
2224 LANL (Los Alamos National Laboratory) 2004 MCNP mdash A General Monte Carlo N-Particle Transport Code Version 5 (Appendix H is not included) LA-UR-03-1987 Volume I Los Alamos [New Mexico] Los Alamos National Laboratory ACC MOL200510240126 [DIRS 176521]
2225 MCNP5 V 140 2007 Windows XP STN 11199-140-00 [DIRS 180515]
2226 Parrington JR Knox HD Breneman SL Baum EM and Feiner F 1996 Nuclides and Isotopes Chart of the Nuclides 15th Edition San Jose California General Electric Company and KAPL Inc TIC 233705 LC Call Number QC7935 N8622 1996
2227 Punatar MK 2001 Summary Report of Commercial Reactor Criticality Data for Crystal River Unit 3 TDR-UDC-NU-000001 REV 02 Las Vegas Nevada Bechtel SAIC Company ACC MOL200107020087 [DIRS 155635]
2228 Sisley SE 2002 Transportation License Application for the FuelSolutionstrade System (TAC No L23311) Submittal of the FuelSolutiontrade Transportation SARs Revision 3 Letter from SE Sisley (BNFL) to the NRC April 11 2002 BFSNRC 02-011 with enclosures TIC 255245 [DIRS 171545]
NOTE Reference 2220 is a direct input but is not QA QA It is justified as acceptable for the intended use as it is directly from the DOE and is considered the best available data on the subject The referenced values cited in Tables 3 and 4 are valid for use since they are reliable and reasonable based on engineering judgment
23 DESIGN CONSTRAINTS
231 10 CFR 71 2008 Energy Packaging and Transportation of Radioactive Material Internet Accessible [DIRS 185678]
12
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
24 DESIGN OUTPUTS
The resu lts of this calculation will be us ed to substan tiate th e dose reduc tion f actor in the Repository ALARA Goal Compliance (Reference 227) which is cited as a reference in a PCSA calculation that supports the License Application
13
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
3 ASSUMPTIONS
31 ASSUMPTIONS REQUIRING VERIFICATION
None
32 ASSUMPTIONS NOT REQUIRING VERIFICATION
Assumptions 321 322 and 323 are m odeling assum ptions and do not require further verification The m aterials and dim ensions for the TAD canister and for the conceptu al transportation casks are only selected to charac terize two tr ansportation casks th at m eet 10 CFR7147 (Reference 231) dose rates when lo aded with the ldquom aximumrdquo and ldquoaveragerdquo pressurized water re actor (PW R) assem blies re spectively There is n o need to v erify those dimensions or m aterials at a later date The ca lculated results in Sect ion 711 verify that the conceptual casks would meet 10 CFR 7147 (Reference 231) dose rates
321 Material and Wall Thickness of TAD Canister
Assumption It is assumed that the TAD canister is made of stainless steel 316 (SS 316) and has a wall thickness of 025 in for the radial and bottom shells
Rationale Currently the design of the TAD canis ter d oes not ex ist Based on a survey of existing m ultipurpose a nd dual purpose caniste rs (DPC) (Ref erence 2214 p 56) a 025 in thickness is below the wall thick ness of any existing c anisters For the purp ose of this calculation this assumption leads to higher and conservative external dose rates Since SS 316 is the sam e material used for the waste pack age inner shell it is a l ogical cho ice f or the TAD canister
Although Reference 2214 is an engineering study with a QA N A status it is used here as an indirect input to support the assumption which is conservative for dose rate calculations
Usage This assumption is used in Sections 621 and 625
322 Material and Thickness of TAD Shield Plug
Assumption It is assu med that the TAD shield plug is made of SS 316 and has a thickness of 11 in
Rationale Currently the design of the TAD canister doe s not exist A thick shield plug of 11 in (Reference 2215 Table 12) is needed to keep the m aximum contact dose rate of the top surface below 1000 mrem hr (Reference 2222 Section 314) Since SS 316 is the sam e material used for the waste package inner shell it is a logical choice for the TAD shield plug
Usage This assumption is used in Section 621
14
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
323 Geometry and Materials of Conceptual TAD Transportation Casks
Assumption Two conceptual TAD transpo rtation casks designated as Cask A and Cask B are assumed to have a cylindrical geom etry and m aterials specified in Tab les 1 and 2 respectively The casks are basically construc ted of an inner layer of SS 316 for ga mma shielding a m iddle layer of 5-borated polyethylen e for neutron shielding and a th in outer layer of SS 316 whic h serves a structural function as well as shielding secondary gamma rays
Both Cask A and Cask B have a cavity height of 53785 cm (21175 in) and a cavity diameter of 16891 cm (6650 in) However Cask A has a total height of 610845 cm (24049 in) and an outside diameter of 26797 cm (10550 in) while the total height and outside diameter of Cask B are 58885 cm (23183 in) and 24765 cm (9750) respectively
Cask A will provide shielding to m eet the exterior radiat ion standards of 10 C FR 7147(b) (Reference 231) when loaded w ith a TAD canister carrying th e maximum PWR spent nuclear fuel (SNF) Cask B will satisf y the same radiation standards when loade d with a TAD caniste r carrying the average PWR SNF
Table 1 Geometry and Materials of Conceptual TAD Transportation Cask A
Component Dimension
Material (cm) (in)
Total Height 61085 2404 9 NA
Outside Diameter 26797 1055 0 NA
Cask Cavity Height 53785 2117 5 NA
Cask Cavity Diameter (Radius) 16891 (8446) 6650 (3325) NA
Radial Gamma Shield Thickness (Radius)a 3302 (11748)a 1300 (4625)a SS 316
Radial Neutron Shield Thickness (Radius)b 1524 (13272)b 600 (5225)b 5-borated polyethylene
Radial Outer Shell Thickness (Radius)c 127 (13399)c 050 (5275)c SS 316
Top Gamma Shield Thickness (Axial Position)d 600 (54385)d 236 (21411)d SS 316
Top Neutron Shield Thickness (Axial Position)d 1000 (55385)d 394 (21805)d 5-borated polyethylene
Top Outer Shell Thickness (Axial Position)d 200 (55585)d 079 (21884)d SS 316
Bottom Gamma Shield Thickness (Axial Position)d 35365 (-360)d 1392 (-1417)d SS 316
Bottom Neutron Shield Thickness (Axial Position)d 15 (-510)d 591 (-2008)d 5-borated polyethylene
Bottom Outer Shell Thickness (Axial Position)d 4 (-550)d 157 (-2165)d SS 316 a11748 = 3302 + 8446 and 4625 = 1300 + 3325 b13272 = 1524 + 11748 and 5225 = 600 + 4625 c13399 = 127 + 13272 and 5275 = 050 + 5225 dCoordinate relative to the bottom of the fuel assembly as modeled in MCNP5
15
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 2 Geometry and Materials of Conceptual TAD Transportation Cask B
Component Dimension
Material (cm) (in)
Total Height 58885 2318 3 NA
Outside Diameter 24765 9750 NA
Cask Cavity Height 53785 2117 5 NA
Cask Cavity Diameter (Radius) 16891 (8446) 6650 (3325) NA
Radial Gamma Shield Thickness (Radius)a 254 (10986)a 1000 (4325)a SS 316
Radial Neutron Shield Thickness (Radius)b 127 (12256)b 500 (4825)b 5-borated polyethylene
Radial Outer Shell Thickness (Radius)c 127 (12383)c 050 (4875)c SS 316
Top Gamma Shield Thickness (Axial Position)d 8 (54585)d 315 (21490)d SS 316
Top Neutron Shield Thickness (Axial Position)d None Non e NA
Top Outer Shell Thickness (Axial Position)d None Non e NA
Bottom Gamma Shield Thickness (Axial Position)d 3837 (-390)d 1510 (-1535)d SS 316
Bottom Neutron Shield Thickness (Axial Position)d 300 (-420)d 118 (-1654)d 5-borated polyethylene
Bottom Outer Shell Thickness (Axial Position)d 100 (-430)d 039 (-1693)d SS 316 a10986 = 254 + 8446 and 4325 = 1000 + 3325 b12256= 127 + 10986 and 4825 = 500+ 4325 c12383 = 127 + 12256 and 4875 = 050 + 4825 dCoordinate relative to the bottom of the fuel assembly as modeled in MCNP5
Rationale Currently a design for the TAD transporta tion cask does not exist The casks assumed for this calculation are so lely for estim ation of the dose reduction due to different source terms This is a conceptual repres entation only used in this calculation to estim ate the parameters of interest
Usage This assumption is used in Sections 61 and 622
324 Usage of Unirradiated Fuel for Commercial SNF
Assumption It is assumed that the active fuel region of the commercial SNF assembly contains the same isotopic concentrations as the fresh uni rradiated fuel and that the concentrations of fresh fuel with 5 initial enrichm ent corresp onding to m aximum SNF are used for all other SNFs
Rationale This assumption is a standard practice for shielding calculations throughout the industry accepted by the U S Nucle ar Regulatory Commission (NRC) (Reference 2228 Table 53-5) It sh ould be noted that this assumption applies to material composition only it does no t apply to source terms which are based on the characteristics of spent fuel
Usage This assumption is used in Sections 624 and 626
325 Homogenization of Radiation Source Regions
Assumption It is assu med that a commercial SNF assembly consis ts of four distinct reg ions (active fuel bottom end-fitting plenum and top end-fitting) The materials and radiation sources
16
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
of each assembly region are homogenized inside a volume defined by the TAD cavity radius and region height
Rationale The assembly representation is consistent with the industry practice for shielding calculations accepted by NRC (Reference 2228 Figure 53-6) The effec t of source homogenization is twofold (1) it d ecreases th e m ass de nsity of the source region and (2) it places source points slightly closer to detector locations thus reducing radiation attenuation The resu lts of Calculation of the Effect of Source Geometry on the 21-PWR WP Dose Rates (Reference 2218 pp 22-26) indicate that th e effect of assem bly homogenization gives nearly the same or conservative dose rates as the explicit fuel assembly model
Usage This assumption is used in Section 624
326 Ignoring Internal Fuel Basket Materials
Assumption It is assumed that the internal fuel basket materials are ignored
Rationale Inclusion of fuel basket m aterials in the smeared m aterial com position would increase the overall density and consequently increase the attenuati on of the radiation Therefore this assumption is conservative
Usage This assumption is used in Sections 621 624 and 626
17
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
4 METHODOLOGY
41 QUALITY ASSURANCE
This calculation was prepared in accordance with EG-PRO-3DP-G04B-00037 Calculations and Analyses (Reference 212) The results of th is calculation provides worker dose assessm ent adjustments and this will id entify radio logical hazards f or f acilities im portant to saf ety Therefore the approved version is designated as QA QA
42 USE OF COMPUTER SOFTWARE
421 Baseline Software
The Monte Carlo N-Particle com puter pr ogram (MCNP5) version 140 (Reference 2225) is used to calculate the dose rates (neutron pr imary gamm a and secondary gamm a) at various locations around a transportation cask and an aging overpack
The software specifications are as follows
bull Program Name MCNP5 bull VersionRevision Number Version 140 bull Operating Systems Windows XP bull Software Tracking Number 11199-140-00 bull Computer Type Dell OPTIPLEX GX620
MCNP5 which is Level 1 software is (a) appropriate for three-dim ensional neutron gamma and coupled neutrongamma shielding calculations (b) used within th e range of validation as documented in Software Validation Report for MCNP5 v140 (Reference 2221) and (c) obtained from Software C onfiguration Managem ent and qualified in accordance with procedure IT-PRO-0012 Qualification of Software (Reference 213) Therefore MCNP5 code is suitable for use in this design calculation All MCNP5 input and output files docum ented in this calculation are provided on a compact disc (CD) as Attachment II
All MCNP cases are executed on one of the following Q com puters QNW -004184 QNW -004187 QNW-004194 and QNW-004196 as shown in the output files
422 Commercial off the Shelf Software
The Excel sof tware is used to c alculate var ious inpu t values (i e atom densities weight percentages geometrical dimensions normalized source spectra and probabilities etc) Standard functions of Excel are also used in this desi gn calculation to display results (ie gamma and neutron dose rates) in tabular and graphic forms and to perform relative error calculations
The software specifications are as follows
bull Program Name Excel bull VersionRevision Number Microsoftreg Excel 2003
18
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
bull This software is installed on a persona l com puter running Microsoft W indows XP (central processing unit number 151834)
The user defined for mulas inputs results and gr aphical representations have been verified by hand calculations or visual inspection and are documented in sufficient detail to allow an independent repetition of the com putations Calculations were verifi ed by hand and graphical representations were found accurate by visual inspection
Per Software Management Microsoftreg Excel is not requir ed to be qualif ied due to its commercial availability status (Reference 211 Attachment 4 p 55 bullet 2)
43 CALCULATION APPROACH
This calculation em ploys the qualified so ftware MCNP5 version 140 (Reference 2225) a three-dimensional Monte Carlo code for pe rforming neutron and coupled neutron-gamm a calculations to estim ate dose rates at sele cted locations on and surrounding a conceptual transportation cask containing a loaded TAD canister
431 MCNP5 Program
MCNP5 a general Monte Carlo part icle transport code sim ulates particle transport through a three-dimensional representation of the nuclear system being analyzed During the random walk of particles through the system described by the geom etry the c ode collects inform ation about various events (su rface cross ing collis ions trac k leng th etc) and es timates fluxes in various geometric configurations specified as tallies by the user It also estimates the statistical precision of the results in the form of relative errors (Reference 2224 pp 1-2 to 1-8)
Per Project Design Criteria Document (Reference 2211 Section 41015) the flux estim ates are converted to dose rates using the Am erican Nuclear Society (ANS) flux-to-dose rate conversion factors for gammas and neutrons (R eference 221) The simple variance reduction techniques of Geometry SplittingRussian Roulette and source probability biasing (Sections 631 and 633) are used to enhance computational efficiency
19
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
5 LIST OF ATTACHMENTS
Number of Pages Attachment I List of Electronic Files on the CD 3 Attachment II Compact Disc NA
20
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
6 CALCULATIONS
This sectio n provides inform ation necess ary to perform the calcu lations in this docum ent Section 61 describes the configurations the type of CSNF to be analyzed the number of MCNP runs and the locations where dose rates are ca lculated Section 62 provides the calculation input that includes the details of the geom etry m odel radiation source term s and m aterial compositions Input specific to MCNP dose -rate conversion factors and relative error calculation are described in the later sections
61 DESCRIPTION OF CALCULATIONS
Dose rate calculations are perform ed with the MCNP5 version 140 com puter code (Reference 2225) Two conceptual transportation casks Cask A and Cask B (Assum ption 323) are employed Each cask contains a TAD canister that is loaded with 21 ident ical PW R SN F assemblies Three PWR source term s are analy zed they are the source term s corresponding to the maximum design basis and average PW R SN Fs The characteris tics of the P WR source terms are presented in S ection 627 Each PWR source term has neutron and ga mma radiation sources that require separate MCNP5 runs For each radiation source an axial profile source and a uniform source for the active fuel region are considered The uniform source for the active fuel region is included in this calculation because this approach was used in combination with source peaking factors in certain calculations (Reference 2216 Sections 37 and 39 and Reference 2217 Section 5242)
The total number of MCNP5 runs is 24 which re sults from a com bination of two conceptual casks three PWR source terms two radiation sources and two axia l source distributions for the active fuel region These 24 runs are categorized into four calcula tion sets Each calculation set consists of six runs that is a combination of three PWR source te rms and two radiation sources The characteristics of each calculation set are as follows
1 Cask A with axial profile sources in the active fuel region
2 Cask A with uniform axial sources in the active fuel region
3 Cask B with axial profile sources in the active fuel region
4 Cask B with uniform axial sources in the active fuel region
For each MCNP5 run dose rates are calculated at the exte rior surfaces and at distances 1 and 2 meters from the exterior surfaces Surface tallies and detector tallies (ring and point detectors) as indicated in Figure 1 are e mployed in all runs Figure 1 is used to illustrate the dep loyment of the surface and detector tallies re lative to the so urce regions and it should not be interpreted as an exact geometry of any particular run Surface tallies are deployed at all three distances while ring and point detectors are used only at 1 m and 2 m and not at the cask surfaces Using point detectors near a surface or in any scattering media is not recommended because very large scores can occur f rom collisions close ( less than a f ew centimeters) to the point detecto rs that can lead to resu lts with high r elative e rrors thus m aking the ca lculation d ifficult to o btain r eliable answers
21
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
For the radial direction surface tallies at the three distances (contact 1 m and 2 m) are computed for three su rface segments (cylindrical rings) between the planes at Z = 145 175 2 05 and 235 cm The geometric locations of the segments are shown in Figure 1 The axial locations of these segments correspond to the m iddle of the active fuel region of the PWR SNF assemblies The average dose rates for each of the segm ents are calculated for the outside surface and surfaces at 1 m and 2 m from the cask surface Two ring detectors (instead of point detectors) are deployed at 1 m and 2 m for the radial dire ction Ring detectors instead of point detectors are used in order to capitalize on the symm etry around the cask axis thus im proving the efficiency of the calculations
In the axial direction the average d ose rates within three concentric radial surfaces defined by radii of 40 80 and 120 cm (shown in Figure 1) are calculated for the top and bottom surfaces and at distances 1 m and 2 m from these surfaces Finally point detectors at 1 m and 2 m from the top and bottom axial surfaces are employed
22
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Point Detector at 2 m x
Ring Ring Detector Detector at 2 m at 1 m
x x
Z = 00 cm
Z = 145 cm
Z = 175 cm
Z = 205 cm
Z = 235 cm
R = 80 cm
R = 120 cm
R = 40 cm
Active Fuel
Shield Plug
Top End-Fitting Plenum
Bottom End-Fitting
Ring Detector at 1 m
x
Point Detector at 1 m x
Ring Detector
at 2 m x
D = 26797 cm
H =
610
845
cm
Point Detector at 1 m x
Point Detector at 2 m x
Figure 1 Geometry and Tally Scheme for the TAD Transportation Cask
23
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
62 CALCULATION INPUT
Technical product input and sources of the input used in the deve lopment of this calculation are documented in this section Tables in this docum ent and in th e associated Microsoftreg Excel spreadsheets referenced m ay present num erical values with m any significant figures these values are not to be considered as high precision values since the significant figures are results of calculated values andor unit conversions
621 TAD Canister
The TAD canis ter will contain either 21 P WR or 44 BW R (boiling water reactor) SNF assemblies (Reference 2222 Section 321) While the canister design is iden tical for both PWR and BWR SNF assemblies the internal basket structure is different depending on the SNF assemblies However the internal basket stru cture m aterial is no t in cluded in the calcu lation model (Assumption 326)
The TAD canister is a right-circu lar cylinder with a diam eter of 665 in and a height between 186 and 212 in (Reference 2222 Section 321) The average and maximum total dose rates on the top surf ace of a loaded TAD ca nister must not exceed 800 and 1000 m remhr respectively (Reference 2222 Section 314) The TAD canister used in this calculation is m ade of SS 316 with a radial wall and bottom thickness of 025 in (Assumption 321) The top of the canister has a shield plug that is 11 in thick SS 316 (Ass umption 322) A thick shield plug is needed to keep the maxim um contact dose rate of th e top surface below 1000 m remhr The overall dimensions of the TAD canister are provided in Table 3
Table 3 Dimensions of TAD Canister
Component Dimension
(in) (cm)
Maximum heighta 212 53848
Outer diametera 665 16891
Thickness of bottom lidb 025 0635
Shell thicknessb 025 0635
Lifting Featurec 6 1524
Height without Lifting Feature 206 52324
Thickness of shield plugd 110 2794
aReference 2222 Section 311 bAssumption 321 cReference 2222 p Attachment C-1 dAssumption 322
622 Conceptual TAD Transportation Casks
Two conceptual TAD transportation casks designa ted as Cask A and Cask B are em ployed in this calculation (Assumption 323) They both have a cylindrical geometry with dimensions and materials specified in Tables 1 and 2 of Section 323 Cask A will provide shielding to meet the exterior radiation standards of 10 CFR 7147(b) (Reference 231) when loaded with a TAD
24
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
canister car rying the m aximum PWR SNF Cask B will s atisfy th e sa me radiatio n standa rds when loaded with a TAD canister c arrying the average PWR SNF The reason to analyze both Casks A and B is to cover a broad range of characteristics of the CSNF
The cavity dimensions of the conceptual cask s are 53785 cm (21175 in) in height and 16891 cm (665 in) in diam eter (Tab les 1 and 2) This cav ity will accommoda te the TAD canister described in Table 3 without the lifting feature This is the geometry model used in the MCNP5 calculations
623 Fuel Assembly Selection
PWR and BWR Source Term Sensitivity Study (Reference 2211 Tables 71 through 84) shows that the source terms generated for the Bamp W 15x15 Mark B fuel assembly with 475 kg uranium loading bound the source terms of other PWR assembly types ther efore this assembly type is selected as the representative PWR fuel assembly The gamma and neutron source terms for the BampW 15x15 Mark B assembly are generated in PWR Source Term Generation and Evaluation (Reference 229) and are used in this calculation
624 BampW 15x15 Mark B PWR Fuel Assembly
BampW 15x15 Mark B fuel assembly consists of four regions top end-fitting plenum active fuel and bottom end-fitting The m aterials and ra diation sources of each assem bly region are homogenized inside a volume defined by the region height and the interior diam eter of the TAD canister (Assumption 325) The active fuel region is homogenized with fresh unirradiated fuel (Assumption 324) Since the internal structure (i e basket) design of t he TAD is currently not finalized the com position of the hom ogenized fuel does not include the basket m aterials (Assumption 326) and therefore does not take cred it for any shielding that these m aterials may provide
Table 4 provides the design param eters for the BampW 15x15 Mark B fuel assembly Data provided here are used in Attachment II PWR_fuel compxls worksheet BampWassy
25
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 4 BampW 15x15 Mark B Fuel Assembly Description
Component Material Characteristic Value Specific Reference Array Size 15 x 15
Reference 2227 Table 2-2 Fuel Pins Assembly 208 Guide Tubes Assembly 16 Instrument Tubes Assembly 1
Assembly NA Pin Pellet Diameter 0936244 cm (03686 in) Reference 2220 p 2A-34 Pin Pitch 144272 cm (0568 in)
Reference 2227 Table 2-2 Active Fuel Height 360172 cm (1418 in) Assembly Width 2168144 cm (8536 in)
Reference 2220 p 2A-31 Assembly Height 4206875 cm (165625 in) Mass U assembly 46363 kg
Guide tube Zircaloy-4 Outer Diameter 13462 cm (053 in)
Reference 2227 Table 2-2
Inner Diameter 126492 cm (0498 in)
Instrument tube Zircaloy-4 Outer Diameter 138193 cm (05441 in) Inner Diameter 112014 cm (0441 in)
Cladding` Zircaloy-4 Inner Diameter 095758 cm (0377 in) Outer Diameter 10922 cm (043 in)
Plenum region NA Length 297688 cm (11720 in) Reference 2220 p 2A-34 Top nozzle SS CF3M MassAssembly (Top) 748 kg
Reference 2220 p 2A-32
Bottom nozzle SS CF3M MassAssembly (Bottom) 816 kg Guide tubes Zircaloy-4 MassAssembly (in Core) 80 kg Instrument tube Zircaloy-4 MassAssembly (in Core) 064 kg Spacer-plenum Inconel-718 MassAssembly (Plenum) 104 kg Spacer-bottom Inconel-718 MassAssembly (Bottom) 13 kg Spacer-in core Inconel-718 MassAssembly (in Core) 49 kg Spring retainer SS CF3M MassAssembly (Top) 091 kg Holddown spring Inconel-718 MassAssembly (Top) 18 kg Upper end plug SS 304 MassAssembly (Top) 006 kg Upper nut SS 304L MassAssembly (Top) 051 kg Lower nut SS 304 MassAssembly (Bottom) 015 kg Grid supports Zircaloy-4 MassAssembly (in Core) 064 kg Plenum spring SS 302 MassAssembly (Plenum) 0042 lb (001905 kg) Reference 2220 p 2A-34
Note Som e d ata i n this tab le ar e given i n British u nits in th e r eferences thes e d ata ar e converted into metric units as the inputs to MCNP5 are in metric units
The assem bly region heights as m odeled in MC NP are presented in Table 5 utilizing values from Table 4 Table 5 is taken from Dose Rate Calculation for Exhaust Main Drifts (Reference 2213 Table 3)
26
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 5 PWR Fuel Assembly Regions
Component Height Reference
Plenum 297688 cm (11720 in) Reference 2220 p 2A-34
Active Fuel 360172 cm (1418 in) Table 3
Bottom End-Fitting 1077 cm (424 in) Calculateda
Top End-Fitting 1998 cm (787 in) Calculatedb
Source Reference 2213 Table 3 aCalculated b ased on data Reference 2227 F igures 2-3 an d 2-7
(Region 9 Height [16723 cm] + Region 10 Height [508 cm] ndash Lo wer Fuel Plenum and End Cap [11033 cm])
bCalculated (Assembly Length ndash Active Fuel Length ndash P lenum Length ndash Bottom End-fitting Length)
625 Material Compositions
The TAD transportation cask com ponent m aterial specifications are defined in Table 1 The TAD canister is constructed of SS 316 (Assumpti on 321) The PWR fuel assembly materials used to homogenize the fuel regions are defined in Table 4 Table 6 c ontains the m aterial compositions defining the TAD canister WP and fuel assemblies
27
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 6 Chemical Compositions of Materials
Material Density (gcc)
Isotopic Weight Percent Reference
SS 302 NA
C 0150 Mn 2000 P 0045 S 0030 Si 0750 Cr 18000 Ni 9000 N 0100 Fe 69925
Attachment II PWR_fuel compxls worksheet ferrous Reference 222 SEC II A SA-240 Table 1 for SS 302 SS 304 and SS 304L Reference 222 SEC II A SA-351SA -351M Table 2 for SS CF3M
SS 304 NA
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 9250 N 0100 Fe 68745
SS 304L NA
C 003 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 10000 N 0100 Fe 6804 5
SS CF3M NA
C 0030 Mn 1500 P 0040 S 0040 Si 1500 Cr 19000 Ni 11000 Mo 2500 Fe 64390
Inconel 718 NA
C 0080 Mn 0350 Si 0350 Cr 19000 Ni 52500 Co 1000 Mo 3050 Fe 16809 Nb 5125 Ti 0900 Al 0500 Cu 0300 S 0015 P 0015 B 0006
Attachment II PWR_fuel compxls worksheet alloys aReference 223 p 666 Table 6 Reference 222 SEC II B SB-637 Table 1 for Inconel 718 Reference 224 Table 2 for Zircaloy 4
Zircaloy 4 656a Cr 0100 Fe 0210 O 0125 Sn 1450 Zr 98115
SS 316 798b
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 17000 Ni 12000 Mo 2500 N 0100 Fe 65495
Attachment II PWR_fuel compxls worksheet others Reference 222 SEC II A SA-240 Table 1 for SS 316 bReference 225 Table X1
626 Homogenization Assembly Materials
The atom density of an element or isotope in atomsbmiddotcm in a homogenized region is calculated according to the following equation (Reference 2223 Appendix B)
M i times N AvogadroNi = Equation 1 Ai timesV times K
where Ni = Atom density of elementisotope i (atomsbmiddotcm) Mi = Mass of elementisotope i (g) NAvogadro = Avogadrorsquos constant 06022 x 1024 (atomsmole)
28
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Ai = Atomic weight of elementisotope i (gmole) V = Homogenization volume (cm3) K = Unit transformation constant = 1024 (bmiddotcmcm3)
Equation 1 is used in A ttachment II spreadsheet PWR_fuel compxls worksheet BampWassy to calculate th e atom dens ities for v arious elem ents and iso topes The m ass of elementsisotop es and Avogadrorsquos constant are provided in Reference 2226
Table 7 lists the com position of the hom ogenized assem bly regions (active fuel plenum top end-fitting and bottom end-fitting) for the PWR assembly The active fuel region contains fresh unirradiated fuel (Assumption 324) Since the internal structure (ie basket) design of the TAD is currently not finalized the composition of either homogenized fuel does not include the basket materials and therefore does not tak e credit for any shielding that thes e materials may provide (Assumption 326)
Table 7 Isotopic Compositions of Homogenized PWR Assembly Regions
Element Isotope
Atom Densities for Homogenized Regions (atomsbsdotcm)
Active Fuel Bottom End-Fitting Plenum Top End-Fitting
10B 861E-09 764E-08 221E-08 570E-08 11B 347E-08 307E-07 890E-08 230E-07 C 519E-07 160E-05 138E-06 993E-06 N -- 570E-07 262E-08 117E-06 O 621E-03 -- 142E-05 -- Al 144E-06 128E-05 371E-06 957E-06 Si 971E-07 243E-04 259E-06 139E-04 P 377E-08 606E-06 102E-07 360E-06 S 365E-08 581E-06 971E-08 340E-06 Ti 147E-06 130E-05 376E-06 971E-06 Cr 320E-05 187E-03 779E-05 113E-03 Mn 497E-07 126E-04 141E-06 749E-05 Fe 303E-05 531E-03 717E-05 313E-03 Co 132E-06 117E-05 340E-06 876E-06 Ni 697E-05 144E-03 180E-04 940E-04 Cu 368E-07 327E-06 945E-07 244E-06 Zr 196E-03 -- 195E-03 -- Nb 430E-06 382E-05 110E-05 285E-05 Mo 248E-06 135E-04 636E-06 791E-05 Sn 223E-05 -- 222E-05 -- 234U 139E-06 -- -- -- 235U 157E-04 -- -- -- 236U 719E-07 -- -- -- 238U 294E-03 -- -- -- Total 114E-02 924E-03 235E-03 557E-03
Source Attachment II spreadsheet PWR_fuel compxls worksheet BampWassy
29
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
The isotopic composition of commercially available 235U enriched uranium is determined by the given initial 235U enrichment using the following equations (Reference 226 p 20)
wt235U =235Uenrichment _ of _ the _ associated _ fuel _ batch Equation 2
wt234U = 0007731times (wt235U )10837 Equation 3
wt236U = 00046times (wt235U ) Equation 4
wt238U =100 minus (wt234U + wt235U + wt236U ) Equation 5
The weight percentages of uran ium isotopes for PWR fuel are ca lculated in Attachm ent II spreadsheet PWR_fuel compxls worksheet BampWassy using Equations 2 through 5
627 PWR Source Terms
This calculation uses the following three PWR source terms bull Maximum source (50 wt initial 235U enrichment 80 GWdMTU burnup and 5-year
decay time) (Reference 229 Section 55) Table 8 lists th e gamma source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Design Basis source (4 0 wt initial 235U enrichment 60 GW dMTU burnup and 10-year decay tim e) (Reference 228 Section 552) Table 9 lists the gamm a source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Average source ( 40 wt initial 235U enrichment 48 GWdMTU burnup and 25-year decay time) (Reference 229 Section 55) Table 10 lists the gamma source terms for the fuel and non-fuel regions and the neutron source term for the fuel region
These sources (ie maximum design basis and av erage) are described in this section For dose rate calculations all the fuel assemblies in a transportation cask are of the sam e characteristics Also gamma radiation source term s for the PWR assem bly are prov ided for the f our assembly regions while neutron source term is only present in the active fuel region Gamma radiation sources in the non-active fuel region are distri buted unif ormly within each source region Gamma and neutron sources in the active fuel re gion are modeled as uni form distributions or with axial source profiles
The PWR gamma and neutron axial source profiles for the active fuel region presented in Table 11 are applied to the active fuel region of all three source terms (ie maximum design basis and average) when appropriate
30
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 8 Gamma and Neutron Sources for the Maximum PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting
Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 594E+11 233E+15 528E+11 379E+11 100E-01 000E+00 100E-01 116E+11 644E+14 609E+10 743E+10 400E-01 805E+07 200E-01 283E+10 522E+14 352E+10 179E+10 900E-01 411E+08 300E-01 141E+09 148E+14 196E+09 891E+08 140E+00 376E+08 400E-01 190E+09 985E+13 586E+09 117E+09 185E+00 276E+08 600E-01 191E+09 153E+15 110E+11 741E+07 300E+00 485E+08 800E-01 435E+09 470E+15 595E+10 237E+09 643E+00 443E+08 100E+00 137E+11 708E+14 803E+09 766E+10 200E+01 393E+07 133E+00 338E+13 455E+14 174E+13 217E+13 Total 211E+09 166E+00 953E+12 130E+14 491E+12 612E+12
--
200E+00 187E+03 144E+12 919E+02 113E+03 250E+00 226E+08 249E+12 116E+08 145E+08 300E+00 351E+05 110E+11 181E+05 225E+05 400E+00 766E-08 139E+10 100E-08 416E-08 500E+00 000E+00 709E+07 000E+00 000E+00 650E+00 000E+00 286E+07 000E+00 000E+00 800E+00 000E+00 558E+06 000E+00 000E+00 100E+01 000E+00 119E+06 000E+00 000E+00
Total 442E+13 113E+16 231E+13 284E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE2R2B14cut bWasteStreamE2R1B14cut cWasteStreamE2R3B14cut dWasteStreamE2R4B14cut
31
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 9 Gamma and Neutron Sources for the Design Basis PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary
(MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 273E+11 121E+15 188E+11 175E+11 100E-01 000E+00 100E-01 528E+10 329E+14 277E+10 339E+10 400E-01 316E+07 200E-01 128E+10 245E+14 117E+10 819E+09 900E-01 161E+08 300E-01 639E+08 713E+13 633E+08 407E+08 140E+00 148E+08 400E-01 850E+08 455E+13 164E+09 533E+08 185E+00 109E+08 600E-01 492E+08 226E+14 269E+10 337E+07 300E+00 191E+08 800E-01 291E+09 237E+15 160E+10 186E+09 643E+00 174E+08 100E+00 540E+09 122E+14 248E+09 341E+09 200E+01 154E+07 133E+00 154E+13 195E+14 797E+12 990E+12 Total 830E+08 166E+00 435E+12 450E+13 225E+12 280E+12
--
200E+00 235E+00 152E+11 149E+02 215E-02 250E+00 103E+08 517E+10 534E+07 664E+07 300E+00 160E+05 379E+09 829E+04 103E+05 400E+00 943E-10 497E+08 155E-10 519E-10 500E+00 000E+00 282E+07 000E+00 000E+00 650E+00 000E+00 113E+07 000E+00 000E+00 800E+00 000E+00 222E+06 000E+00 000E+00 100E+01 000E+00 471E+05 000E+00 000E+00
Total 201E+13 486E+15 105E+13 129E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B11cut bWasteStreamE5R1B11cut cWasteStreamE5R3B11cut dWasteStreamE5R4B11cut
32
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 10 Gamma and Neutron Sources for the Average PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 336E+10 670E+14 186E+10 217E+10 100E-01 00000E+00 100E-01 602E+09 199E+14 314E+09 387E+09 400E-01 748E+06 200E-01 146E+09 126E+14 853E+08 936E+08 900E-01 382E+07 300E-01 730E+07 389E+13 439E+07 469E+07 140E+00 352E+07 400E-01 947E+07 263E+13 716E+07 607E+07 185E+00 261E+07 600E-01 141E+07 205E+13 504E+08 383E+06 300E+00 469E+07 800E-01 208E+09 124E+15 192E+09 144E+09 643E+00 418E+07 100E+00 208E+09 110E+13 164E+09 144E+09 200E+01 365E+06 133E+00 175E+12 295E+13 909E+11 112E+12 Total 199E+08 166E+00 494E+11 513E+12 257E+11 318E+11
--
200E+00 973E-01 675E+10 614E+01 872E-03 250E+00 117E+07 353E+09 609E+06 754E+06 300E+00 182E+04 288E+08 944E+03 117E+04 400E+00 186E-11 198E+07 149E-11 127E-11 500E+00 000E+00 669E+06 000E+00 000E+00 650E+00 000E+00 269E+06 000E+00 000E+00 800E+00 000E+00 527E+05 000E+00 000E+00 100E+01 000E+00 112E+05 000E+00 000E+00
Total 229E+12 237E+15 119E+12 147E+12
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B9cut bWasteStreamE5R1B9cut cWasteStreamE5R3B9cut dWasteStreamE5R4B9cut
33
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 11 Gamma and Neutron Axial Source Profiles for a PWR Assembly
Axial boundaries (From midplane)
(cm)
TOP BOTTOM
Neutron Gamma Ne utron Gamma 000 1554 1117 1554 1117 1143 1537 1114 1571 1120 2286 1521 1111 1588 1123 3429 1504 1108 1605 1126 4572 1486 1104 1622 1129 5715 1464 1100 1636 1131 6858 1438 1095 1648 1133 8001 1401 1088 1657 1135 9144 1350 1078 1654 1134
10287 1277 1063 1625 1129 11430 1165 1039 1554 1117 12573 0998 09995 1414 1091 13716 0769 09365 1172 1041 14859 0492 08375 0816 0951 16002 0220 06850 0402 0797 17145 0046 04625 0092 0551 18288 00 00 00 00
Source Reference 2219 Table S445
34
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
63 MCNP SPECIFIC INPUT
631 Source Probability
A linear radial distribution is used for all gamma and neutron sources The linear radial distribution is sam pled usi ng the built-in power function p(x) = xc a with a = 1 for the radial direction This sampling method results in a uniform source distribution over the area bounded by the outer radius of the source
The source axial distributions are unifor m for all four source regions The a xial uni form xp(x) = c distribution is sampled using the built-in power function a with a = 0 for extent
The energy distribu tions of the gamma and neutron sour ce term s are treated as energ y probabilities and are applied in MCNP5 using SISP cards
632 Dose Rate and Flux Tallies
MCNP5 dose rate calculations feature separate runs for the following calculation types
bull a photon transport calculation for prim ary ga mma contribution to the dose rates fr om photon fluxes
bull a coupled neutronphoton transport calculat ion for neutrons a nd secondary gamma (photons generated by neutron be ing captured) contributions to dose rates from neutron and gamma fluxes
The tally type F2 is us ed in th is d esign ca lculation as f lux estim ators The type F2 tally evaluates the flux averaged over a surface in particlescm2s
To generate dose ra tes in te rms of remhr the FM (tally multiplier ) and DEDF (dose energydose conversion factors) cards are used to en ter the tally multiplier f actor (source intensity in particless) energy boundaries in MeV and corresponding dose conversion factors in (remhr)(particlescm2s) respectively These factors were used in the input files
In order for the F2 tally to accum ulate flux ov er a surface a specific s urface area is requ ired The SD cards are used to enter a surface area in cm2 over which the flux will be tallied for an F2 tally
633 Variance Reduction Techniques
Variance reduction technique is usually em ployed in order to increase the efficiency of a calculation and obtain statistically m eaningful results within re asonable com puter tim e In Monte Carlo calculations when variance reduction scheme is employed the weights of particles are adjusted in order to account for the biasing and to preserve a fair game
Geometry splitting and Russian roulette techniques described in Reference 2224 (pp 2-140 ndash 2-142) are useful in shielding calculations and therefore deployed in all the MCNP5 runs
35
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
As particles migrate in an important direction (toward the detector) they are increased in number to provide better sampling by means of geometry splitting across geometric boundaries Russian roulette (the reverse process) is played when particles travel in an unimportant direction to allow termination of unim portant histories The IMP card required for every cel l ca rd is us ed to implement this technique
The other variance reduction technique deployed in the MC NP5 runs is source intensity biasing for the gamma sources from the four source regions (active fuel bottom end-fitting plenum and top end-fitting) The natural total gamma source intensity of comm ercial SNF is dom inated by the gamma source in the active fuel region This active fuel gamma source usually accounts for over 95 o f the total g amma source intens ity In order to im prove the efficiency of the axial dose rate calculations a biased source probability distribution is employed for the prim ary gamma dose rate calculations The biased gamma source probability distribution is chosen to be 005 080 010 and 005 for the bottom end-fitting the active fuel the plenum and the top end-fitting regions respectively
64 DOSE CONVERSION FACTORS
Project Design Criteria Document (Reference 2211 Se ction 41015) requires the use of flux-to-dose rate conversion fact ors from ANSIANS-611-1977 (Reference 221) for dose rate evaluations Table 16 lists the neutron and ga mma dose conversion factors used in the MCNP5 calculations
Table 12 Gamma and Neutron Flux to Dose Conversion Factors
Gamma Neutron Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
001 396E-06 140 251E-06 250E-08 367E-06 003 582E-07 180 299E-06 100E-07 367E-06 005 290E-07 220 342E-06 100E-06 446E-06 007 258E-07 260 382E-06 100E-05 454E-06 010 283E-07 280 401E-06 100E-04 418E-06 015 379E-07 325 441E-06 100E-03 376E-06 020 501E-07 375 483E-06 100E-02 356E-06 025 631E-07 425 523E-06 100E-01 217E-05 030 759E-07 475 560E-06 500E-01 926E-05 035 878E-07 500 580E-06 100E+00 132E-04 040 985E-07 525 601E-06 250E+00 125E-04 045 108E-06 575 637E-06 500E+00 156E-04 050 117E-06 625 674E-06 700E+00 147E-04 055 127E-06 675 711E-06 100E+01 147E-04 060 136E-06 750 766E-06 140E+01 208E-04 065 144E-06 900 877E-06 200E+01 227E-04 070 152E-06 1100 103E-05 080 168E-06 1300 118E-05 100 198E-06 1500 133E-05
Source Reference 221 Tables 1 and 3
36
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION
By def inition (Ref erence 2224 Equation 219) the estimated st atistic relative error of the i component is
Ri = Si
2
Equation 6Ti
where i = tally component index Ri = relative error of the i component S2
i = variance of the i component Ti = tally i component
For a result (ie dose rate) computed as a sum of different tallies the statistical relative error of the computed value is o btained from the variance of the result - S2
total which is th e sum of the estimated variances of the individual tallies S2
i n
2 2STotal = sum Si Equation 7 i=1
where S2Total = total estimated variance
n = total number of components Therefore the total tally value (dose rate) and the associated relative error are derived according to Equations 8 and 9
n TTotal = sumTi Equation 8
i=1
n n
sum (Ri timesTi )2
2 sum Si 2
STotal = i=1 = i=1 Equation 9RTotal = TTotal TTotal TTotal
where RTotal = total estimated relative error TTotal = total estimated tally
Equations 8 and 9 are utilized in Attachm ent II to ev aluate to tal dos e ra tes and their r elative errors
37
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
7 RESULTS AND CONCLUSIONS
71 RESULTS
The following sections summarize the results of this calculation Section 711 presents results for Conceptual Cask A while Section 712 for Conceptual Cask B Section 713 provides comparisons of the dose-rate reduction factors du e to the two conceptual casks and the axial source distributions in the active fuel region Do se rates and relative errors can be found in Attachment II within the output files and Excel files
711 Dose Rates of Conceptual Cask A
This section presents dose-rate results of the calculation sets 1 and 2 as described in Section 61 for Cask A Set 1 has axial p rofile sources in the active fuel region a nd consist of six runs resulting from the three PWR SNF source term s (maximum design basis and average) and the two radiation sources (gammas and neutrons) Set 2 has uniform axial sources in the active fuel region and consists of six run s r esulting f rom the th ree P WR SNF source term s and th e tw o radiation sources
As described in Section 61 dose ra tes are calculated at the three exterior surfaces (radial top and bottom) and at distances 1 m and 2 m from the exterior surfaces The total dose rates for set 1 are presented in Tables 13 14 and 15 for the ra dial top and bottom dire ctions respectively However the com ponents (primary gamma neutr on and secondary gamma) contributing to the total dose rates as well as the re lative error calculations can be found in Attachment II Excel file MCNP-Results1xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 2 are shown in Tables 16 17 and 18 The dose-rate components and the relative errors can be found in A ttachment II Excel file MCNP-Results2xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 13 and 16 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 14 and 17 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 15 and 18 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carrying th e maximum PWR SNF Based on the results in Tables 13 through 18 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask A indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these 6 tables the d ose-rate red uction f actors between the m aximum and the design basis fuels the maxim um and the averag e fuels and th e design basis and the average fuels are a lso presented
38
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 320E-02 00237 116E-02 00222 262E-03 00219 275 1223 445
1 m 133E-02 00164 494E-03 00171 106E-03 00162 269 1261 468 2 m 749E-03 00198 285E-03 00225 584E-04 00162 263 1282 488
Ring Detectors 1 m 133E-02 00116 492E-03 00115 108E-03 00124 271 1229 454 2 m 756E-03 00118 279E-03 00110 605E-04 00128 271 1250 462
Source Attachment II MCNP-Results1xls worksheet Summary
Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 142E-02 00368 628E-03 00446 934E-04 00483 226 1520 672
1 m 570E-03 00289 263E-03 00426 375E-04 00381 217 1520 701 2 m 265E-03 00364 123E-03 00547 169E-04 00374 216 1575 730
Point Detectors 1 m 598E-03 00238 274E-03 00271 402E-04 00354 219 1489 681 2 m 273E-03 00218 123E-03 00245 180E-04 00336 221 1515 684
Source Attachment II MCNP-Results1xls worksheet Summary
Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 653E-03 00298 265E-03 00276 510E-04 00341 247 1278 518
1 m 276E-03 00238 112E-03 00208 207E-04 00249 248 1334 539 2 m 125E-03 00185 508E-04 00199 933E-05 00246 246 1336 544
Point Detectors 1 m 291E-03 00227 118E-03 00203 218E-04 00242 247 1335 540 2 m 130E-03 00209 524E-04 00187 955E-05 00233 247 1357 549
Source Attachment II MCNP-Results1xls worksheet Summary
Tables 13 14 and 15 are results of calculation set 1 for conceptual Cask A with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
39
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 265E-02 00247 990E-03 00222 215E-03 00278 268 1234 461
1 m 116E-02 00178 468E-03 00549 960E-04 00189 248 1208 488 2 m 713E-03 00273 265E-03 00161 602E-04 00360 269 1184 439
Ring Detectors 1 m 117E-02 00120 454E-03 00132 979E-04 00141 259 1199 463 2 m 722E-03 00130 276E-03 00141 589E-04 00153 261 1226 469
Source Attachment II MCNP-Results2xls worksheet Summary
Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 199E-02 00461 827E-03 00455 147E-03 00536 241 1359 564
1 m 849E-03 00564 323E-03 00314 563E-04 00418 263 1507 574 2 m 415E-03 00832 158E-03 00603 253E-04 00501 263 1641 623
Point Detectors 1 m 877E-03 00348 353E-03 00275 615E-04 00391 248 1426 574 2 m 393E-03 00341 160E-03 00278 270E-04 00378 246 1454 590
Source Attachment II MCNP-Results2xls worksheet Summary
Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 879E-03 00374 356E-03 00333 669E-04 00406 247 1315 533
1 m 365E-03 00223 147E-03 00209 269E-04 00253 248 1358 548 2 m 164E-03 00229 674E-04 00205 120E-04 00248 243 1364 560
Point Detectors 1 m 383E-03 00217 155E-03 00204 285E-04 00248 247 1347 546 2 m 172E-03 00197 689E-04 00186 124E-04 00225 249 1391 558
Source Attachment II MCNP-Results2xls worksheet Summary
Tables 16 17 and 18 ar e results of calculation set 2 for conceptual Cask A with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
40
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
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11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
DISCLAIMER
The calculations contained in this docum ent were developed by Bechtel SAIC Company LLC and are intended solely for the use of Bechtel SAIC Com pany LLC in its work for the Yucca Mountain Project
2
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
CONTENTS
Page
1 PURPOSE 9
2 REFERENCES 10 21 PROJECT PROCEDURESDIRECTIVES 10 22 DESIGN INPUTS10 23 DESIGN CONSTRAINTS 12 24 DESIGN OUTPUTS13
3 ASSUMPTIONS 14 31 ASSUMPTIONS REQUIRING VERIFICATION14 32 ASSUMPTIONS NOT REQUIRING VERIFICATION14
321 Material and Wall Thickness of TAD Canister 14 322 Material and Thickness of TAD Shield Plug 14 323 Geometry and Materials of Conceptual TAD Transportation Casks 15 324 Usage of Unirradiated Fuel for Commercial SNF 16 325 Homogenization of Radiation Source Regions 16 326 Ignoring Internal Fuel Basket Materials 17
4 METHODOLOGY 18 41 QUALITY ASSURANCE18 42 USE OF COMPUTER SOFTWARE18
421 Baseline Software 18 422 Commercial off the Shelf Software 18
43 CALCULATION APPROACH19 431 MCNP5 Program 19
5 LIST OF ATTACHMENTS 20
6 CALCULATIONS 21 61 DESCRIPTION OF CALCULATIONS21 62 CALCULATION INPUT 24
621 TAD Canister 24 622 Conceptual TAD Transportation Casks 24 623 Fuel Assembly Selection 25 624 BampW 15x15 Mark B PWR Fuel Assembly 25 625 Material Compositions 27 626 Homogenization Assembly Materials 28 627 PWR Source Terms 30
63 MCNP SPECIFIC INPUT 35 631 Source Probability 35 632 Dose Rate and Flux Tallies 35 633 Variance Reduction Techniques 35
64 DOSE CONVERSION FACTORS 36
3
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION 37
7 RESULTS AND CONCLUSIONS 38 71 RESULTS 38
711 Dose Rates of Conceptual Cask A 38 712 Dose Rates of Conceptual Cask B 41 713 Comparison of Dose-Rate Reduction Factors 44
72 CONCLUSIONS46 ATTACHMENT I ELECTRONIC FILES ON COMPACT DISCI-1
4
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
FIGURES
Page
Figure 1 Geometry and Tally Scheme for the TAD Transportation Cask 23
5
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
TABLES
Page
Table 1 Geometry and Materials of Conceptual TAD Transportation Cask A 15 Table 2 Geometry and Materials of Conceptual TAD Transportation Cask B 16 Table 3 Dimensions of TAD Canister 24 Table 4 BampW 15x15 Mark B Fuel Assembly Description 26 Table 5 PWR Fuel Assembly Regions 27 Table 6 Chemical Compositions of Materials 28 Table 7 Isotopic Compositions of Homogenized PWR Assembly Regions 29 Table 8 Gamma and Neutron Sources for the Maximum PWR SNF Assembly 31 Table 9 Gamma and Neutron Sources for the Design Basis PWR SNF Assembly 32 Table 10 Gamma and Neutron Sources for the Average PWR SNF Assembly 33 Table 11 Gamma and Neutron Axial Source Profiles for a PWR Assembly 34 Table 12 Gamma and Neutron Flux to Dose Conversion Factors 36 Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources 39 Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources 39 Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources 39 Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources 40 Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources 40 Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources 40 Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources 42 Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources 42 Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources 42 Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources 43 Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources 43 Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources 43 Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources 44 Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources 45 Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources 45 Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources 45 Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources 45 Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial
Sources 46 Table 31 Recommended Average Radial Dose-Rate Reduction Factors 46 Table 32 Recommended Average Top Dose-Rate Reduction Factors 46 Table 33 Recommended Average Bottom Dose-Rate Reduction Factors 46 Table I-1 Listing of Electronic Files on Compact DiscI-1
6
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ACRONYMS AND ABBREVIATIONS
ACRONYMS
ANS American Nuclear Society
ANSI American National Standards Institute
ASTM American Society for Testing and Materials
BSC Bechtel SAIC Company LLC
BWR Boiling Water Reactor
CD Compact disc
CSNF Commercial Spent Nuclear Fuel
DB Design Basis
DOE U S Department of Energy
DPC Dual Purpose Canister
NRC U S Nuclear Regulatory Commission
PCSA Preclosure Safety Analysis
PWR Pressurized Water Reactor
RPM Repository Project Management
SNF Spent Nuclear Fuel
SS 316 Stainless Steel 316
TAD Transportation Aging and Disposal
WP Waste Package
YMP Yucca Mountain Project
ABBREVIATIONS and UNITS
b barn
cm centimeter
7
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
g gram
GWd gigawatt-day
hr hour
in inch
kg kilogram
m meter
mrem millirem
MeV million electron volt
MTU metric ton uranium
s second
8
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
1 PURPOSE
The purpose of this calculation is to calcu late th e dose ra tes of two conceptua l tr ansportation casks each carrying a Transportation Aging and Disposal (TAD) canister separately loaded with the average design basis (DB) and m aximum comm ercial spent nuc lear fuel (CSNF) assemblies Then the dose-ra te reduction f actors between the m aximum and the design basis fuels the d esign bas is and the average fuels and the m aximum and the averag e fuels are computed
The results of this calculation may be used to substantiate the dose-rate reduction factors such as those in the engineering study Repository ALARA Goal Compliance (Reference 227) which is cited as a reference in a Preclosure Safety Analyses (PCSA) calculation that supports the License Application
The calculations contained in this docum ent are developed by Nuclear and Radiological Engineering of the Repository Project Mana gement (RPM) organization Yucca Mountain Project (YMP) personnel from Nuclear and Radiological Engineering should be consulted before use of the calculations for purposes other than those stated herein or use by individuals other than personnel in Nuclear and Radiological Engineering
9
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
2 REFERENCES
21 PROJECT PROCEDURESDIRECTIVES
211 IT-PRO-0011 Rev 0010 Software Management Las Vegas Nevada Bechtel SAIC Company
212 EG-PRO-3DP-G04B-00037 Rev 14 Calculations and Analyses Las Vegas Nevada Bechtel SAIC Company
213 IT-PRO-0012 Rev 007 Qualification of Software Las Vegas Nevada Bechtel SAIC Company
22 DESIGN INPUTS
221 ANSIANS-611-1977 Neutron and Gamma-Ray Flux-to-Dose-Rate Factors La Grange Park Illinois American Nuclear Society TIC 239401
222 ASME (American Society of Mechanical Engineers) 2004 2004 ASME Boiler and Pressure Vessel Code 2004 Edition New York New York American Society of Mechanical Engineers TIC 256479 ISBN 0-7918-2899-9
223 ASM International 1990 Properties and Selection Nonferrous Alloys and Special-Purpose Materials Specific Metals and Alloys Volume 2 of Metals Handbook 10th Edition Page 666 [Materials Park Ohio] American Society for Metals TIC 239807
224 ASTM (American Society for Testing and Materials) B 811-90 1991 Standard Specification for Wrought Zirconium Alloy Seamless Tubes for Nuclear Reactor Fuel Cladding Philadelphia Pennsylvania American Society for Testing and Materials TIC 239780
225 ASTM G 1-90 (Reapproved 1999) 1999 Standard Practice for Preparing Cleaning and Evaluating Corrosion Test Specimens West Conshohocken Pennsylvania American Society for Testing and Materials TIC 238771
226 Bowman SM Hermann OW and Brady MC 1995 Sequoyah Unit 2 Cycle 3 Volume 2 of Scale-4 Analysis of Pressurized Water Reactor Critical Configurations ORNLTM-12294V2 Oak Ridge Tennessee Oak Ridge National Laboratory TIC 244397 [DIRS 123796]
227 BSC (Bechtel SAIC Company LLC) 2008 Repository ALARA Goal Compliance 000-30R-MGR0-04000-000 REV 000 Las Vegas Nevada Bechtel SAIC Company ACC ENG200802050014 [DIRS 184957]
228 BSC 2002 Subsurface Shielding Source Term Specification Calculation 000-00C-WER0-00100-000-00A Las Vegas Nevada Bechtel SAIC Company ACC MOL200212160076 ENG200508150022
10
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
229 BSC 2004 PWR Source Term Generation and Evaluation 000-00C-MGR0-00100-000-00B Las Vegas Nevada Bechtel SAIC Company ACC ENG200405240007
2210 BSC 2008 Basis of Design for the TAD Canister-Based Repository Design Concept 000-3DR-MGR0-00300-000-003 Las Vegas Nevada Bechtel SAIC Company ACC ENG200810060001
2211 BSC 2007 Project Design Criteria Document 000-3DR-MGR0-00100-000-007 Las Vegas Nevada Bechtel SAIC Company ACC ENG200710160005 ENG200711080001 ENG200712200003 ENG200801070001 ENG200801070002 ENG200801070016 ENG200801070017 ENG200801310006 ENG200803050002 ENG200803050011 ENG200803050012 ENG200803060009 ENG200803130004 ENG200807100001 ENG200811120006 ENG200811140004
2212 BSC 2004 PWR and BWR Source Term Sensitivity Study 000-00C-MGR0-00300-000-00A Las Vegas Nevada Bechtel SAIC Company ACC ENG200401140003 ENG200508150023
2213 BSC 2007 Dose Rate Calculation for Exhaust Main Drifts 800-00C-SS00-00700-000-00B Las Vegas Nevada Bechtel SAIC Company ACC ENG200711050017 ENG200803060001
2214 BSC 2006 Dual Purpose Canister Opening Study 050-30R-WHS0-00600-000-000 Las Vegas Nevada Bechtel SAIC Company ACC ENG200612200023
2215 BSC 2007 GROA Shielding Requirements Calculation 000-00C-MGR0-03300-000-00B Las Vegas Nevada Bechtel SAIC Company ACC ENG200705290037
2216 BSC 2002 Concrete Shielding Calculation for Dry Facility 1 110-00C-CS10-00100-000-00A Las Vegas Nevada Bechtel SAIC Company ACC MOL200301140075
2217 BSC 2003 Shielding Design Calculations for Dry Facility 1 110-00C-CS10-00200-000-00A Las Vegas Nevada Bechtel SAIC Company ACC ENG200306020003
2218 CRWMS MampO 1998 Calculation of the Effect of Source Geometry on the 21-PWR WP Dose Rates BBAC00000-01717-0210-00004 REV 00 Las Vegas Nevada CRWMS MampO ACC MOL199902220059 [DIRS 102134]
2219 CRWMS MampO 2000 Users Manual for SCALE-44A 10129-UM-44A-00 Las Vegas Nevada CRWMS MampO ACC MOL200011300136 MOL200108220084 MOL200108220085 MOL200108220086 MOL200108220087 [DIRS 153872]
2220 DOE (US Department of Energy) 1987 Appendix 2A Physical Descriptions of LWR Fuel Assemblies Volume 3 of Characteristics of Spent Fuel High-Level Waste and Other Radioactive Wastes Which May Require Long-Term Isolation DOERW-0184 Washington DC US Department of Energy Office of Civilian Radioactive Waste Management ACC HQX198804050024 [DIRS 132333]
11
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
2221 DOE 2007 Software Validation Report for MCNP5 v140 Document ID 11199-SVR-140-00-WINXP Las Vegas Nevada US Department of Energy Office of Repository Development ACC MOL200702280252 [DIRS 180516]
2222 DOE 2008 Transportation Aging and Disposal Canister System Performance Specification WMO-TADCS-000001 Rev 1 ICN 1 Washington DC US Department of Energy Office of Civilian Radioactive Waste Management ACC DOC200803310001 [DIRS 185304]
2223 Harmon CD II Busch RD Briesmeister JF and Forster RA 1994 Criticality Calculations with MCNPtrade A Primer LA-12827-M Los Alamos New Mexico Los Alamos National Laboratory TIC 234014 [DIRS 154532]
2224 LANL (Los Alamos National Laboratory) 2004 MCNP mdash A General Monte Carlo N-Particle Transport Code Version 5 (Appendix H is not included) LA-UR-03-1987 Volume I Los Alamos [New Mexico] Los Alamos National Laboratory ACC MOL200510240126 [DIRS 176521]
2225 MCNP5 V 140 2007 Windows XP STN 11199-140-00 [DIRS 180515]
2226 Parrington JR Knox HD Breneman SL Baum EM and Feiner F 1996 Nuclides and Isotopes Chart of the Nuclides 15th Edition San Jose California General Electric Company and KAPL Inc TIC 233705 LC Call Number QC7935 N8622 1996
2227 Punatar MK 2001 Summary Report of Commercial Reactor Criticality Data for Crystal River Unit 3 TDR-UDC-NU-000001 REV 02 Las Vegas Nevada Bechtel SAIC Company ACC MOL200107020087 [DIRS 155635]
2228 Sisley SE 2002 Transportation License Application for the FuelSolutionstrade System (TAC No L23311) Submittal of the FuelSolutiontrade Transportation SARs Revision 3 Letter from SE Sisley (BNFL) to the NRC April 11 2002 BFSNRC 02-011 with enclosures TIC 255245 [DIRS 171545]
NOTE Reference 2220 is a direct input but is not QA QA It is justified as acceptable for the intended use as it is directly from the DOE and is considered the best available data on the subject The referenced values cited in Tables 3 and 4 are valid for use since they are reliable and reasonable based on engineering judgment
23 DESIGN CONSTRAINTS
231 10 CFR 71 2008 Energy Packaging and Transportation of Radioactive Material Internet Accessible [DIRS 185678]
12
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
24 DESIGN OUTPUTS
The resu lts of this calculation will be us ed to substan tiate th e dose reduc tion f actor in the Repository ALARA Goal Compliance (Reference 227) which is cited as a reference in a PCSA calculation that supports the License Application
13
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
3 ASSUMPTIONS
31 ASSUMPTIONS REQUIRING VERIFICATION
None
32 ASSUMPTIONS NOT REQUIRING VERIFICATION
Assumptions 321 322 and 323 are m odeling assum ptions and do not require further verification The m aterials and dim ensions for the TAD canister and for the conceptu al transportation casks are only selected to charac terize two tr ansportation casks th at m eet 10 CFR7147 (Reference 231) dose rates when lo aded with the ldquom aximumrdquo and ldquoaveragerdquo pressurized water re actor (PW R) assem blies re spectively There is n o need to v erify those dimensions or m aterials at a later date The ca lculated results in Sect ion 711 verify that the conceptual casks would meet 10 CFR 7147 (Reference 231) dose rates
321 Material and Wall Thickness of TAD Canister
Assumption It is assumed that the TAD canister is made of stainless steel 316 (SS 316) and has a wall thickness of 025 in for the radial and bottom shells
Rationale Currently the design of the TAD canis ter d oes not ex ist Based on a survey of existing m ultipurpose a nd dual purpose caniste rs (DPC) (Ref erence 2214 p 56) a 025 in thickness is below the wall thick ness of any existing c anisters For the purp ose of this calculation this assumption leads to higher and conservative external dose rates Since SS 316 is the sam e material used for the waste pack age inner shell it is a l ogical cho ice f or the TAD canister
Although Reference 2214 is an engineering study with a QA N A status it is used here as an indirect input to support the assumption which is conservative for dose rate calculations
Usage This assumption is used in Sections 621 and 625
322 Material and Thickness of TAD Shield Plug
Assumption It is assu med that the TAD shield plug is made of SS 316 and has a thickness of 11 in
Rationale Currently the design of the TAD canister doe s not exist A thick shield plug of 11 in (Reference 2215 Table 12) is needed to keep the m aximum contact dose rate of the top surface below 1000 mrem hr (Reference 2222 Section 314) Since SS 316 is the sam e material used for the waste package inner shell it is a logical choice for the TAD shield plug
Usage This assumption is used in Section 621
14
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
323 Geometry and Materials of Conceptual TAD Transportation Casks
Assumption Two conceptual TAD transpo rtation casks designated as Cask A and Cask B are assumed to have a cylindrical geom etry and m aterials specified in Tab les 1 and 2 respectively The casks are basically construc ted of an inner layer of SS 316 for ga mma shielding a m iddle layer of 5-borated polyethylen e for neutron shielding and a th in outer layer of SS 316 whic h serves a structural function as well as shielding secondary gamma rays
Both Cask A and Cask B have a cavity height of 53785 cm (21175 in) and a cavity diameter of 16891 cm (6650 in) However Cask A has a total height of 610845 cm (24049 in) and an outside diameter of 26797 cm (10550 in) while the total height and outside diameter of Cask B are 58885 cm (23183 in) and 24765 cm (9750) respectively
Cask A will provide shielding to m eet the exterior radiat ion standards of 10 C FR 7147(b) (Reference 231) when loaded w ith a TAD canister carrying th e maximum PWR spent nuclear fuel (SNF) Cask B will satisf y the same radiation standards when loade d with a TAD caniste r carrying the average PWR SNF
Table 1 Geometry and Materials of Conceptual TAD Transportation Cask A
Component Dimension
Material (cm) (in)
Total Height 61085 2404 9 NA
Outside Diameter 26797 1055 0 NA
Cask Cavity Height 53785 2117 5 NA
Cask Cavity Diameter (Radius) 16891 (8446) 6650 (3325) NA
Radial Gamma Shield Thickness (Radius)a 3302 (11748)a 1300 (4625)a SS 316
Radial Neutron Shield Thickness (Radius)b 1524 (13272)b 600 (5225)b 5-borated polyethylene
Radial Outer Shell Thickness (Radius)c 127 (13399)c 050 (5275)c SS 316
Top Gamma Shield Thickness (Axial Position)d 600 (54385)d 236 (21411)d SS 316
Top Neutron Shield Thickness (Axial Position)d 1000 (55385)d 394 (21805)d 5-borated polyethylene
Top Outer Shell Thickness (Axial Position)d 200 (55585)d 079 (21884)d SS 316
Bottom Gamma Shield Thickness (Axial Position)d 35365 (-360)d 1392 (-1417)d SS 316
Bottom Neutron Shield Thickness (Axial Position)d 15 (-510)d 591 (-2008)d 5-borated polyethylene
Bottom Outer Shell Thickness (Axial Position)d 4 (-550)d 157 (-2165)d SS 316 a11748 = 3302 + 8446 and 4625 = 1300 + 3325 b13272 = 1524 + 11748 and 5225 = 600 + 4625 c13399 = 127 + 13272 and 5275 = 050 + 5225 dCoordinate relative to the bottom of the fuel assembly as modeled in MCNP5
15
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 2 Geometry and Materials of Conceptual TAD Transportation Cask B
Component Dimension
Material (cm) (in)
Total Height 58885 2318 3 NA
Outside Diameter 24765 9750 NA
Cask Cavity Height 53785 2117 5 NA
Cask Cavity Diameter (Radius) 16891 (8446) 6650 (3325) NA
Radial Gamma Shield Thickness (Radius)a 254 (10986)a 1000 (4325)a SS 316
Radial Neutron Shield Thickness (Radius)b 127 (12256)b 500 (4825)b 5-borated polyethylene
Radial Outer Shell Thickness (Radius)c 127 (12383)c 050 (4875)c SS 316
Top Gamma Shield Thickness (Axial Position)d 8 (54585)d 315 (21490)d SS 316
Top Neutron Shield Thickness (Axial Position)d None Non e NA
Top Outer Shell Thickness (Axial Position)d None Non e NA
Bottom Gamma Shield Thickness (Axial Position)d 3837 (-390)d 1510 (-1535)d SS 316
Bottom Neutron Shield Thickness (Axial Position)d 300 (-420)d 118 (-1654)d 5-borated polyethylene
Bottom Outer Shell Thickness (Axial Position)d 100 (-430)d 039 (-1693)d SS 316 a10986 = 254 + 8446 and 4325 = 1000 + 3325 b12256= 127 + 10986 and 4825 = 500+ 4325 c12383 = 127 + 12256 and 4875 = 050 + 4825 dCoordinate relative to the bottom of the fuel assembly as modeled in MCNP5
Rationale Currently a design for the TAD transporta tion cask does not exist The casks assumed for this calculation are so lely for estim ation of the dose reduction due to different source terms This is a conceptual repres entation only used in this calculation to estim ate the parameters of interest
Usage This assumption is used in Sections 61 and 622
324 Usage of Unirradiated Fuel for Commercial SNF
Assumption It is assumed that the active fuel region of the commercial SNF assembly contains the same isotopic concentrations as the fresh uni rradiated fuel and that the concentrations of fresh fuel with 5 initial enrichm ent corresp onding to m aximum SNF are used for all other SNFs
Rationale This assumption is a standard practice for shielding calculations throughout the industry accepted by the U S Nucle ar Regulatory Commission (NRC) (Reference 2228 Table 53-5) It sh ould be noted that this assumption applies to material composition only it does no t apply to source terms which are based on the characteristics of spent fuel
Usage This assumption is used in Sections 624 and 626
325 Homogenization of Radiation Source Regions
Assumption It is assu med that a commercial SNF assembly consis ts of four distinct reg ions (active fuel bottom end-fitting plenum and top end-fitting) The materials and radiation sources
16
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
of each assembly region are homogenized inside a volume defined by the TAD cavity radius and region height
Rationale The assembly representation is consistent with the industry practice for shielding calculations accepted by NRC (Reference 2228 Figure 53-6) The effec t of source homogenization is twofold (1) it d ecreases th e m ass de nsity of the source region and (2) it places source points slightly closer to detector locations thus reducing radiation attenuation The resu lts of Calculation of the Effect of Source Geometry on the 21-PWR WP Dose Rates (Reference 2218 pp 22-26) indicate that th e effect of assem bly homogenization gives nearly the same or conservative dose rates as the explicit fuel assembly model
Usage This assumption is used in Section 624
326 Ignoring Internal Fuel Basket Materials
Assumption It is assumed that the internal fuel basket materials are ignored
Rationale Inclusion of fuel basket m aterials in the smeared m aterial com position would increase the overall density and consequently increase the attenuati on of the radiation Therefore this assumption is conservative
Usage This assumption is used in Sections 621 624 and 626
17
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
4 METHODOLOGY
41 QUALITY ASSURANCE
This calculation was prepared in accordance with EG-PRO-3DP-G04B-00037 Calculations and Analyses (Reference 212) The results of th is calculation provides worker dose assessm ent adjustments and this will id entify radio logical hazards f or f acilities im portant to saf ety Therefore the approved version is designated as QA QA
42 USE OF COMPUTER SOFTWARE
421 Baseline Software
The Monte Carlo N-Particle com puter pr ogram (MCNP5) version 140 (Reference 2225) is used to calculate the dose rates (neutron pr imary gamm a and secondary gamm a) at various locations around a transportation cask and an aging overpack
The software specifications are as follows
bull Program Name MCNP5 bull VersionRevision Number Version 140 bull Operating Systems Windows XP bull Software Tracking Number 11199-140-00 bull Computer Type Dell OPTIPLEX GX620
MCNP5 which is Level 1 software is (a) appropriate for three-dim ensional neutron gamma and coupled neutrongamma shielding calculations (b) used within th e range of validation as documented in Software Validation Report for MCNP5 v140 (Reference 2221) and (c) obtained from Software C onfiguration Managem ent and qualified in accordance with procedure IT-PRO-0012 Qualification of Software (Reference 213) Therefore MCNP5 code is suitable for use in this design calculation All MCNP5 input and output files docum ented in this calculation are provided on a compact disc (CD) as Attachment II
All MCNP cases are executed on one of the following Q com puters QNW -004184 QNW -004187 QNW-004194 and QNW-004196 as shown in the output files
422 Commercial off the Shelf Software
The Excel sof tware is used to c alculate var ious inpu t values (i e atom densities weight percentages geometrical dimensions normalized source spectra and probabilities etc) Standard functions of Excel are also used in this desi gn calculation to display results (ie gamma and neutron dose rates) in tabular and graphic forms and to perform relative error calculations
The software specifications are as follows
bull Program Name Excel bull VersionRevision Number Microsoftreg Excel 2003
18
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
bull This software is installed on a persona l com puter running Microsoft W indows XP (central processing unit number 151834)
The user defined for mulas inputs results and gr aphical representations have been verified by hand calculations or visual inspection and are documented in sufficient detail to allow an independent repetition of the com putations Calculations were verifi ed by hand and graphical representations were found accurate by visual inspection
Per Software Management Microsoftreg Excel is not requir ed to be qualif ied due to its commercial availability status (Reference 211 Attachment 4 p 55 bullet 2)
43 CALCULATION APPROACH
This calculation em ploys the qualified so ftware MCNP5 version 140 (Reference 2225) a three-dimensional Monte Carlo code for pe rforming neutron and coupled neutron-gamm a calculations to estim ate dose rates at sele cted locations on and surrounding a conceptual transportation cask containing a loaded TAD canister
431 MCNP5 Program
MCNP5 a general Monte Carlo part icle transport code sim ulates particle transport through a three-dimensional representation of the nuclear system being analyzed During the random walk of particles through the system described by the geom etry the c ode collects inform ation about various events (su rface cross ing collis ions trac k leng th etc) and es timates fluxes in various geometric configurations specified as tallies by the user It also estimates the statistical precision of the results in the form of relative errors (Reference 2224 pp 1-2 to 1-8)
Per Project Design Criteria Document (Reference 2211 Section 41015) the flux estim ates are converted to dose rates using the Am erican Nuclear Society (ANS) flux-to-dose rate conversion factors for gammas and neutrons (R eference 221) The simple variance reduction techniques of Geometry SplittingRussian Roulette and source probability biasing (Sections 631 and 633) are used to enhance computational efficiency
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Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
5 LIST OF ATTACHMENTS
Number of Pages Attachment I List of Electronic Files on the CD 3 Attachment II Compact Disc NA
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Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
6 CALCULATIONS
This sectio n provides inform ation necess ary to perform the calcu lations in this docum ent Section 61 describes the configurations the type of CSNF to be analyzed the number of MCNP runs and the locations where dose rates are ca lculated Section 62 provides the calculation input that includes the details of the geom etry m odel radiation source term s and m aterial compositions Input specific to MCNP dose -rate conversion factors and relative error calculation are described in the later sections
61 DESCRIPTION OF CALCULATIONS
Dose rate calculations are perform ed with the MCNP5 version 140 com puter code (Reference 2225) Two conceptual transportation casks Cask A and Cask B (Assum ption 323) are employed Each cask contains a TAD canister that is loaded with 21 ident ical PW R SN F assemblies Three PWR source term s are analy zed they are the source term s corresponding to the maximum design basis and average PW R SN Fs The characteris tics of the P WR source terms are presented in S ection 627 Each PWR source term has neutron and ga mma radiation sources that require separate MCNP5 runs For each radiation source an axial profile source and a uniform source for the active fuel region are considered The uniform source for the active fuel region is included in this calculation because this approach was used in combination with source peaking factors in certain calculations (Reference 2216 Sections 37 and 39 and Reference 2217 Section 5242)
The total number of MCNP5 runs is 24 which re sults from a com bination of two conceptual casks three PWR source terms two radiation sources and two axia l source distributions for the active fuel region These 24 runs are categorized into four calcula tion sets Each calculation set consists of six runs that is a combination of three PWR source te rms and two radiation sources The characteristics of each calculation set are as follows
1 Cask A with axial profile sources in the active fuel region
2 Cask A with uniform axial sources in the active fuel region
3 Cask B with axial profile sources in the active fuel region
4 Cask B with uniform axial sources in the active fuel region
For each MCNP5 run dose rates are calculated at the exte rior surfaces and at distances 1 and 2 meters from the exterior surfaces Surface tallies and detector tallies (ring and point detectors) as indicated in Figure 1 are e mployed in all runs Figure 1 is used to illustrate the dep loyment of the surface and detector tallies re lative to the so urce regions and it should not be interpreted as an exact geometry of any particular run Surface tallies are deployed at all three distances while ring and point detectors are used only at 1 m and 2 m and not at the cask surfaces Using point detectors near a surface or in any scattering media is not recommended because very large scores can occur f rom collisions close ( less than a f ew centimeters) to the point detecto rs that can lead to resu lts with high r elative e rrors thus m aking the ca lculation d ifficult to o btain r eliable answers
21
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
For the radial direction surface tallies at the three distances (contact 1 m and 2 m) are computed for three su rface segments (cylindrical rings) between the planes at Z = 145 175 2 05 and 235 cm The geometric locations of the segments are shown in Figure 1 The axial locations of these segments correspond to the m iddle of the active fuel region of the PWR SNF assemblies The average dose rates for each of the segm ents are calculated for the outside surface and surfaces at 1 m and 2 m from the cask surface Two ring detectors (instead of point detectors) are deployed at 1 m and 2 m for the radial dire ction Ring detectors instead of point detectors are used in order to capitalize on the symm etry around the cask axis thus im proving the efficiency of the calculations
In the axial direction the average d ose rates within three concentric radial surfaces defined by radii of 40 80 and 120 cm (shown in Figure 1) are calculated for the top and bottom surfaces and at distances 1 m and 2 m from these surfaces Finally point detectors at 1 m and 2 m from the top and bottom axial surfaces are employed
22
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Point Detector at 2 m x
Ring Ring Detector Detector at 2 m at 1 m
x x
Z = 00 cm
Z = 145 cm
Z = 175 cm
Z = 205 cm
Z = 235 cm
R = 80 cm
R = 120 cm
R = 40 cm
Active Fuel
Shield Plug
Top End-Fitting Plenum
Bottom End-Fitting
Ring Detector at 1 m
x
Point Detector at 1 m x
Ring Detector
at 2 m x
D = 26797 cm
H =
610
845
cm
Point Detector at 1 m x
Point Detector at 2 m x
Figure 1 Geometry and Tally Scheme for the TAD Transportation Cask
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Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
62 CALCULATION INPUT
Technical product input and sources of the input used in the deve lopment of this calculation are documented in this section Tables in this docum ent and in th e associated Microsoftreg Excel spreadsheets referenced m ay present num erical values with m any significant figures these values are not to be considered as high precision values since the significant figures are results of calculated values andor unit conversions
621 TAD Canister
The TAD canis ter will contain either 21 P WR or 44 BW R (boiling water reactor) SNF assemblies (Reference 2222 Section 321) While the canister design is iden tical for both PWR and BWR SNF assemblies the internal basket structure is different depending on the SNF assemblies However the internal basket stru cture m aterial is no t in cluded in the calcu lation model (Assumption 326)
The TAD canister is a right-circu lar cylinder with a diam eter of 665 in and a height between 186 and 212 in (Reference 2222 Section 321) The average and maximum total dose rates on the top surf ace of a loaded TAD ca nister must not exceed 800 and 1000 m remhr respectively (Reference 2222 Section 314) The TAD canister used in this calculation is m ade of SS 316 with a radial wall and bottom thickness of 025 in (Assumption 321) The top of the canister has a shield plug that is 11 in thick SS 316 (Ass umption 322) A thick shield plug is needed to keep the maxim um contact dose rate of th e top surface below 1000 m remhr The overall dimensions of the TAD canister are provided in Table 3
Table 3 Dimensions of TAD Canister
Component Dimension
(in) (cm)
Maximum heighta 212 53848
Outer diametera 665 16891
Thickness of bottom lidb 025 0635
Shell thicknessb 025 0635
Lifting Featurec 6 1524
Height without Lifting Feature 206 52324
Thickness of shield plugd 110 2794
aReference 2222 Section 311 bAssumption 321 cReference 2222 p Attachment C-1 dAssumption 322
622 Conceptual TAD Transportation Casks
Two conceptual TAD transportation casks designa ted as Cask A and Cask B are em ployed in this calculation (Assumption 323) They both have a cylindrical geometry with dimensions and materials specified in Tables 1 and 2 of Section 323 Cask A will provide shielding to meet the exterior radiation standards of 10 CFR 7147(b) (Reference 231) when loaded with a TAD
24
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
canister car rying the m aximum PWR SNF Cask B will s atisfy th e sa me radiatio n standa rds when loaded with a TAD canister c arrying the average PWR SNF The reason to analyze both Casks A and B is to cover a broad range of characteristics of the CSNF
The cavity dimensions of the conceptual cask s are 53785 cm (21175 in) in height and 16891 cm (665 in) in diam eter (Tab les 1 and 2) This cav ity will accommoda te the TAD canister described in Table 3 without the lifting feature This is the geometry model used in the MCNP5 calculations
623 Fuel Assembly Selection
PWR and BWR Source Term Sensitivity Study (Reference 2211 Tables 71 through 84) shows that the source terms generated for the Bamp W 15x15 Mark B fuel assembly with 475 kg uranium loading bound the source terms of other PWR assembly types ther efore this assembly type is selected as the representative PWR fuel assembly The gamma and neutron source terms for the BampW 15x15 Mark B assembly are generated in PWR Source Term Generation and Evaluation (Reference 229) and are used in this calculation
624 BampW 15x15 Mark B PWR Fuel Assembly
BampW 15x15 Mark B fuel assembly consists of four regions top end-fitting plenum active fuel and bottom end-fitting The m aterials and ra diation sources of each assem bly region are homogenized inside a volume defined by the region height and the interior diam eter of the TAD canister (Assumption 325) The active fuel region is homogenized with fresh unirradiated fuel (Assumption 324) Since the internal structure (i e basket) design of t he TAD is currently not finalized the com position of the hom ogenized fuel does not include the basket m aterials (Assumption 326) and therefore does not take cred it for any shielding that these m aterials may provide
Table 4 provides the design param eters for the BampW 15x15 Mark B fuel assembly Data provided here are used in Attachment II PWR_fuel compxls worksheet BampWassy
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Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 4 BampW 15x15 Mark B Fuel Assembly Description
Component Material Characteristic Value Specific Reference Array Size 15 x 15
Reference 2227 Table 2-2 Fuel Pins Assembly 208 Guide Tubes Assembly 16 Instrument Tubes Assembly 1
Assembly NA Pin Pellet Diameter 0936244 cm (03686 in) Reference 2220 p 2A-34 Pin Pitch 144272 cm (0568 in)
Reference 2227 Table 2-2 Active Fuel Height 360172 cm (1418 in) Assembly Width 2168144 cm (8536 in)
Reference 2220 p 2A-31 Assembly Height 4206875 cm (165625 in) Mass U assembly 46363 kg
Guide tube Zircaloy-4 Outer Diameter 13462 cm (053 in)
Reference 2227 Table 2-2
Inner Diameter 126492 cm (0498 in)
Instrument tube Zircaloy-4 Outer Diameter 138193 cm (05441 in) Inner Diameter 112014 cm (0441 in)
Cladding` Zircaloy-4 Inner Diameter 095758 cm (0377 in) Outer Diameter 10922 cm (043 in)
Plenum region NA Length 297688 cm (11720 in) Reference 2220 p 2A-34 Top nozzle SS CF3M MassAssembly (Top) 748 kg
Reference 2220 p 2A-32
Bottom nozzle SS CF3M MassAssembly (Bottom) 816 kg Guide tubes Zircaloy-4 MassAssembly (in Core) 80 kg Instrument tube Zircaloy-4 MassAssembly (in Core) 064 kg Spacer-plenum Inconel-718 MassAssembly (Plenum) 104 kg Spacer-bottom Inconel-718 MassAssembly (Bottom) 13 kg Spacer-in core Inconel-718 MassAssembly (in Core) 49 kg Spring retainer SS CF3M MassAssembly (Top) 091 kg Holddown spring Inconel-718 MassAssembly (Top) 18 kg Upper end plug SS 304 MassAssembly (Top) 006 kg Upper nut SS 304L MassAssembly (Top) 051 kg Lower nut SS 304 MassAssembly (Bottom) 015 kg Grid supports Zircaloy-4 MassAssembly (in Core) 064 kg Plenum spring SS 302 MassAssembly (Plenum) 0042 lb (001905 kg) Reference 2220 p 2A-34
Note Som e d ata i n this tab le ar e given i n British u nits in th e r eferences thes e d ata ar e converted into metric units as the inputs to MCNP5 are in metric units
The assem bly region heights as m odeled in MC NP are presented in Table 5 utilizing values from Table 4 Table 5 is taken from Dose Rate Calculation for Exhaust Main Drifts (Reference 2213 Table 3)
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Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 5 PWR Fuel Assembly Regions
Component Height Reference
Plenum 297688 cm (11720 in) Reference 2220 p 2A-34
Active Fuel 360172 cm (1418 in) Table 3
Bottom End-Fitting 1077 cm (424 in) Calculateda
Top End-Fitting 1998 cm (787 in) Calculatedb
Source Reference 2213 Table 3 aCalculated b ased on data Reference 2227 F igures 2-3 an d 2-7
(Region 9 Height [16723 cm] + Region 10 Height [508 cm] ndash Lo wer Fuel Plenum and End Cap [11033 cm])
bCalculated (Assembly Length ndash Active Fuel Length ndash P lenum Length ndash Bottom End-fitting Length)
625 Material Compositions
The TAD transportation cask com ponent m aterial specifications are defined in Table 1 The TAD canister is constructed of SS 316 (Assumpti on 321) The PWR fuel assembly materials used to homogenize the fuel regions are defined in Table 4 Table 6 c ontains the m aterial compositions defining the TAD canister WP and fuel assemblies
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Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 6 Chemical Compositions of Materials
Material Density (gcc)
Isotopic Weight Percent Reference
SS 302 NA
C 0150 Mn 2000 P 0045 S 0030 Si 0750 Cr 18000 Ni 9000 N 0100 Fe 69925
Attachment II PWR_fuel compxls worksheet ferrous Reference 222 SEC II A SA-240 Table 1 for SS 302 SS 304 and SS 304L Reference 222 SEC II A SA-351SA -351M Table 2 for SS CF3M
SS 304 NA
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 9250 N 0100 Fe 68745
SS 304L NA
C 003 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 10000 N 0100 Fe 6804 5
SS CF3M NA
C 0030 Mn 1500 P 0040 S 0040 Si 1500 Cr 19000 Ni 11000 Mo 2500 Fe 64390
Inconel 718 NA
C 0080 Mn 0350 Si 0350 Cr 19000 Ni 52500 Co 1000 Mo 3050 Fe 16809 Nb 5125 Ti 0900 Al 0500 Cu 0300 S 0015 P 0015 B 0006
Attachment II PWR_fuel compxls worksheet alloys aReference 223 p 666 Table 6 Reference 222 SEC II B SB-637 Table 1 for Inconel 718 Reference 224 Table 2 for Zircaloy 4
Zircaloy 4 656a Cr 0100 Fe 0210 O 0125 Sn 1450 Zr 98115
SS 316 798b
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 17000 Ni 12000 Mo 2500 N 0100 Fe 65495
Attachment II PWR_fuel compxls worksheet others Reference 222 SEC II A SA-240 Table 1 for SS 316 bReference 225 Table X1
626 Homogenization Assembly Materials
The atom density of an element or isotope in atomsbmiddotcm in a homogenized region is calculated according to the following equation (Reference 2223 Appendix B)
M i times N AvogadroNi = Equation 1 Ai timesV times K
where Ni = Atom density of elementisotope i (atomsbmiddotcm) Mi = Mass of elementisotope i (g) NAvogadro = Avogadrorsquos constant 06022 x 1024 (atomsmole)
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Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Ai = Atomic weight of elementisotope i (gmole) V = Homogenization volume (cm3) K = Unit transformation constant = 1024 (bmiddotcmcm3)
Equation 1 is used in A ttachment II spreadsheet PWR_fuel compxls worksheet BampWassy to calculate th e atom dens ities for v arious elem ents and iso topes The m ass of elementsisotop es and Avogadrorsquos constant are provided in Reference 2226
Table 7 lists the com position of the hom ogenized assem bly regions (active fuel plenum top end-fitting and bottom end-fitting) for the PWR assembly The active fuel region contains fresh unirradiated fuel (Assumption 324) Since the internal structure (ie basket) design of the TAD is currently not finalized the composition of either homogenized fuel does not include the basket materials and therefore does not tak e credit for any shielding that thes e materials may provide (Assumption 326)
Table 7 Isotopic Compositions of Homogenized PWR Assembly Regions
Element Isotope
Atom Densities for Homogenized Regions (atomsbsdotcm)
Active Fuel Bottom End-Fitting Plenum Top End-Fitting
10B 861E-09 764E-08 221E-08 570E-08 11B 347E-08 307E-07 890E-08 230E-07 C 519E-07 160E-05 138E-06 993E-06 N -- 570E-07 262E-08 117E-06 O 621E-03 -- 142E-05 -- Al 144E-06 128E-05 371E-06 957E-06 Si 971E-07 243E-04 259E-06 139E-04 P 377E-08 606E-06 102E-07 360E-06 S 365E-08 581E-06 971E-08 340E-06 Ti 147E-06 130E-05 376E-06 971E-06 Cr 320E-05 187E-03 779E-05 113E-03 Mn 497E-07 126E-04 141E-06 749E-05 Fe 303E-05 531E-03 717E-05 313E-03 Co 132E-06 117E-05 340E-06 876E-06 Ni 697E-05 144E-03 180E-04 940E-04 Cu 368E-07 327E-06 945E-07 244E-06 Zr 196E-03 -- 195E-03 -- Nb 430E-06 382E-05 110E-05 285E-05 Mo 248E-06 135E-04 636E-06 791E-05 Sn 223E-05 -- 222E-05 -- 234U 139E-06 -- -- -- 235U 157E-04 -- -- -- 236U 719E-07 -- -- -- 238U 294E-03 -- -- -- Total 114E-02 924E-03 235E-03 557E-03
Source Attachment II spreadsheet PWR_fuel compxls worksheet BampWassy
29
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
The isotopic composition of commercially available 235U enriched uranium is determined by the given initial 235U enrichment using the following equations (Reference 226 p 20)
wt235U =235Uenrichment _ of _ the _ associated _ fuel _ batch Equation 2
wt234U = 0007731times (wt235U )10837 Equation 3
wt236U = 00046times (wt235U ) Equation 4
wt238U =100 minus (wt234U + wt235U + wt236U ) Equation 5
The weight percentages of uran ium isotopes for PWR fuel are ca lculated in Attachm ent II spreadsheet PWR_fuel compxls worksheet BampWassy using Equations 2 through 5
627 PWR Source Terms
This calculation uses the following three PWR source terms bull Maximum source (50 wt initial 235U enrichment 80 GWdMTU burnup and 5-year
decay time) (Reference 229 Section 55) Table 8 lists th e gamma source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Design Basis source (4 0 wt initial 235U enrichment 60 GW dMTU burnup and 10-year decay tim e) (Reference 228 Section 552) Table 9 lists the gamm a source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Average source ( 40 wt initial 235U enrichment 48 GWdMTU burnup and 25-year decay time) (Reference 229 Section 55) Table 10 lists the gamma source terms for the fuel and non-fuel regions and the neutron source term for the fuel region
These sources (ie maximum design basis and av erage) are described in this section For dose rate calculations all the fuel assemblies in a transportation cask are of the sam e characteristics Also gamma radiation source term s for the PWR assem bly are prov ided for the f our assembly regions while neutron source term is only present in the active fuel region Gamma radiation sources in the non-active fuel region are distri buted unif ormly within each source region Gamma and neutron sources in the active fuel re gion are modeled as uni form distributions or with axial source profiles
The PWR gamma and neutron axial source profiles for the active fuel region presented in Table 11 are applied to the active fuel region of all three source terms (ie maximum design basis and average) when appropriate
30
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 8 Gamma and Neutron Sources for the Maximum PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting
Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 594E+11 233E+15 528E+11 379E+11 100E-01 000E+00 100E-01 116E+11 644E+14 609E+10 743E+10 400E-01 805E+07 200E-01 283E+10 522E+14 352E+10 179E+10 900E-01 411E+08 300E-01 141E+09 148E+14 196E+09 891E+08 140E+00 376E+08 400E-01 190E+09 985E+13 586E+09 117E+09 185E+00 276E+08 600E-01 191E+09 153E+15 110E+11 741E+07 300E+00 485E+08 800E-01 435E+09 470E+15 595E+10 237E+09 643E+00 443E+08 100E+00 137E+11 708E+14 803E+09 766E+10 200E+01 393E+07 133E+00 338E+13 455E+14 174E+13 217E+13 Total 211E+09 166E+00 953E+12 130E+14 491E+12 612E+12
--
200E+00 187E+03 144E+12 919E+02 113E+03 250E+00 226E+08 249E+12 116E+08 145E+08 300E+00 351E+05 110E+11 181E+05 225E+05 400E+00 766E-08 139E+10 100E-08 416E-08 500E+00 000E+00 709E+07 000E+00 000E+00 650E+00 000E+00 286E+07 000E+00 000E+00 800E+00 000E+00 558E+06 000E+00 000E+00 100E+01 000E+00 119E+06 000E+00 000E+00
Total 442E+13 113E+16 231E+13 284E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE2R2B14cut bWasteStreamE2R1B14cut cWasteStreamE2R3B14cut dWasteStreamE2R4B14cut
31
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 9 Gamma and Neutron Sources for the Design Basis PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary
(MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 273E+11 121E+15 188E+11 175E+11 100E-01 000E+00 100E-01 528E+10 329E+14 277E+10 339E+10 400E-01 316E+07 200E-01 128E+10 245E+14 117E+10 819E+09 900E-01 161E+08 300E-01 639E+08 713E+13 633E+08 407E+08 140E+00 148E+08 400E-01 850E+08 455E+13 164E+09 533E+08 185E+00 109E+08 600E-01 492E+08 226E+14 269E+10 337E+07 300E+00 191E+08 800E-01 291E+09 237E+15 160E+10 186E+09 643E+00 174E+08 100E+00 540E+09 122E+14 248E+09 341E+09 200E+01 154E+07 133E+00 154E+13 195E+14 797E+12 990E+12 Total 830E+08 166E+00 435E+12 450E+13 225E+12 280E+12
--
200E+00 235E+00 152E+11 149E+02 215E-02 250E+00 103E+08 517E+10 534E+07 664E+07 300E+00 160E+05 379E+09 829E+04 103E+05 400E+00 943E-10 497E+08 155E-10 519E-10 500E+00 000E+00 282E+07 000E+00 000E+00 650E+00 000E+00 113E+07 000E+00 000E+00 800E+00 000E+00 222E+06 000E+00 000E+00 100E+01 000E+00 471E+05 000E+00 000E+00
Total 201E+13 486E+15 105E+13 129E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B11cut bWasteStreamE5R1B11cut cWasteStreamE5R3B11cut dWasteStreamE5R4B11cut
32
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 10 Gamma and Neutron Sources for the Average PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 336E+10 670E+14 186E+10 217E+10 100E-01 00000E+00 100E-01 602E+09 199E+14 314E+09 387E+09 400E-01 748E+06 200E-01 146E+09 126E+14 853E+08 936E+08 900E-01 382E+07 300E-01 730E+07 389E+13 439E+07 469E+07 140E+00 352E+07 400E-01 947E+07 263E+13 716E+07 607E+07 185E+00 261E+07 600E-01 141E+07 205E+13 504E+08 383E+06 300E+00 469E+07 800E-01 208E+09 124E+15 192E+09 144E+09 643E+00 418E+07 100E+00 208E+09 110E+13 164E+09 144E+09 200E+01 365E+06 133E+00 175E+12 295E+13 909E+11 112E+12 Total 199E+08 166E+00 494E+11 513E+12 257E+11 318E+11
--
200E+00 973E-01 675E+10 614E+01 872E-03 250E+00 117E+07 353E+09 609E+06 754E+06 300E+00 182E+04 288E+08 944E+03 117E+04 400E+00 186E-11 198E+07 149E-11 127E-11 500E+00 000E+00 669E+06 000E+00 000E+00 650E+00 000E+00 269E+06 000E+00 000E+00 800E+00 000E+00 527E+05 000E+00 000E+00 100E+01 000E+00 112E+05 000E+00 000E+00
Total 229E+12 237E+15 119E+12 147E+12
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B9cut bWasteStreamE5R1B9cut cWasteStreamE5R3B9cut dWasteStreamE5R4B9cut
33
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 11 Gamma and Neutron Axial Source Profiles for a PWR Assembly
Axial boundaries (From midplane)
(cm)
TOP BOTTOM
Neutron Gamma Ne utron Gamma 000 1554 1117 1554 1117 1143 1537 1114 1571 1120 2286 1521 1111 1588 1123 3429 1504 1108 1605 1126 4572 1486 1104 1622 1129 5715 1464 1100 1636 1131 6858 1438 1095 1648 1133 8001 1401 1088 1657 1135 9144 1350 1078 1654 1134
10287 1277 1063 1625 1129 11430 1165 1039 1554 1117 12573 0998 09995 1414 1091 13716 0769 09365 1172 1041 14859 0492 08375 0816 0951 16002 0220 06850 0402 0797 17145 0046 04625 0092 0551 18288 00 00 00 00
Source Reference 2219 Table S445
34
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
63 MCNP SPECIFIC INPUT
631 Source Probability
A linear radial distribution is used for all gamma and neutron sources The linear radial distribution is sam pled usi ng the built-in power function p(x) = xc a with a = 1 for the radial direction This sampling method results in a uniform source distribution over the area bounded by the outer radius of the source
The source axial distributions are unifor m for all four source regions The a xial uni form xp(x) = c distribution is sampled using the built-in power function a with a = 0 for extent
The energy distribu tions of the gamma and neutron sour ce term s are treated as energ y probabilities and are applied in MCNP5 using SISP cards
632 Dose Rate and Flux Tallies
MCNP5 dose rate calculations feature separate runs for the following calculation types
bull a photon transport calculation for prim ary ga mma contribution to the dose rates fr om photon fluxes
bull a coupled neutronphoton transport calculat ion for neutrons a nd secondary gamma (photons generated by neutron be ing captured) contributions to dose rates from neutron and gamma fluxes
The tally type F2 is us ed in th is d esign ca lculation as f lux estim ators The type F2 tally evaluates the flux averaged over a surface in particlescm2s
To generate dose ra tes in te rms of remhr the FM (tally multiplier ) and DEDF (dose energydose conversion factors) cards are used to en ter the tally multiplier f actor (source intensity in particless) energy boundaries in MeV and corresponding dose conversion factors in (remhr)(particlescm2s) respectively These factors were used in the input files
In order for the F2 tally to accum ulate flux ov er a surface a specific s urface area is requ ired The SD cards are used to enter a surface area in cm2 over which the flux will be tallied for an F2 tally
633 Variance Reduction Techniques
Variance reduction technique is usually em ployed in order to increase the efficiency of a calculation and obtain statistically m eaningful results within re asonable com puter tim e In Monte Carlo calculations when variance reduction scheme is employed the weights of particles are adjusted in order to account for the biasing and to preserve a fair game
Geometry splitting and Russian roulette techniques described in Reference 2224 (pp 2-140 ndash 2-142) are useful in shielding calculations and therefore deployed in all the MCNP5 runs
35
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
As particles migrate in an important direction (toward the detector) they are increased in number to provide better sampling by means of geometry splitting across geometric boundaries Russian roulette (the reverse process) is played when particles travel in an unimportant direction to allow termination of unim portant histories The IMP card required for every cel l ca rd is us ed to implement this technique
The other variance reduction technique deployed in the MC NP5 runs is source intensity biasing for the gamma sources from the four source regions (active fuel bottom end-fitting plenum and top end-fitting) The natural total gamma source intensity of comm ercial SNF is dom inated by the gamma source in the active fuel region This active fuel gamma source usually accounts for over 95 o f the total g amma source intens ity In order to im prove the efficiency of the axial dose rate calculations a biased source probability distribution is employed for the prim ary gamma dose rate calculations The biased gamma source probability distribution is chosen to be 005 080 010 and 005 for the bottom end-fitting the active fuel the plenum and the top end-fitting regions respectively
64 DOSE CONVERSION FACTORS
Project Design Criteria Document (Reference 2211 Se ction 41015) requires the use of flux-to-dose rate conversion fact ors from ANSIANS-611-1977 (Reference 221) for dose rate evaluations Table 16 lists the neutron and ga mma dose conversion factors used in the MCNP5 calculations
Table 12 Gamma and Neutron Flux to Dose Conversion Factors
Gamma Neutron Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
001 396E-06 140 251E-06 250E-08 367E-06 003 582E-07 180 299E-06 100E-07 367E-06 005 290E-07 220 342E-06 100E-06 446E-06 007 258E-07 260 382E-06 100E-05 454E-06 010 283E-07 280 401E-06 100E-04 418E-06 015 379E-07 325 441E-06 100E-03 376E-06 020 501E-07 375 483E-06 100E-02 356E-06 025 631E-07 425 523E-06 100E-01 217E-05 030 759E-07 475 560E-06 500E-01 926E-05 035 878E-07 500 580E-06 100E+00 132E-04 040 985E-07 525 601E-06 250E+00 125E-04 045 108E-06 575 637E-06 500E+00 156E-04 050 117E-06 625 674E-06 700E+00 147E-04 055 127E-06 675 711E-06 100E+01 147E-04 060 136E-06 750 766E-06 140E+01 208E-04 065 144E-06 900 877E-06 200E+01 227E-04 070 152E-06 1100 103E-05 080 168E-06 1300 118E-05 100 198E-06 1500 133E-05
Source Reference 221 Tables 1 and 3
36
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION
By def inition (Ref erence 2224 Equation 219) the estimated st atistic relative error of the i component is
Ri = Si
2
Equation 6Ti
where i = tally component index Ri = relative error of the i component S2
i = variance of the i component Ti = tally i component
For a result (ie dose rate) computed as a sum of different tallies the statistical relative error of the computed value is o btained from the variance of the result - S2
total which is th e sum of the estimated variances of the individual tallies S2
i n
2 2STotal = sum Si Equation 7 i=1
where S2Total = total estimated variance
n = total number of components Therefore the total tally value (dose rate) and the associated relative error are derived according to Equations 8 and 9
n TTotal = sumTi Equation 8
i=1
n n
sum (Ri timesTi )2
2 sum Si 2
STotal = i=1 = i=1 Equation 9RTotal = TTotal TTotal TTotal
where RTotal = total estimated relative error TTotal = total estimated tally
Equations 8 and 9 are utilized in Attachm ent II to ev aluate to tal dos e ra tes and their r elative errors
37
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
7 RESULTS AND CONCLUSIONS
71 RESULTS
The following sections summarize the results of this calculation Section 711 presents results for Conceptual Cask A while Section 712 for Conceptual Cask B Section 713 provides comparisons of the dose-rate reduction factors du e to the two conceptual casks and the axial source distributions in the active fuel region Do se rates and relative errors can be found in Attachment II within the output files and Excel files
711 Dose Rates of Conceptual Cask A
This section presents dose-rate results of the calculation sets 1 and 2 as described in Section 61 for Cask A Set 1 has axial p rofile sources in the active fuel region a nd consist of six runs resulting from the three PWR SNF source term s (maximum design basis and average) and the two radiation sources (gammas and neutrons) Set 2 has uniform axial sources in the active fuel region and consists of six run s r esulting f rom the th ree P WR SNF source term s and th e tw o radiation sources
As described in Section 61 dose ra tes are calculated at the three exterior surfaces (radial top and bottom) and at distances 1 m and 2 m from the exterior surfaces The total dose rates for set 1 are presented in Tables 13 14 and 15 for the ra dial top and bottom dire ctions respectively However the com ponents (primary gamma neutr on and secondary gamma) contributing to the total dose rates as well as the re lative error calculations can be found in Attachment II Excel file MCNP-Results1xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 2 are shown in Tables 16 17 and 18 The dose-rate components and the relative errors can be found in A ttachment II Excel file MCNP-Results2xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 13 and 16 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 14 and 17 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 15 and 18 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carrying th e maximum PWR SNF Based on the results in Tables 13 through 18 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask A indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these 6 tables the d ose-rate red uction f actors between the m aximum and the design basis fuels the maxim um and the averag e fuels and th e design basis and the average fuels are a lso presented
38
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 320E-02 00237 116E-02 00222 262E-03 00219 275 1223 445
1 m 133E-02 00164 494E-03 00171 106E-03 00162 269 1261 468 2 m 749E-03 00198 285E-03 00225 584E-04 00162 263 1282 488
Ring Detectors 1 m 133E-02 00116 492E-03 00115 108E-03 00124 271 1229 454 2 m 756E-03 00118 279E-03 00110 605E-04 00128 271 1250 462
Source Attachment II MCNP-Results1xls worksheet Summary
Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 142E-02 00368 628E-03 00446 934E-04 00483 226 1520 672
1 m 570E-03 00289 263E-03 00426 375E-04 00381 217 1520 701 2 m 265E-03 00364 123E-03 00547 169E-04 00374 216 1575 730
Point Detectors 1 m 598E-03 00238 274E-03 00271 402E-04 00354 219 1489 681 2 m 273E-03 00218 123E-03 00245 180E-04 00336 221 1515 684
Source Attachment II MCNP-Results1xls worksheet Summary
Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 653E-03 00298 265E-03 00276 510E-04 00341 247 1278 518
1 m 276E-03 00238 112E-03 00208 207E-04 00249 248 1334 539 2 m 125E-03 00185 508E-04 00199 933E-05 00246 246 1336 544
Point Detectors 1 m 291E-03 00227 118E-03 00203 218E-04 00242 247 1335 540 2 m 130E-03 00209 524E-04 00187 955E-05 00233 247 1357 549
Source Attachment II MCNP-Results1xls worksheet Summary
Tables 13 14 and 15 are results of calculation set 1 for conceptual Cask A with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
39
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 265E-02 00247 990E-03 00222 215E-03 00278 268 1234 461
1 m 116E-02 00178 468E-03 00549 960E-04 00189 248 1208 488 2 m 713E-03 00273 265E-03 00161 602E-04 00360 269 1184 439
Ring Detectors 1 m 117E-02 00120 454E-03 00132 979E-04 00141 259 1199 463 2 m 722E-03 00130 276E-03 00141 589E-04 00153 261 1226 469
Source Attachment II MCNP-Results2xls worksheet Summary
Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 199E-02 00461 827E-03 00455 147E-03 00536 241 1359 564
1 m 849E-03 00564 323E-03 00314 563E-04 00418 263 1507 574 2 m 415E-03 00832 158E-03 00603 253E-04 00501 263 1641 623
Point Detectors 1 m 877E-03 00348 353E-03 00275 615E-04 00391 248 1426 574 2 m 393E-03 00341 160E-03 00278 270E-04 00378 246 1454 590
Source Attachment II MCNP-Results2xls worksheet Summary
Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 879E-03 00374 356E-03 00333 669E-04 00406 247 1315 533
1 m 365E-03 00223 147E-03 00209 269E-04 00253 248 1358 548 2 m 164E-03 00229 674E-04 00205 120E-04 00248 243 1364 560
Point Detectors 1 m 383E-03 00217 155E-03 00204 285E-04 00248 247 1347 546 2 m 172E-03 00197 689E-04 00186 124E-04 00225 249 1391 558
Source Attachment II MCNP-Results2xls worksheet Summary
Tables 16 17 and 18 ar e results of calculation set 2 for conceptual Cask A with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
40
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
CONTENTS
Page
1 PURPOSE 9
2 REFERENCES 10 21 PROJECT PROCEDURESDIRECTIVES 10 22 DESIGN INPUTS10 23 DESIGN CONSTRAINTS 12 24 DESIGN OUTPUTS13
3 ASSUMPTIONS 14 31 ASSUMPTIONS REQUIRING VERIFICATION14 32 ASSUMPTIONS NOT REQUIRING VERIFICATION14
321 Material and Wall Thickness of TAD Canister 14 322 Material and Thickness of TAD Shield Plug 14 323 Geometry and Materials of Conceptual TAD Transportation Casks 15 324 Usage of Unirradiated Fuel for Commercial SNF 16 325 Homogenization of Radiation Source Regions 16 326 Ignoring Internal Fuel Basket Materials 17
4 METHODOLOGY 18 41 QUALITY ASSURANCE18 42 USE OF COMPUTER SOFTWARE18
421 Baseline Software 18 422 Commercial off the Shelf Software 18
43 CALCULATION APPROACH19 431 MCNP5 Program 19
5 LIST OF ATTACHMENTS 20
6 CALCULATIONS 21 61 DESCRIPTION OF CALCULATIONS21 62 CALCULATION INPUT 24
621 TAD Canister 24 622 Conceptual TAD Transportation Casks 24 623 Fuel Assembly Selection 25 624 BampW 15x15 Mark B PWR Fuel Assembly 25 625 Material Compositions 27 626 Homogenization Assembly Materials 28 627 PWR Source Terms 30
63 MCNP SPECIFIC INPUT 35 631 Source Probability 35 632 Dose Rate and Flux Tallies 35 633 Variance Reduction Techniques 35
64 DOSE CONVERSION FACTORS 36
3
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION 37
7 RESULTS AND CONCLUSIONS 38 71 RESULTS 38
711 Dose Rates of Conceptual Cask A 38 712 Dose Rates of Conceptual Cask B 41 713 Comparison of Dose-Rate Reduction Factors 44
72 CONCLUSIONS46 ATTACHMENT I ELECTRONIC FILES ON COMPACT DISCI-1
4
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
FIGURES
Page
Figure 1 Geometry and Tally Scheme for the TAD Transportation Cask 23
5
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
TABLES
Page
Table 1 Geometry and Materials of Conceptual TAD Transportation Cask A 15 Table 2 Geometry and Materials of Conceptual TAD Transportation Cask B 16 Table 3 Dimensions of TAD Canister 24 Table 4 BampW 15x15 Mark B Fuel Assembly Description 26 Table 5 PWR Fuel Assembly Regions 27 Table 6 Chemical Compositions of Materials 28 Table 7 Isotopic Compositions of Homogenized PWR Assembly Regions 29 Table 8 Gamma and Neutron Sources for the Maximum PWR SNF Assembly 31 Table 9 Gamma and Neutron Sources for the Design Basis PWR SNF Assembly 32 Table 10 Gamma and Neutron Sources for the Average PWR SNF Assembly 33 Table 11 Gamma and Neutron Axial Source Profiles for a PWR Assembly 34 Table 12 Gamma and Neutron Flux to Dose Conversion Factors 36 Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources 39 Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources 39 Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources 39 Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources 40 Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources 40 Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources 40 Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources 42 Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources 42 Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources 42 Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources 43 Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources 43 Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources 43 Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources 44 Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources 45 Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources 45 Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources 45 Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources 45 Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial
Sources 46 Table 31 Recommended Average Radial Dose-Rate Reduction Factors 46 Table 32 Recommended Average Top Dose-Rate Reduction Factors 46 Table 33 Recommended Average Bottom Dose-Rate Reduction Factors 46 Table I-1 Listing of Electronic Files on Compact DiscI-1
6
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ACRONYMS AND ABBREVIATIONS
ACRONYMS
ANS American Nuclear Society
ANSI American National Standards Institute
ASTM American Society for Testing and Materials
BSC Bechtel SAIC Company LLC
BWR Boiling Water Reactor
CD Compact disc
CSNF Commercial Spent Nuclear Fuel
DB Design Basis
DOE U S Department of Energy
DPC Dual Purpose Canister
NRC U S Nuclear Regulatory Commission
PCSA Preclosure Safety Analysis
PWR Pressurized Water Reactor
RPM Repository Project Management
SNF Spent Nuclear Fuel
SS 316 Stainless Steel 316
TAD Transportation Aging and Disposal
WP Waste Package
YMP Yucca Mountain Project
ABBREVIATIONS and UNITS
b barn
cm centimeter
7
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
g gram
GWd gigawatt-day
hr hour
in inch
kg kilogram
m meter
mrem millirem
MeV million electron volt
MTU metric ton uranium
s second
8
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
1 PURPOSE
The purpose of this calculation is to calcu late th e dose ra tes of two conceptua l tr ansportation casks each carrying a Transportation Aging and Disposal (TAD) canister separately loaded with the average design basis (DB) and m aximum comm ercial spent nuc lear fuel (CSNF) assemblies Then the dose-ra te reduction f actors between the m aximum and the design basis fuels the d esign bas is and the average fuels and the m aximum and the averag e fuels are computed
The results of this calculation may be used to substantiate the dose-rate reduction factors such as those in the engineering study Repository ALARA Goal Compliance (Reference 227) which is cited as a reference in a Preclosure Safety Analyses (PCSA) calculation that supports the License Application
The calculations contained in this docum ent are developed by Nuclear and Radiological Engineering of the Repository Project Mana gement (RPM) organization Yucca Mountain Project (YMP) personnel from Nuclear and Radiological Engineering should be consulted before use of the calculations for purposes other than those stated herein or use by individuals other than personnel in Nuclear and Radiological Engineering
9
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
2 REFERENCES
21 PROJECT PROCEDURESDIRECTIVES
211 IT-PRO-0011 Rev 0010 Software Management Las Vegas Nevada Bechtel SAIC Company
212 EG-PRO-3DP-G04B-00037 Rev 14 Calculations and Analyses Las Vegas Nevada Bechtel SAIC Company
213 IT-PRO-0012 Rev 007 Qualification of Software Las Vegas Nevada Bechtel SAIC Company
22 DESIGN INPUTS
221 ANSIANS-611-1977 Neutron and Gamma-Ray Flux-to-Dose-Rate Factors La Grange Park Illinois American Nuclear Society TIC 239401
222 ASME (American Society of Mechanical Engineers) 2004 2004 ASME Boiler and Pressure Vessel Code 2004 Edition New York New York American Society of Mechanical Engineers TIC 256479 ISBN 0-7918-2899-9
223 ASM International 1990 Properties and Selection Nonferrous Alloys and Special-Purpose Materials Specific Metals and Alloys Volume 2 of Metals Handbook 10th Edition Page 666 [Materials Park Ohio] American Society for Metals TIC 239807
224 ASTM (American Society for Testing and Materials) B 811-90 1991 Standard Specification for Wrought Zirconium Alloy Seamless Tubes for Nuclear Reactor Fuel Cladding Philadelphia Pennsylvania American Society for Testing and Materials TIC 239780
225 ASTM G 1-90 (Reapproved 1999) 1999 Standard Practice for Preparing Cleaning and Evaluating Corrosion Test Specimens West Conshohocken Pennsylvania American Society for Testing and Materials TIC 238771
226 Bowman SM Hermann OW and Brady MC 1995 Sequoyah Unit 2 Cycle 3 Volume 2 of Scale-4 Analysis of Pressurized Water Reactor Critical Configurations ORNLTM-12294V2 Oak Ridge Tennessee Oak Ridge National Laboratory TIC 244397 [DIRS 123796]
227 BSC (Bechtel SAIC Company LLC) 2008 Repository ALARA Goal Compliance 000-30R-MGR0-04000-000 REV 000 Las Vegas Nevada Bechtel SAIC Company ACC ENG200802050014 [DIRS 184957]
228 BSC 2002 Subsurface Shielding Source Term Specification Calculation 000-00C-WER0-00100-000-00A Las Vegas Nevada Bechtel SAIC Company ACC MOL200212160076 ENG200508150022
10
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
229 BSC 2004 PWR Source Term Generation and Evaluation 000-00C-MGR0-00100-000-00B Las Vegas Nevada Bechtel SAIC Company ACC ENG200405240007
2210 BSC 2008 Basis of Design for the TAD Canister-Based Repository Design Concept 000-3DR-MGR0-00300-000-003 Las Vegas Nevada Bechtel SAIC Company ACC ENG200810060001
2211 BSC 2007 Project Design Criteria Document 000-3DR-MGR0-00100-000-007 Las Vegas Nevada Bechtel SAIC Company ACC ENG200710160005 ENG200711080001 ENG200712200003 ENG200801070001 ENG200801070002 ENG200801070016 ENG200801070017 ENG200801310006 ENG200803050002 ENG200803050011 ENG200803050012 ENG200803060009 ENG200803130004 ENG200807100001 ENG200811120006 ENG200811140004
2212 BSC 2004 PWR and BWR Source Term Sensitivity Study 000-00C-MGR0-00300-000-00A Las Vegas Nevada Bechtel SAIC Company ACC ENG200401140003 ENG200508150023
2213 BSC 2007 Dose Rate Calculation for Exhaust Main Drifts 800-00C-SS00-00700-000-00B Las Vegas Nevada Bechtel SAIC Company ACC ENG200711050017 ENG200803060001
2214 BSC 2006 Dual Purpose Canister Opening Study 050-30R-WHS0-00600-000-000 Las Vegas Nevada Bechtel SAIC Company ACC ENG200612200023
2215 BSC 2007 GROA Shielding Requirements Calculation 000-00C-MGR0-03300-000-00B Las Vegas Nevada Bechtel SAIC Company ACC ENG200705290037
2216 BSC 2002 Concrete Shielding Calculation for Dry Facility 1 110-00C-CS10-00100-000-00A Las Vegas Nevada Bechtel SAIC Company ACC MOL200301140075
2217 BSC 2003 Shielding Design Calculations for Dry Facility 1 110-00C-CS10-00200-000-00A Las Vegas Nevada Bechtel SAIC Company ACC ENG200306020003
2218 CRWMS MampO 1998 Calculation of the Effect of Source Geometry on the 21-PWR WP Dose Rates BBAC00000-01717-0210-00004 REV 00 Las Vegas Nevada CRWMS MampO ACC MOL199902220059 [DIRS 102134]
2219 CRWMS MampO 2000 Users Manual for SCALE-44A 10129-UM-44A-00 Las Vegas Nevada CRWMS MampO ACC MOL200011300136 MOL200108220084 MOL200108220085 MOL200108220086 MOL200108220087 [DIRS 153872]
2220 DOE (US Department of Energy) 1987 Appendix 2A Physical Descriptions of LWR Fuel Assemblies Volume 3 of Characteristics of Spent Fuel High-Level Waste and Other Radioactive Wastes Which May Require Long-Term Isolation DOERW-0184 Washington DC US Department of Energy Office of Civilian Radioactive Waste Management ACC HQX198804050024 [DIRS 132333]
11
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
2221 DOE 2007 Software Validation Report for MCNP5 v140 Document ID 11199-SVR-140-00-WINXP Las Vegas Nevada US Department of Energy Office of Repository Development ACC MOL200702280252 [DIRS 180516]
2222 DOE 2008 Transportation Aging and Disposal Canister System Performance Specification WMO-TADCS-000001 Rev 1 ICN 1 Washington DC US Department of Energy Office of Civilian Radioactive Waste Management ACC DOC200803310001 [DIRS 185304]
2223 Harmon CD II Busch RD Briesmeister JF and Forster RA 1994 Criticality Calculations with MCNPtrade A Primer LA-12827-M Los Alamos New Mexico Los Alamos National Laboratory TIC 234014 [DIRS 154532]
2224 LANL (Los Alamos National Laboratory) 2004 MCNP mdash A General Monte Carlo N-Particle Transport Code Version 5 (Appendix H is not included) LA-UR-03-1987 Volume I Los Alamos [New Mexico] Los Alamos National Laboratory ACC MOL200510240126 [DIRS 176521]
2225 MCNP5 V 140 2007 Windows XP STN 11199-140-00 [DIRS 180515]
2226 Parrington JR Knox HD Breneman SL Baum EM and Feiner F 1996 Nuclides and Isotopes Chart of the Nuclides 15th Edition San Jose California General Electric Company and KAPL Inc TIC 233705 LC Call Number QC7935 N8622 1996
2227 Punatar MK 2001 Summary Report of Commercial Reactor Criticality Data for Crystal River Unit 3 TDR-UDC-NU-000001 REV 02 Las Vegas Nevada Bechtel SAIC Company ACC MOL200107020087 [DIRS 155635]
2228 Sisley SE 2002 Transportation License Application for the FuelSolutionstrade System (TAC No L23311) Submittal of the FuelSolutiontrade Transportation SARs Revision 3 Letter from SE Sisley (BNFL) to the NRC April 11 2002 BFSNRC 02-011 with enclosures TIC 255245 [DIRS 171545]
NOTE Reference 2220 is a direct input but is not QA QA It is justified as acceptable for the intended use as it is directly from the DOE and is considered the best available data on the subject The referenced values cited in Tables 3 and 4 are valid for use since they are reliable and reasonable based on engineering judgment
23 DESIGN CONSTRAINTS
231 10 CFR 71 2008 Energy Packaging and Transportation of Radioactive Material Internet Accessible [DIRS 185678]
12
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
24 DESIGN OUTPUTS
The resu lts of this calculation will be us ed to substan tiate th e dose reduc tion f actor in the Repository ALARA Goal Compliance (Reference 227) which is cited as a reference in a PCSA calculation that supports the License Application
13
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
3 ASSUMPTIONS
31 ASSUMPTIONS REQUIRING VERIFICATION
None
32 ASSUMPTIONS NOT REQUIRING VERIFICATION
Assumptions 321 322 and 323 are m odeling assum ptions and do not require further verification The m aterials and dim ensions for the TAD canister and for the conceptu al transportation casks are only selected to charac terize two tr ansportation casks th at m eet 10 CFR7147 (Reference 231) dose rates when lo aded with the ldquom aximumrdquo and ldquoaveragerdquo pressurized water re actor (PW R) assem blies re spectively There is n o need to v erify those dimensions or m aterials at a later date The ca lculated results in Sect ion 711 verify that the conceptual casks would meet 10 CFR 7147 (Reference 231) dose rates
321 Material and Wall Thickness of TAD Canister
Assumption It is assumed that the TAD canister is made of stainless steel 316 (SS 316) and has a wall thickness of 025 in for the radial and bottom shells
Rationale Currently the design of the TAD canis ter d oes not ex ist Based on a survey of existing m ultipurpose a nd dual purpose caniste rs (DPC) (Ref erence 2214 p 56) a 025 in thickness is below the wall thick ness of any existing c anisters For the purp ose of this calculation this assumption leads to higher and conservative external dose rates Since SS 316 is the sam e material used for the waste pack age inner shell it is a l ogical cho ice f or the TAD canister
Although Reference 2214 is an engineering study with a QA N A status it is used here as an indirect input to support the assumption which is conservative for dose rate calculations
Usage This assumption is used in Sections 621 and 625
322 Material and Thickness of TAD Shield Plug
Assumption It is assu med that the TAD shield plug is made of SS 316 and has a thickness of 11 in
Rationale Currently the design of the TAD canister doe s not exist A thick shield plug of 11 in (Reference 2215 Table 12) is needed to keep the m aximum contact dose rate of the top surface below 1000 mrem hr (Reference 2222 Section 314) Since SS 316 is the sam e material used for the waste package inner shell it is a logical choice for the TAD shield plug
Usage This assumption is used in Section 621
14
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
323 Geometry and Materials of Conceptual TAD Transportation Casks
Assumption Two conceptual TAD transpo rtation casks designated as Cask A and Cask B are assumed to have a cylindrical geom etry and m aterials specified in Tab les 1 and 2 respectively The casks are basically construc ted of an inner layer of SS 316 for ga mma shielding a m iddle layer of 5-borated polyethylen e for neutron shielding and a th in outer layer of SS 316 whic h serves a structural function as well as shielding secondary gamma rays
Both Cask A and Cask B have a cavity height of 53785 cm (21175 in) and a cavity diameter of 16891 cm (6650 in) However Cask A has a total height of 610845 cm (24049 in) and an outside diameter of 26797 cm (10550 in) while the total height and outside diameter of Cask B are 58885 cm (23183 in) and 24765 cm (9750) respectively
Cask A will provide shielding to m eet the exterior radiat ion standards of 10 C FR 7147(b) (Reference 231) when loaded w ith a TAD canister carrying th e maximum PWR spent nuclear fuel (SNF) Cask B will satisf y the same radiation standards when loade d with a TAD caniste r carrying the average PWR SNF
Table 1 Geometry and Materials of Conceptual TAD Transportation Cask A
Component Dimension
Material (cm) (in)
Total Height 61085 2404 9 NA
Outside Diameter 26797 1055 0 NA
Cask Cavity Height 53785 2117 5 NA
Cask Cavity Diameter (Radius) 16891 (8446) 6650 (3325) NA
Radial Gamma Shield Thickness (Radius)a 3302 (11748)a 1300 (4625)a SS 316
Radial Neutron Shield Thickness (Radius)b 1524 (13272)b 600 (5225)b 5-borated polyethylene
Radial Outer Shell Thickness (Radius)c 127 (13399)c 050 (5275)c SS 316
Top Gamma Shield Thickness (Axial Position)d 600 (54385)d 236 (21411)d SS 316
Top Neutron Shield Thickness (Axial Position)d 1000 (55385)d 394 (21805)d 5-borated polyethylene
Top Outer Shell Thickness (Axial Position)d 200 (55585)d 079 (21884)d SS 316
Bottom Gamma Shield Thickness (Axial Position)d 35365 (-360)d 1392 (-1417)d SS 316
Bottom Neutron Shield Thickness (Axial Position)d 15 (-510)d 591 (-2008)d 5-borated polyethylene
Bottom Outer Shell Thickness (Axial Position)d 4 (-550)d 157 (-2165)d SS 316 a11748 = 3302 + 8446 and 4625 = 1300 + 3325 b13272 = 1524 + 11748 and 5225 = 600 + 4625 c13399 = 127 + 13272 and 5275 = 050 + 5225 dCoordinate relative to the bottom of the fuel assembly as modeled in MCNP5
15
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 2 Geometry and Materials of Conceptual TAD Transportation Cask B
Component Dimension
Material (cm) (in)
Total Height 58885 2318 3 NA
Outside Diameter 24765 9750 NA
Cask Cavity Height 53785 2117 5 NA
Cask Cavity Diameter (Radius) 16891 (8446) 6650 (3325) NA
Radial Gamma Shield Thickness (Radius)a 254 (10986)a 1000 (4325)a SS 316
Radial Neutron Shield Thickness (Radius)b 127 (12256)b 500 (4825)b 5-borated polyethylene
Radial Outer Shell Thickness (Radius)c 127 (12383)c 050 (4875)c SS 316
Top Gamma Shield Thickness (Axial Position)d 8 (54585)d 315 (21490)d SS 316
Top Neutron Shield Thickness (Axial Position)d None Non e NA
Top Outer Shell Thickness (Axial Position)d None Non e NA
Bottom Gamma Shield Thickness (Axial Position)d 3837 (-390)d 1510 (-1535)d SS 316
Bottom Neutron Shield Thickness (Axial Position)d 300 (-420)d 118 (-1654)d 5-borated polyethylene
Bottom Outer Shell Thickness (Axial Position)d 100 (-430)d 039 (-1693)d SS 316 a10986 = 254 + 8446 and 4325 = 1000 + 3325 b12256= 127 + 10986 and 4825 = 500+ 4325 c12383 = 127 + 12256 and 4875 = 050 + 4825 dCoordinate relative to the bottom of the fuel assembly as modeled in MCNP5
Rationale Currently a design for the TAD transporta tion cask does not exist The casks assumed for this calculation are so lely for estim ation of the dose reduction due to different source terms This is a conceptual repres entation only used in this calculation to estim ate the parameters of interest
Usage This assumption is used in Sections 61 and 622
324 Usage of Unirradiated Fuel for Commercial SNF
Assumption It is assumed that the active fuel region of the commercial SNF assembly contains the same isotopic concentrations as the fresh uni rradiated fuel and that the concentrations of fresh fuel with 5 initial enrichm ent corresp onding to m aximum SNF are used for all other SNFs
Rationale This assumption is a standard practice for shielding calculations throughout the industry accepted by the U S Nucle ar Regulatory Commission (NRC) (Reference 2228 Table 53-5) It sh ould be noted that this assumption applies to material composition only it does no t apply to source terms which are based on the characteristics of spent fuel
Usage This assumption is used in Sections 624 and 626
325 Homogenization of Radiation Source Regions
Assumption It is assu med that a commercial SNF assembly consis ts of four distinct reg ions (active fuel bottom end-fitting plenum and top end-fitting) The materials and radiation sources
16
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
of each assembly region are homogenized inside a volume defined by the TAD cavity radius and region height
Rationale The assembly representation is consistent with the industry practice for shielding calculations accepted by NRC (Reference 2228 Figure 53-6) The effec t of source homogenization is twofold (1) it d ecreases th e m ass de nsity of the source region and (2) it places source points slightly closer to detector locations thus reducing radiation attenuation The resu lts of Calculation of the Effect of Source Geometry on the 21-PWR WP Dose Rates (Reference 2218 pp 22-26) indicate that th e effect of assem bly homogenization gives nearly the same or conservative dose rates as the explicit fuel assembly model
Usage This assumption is used in Section 624
326 Ignoring Internal Fuel Basket Materials
Assumption It is assumed that the internal fuel basket materials are ignored
Rationale Inclusion of fuel basket m aterials in the smeared m aterial com position would increase the overall density and consequently increase the attenuati on of the radiation Therefore this assumption is conservative
Usage This assumption is used in Sections 621 624 and 626
17
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
4 METHODOLOGY
41 QUALITY ASSURANCE
This calculation was prepared in accordance with EG-PRO-3DP-G04B-00037 Calculations and Analyses (Reference 212) The results of th is calculation provides worker dose assessm ent adjustments and this will id entify radio logical hazards f or f acilities im portant to saf ety Therefore the approved version is designated as QA QA
42 USE OF COMPUTER SOFTWARE
421 Baseline Software
The Monte Carlo N-Particle com puter pr ogram (MCNP5) version 140 (Reference 2225) is used to calculate the dose rates (neutron pr imary gamm a and secondary gamm a) at various locations around a transportation cask and an aging overpack
The software specifications are as follows
bull Program Name MCNP5 bull VersionRevision Number Version 140 bull Operating Systems Windows XP bull Software Tracking Number 11199-140-00 bull Computer Type Dell OPTIPLEX GX620
MCNP5 which is Level 1 software is (a) appropriate for three-dim ensional neutron gamma and coupled neutrongamma shielding calculations (b) used within th e range of validation as documented in Software Validation Report for MCNP5 v140 (Reference 2221) and (c) obtained from Software C onfiguration Managem ent and qualified in accordance with procedure IT-PRO-0012 Qualification of Software (Reference 213) Therefore MCNP5 code is suitable for use in this design calculation All MCNP5 input and output files docum ented in this calculation are provided on a compact disc (CD) as Attachment II
All MCNP cases are executed on one of the following Q com puters QNW -004184 QNW -004187 QNW-004194 and QNW-004196 as shown in the output files
422 Commercial off the Shelf Software
The Excel sof tware is used to c alculate var ious inpu t values (i e atom densities weight percentages geometrical dimensions normalized source spectra and probabilities etc) Standard functions of Excel are also used in this desi gn calculation to display results (ie gamma and neutron dose rates) in tabular and graphic forms and to perform relative error calculations
The software specifications are as follows
bull Program Name Excel bull VersionRevision Number Microsoftreg Excel 2003
18
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
bull This software is installed on a persona l com puter running Microsoft W indows XP (central processing unit number 151834)
The user defined for mulas inputs results and gr aphical representations have been verified by hand calculations or visual inspection and are documented in sufficient detail to allow an independent repetition of the com putations Calculations were verifi ed by hand and graphical representations were found accurate by visual inspection
Per Software Management Microsoftreg Excel is not requir ed to be qualif ied due to its commercial availability status (Reference 211 Attachment 4 p 55 bullet 2)
43 CALCULATION APPROACH
This calculation em ploys the qualified so ftware MCNP5 version 140 (Reference 2225) a three-dimensional Monte Carlo code for pe rforming neutron and coupled neutron-gamm a calculations to estim ate dose rates at sele cted locations on and surrounding a conceptual transportation cask containing a loaded TAD canister
431 MCNP5 Program
MCNP5 a general Monte Carlo part icle transport code sim ulates particle transport through a three-dimensional representation of the nuclear system being analyzed During the random walk of particles through the system described by the geom etry the c ode collects inform ation about various events (su rface cross ing collis ions trac k leng th etc) and es timates fluxes in various geometric configurations specified as tallies by the user It also estimates the statistical precision of the results in the form of relative errors (Reference 2224 pp 1-2 to 1-8)
Per Project Design Criteria Document (Reference 2211 Section 41015) the flux estim ates are converted to dose rates using the Am erican Nuclear Society (ANS) flux-to-dose rate conversion factors for gammas and neutrons (R eference 221) The simple variance reduction techniques of Geometry SplittingRussian Roulette and source probability biasing (Sections 631 and 633) are used to enhance computational efficiency
19
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
5 LIST OF ATTACHMENTS
Number of Pages Attachment I List of Electronic Files on the CD 3 Attachment II Compact Disc NA
20
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
6 CALCULATIONS
This sectio n provides inform ation necess ary to perform the calcu lations in this docum ent Section 61 describes the configurations the type of CSNF to be analyzed the number of MCNP runs and the locations where dose rates are ca lculated Section 62 provides the calculation input that includes the details of the geom etry m odel radiation source term s and m aterial compositions Input specific to MCNP dose -rate conversion factors and relative error calculation are described in the later sections
61 DESCRIPTION OF CALCULATIONS
Dose rate calculations are perform ed with the MCNP5 version 140 com puter code (Reference 2225) Two conceptual transportation casks Cask A and Cask B (Assum ption 323) are employed Each cask contains a TAD canister that is loaded with 21 ident ical PW R SN F assemblies Three PWR source term s are analy zed they are the source term s corresponding to the maximum design basis and average PW R SN Fs The characteris tics of the P WR source terms are presented in S ection 627 Each PWR source term has neutron and ga mma radiation sources that require separate MCNP5 runs For each radiation source an axial profile source and a uniform source for the active fuel region are considered The uniform source for the active fuel region is included in this calculation because this approach was used in combination with source peaking factors in certain calculations (Reference 2216 Sections 37 and 39 and Reference 2217 Section 5242)
The total number of MCNP5 runs is 24 which re sults from a com bination of two conceptual casks three PWR source terms two radiation sources and two axia l source distributions for the active fuel region These 24 runs are categorized into four calcula tion sets Each calculation set consists of six runs that is a combination of three PWR source te rms and two radiation sources The characteristics of each calculation set are as follows
1 Cask A with axial profile sources in the active fuel region
2 Cask A with uniform axial sources in the active fuel region
3 Cask B with axial profile sources in the active fuel region
4 Cask B with uniform axial sources in the active fuel region
For each MCNP5 run dose rates are calculated at the exte rior surfaces and at distances 1 and 2 meters from the exterior surfaces Surface tallies and detector tallies (ring and point detectors) as indicated in Figure 1 are e mployed in all runs Figure 1 is used to illustrate the dep loyment of the surface and detector tallies re lative to the so urce regions and it should not be interpreted as an exact geometry of any particular run Surface tallies are deployed at all three distances while ring and point detectors are used only at 1 m and 2 m and not at the cask surfaces Using point detectors near a surface or in any scattering media is not recommended because very large scores can occur f rom collisions close ( less than a f ew centimeters) to the point detecto rs that can lead to resu lts with high r elative e rrors thus m aking the ca lculation d ifficult to o btain r eliable answers
21
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
For the radial direction surface tallies at the three distances (contact 1 m and 2 m) are computed for three su rface segments (cylindrical rings) between the planes at Z = 145 175 2 05 and 235 cm The geometric locations of the segments are shown in Figure 1 The axial locations of these segments correspond to the m iddle of the active fuel region of the PWR SNF assemblies The average dose rates for each of the segm ents are calculated for the outside surface and surfaces at 1 m and 2 m from the cask surface Two ring detectors (instead of point detectors) are deployed at 1 m and 2 m for the radial dire ction Ring detectors instead of point detectors are used in order to capitalize on the symm etry around the cask axis thus im proving the efficiency of the calculations
In the axial direction the average d ose rates within three concentric radial surfaces defined by radii of 40 80 and 120 cm (shown in Figure 1) are calculated for the top and bottom surfaces and at distances 1 m and 2 m from these surfaces Finally point detectors at 1 m and 2 m from the top and bottom axial surfaces are employed
22
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Point Detector at 2 m x
Ring Ring Detector Detector at 2 m at 1 m
x x
Z = 00 cm
Z = 145 cm
Z = 175 cm
Z = 205 cm
Z = 235 cm
R = 80 cm
R = 120 cm
R = 40 cm
Active Fuel
Shield Plug
Top End-Fitting Plenum
Bottom End-Fitting
Ring Detector at 1 m
x
Point Detector at 1 m x
Ring Detector
at 2 m x
D = 26797 cm
H =
610
845
cm
Point Detector at 1 m x
Point Detector at 2 m x
Figure 1 Geometry and Tally Scheme for the TAD Transportation Cask
23
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
62 CALCULATION INPUT
Technical product input and sources of the input used in the deve lopment of this calculation are documented in this section Tables in this docum ent and in th e associated Microsoftreg Excel spreadsheets referenced m ay present num erical values with m any significant figures these values are not to be considered as high precision values since the significant figures are results of calculated values andor unit conversions
621 TAD Canister
The TAD canis ter will contain either 21 P WR or 44 BW R (boiling water reactor) SNF assemblies (Reference 2222 Section 321) While the canister design is iden tical for both PWR and BWR SNF assemblies the internal basket structure is different depending on the SNF assemblies However the internal basket stru cture m aterial is no t in cluded in the calcu lation model (Assumption 326)
The TAD canister is a right-circu lar cylinder with a diam eter of 665 in and a height between 186 and 212 in (Reference 2222 Section 321) The average and maximum total dose rates on the top surf ace of a loaded TAD ca nister must not exceed 800 and 1000 m remhr respectively (Reference 2222 Section 314) The TAD canister used in this calculation is m ade of SS 316 with a radial wall and bottom thickness of 025 in (Assumption 321) The top of the canister has a shield plug that is 11 in thick SS 316 (Ass umption 322) A thick shield plug is needed to keep the maxim um contact dose rate of th e top surface below 1000 m remhr The overall dimensions of the TAD canister are provided in Table 3
Table 3 Dimensions of TAD Canister
Component Dimension
(in) (cm)
Maximum heighta 212 53848
Outer diametera 665 16891
Thickness of bottom lidb 025 0635
Shell thicknessb 025 0635
Lifting Featurec 6 1524
Height without Lifting Feature 206 52324
Thickness of shield plugd 110 2794
aReference 2222 Section 311 bAssumption 321 cReference 2222 p Attachment C-1 dAssumption 322
622 Conceptual TAD Transportation Casks
Two conceptual TAD transportation casks designa ted as Cask A and Cask B are em ployed in this calculation (Assumption 323) They both have a cylindrical geometry with dimensions and materials specified in Tables 1 and 2 of Section 323 Cask A will provide shielding to meet the exterior radiation standards of 10 CFR 7147(b) (Reference 231) when loaded with a TAD
24
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
canister car rying the m aximum PWR SNF Cask B will s atisfy th e sa me radiatio n standa rds when loaded with a TAD canister c arrying the average PWR SNF The reason to analyze both Casks A and B is to cover a broad range of characteristics of the CSNF
The cavity dimensions of the conceptual cask s are 53785 cm (21175 in) in height and 16891 cm (665 in) in diam eter (Tab les 1 and 2) This cav ity will accommoda te the TAD canister described in Table 3 without the lifting feature This is the geometry model used in the MCNP5 calculations
623 Fuel Assembly Selection
PWR and BWR Source Term Sensitivity Study (Reference 2211 Tables 71 through 84) shows that the source terms generated for the Bamp W 15x15 Mark B fuel assembly with 475 kg uranium loading bound the source terms of other PWR assembly types ther efore this assembly type is selected as the representative PWR fuel assembly The gamma and neutron source terms for the BampW 15x15 Mark B assembly are generated in PWR Source Term Generation and Evaluation (Reference 229) and are used in this calculation
624 BampW 15x15 Mark B PWR Fuel Assembly
BampW 15x15 Mark B fuel assembly consists of four regions top end-fitting plenum active fuel and bottom end-fitting The m aterials and ra diation sources of each assem bly region are homogenized inside a volume defined by the region height and the interior diam eter of the TAD canister (Assumption 325) The active fuel region is homogenized with fresh unirradiated fuel (Assumption 324) Since the internal structure (i e basket) design of t he TAD is currently not finalized the com position of the hom ogenized fuel does not include the basket m aterials (Assumption 326) and therefore does not take cred it for any shielding that these m aterials may provide
Table 4 provides the design param eters for the BampW 15x15 Mark B fuel assembly Data provided here are used in Attachment II PWR_fuel compxls worksheet BampWassy
25
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 4 BampW 15x15 Mark B Fuel Assembly Description
Component Material Characteristic Value Specific Reference Array Size 15 x 15
Reference 2227 Table 2-2 Fuel Pins Assembly 208 Guide Tubes Assembly 16 Instrument Tubes Assembly 1
Assembly NA Pin Pellet Diameter 0936244 cm (03686 in) Reference 2220 p 2A-34 Pin Pitch 144272 cm (0568 in)
Reference 2227 Table 2-2 Active Fuel Height 360172 cm (1418 in) Assembly Width 2168144 cm (8536 in)
Reference 2220 p 2A-31 Assembly Height 4206875 cm (165625 in) Mass U assembly 46363 kg
Guide tube Zircaloy-4 Outer Diameter 13462 cm (053 in)
Reference 2227 Table 2-2
Inner Diameter 126492 cm (0498 in)
Instrument tube Zircaloy-4 Outer Diameter 138193 cm (05441 in) Inner Diameter 112014 cm (0441 in)
Cladding` Zircaloy-4 Inner Diameter 095758 cm (0377 in) Outer Diameter 10922 cm (043 in)
Plenum region NA Length 297688 cm (11720 in) Reference 2220 p 2A-34 Top nozzle SS CF3M MassAssembly (Top) 748 kg
Reference 2220 p 2A-32
Bottom nozzle SS CF3M MassAssembly (Bottom) 816 kg Guide tubes Zircaloy-4 MassAssembly (in Core) 80 kg Instrument tube Zircaloy-4 MassAssembly (in Core) 064 kg Spacer-plenum Inconel-718 MassAssembly (Plenum) 104 kg Spacer-bottom Inconel-718 MassAssembly (Bottom) 13 kg Spacer-in core Inconel-718 MassAssembly (in Core) 49 kg Spring retainer SS CF3M MassAssembly (Top) 091 kg Holddown spring Inconel-718 MassAssembly (Top) 18 kg Upper end plug SS 304 MassAssembly (Top) 006 kg Upper nut SS 304L MassAssembly (Top) 051 kg Lower nut SS 304 MassAssembly (Bottom) 015 kg Grid supports Zircaloy-4 MassAssembly (in Core) 064 kg Plenum spring SS 302 MassAssembly (Plenum) 0042 lb (001905 kg) Reference 2220 p 2A-34
Note Som e d ata i n this tab le ar e given i n British u nits in th e r eferences thes e d ata ar e converted into metric units as the inputs to MCNP5 are in metric units
The assem bly region heights as m odeled in MC NP are presented in Table 5 utilizing values from Table 4 Table 5 is taken from Dose Rate Calculation for Exhaust Main Drifts (Reference 2213 Table 3)
26
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 5 PWR Fuel Assembly Regions
Component Height Reference
Plenum 297688 cm (11720 in) Reference 2220 p 2A-34
Active Fuel 360172 cm (1418 in) Table 3
Bottom End-Fitting 1077 cm (424 in) Calculateda
Top End-Fitting 1998 cm (787 in) Calculatedb
Source Reference 2213 Table 3 aCalculated b ased on data Reference 2227 F igures 2-3 an d 2-7
(Region 9 Height [16723 cm] + Region 10 Height [508 cm] ndash Lo wer Fuel Plenum and End Cap [11033 cm])
bCalculated (Assembly Length ndash Active Fuel Length ndash P lenum Length ndash Bottom End-fitting Length)
625 Material Compositions
The TAD transportation cask com ponent m aterial specifications are defined in Table 1 The TAD canister is constructed of SS 316 (Assumpti on 321) The PWR fuel assembly materials used to homogenize the fuel regions are defined in Table 4 Table 6 c ontains the m aterial compositions defining the TAD canister WP and fuel assemblies
27
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 6 Chemical Compositions of Materials
Material Density (gcc)
Isotopic Weight Percent Reference
SS 302 NA
C 0150 Mn 2000 P 0045 S 0030 Si 0750 Cr 18000 Ni 9000 N 0100 Fe 69925
Attachment II PWR_fuel compxls worksheet ferrous Reference 222 SEC II A SA-240 Table 1 for SS 302 SS 304 and SS 304L Reference 222 SEC II A SA-351SA -351M Table 2 for SS CF3M
SS 304 NA
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 9250 N 0100 Fe 68745
SS 304L NA
C 003 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 10000 N 0100 Fe 6804 5
SS CF3M NA
C 0030 Mn 1500 P 0040 S 0040 Si 1500 Cr 19000 Ni 11000 Mo 2500 Fe 64390
Inconel 718 NA
C 0080 Mn 0350 Si 0350 Cr 19000 Ni 52500 Co 1000 Mo 3050 Fe 16809 Nb 5125 Ti 0900 Al 0500 Cu 0300 S 0015 P 0015 B 0006
Attachment II PWR_fuel compxls worksheet alloys aReference 223 p 666 Table 6 Reference 222 SEC II B SB-637 Table 1 for Inconel 718 Reference 224 Table 2 for Zircaloy 4
Zircaloy 4 656a Cr 0100 Fe 0210 O 0125 Sn 1450 Zr 98115
SS 316 798b
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 17000 Ni 12000 Mo 2500 N 0100 Fe 65495
Attachment II PWR_fuel compxls worksheet others Reference 222 SEC II A SA-240 Table 1 for SS 316 bReference 225 Table X1
626 Homogenization Assembly Materials
The atom density of an element or isotope in atomsbmiddotcm in a homogenized region is calculated according to the following equation (Reference 2223 Appendix B)
M i times N AvogadroNi = Equation 1 Ai timesV times K
where Ni = Atom density of elementisotope i (atomsbmiddotcm) Mi = Mass of elementisotope i (g) NAvogadro = Avogadrorsquos constant 06022 x 1024 (atomsmole)
28
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Ai = Atomic weight of elementisotope i (gmole) V = Homogenization volume (cm3) K = Unit transformation constant = 1024 (bmiddotcmcm3)
Equation 1 is used in A ttachment II spreadsheet PWR_fuel compxls worksheet BampWassy to calculate th e atom dens ities for v arious elem ents and iso topes The m ass of elementsisotop es and Avogadrorsquos constant are provided in Reference 2226
Table 7 lists the com position of the hom ogenized assem bly regions (active fuel plenum top end-fitting and bottom end-fitting) for the PWR assembly The active fuel region contains fresh unirradiated fuel (Assumption 324) Since the internal structure (ie basket) design of the TAD is currently not finalized the composition of either homogenized fuel does not include the basket materials and therefore does not tak e credit for any shielding that thes e materials may provide (Assumption 326)
Table 7 Isotopic Compositions of Homogenized PWR Assembly Regions
Element Isotope
Atom Densities for Homogenized Regions (atomsbsdotcm)
Active Fuel Bottom End-Fitting Plenum Top End-Fitting
10B 861E-09 764E-08 221E-08 570E-08 11B 347E-08 307E-07 890E-08 230E-07 C 519E-07 160E-05 138E-06 993E-06 N -- 570E-07 262E-08 117E-06 O 621E-03 -- 142E-05 -- Al 144E-06 128E-05 371E-06 957E-06 Si 971E-07 243E-04 259E-06 139E-04 P 377E-08 606E-06 102E-07 360E-06 S 365E-08 581E-06 971E-08 340E-06 Ti 147E-06 130E-05 376E-06 971E-06 Cr 320E-05 187E-03 779E-05 113E-03 Mn 497E-07 126E-04 141E-06 749E-05 Fe 303E-05 531E-03 717E-05 313E-03 Co 132E-06 117E-05 340E-06 876E-06 Ni 697E-05 144E-03 180E-04 940E-04 Cu 368E-07 327E-06 945E-07 244E-06 Zr 196E-03 -- 195E-03 -- Nb 430E-06 382E-05 110E-05 285E-05 Mo 248E-06 135E-04 636E-06 791E-05 Sn 223E-05 -- 222E-05 -- 234U 139E-06 -- -- -- 235U 157E-04 -- -- -- 236U 719E-07 -- -- -- 238U 294E-03 -- -- -- Total 114E-02 924E-03 235E-03 557E-03
Source Attachment II spreadsheet PWR_fuel compxls worksheet BampWassy
29
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
The isotopic composition of commercially available 235U enriched uranium is determined by the given initial 235U enrichment using the following equations (Reference 226 p 20)
wt235U =235Uenrichment _ of _ the _ associated _ fuel _ batch Equation 2
wt234U = 0007731times (wt235U )10837 Equation 3
wt236U = 00046times (wt235U ) Equation 4
wt238U =100 minus (wt234U + wt235U + wt236U ) Equation 5
The weight percentages of uran ium isotopes for PWR fuel are ca lculated in Attachm ent II spreadsheet PWR_fuel compxls worksheet BampWassy using Equations 2 through 5
627 PWR Source Terms
This calculation uses the following three PWR source terms bull Maximum source (50 wt initial 235U enrichment 80 GWdMTU burnup and 5-year
decay time) (Reference 229 Section 55) Table 8 lists th e gamma source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Design Basis source (4 0 wt initial 235U enrichment 60 GW dMTU burnup and 10-year decay tim e) (Reference 228 Section 552) Table 9 lists the gamm a source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Average source ( 40 wt initial 235U enrichment 48 GWdMTU burnup and 25-year decay time) (Reference 229 Section 55) Table 10 lists the gamma source terms for the fuel and non-fuel regions and the neutron source term for the fuel region
These sources (ie maximum design basis and av erage) are described in this section For dose rate calculations all the fuel assemblies in a transportation cask are of the sam e characteristics Also gamma radiation source term s for the PWR assem bly are prov ided for the f our assembly regions while neutron source term is only present in the active fuel region Gamma radiation sources in the non-active fuel region are distri buted unif ormly within each source region Gamma and neutron sources in the active fuel re gion are modeled as uni form distributions or with axial source profiles
The PWR gamma and neutron axial source profiles for the active fuel region presented in Table 11 are applied to the active fuel region of all three source terms (ie maximum design basis and average) when appropriate
30
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 8 Gamma and Neutron Sources for the Maximum PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting
Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 594E+11 233E+15 528E+11 379E+11 100E-01 000E+00 100E-01 116E+11 644E+14 609E+10 743E+10 400E-01 805E+07 200E-01 283E+10 522E+14 352E+10 179E+10 900E-01 411E+08 300E-01 141E+09 148E+14 196E+09 891E+08 140E+00 376E+08 400E-01 190E+09 985E+13 586E+09 117E+09 185E+00 276E+08 600E-01 191E+09 153E+15 110E+11 741E+07 300E+00 485E+08 800E-01 435E+09 470E+15 595E+10 237E+09 643E+00 443E+08 100E+00 137E+11 708E+14 803E+09 766E+10 200E+01 393E+07 133E+00 338E+13 455E+14 174E+13 217E+13 Total 211E+09 166E+00 953E+12 130E+14 491E+12 612E+12
--
200E+00 187E+03 144E+12 919E+02 113E+03 250E+00 226E+08 249E+12 116E+08 145E+08 300E+00 351E+05 110E+11 181E+05 225E+05 400E+00 766E-08 139E+10 100E-08 416E-08 500E+00 000E+00 709E+07 000E+00 000E+00 650E+00 000E+00 286E+07 000E+00 000E+00 800E+00 000E+00 558E+06 000E+00 000E+00 100E+01 000E+00 119E+06 000E+00 000E+00
Total 442E+13 113E+16 231E+13 284E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE2R2B14cut bWasteStreamE2R1B14cut cWasteStreamE2R3B14cut dWasteStreamE2R4B14cut
31
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 9 Gamma and Neutron Sources for the Design Basis PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary
(MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 273E+11 121E+15 188E+11 175E+11 100E-01 000E+00 100E-01 528E+10 329E+14 277E+10 339E+10 400E-01 316E+07 200E-01 128E+10 245E+14 117E+10 819E+09 900E-01 161E+08 300E-01 639E+08 713E+13 633E+08 407E+08 140E+00 148E+08 400E-01 850E+08 455E+13 164E+09 533E+08 185E+00 109E+08 600E-01 492E+08 226E+14 269E+10 337E+07 300E+00 191E+08 800E-01 291E+09 237E+15 160E+10 186E+09 643E+00 174E+08 100E+00 540E+09 122E+14 248E+09 341E+09 200E+01 154E+07 133E+00 154E+13 195E+14 797E+12 990E+12 Total 830E+08 166E+00 435E+12 450E+13 225E+12 280E+12
--
200E+00 235E+00 152E+11 149E+02 215E-02 250E+00 103E+08 517E+10 534E+07 664E+07 300E+00 160E+05 379E+09 829E+04 103E+05 400E+00 943E-10 497E+08 155E-10 519E-10 500E+00 000E+00 282E+07 000E+00 000E+00 650E+00 000E+00 113E+07 000E+00 000E+00 800E+00 000E+00 222E+06 000E+00 000E+00 100E+01 000E+00 471E+05 000E+00 000E+00
Total 201E+13 486E+15 105E+13 129E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B11cut bWasteStreamE5R1B11cut cWasteStreamE5R3B11cut dWasteStreamE5R4B11cut
32
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 10 Gamma and Neutron Sources for the Average PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 336E+10 670E+14 186E+10 217E+10 100E-01 00000E+00 100E-01 602E+09 199E+14 314E+09 387E+09 400E-01 748E+06 200E-01 146E+09 126E+14 853E+08 936E+08 900E-01 382E+07 300E-01 730E+07 389E+13 439E+07 469E+07 140E+00 352E+07 400E-01 947E+07 263E+13 716E+07 607E+07 185E+00 261E+07 600E-01 141E+07 205E+13 504E+08 383E+06 300E+00 469E+07 800E-01 208E+09 124E+15 192E+09 144E+09 643E+00 418E+07 100E+00 208E+09 110E+13 164E+09 144E+09 200E+01 365E+06 133E+00 175E+12 295E+13 909E+11 112E+12 Total 199E+08 166E+00 494E+11 513E+12 257E+11 318E+11
--
200E+00 973E-01 675E+10 614E+01 872E-03 250E+00 117E+07 353E+09 609E+06 754E+06 300E+00 182E+04 288E+08 944E+03 117E+04 400E+00 186E-11 198E+07 149E-11 127E-11 500E+00 000E+00 669E+06 000E+00 000E+00 650E+00 000E+00 269E+06 000E+00 000E+00 800E+00 000E+00 527E+05 000E+00 000E+00 100E+01 000E+00 112E+05 000E+00 000E+00
Total 229E+12 237E+15 119E+12 147E+12
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B9cut bWasteStreamE5R1B9cut cWasteStreamE5R3B9cut dWasteStreamE5R4B9cut
33
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 11 Gamma and Neutron Axial Source Profiles for a PWR Assembly
Axial boundaries (From midplane)
(cm)
TOP BOTTOM
Neutron Gamma Ne utron Gamma 000 1554 1117 1554 1117 1143 1537 1114 1571 1120 2286 1521 1111 1588 1123 3429 1504 1108 1605 1126 4572 1486 1104 1622 1129 5715 1464 1100 1636 1131 6858 1438 1095 1648 1133 8001 1401 1088 1657 1135 9144 1350 1078 1654 1134
10287 1277 1063 1625 1129 11430 1165 1039 1554 1117 12573 0998 09995 1414 1091 13716 0769 09365 1172 1041 14859 0492 08375 0816 0951 16002 0220 06850 0402 0797 17145 0046 04625 0092 0551 18288 00 00 00 00
Source Reference 2219 Table S445
34
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
63 MCNP SPECIFIC INPUT
631 Source Probability
A linear radial distribution is used for all gamma and neutron sources The linear radial distribution is sam pled usi ng the built-in power function p(x) = xc a with a = 1 for the radial direction This sampling method results in a uniform source distribution over the area bounded by the outer radius of the source
The source axial distributions are unifor m for all four source regions The a xial uni form xp(x) = c distribution is sampled using the built-in power function a with a = 0 for extent
The energy distribu tions of the gamma and neutron sour ce term s are treated as energ y probabilities and are applied in MCNP5 using SISP cards
632 Dose Rate and Flux Tallies
MCNP5 dose rate calculations feature separate runs for the following calculation types
bull a photon transport calculation for prim ary ga mma contribution to the dose rates fr om photon fluxes
bull a coupled neutronphoton transport calculat ion for neutrons a nd secondary gamma (photons generated by neutron be ing captured) contributions to dose rates from neutron and gamma fluxes
The tally type F2 is us ed in th is d esign ca lculation as f lux estim ators The type F2 tally evaluates the flux averaged over a surface in particlescm2s
To generate dose ra tes in te rms of remhr the FM (tally multiplier ) and DEDF (dose energydose conversion factors) cards are used to en ter the tally multiplier f actor (source intensity in particless) energy boundaries in MeV and corresponding dose conversion factors in (remhr)(particlescm2s) respectively These factors were used in the input files
In order for the F2 tally to accum ulate flux ov er a surface a specific s urface area is requ ired The SD cards are used to enter a surface area in cm2 over which the flux will be tallied for an F2 tally
633 Variance Reduction Techniques
Variance reduction technique is usually em ployed in order to increase the efficiency of a calculation and obtain statistically m eaningful results within re asonable com puter tim e In Monte Carlo calculations when variance reduction scheme is employed the weights of particles are adjusted in order to account for the biasing and to preserve a fair game
Geometry splitting and Russian roulette techniques described in Reference 2224 (pp 2-140 ndash 2-142) are useful in shielding calculations and therefore deployed in all the MCNP5 runs
35
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
As particles migrate in an important direction (toward the detector) they are increased in number to provide better sampling by means of geometry splitting across geometric boundaries Russian roulette (the reverse process) is played when particles travel in an unimportant direction to allow termination of unim portant histories The IMP card required for every cel l ca rd is us ed to implement this technique
The other variance reduction technique deployed in the MC NP5 runs is source intensity biasing for the gamma sources from the four source regions (active fuel bottom end-fitting plenum and top end-fitting) The natural total gamma source intensity of comm ercial SNF is dom inated by the gamma source in the active fuel region This active fuel gamma source usually accounts for over 95 o f the total g amma source intens ity In order to im prove the efficiency of the axial dose rate calculations a biased source probability distribution is employed for the prim ary gamma dose rate calculations The biased gamma source probability distribution is chosen to be 005 080 010 and 005 for the bottom end-fitting the active fuel the plenum and the top end-fitting regions respectively
64 DOSE CONVERSION FACTORS
Project Design Criteria Document (Reference 2211 Se ction 41015) requires the use of flux-to-dose rate conversion fact ors from ANSIANS-611-1977 (Reference 221) for dose rate evaluations Table 16 lists the neutron and ga mma dose conversion factors used in the MCNP5 calculations
Table 12 Gamma and Neutron Flux to Dose Conversion Factors
Gamma Neutron Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
001 396E-06 140 251E-06 250E-08 367E-06 003 582E-07 180 299E-06 100E-07 367E-06 005 290E-07 220 342E-06 100E-06 446E-06 007 258E-07 260 382E-06 100E-05 454E-06 010 283E-07 280 401E-06 100E-04 418E-06 015 379E-07 325 441E-06 100E-03 376E-06 020 501E-07 375 483E-06 100E-02 356E-06 025 631E-07 425 523E-06 100E-01 217E-05 030 759E-07 475 560E-06 500E-01 926E-05 035 878E-07 500 580E-06 100E+00 132E-04 040 985E-07 525 601E-06 250E+00 125E-04 045 108E-06 575 637E-06 500E+00 156E-04 050 117E-06 625 674E-06 700E+00 147E-04 055 127E-06 675 711E-06 100E+01 147E-04 060 136E-06 750 766E-06 140E+01 208E-04 065 144E-06 900 877E-06 200E+01 227E-04 070 152E-06 1100 103E-05 080 168E-06 1300 118E-05 100 198E-06 1500 133E-05
Source Reference 221 Tables 1 and 3
36
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION
By def inition (Ref erence 2224 Equation 219) the estimated st atistic relative error of the i component is
Ri = Si
2
Equation 6Ti
where i = tally component index Ri = relative error of the i component S2
i = variance of the i component Ti = tally i component
For a result (ie dose rate) computed as a sum of different tallies the statistical relative error of the computed value is o btained from the variance of the result - S2
total which is th e sum of the estimated variances of the individual tallies S2
i n
2 2STotal = sum Si Equation 7 i=1
where S2Total = total estimated variance
n = total number of components Therefore the total tally value (dose rate) and the associated relative error are derived according to Equations 8 and 9
n TTotal = sumTi Equation 8
i=1
n n
sum (Ri timesTi )2
2 sum Si 2
STotal = i=1 = i=1 Equation 9RTotal = TTotal TTotal TTotal
where RTotal = total estimated relative error TTotal = total estimated tally
Equations 8 and 9 are utilized in Attachm ent II to ev aluate to tal dos e ra tes and their r elative errors
37
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
7 RESULTS AND CONCLUSIONS
71 RESULTS
The following sections summarize the results of this calculation Section 711 presents results for Conceptual Cask A while Section 712 for Conceptual Cask B Section 713 provides comparisons of the dose-rate reduction factors du e to the two conceptual casks and the axial source distributions in the active fuel region Do se rates and relative errors can be found in Attachment II within the output files and Excel files
711 Dose Rates of Conceptual Cask A
This section presents dose-rate results of the calculation sets 1 and 2 as described in Section 61 for Cask A Set 1 has axial p rofile sources in the active fuel region a nd consist of six runs resulting from the three PWR SNF source term s (maximum design basis and average) and the two radiation sources (gammas and neutrons) Set 2 has uniform axial sources in the active fuel region and consists of six run s r esulting f rom the th ree P WR SNF source term s and th e tw o radiation sources
As described in Section 61 dose ra tes are calculated at the three exterior surfaces (radial top and bottom) and at distances 1 m and 2 m from the exterior surfaces The total dose rates for set 1 are presented in Tables 13 14 and 15 for the ra dial top and bottom dire ctions respectively However the com ponents (primary gamma neutr on and secondary gamma) contributing to the total dose rates as well as the re lative error calculations can be found in Attachment II Excel file MCNP-Results1xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 2 are shown in Tables 16 17 and 18 The dose-rate components and the relative errors can be found in A ttachment II Excel file MCNP-Results2xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 13 and 16 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 14 and 17 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 15 and 18 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carrying th e maximum PWR SNF Based on the results in Tables 13 through 18 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask A indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these 6 tables the d ose-rate red uction f actors between the m aximum and the design basis fuels the maxim um and the averag e fuels and th e design basis and the average fuels are a lso presented
38
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 320E-02 00237 116E-02 00222 262E-03 00219 275 1223 445
1 m 133E-02 00164 494E-03 00171 106E-03 00162 269 1261 468 2 m 749E-03 00198 285E-03 00225 584E-04 00162 263 1282 488
Ring Detectors 1 m 133E-02 00116 492E-03 00115 108E-03 00124 271 1229 454 2 m 756E-03 00118 279E-03 00110 605E-04 00128 271 1250 462
Source Attachment II MCNP-Results1xls worksheet Summary
Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 142E-02 00368 628E-03 00446 934E-04 00483 226 1520 672
1 m 570E-03 00289 263E-03 00426 375E-04 00381 217 1520 701 2 m 265E-03 00364 123E-03 00547 169E-04 00374 216 1575 730
Point Detectors 1 m 598E-03 00238 274E-03 00271 402E-04 00354 219 1489 681 2 m 273E-03 00218 123E-03 00245 180E-04 00336 221 1515 684
Source Attachment II MCNP-Results1xls worksheet Summary
Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 653E-03 00298 265E-03 00276 510E-04 00341 247 1278 518
1 m 276E-03 00238 112E-03 00208 207E-04 00249 248 1334 539 2 m 125E-03 00185 508E-04 00199 933E-05 00246 246 1336 544
Point Detectors 1 m 291E-03 00227 118E-03 00203 218E-04 00242 247 1335 540 2 m 130E-03 00209 524E-04 00187 955E-05 00233 247 1357 549
Source Attachment II MCNP-Results1xls worksheet Summary
Tables 13 14 and 15 are results of calculation set 1 for conceptual Cask A with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
39
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 265E-02 00247 990E-03 00222 215E-03 00278 268 1234 461
1 m 116E-02 00178 468E-03 00549 960E-04 00189 248 1208 488 2 m 713E-03 00273 265E-03 00161 602E-04 00360 269 1184 439
Ring Detectors 1 m 117E-02 00120 454E-03 00132 979E-04 00141 259 1199 463 2 m 722E-03 00130 276E-03 00141 589E-04 00153 261 1226 469
Source Attachment II MCNP-Results2xls worksheet Summary
Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 199E-02 00461 827E-03 00455 147E-03 00536 241 1359 564
1 m 849E-03 00564 323E-03 00314 563E-04 00418 263 1507 574 2 m 415E-03 00832 158E-03 00603 253E-04 00501 263 1641 623
Point Detectors 1 m 877E-03 00348 353E-03 00275 615E-04 00391 248 1426 574 2 m 393E-03 00341 160E-03 00278 270E-04 00378 246 1454 590
Source Attachment II MCNP-Results2xls worksheet Summary
Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 879E-03 00374 356E-03 00333 669E-04 00406 247 1315 533
1 m 365E-03 00223 147E-03 00209 269E-04 00253 248 1358 548 2 m 164E-03 00229 674E-04 00205 120E-04 00248 243 1364 560
Point Detectors 1 m 383E-03 00217 155E-03 00204 285E-04 00248 247 1347 546 2 m 172E-03 00197 689E-04 00186 124E-04 00225 249 1391 558
Source Attachment II MCNP-Results2xls worksheet Summary
Tables 16 17 and 18 ar e results of calculation set 2 for conceptual Cask A with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
40
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION 37
7 RESULTS AND CONCLUSIONS 38 71 RESULTS 38
711 Dose Rates of Conceptual Cask A 38 712 Dose Rates of Conceptual Cask B 41 713 Comparison of Dose-Rate Reduction Factors 44
72 CONCLUSIONS46 ATTACHMENT I ELECTRONIC FILES ON COMPACT DISCI-1
4
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
FIGURES
Page
Figure 1 Geometry and Tally Scheme for the TAD Transportation Cask 23
5
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
TABLES
Page
Table 1 Geometry and Materials of Conceptual TAD Transportation Cask A 15 Table 2 Geometry and Materials of Conceptual TAD Transportation Cask B 16 Table 3 Dimensions of TAD Canister 24 Table 4 BampW 15x15 Mark B Fuel Assembly Description 26 Table 5 PWR Fuel Assembly Regions 27 Table 6 Chemical Compositions of Materials 28 Table 7 Isotopic Compositions of Homogenized PWR Assembly Regions 29 Table 8 Gamma and Neutron Sources for the Maximum PWR SNF Assembly 31 Table 9 Gamma and Neutron Sources for the Design Basis PWR SNF Assembly 32 Table 10 Gamma and Neutron Sources for the Average PWR SNF Assembly 33 Table 11 Gamma and Neutron Axial Source Profiles for a PWR Assembly 34 Table 12 Gamma and Neutron Flux to Dose Conversion Factors 36 Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources 39 Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources 39 Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources 39 Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources 40 Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources 40 Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources 40 Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources 42 Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources 42 Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources 42 Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources 43 Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources 43 Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources 43 Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources 44 Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources 45 Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources 45 Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources 45 Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources 45 Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial
Sources 46 Table 31 Recommended Average Radial Dose-Rate Reduction Factors 46 Table 32 Recommended Average Top Dose-Rate Reduction Factors 46 Table 33 Recommended Average Bottom Dose-Rate Reduction Factors 46 Table I-1 Listing of Electronic Files on Compact DiscI-1
6
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ACRONYMS AND ABBREVIATIONS
ACRONYMS
ANS American Nuclear Society
ANSI American National Standards Institute
ASTM American Society for Testing and Materials
BSC Bechtel SAIC Company LLC
BWR Boiling Water Reactor
CD Compact disc
CSNF Commercial Spent Nuclear Fuel
DB Design Basis
DOE U S Department of Energy
DPC Dual Purpose Canister
NRC U S Nuclear Regulatory Commission
PCSA Preclosure Safety Analysis
PWR Pressurized Water Reactor
RPM Repository Project Management
SNF Spent Nuclear Fuel
SS 316 Stainless Steel 316
TAD Transportation Aging and Disposal
WP Waste Package
YMP Yucca Mountain Project
ABBREVIATIONS and UNITS
b barn
cm centimeter
7
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
g gram
GWd gigawatt-day
hr hour
in inch
kg kilogram
m meter
mrem millirem
MeV million electron volt
MTU metric ton uranium
s second
8
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
1 PURPOSE
The purpose of this calculation is to calcu late th e dose ra tes of two conceptua l tr ansportation casks each carrying a Transportation Aging and Disposal (TAD) canister separately loaded with the average design basis (DB) and m aximum comm ercial spent nuc lear fuel (CSNF) assemblies Then the dose-ra te reduction f actors between the m aximum and the design basis fuels the d esign bas is and the average fuels and the m aximum and the averag e fuels are computed
The results of this calculation may be used to substantiate the dose-rate reduction factors such as those in the engineering study Repository ALARA Goal Compliance (Reference 227) which is cited as a reference in a Preclosure Safety Analyses (PCSA) calculation that supports the License Application
The calculations contained in this docum ent are developed by Nuclear and Radiological Engineering of the Repository Project Mana gement (RPM) organization Yucca Mountain Project (YMP) personnel from Nuclear and Radiological Engineering should be consulted before use of the calculations for purposes other than those stated herein or use by individuals other than personnel in Nuclear and Radiological Engineering
9
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
2 REFERENCES
21 PROJECT PROCEDURESDIRECTIVES
211 IT-PRO-0011 Rev 0010 Software Management Las Vegas Nevada Bechtel SAIC Company
212 EG-PRO-3DP-G04B-00037 Rev 14 Calculations and Analyses Las Vegas Nevada Bechtel SAIC Company
213 IT-PRO-0012 Rev 007 Qualification of Software Las Vegas Nevada Bechtel SAIC Company
22 DESIGN INPUTS
221 ANSIANS-611-1977 Neutron and Gamma-Ray Flux-to-Dose-Rate Factors La Grange Park Illinois American Nuclear Society TIC 239401
222 ASME (American Society of Mechanical Engineers) 2004 2004 ASME Boiler and Pressure Vessel Code 2004 Edition New York New York American Society of Mechanical Engineers TIC 256479 ISBN 0-7918-2899-9
223 ASM International 1990 Properties and Selection Nonferrous Alloys and Special-Purpose Materials Specific Metals and Alloys Volume 2 of Metals Handbook 10th Edition Page 666 [Materials Park Ohio] American Society for Metals TIC 239807
224 ASTM (American Society for Testing and Materials) B 811-90 1991 Standard Specification for Wrought Zirconium Alloy Seamless Tubes for Nuclear Reactor Fuel Cladding Philadelphia Pennsylvania American Society for Testing and Materials TIC 239780
225 ASTM G 1-90 (Reapproved 1999) 1999 Standard Practice for Preparing Cleaning and Evaluating Corrosion Test Specimens West Conshohocken Pennsylvania American Society for Testing and Materials TIC 238771
226 Bowman SM Hermann OW and Brady MC 1995 Sequoyah Unit 2 Cycle 3 Volume 2 of Scale-4 Analysis of Pressurized Water Reactor Critical Configurations ORNLTM-12294V2 Oak Ridge Tennessee Oak Ridge National Laboratory TIC 244397 [DIRS 123796]
227 BSC (Bechtel SAIC Company LLC) 2008 Repository ALARA Goal Compliance 000-30R-MGR0-04000-000 REV 000 Las Vegas Nevada Bechtel SAIC Company ACC ENG200802050014 [DIRS 184957]
228 BSC 2002 Subsurface Shielding Source Term Specification Calculation 000-00C-WER0-00100-000-00A Las Vegas Nevada Bechtel SAIC Company ACC MOL200212160076 ENG200508150022
10
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
229 BSC 2004 PWR Source Term Generation and Evaluation 000-00C-MGR0-00100-000-00B Las Vegas Nevada Bechtel SAIC Company ACC ENG200405240007
2210 BSC 2008 Basis of Design for the TAD Canister-Based Repository Design Concept 000-3DR-MGR0-00300-000-003 Las Vegas Nevada Bechtel SAIC Company ACC ENG200810060001
2211 BSC 2007 Project Design Criteria Document 000-3DR-MGR0-00100-000-007 Las Vegas Nevada Bechtel SAIC Company ACC ENG200710160005 ENG200711080001 ENG200712200003 ENG200801070001 ENG200801070002 ENG200801070016 ENG200801070017 ENG200801310006 ENG200803050002 ENG200803050011 ENG200803050012 ENG200803060009 ENG200803130004 ENG200807100001 ENG200811120006 ENG200811140004
2212 BSC 2004 PWR and BWR Source Term Sensitivity Study 000-00C-MGR0-00300-000-00A Las Vegas Nevada Bechtel SAIC Company ACC ENG200401140003 ENG200508150023
2213 BSC 2007 Dose Rate Calculation for Exhaust Main Drifts 800-00C-SS00-00700-000-00B Las Vegas Nevada Bechtel SAIC Company ACC ENG200711050017 ENG200803060001
2214 BSC 2006 Dual Purpose Canister Opening Study 050-30R-WHS0-00600-000-000 Las Vegas Nevada Bechtel SAIC Company ACC ENG200612200023
2215 BSC 2007 GROA Shielding Requirements Calculation 000-00C-MGR0-03300-000-00B Las Vegas Nevada Bechtel SAIC Company ACC ENG200705290037
2216 BSC 2002 Concrete Shielding Calculation for Dry Facility 1 110-00C-CS10-00100-000-00A Las Vegas Nevada Bechtel SAIC Company ACC MOL200301140075
2217 BSC 2003 Shielding Design Calculations for Dry Facility 1 110-00C-CS10-00200-000-00A Las Vegas Nevada Bechtel SAIC Company ACC ENG200306020003
2218 CRWMS MampO 1998 Calculation of the Effect of Source Geometry on the 21-PWR WP Dose Rates BBAC00000-01717-0210-00004 REV 00 Las Vegas Nevada CRWMS MampO ACC MOL199902220059 [DIRS 102134]
2219 CRWMS MampO 2000 Users Manual for SCALE-44A 10129-UM-44A-00 Las Vegas Nevada CRWMS MampO ACC MOL200011300136 MOL200108220084 MOL200108220085 MOL200108220086 MOL200108220087 [DIRS 153872]
2220 DOE (US Department of Energy) 1987 Appendix 2A Physical Descriptions of LWR Fuel Assemblies Volume 3 of Characteristics of Spent Fuel High-Level Waste and Other Radioactive Wastes Which May Require Long-Term Isolation DOERW-0184 Washington DC US Department of Energy Office of Civilian Radioactive Waste Management ACC HQX198804050024 [DIRS 132333]
11
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
2221 DOE 2007 Software Validation Report for MCNP5 v140 Document ID 11199-SVR-140-00-WINXP Las Vegas Nevada US Department of Energy Office of Repository Development ACC MOL200702280252 [DIRS 180516]
2222 DOE 2008 Transportation Aging and Disposal Canister System Performance Specification WMO-TADCS-000001 Rev 1 ICN 1 Washington DC US Department of Energy Office of Civilian Radioactive Waste Management ACC DOC200803310001 [DIRS 185304]
2223 Harmon CD II Busch RD Briesmeister JF and Forster RA 1994 Criticality Calculations with MCNPtrade A Primer LA-12827-M Los Alamos New Mexico Los Alamos National Laboratory TIC 234014 [DIRS 154532]
2224 LANL (Los Alamos National Laboratory) 2004 MCNP mdash A General Monte Carlo N-Particle Transport Code Version 5 (Appendix H is not included) LA-UR-03-1987 Volume I Los Alamos [New Mexico] Los Alamos National Laboratory ACC MOL200510240126 [DIRS 176521]
2225 MCNP5 V 140 2007 Windows XP STN 11199-140-00 [DIRS 180515]
2226 Parrington JR Knox HD Breneman SL Baum EM and Feiner F 1996 Nuclides and Isotopes Chart of the Nuclides 15th Edition San Jose California General Electric Company and KAPL Inc TIC 233705 LC Call Number QC7935 N8622 1996
2227 Punatar MK 2001 Summary Report of Commercial Reactor Criticality Data for Crystal River Unit 3 TDR-UDC-NU-000001 REV 02 Las Vegas Nevada Bechtel SAIC Company ACC MOL200107020087 [DIRS 155635]
2228 Sisley SE 2002 Transportation License Application for the FuelSolutionstrade System (TAC No L23311) Submittal of the FuelSolutiontrade Transportation SARs Revision 3 Letter from SE Sisley (BNFL) to the NRC April 11 2002 BFSNRC 02-011 with enclosures TIC 255245 [DIRS 171545]
NOTE Reference 2220 is a direct input but is not QA QA It is justified as acceptable for the intended use as it is directly from the DOE and is considered the best available data on the subject The referenced values cited in Tables 3 and 4 are valid for use since they are reliable and reasonable based on engineering judgment
23 DESIGN CONSTRAINTS
231 10 CFR 71 2008 Energy Packaging and Transportation of Radioactive Material Internet Accessible [DIRS 185678]
12
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
24 DESIGN OUTPUTS
The resu lts of this calculation will be us ed to substan tiate th e dose reduc tion f actor in the Repository ALARA Goal Compliance (Reference 227) which is cited as a reference in a PCSA calculation that supports the License Application
13
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
3 ASSUMPTIONS
31 ASSUMPTIONS REQUIRING VERIFICATION
None
32 ASSUMPTIONS NOT REQUIRING VERIFICATION
Assumptions 321 322 and 323 are m odeling assum ptions and do not require further verification The m aterials and dim ensions for the TAD canister and for the conceptu al transportation casks are only selected to charac terize two tr ansportation casks th at m eet 10 CFR7147 (Reference 231) dose rates when lo aded with the ldquom aximumrdquo and ldquoaveragerdquo pressurized water re actor (PW R) assem blies re spectively There is n o need to v erify those dimensions or m aterials at a later date The ca lculated results in Sect ion 711 verify that the conceptual casks would meet 10 CFR 7147 (Reference 231) dose rates
321 Material and Wall Thickness of TAD Canister
Assumption It is assumed that the TAD canister is made of stainless steel 316 (SS 316) and has a wall thickness of 025 in for the radial and bottom shells
Rationale Currently the design of the TAD canis ter d oes not ex ist Based on a survey of existing m ultipurpose a nd dual purpose caniste rs (DPC) (Ref erence 2214 p 56) a 025 in thickness is below the wall thick ness of any existing c anisters For the purp ose of this calculation this assumption leads to higher and conservative external dose rates Since SS 316 is the sam e material used for the waste pack age inner shell it is a l ogical cho ice f or the TAD canister
Although Reference 2214 is an engineering study with a QA N A status it is used here as an indirect input to support the assumption which is conservative for dose rate calculations
Usage This assumption is used in Sections 621 and 625
322 Material and Thickness of TAD Shield Plug
Assumption It is assu med that the TAD shield plug is made of SS 316 and has a thickness of 11 in
Rationale Currently the design of the TAD canister doe s not exist A thick shield plug of 11 in (Reference 2215 Table 12) is needed to keep the m aximum contact dose rate of the top surface below 1000 mrem hr (Reference 2222 Section 314) Since SS 316 is the sam e material used for the waste package inner shell it is a logical choice for the TAD shield plug
Usage This assumption is used in Section 621
14
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
323 Geometry and Materials of Conceptual TAD Transportation Casks
Assumption Two conceptual TAD transpo rtation casks designated as Cask A and Cask B are assumed to have a cylindrical geom etry and m aterials specified in Tab les 1 and 2 respectively The casks are basically construc ted of an inner layer of SS 316 for ga mma shielding a m iddle layer of 5-borated polyethylen e for neutron shielding and a th in outer layer of SS 316 whic h serves a structural function as well as shielding secondary gamma rays
Both Cask A and Cask B have a cavity height of 53785 cm (21175 in) and a cavity diameter of 16891 cm (6650 in) However Cask A has a total height of 610845 cm (24049 in) and an outside diameter of 26797 cm (10550 in) while the total height and outside diameter of Cask B are 58885 cm (23183 in) and 24765 cm (9750) respectively
Cask A will provide shielding to m eet the exterior radiat ion standards of 10 C FR 7147(b) (Reference 231) when loaded w ith a TAD canister carrying th e maximum PWR spent nuclear fuel (SNF) Cask B will satisf y the same radiation standards when loade d with a TAD caniste r carrying the average PWR SNF
Table 1 Geometry and Materials of Conceptual TAD Transportation Cask A
Component Dimension
Material (cm) (in)
Total Height 61085 2404 9 NA
Outside Diameter 26797 1055 0 NA
Cask Cavity Height 53785 2117 5 NA
Cask Cavity Diameter (Radius) 16891 (8446) 6650 (3325) NA
Radial Gamma Shield Thickness (Radius)a 3302 (11748)a 1300 (4625)a SS 316
Radial Neutron Shield Thickness (Radius)b 1524 (13272)b 600 (5225)b 5-borated polyethylene
Radial Outer Shell Thickness (Radius)c 127 (13399)c 050 (5275)c SS 316
Top Gamma Shield Thickness (Axial Position)d 600 (54385)d 236 (21411)d SS 316
Top Neutron Shield Thickness (Axial Position)d 1000 (55385)d 394 (21805)d 5-borated polyethylene
Top Outer Shell Thickness (Axial Position)d 200 (55585)d 079 (21884)d SS 316
Bottom Gamma Shield Thickness (Axial Position)d 35365 (-360)d 1392 (-1417)d SS 316
Bottom Neutron Shield Thickness (Axial Position)d 15 (-510)d 591 (-2008)d 5-borated polyethylene
Bottom Outer Shell Thickness (Axial Position)d 4 (-550)d 157 (-2165)d SS 316 a11748 = 3302 + 8446 and 4625 = 1300 + 3325 b13272 = 1524 + 11748 and 5225 = 600 + 4625 c13399 = 127 + 13272 and 5275 = 050 + 5225 dCoordinate relative to the bottom of the fuel assembly as modeled in MCNP5
15
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 2 Geometry and Materials of Conceptual TAD Transportation Cask B
Component Dimension
Material (cm) (in)
Total Height 58885 2318 3 NA
Outside Diameter 24765 9750 NA
Cask Cavity Height 53785 2117 5 NA
Cask Cavity Diameter (Radius) 16891 (8446) 6650 (3325) NA
Radial Gamma Shield Thickness (Radius)a 254 (10986)a 1000 (4325)a SS 316
Radial Neutron Shield Thickness (Radius)b 127 (12256)b 500 (4825)b 5-borated polyethylene
Radial Outer Shell Thickness (Radius)c 127 (12383)c 050 (4875)c SS 316
Top Gamma Shield Thickness (Axial Position)d 8 (54585)d 315 (21490)d SS 316
Top Neutron Shield Thickness (Axial Position)d None Non e NA
Top Outer Shell Thickness (Axial Position)d None Non e NA
Bottom Gamma Shield Thickness (Axial Position)d 3837 (-390)d 1510 (-1535)d SS 316
Bottom Neutron Shield Thickness (Axial Position)d 300 (-420)d 118 (-1654)d 5-borated polyethylene
Bottom Outer Shell Thickness (Axial Position)d 100 (-430)d 039 (-1693)d SS 316 a10986 = 254 + 8446 and 4325 = 1000 + 3325 b12256= 127 + 10986 and 4825 = 500+ 4325 c12383 = 127 + 12256 and 4875 = 050 + 4825 dCoordinate relative to the bottom of the fuel assembly as modeled in MCNP5
Rationale Currently a design for the TAD transporta tion cask does not exist The casks assumed for this calculation are so lely for estim ation of the dose reduction due to different source terms This is a conceptual repres entation only used in this calculation to estim ate the parameters of interest
Usage This assumption is used in Sections 61 and 622
324 Usage of Unirradiated Fuel for Commercial SNF
Assumption It is assumed that the active fuel region of the commercial SNF assembly contains the same isotopic concentrations as the fresh uni rradiated fuel and that the concentrations of fresh fuel with 5 initial enrichm ent corresp onding to m aximum SNF are used for all other SNFs
Rationale This assumption is a standard practice for shielding calculations throughout the industry accepted by the U S Nucle ar Regulatory Commission (NRC) (Reference 2228 Table 53-5) It sh ould be noted that this assumption applies to material composition only it does no t apply to source terms which are based on the characteristics of spent fuel
Usage This assumption is used in Sections 624 and 626
325 Homogenization of Radiation Source Regions
Assumption It is assu med that a commercial SNF assembly consis ts of four distinct reg ions (active fuel bottom end-fitting plenum and top end-fitting) The materials and radiation sources
16
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
of each assembly region are homogenized inside a volume defined by the TAD cavity radius and region height
Rationale The assembly representation is consistent with the industry practice for shielding calculations accepted by NRC (Reference 2228 Figure 53-6) The effec t of source homogenization is twofold (1) it d ecreases th e m ass de nsity of the source region and (2) it places source points slightly closer to detector locations thus reducing radiation attenuation The resu lts of Calculation of the Effect of Source Geometry on the 21-PWR WP Dose Rates (Reference 2218 pp 22-26) indicate that th e effect of assem bly homogenization gives nearly the same or conservative dose rates as the explicit fuel assembly model
Usage This assumption is used in Section 624
326 Ignoring Internal Fuel Basket Materials
Assumption It is assumed that the internal fuel basket materials are ignored
Rationale Inclusion of fuel basket m aterials in the smeared m aterial com position would increase the overall density and consequently increase the attenuati on of the radiation Therefore this assumption is conservative
Usage This assumption is used in Sections 621 624 and 626
17
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
4 METHODOLOGY
41 QUALITY ASSURANCE
This calculation was prepared in accordance with EG-PRO-3DP-G04B-00037 Calculations and Analyses (Reference 212) The results of th is calculation provides worker dose assessm ent adjustments and this will id entify radio logical hazards f or f acilities im portant to saf ety Therefore the approved version is designated as QA QA
42 USE OF COMPUTER SOFTWARE
421 Baseline Software
The Monte Carlo N-Particle com puter pr ogram (MCNP5) version 140 (Reference 2225) is used to calculate the dose rates (neutron pr imary gamm a and secondary gamm a) at various locations around a transportation cask and an aging overpack
The software specifications are as follows
bull Program Name MCNP5 bull VersionRevision Number Version 140 bull Operating Systems Windows XP bull Software Tracking Number 11199-140-00 bull Computer Type Dell OPTIPLEX GX620
MCNP5 which is Level 1 software is (a) appropriate for three-dim ensional neutron gamma and coupled neutrongamma shielding calculations (b) used within th e range of validation as documented in Software Validation Report for MCNP5 v140 (Reference 2221) and (c) obtained from Software C onfiguration Managem ent and qualified in accordance with procedure IT-PRO-0012 Qualification of Software (Reference 213) Therefore MCNP5 code is suitable for use in this design calculation All MCNP5 input and output files docum ented in this calculation are provided on a compact disc (CD) as Attachment II
All MCNP cases are executed on one of the following Q com puters QNW -004184 QNW -004187 QNW-004194 and QNW-004196 as shown in the output files
422 Commercial off the Shelf Software
The Excel sof tware is used to c alculate var ious inpu t values (i e atom densities weight percentages geometrical dimensions normalized source spectra and probabilities etc) Standard functions of Excel are also used in this desi gn calculation to display results (ie gamma and neutron dose rates) in tabular and graphic forms and to perform relative error calculations
The software specifications are as follows
bull Program Name Excel bull VersionRevision Number Microsoftreg Excel 2003
18
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
bull This software is installed on a persona l com puter running Microsoft W indows XP (central processing unit number 151834)
The user defined for mulas inputs results and gr aphical representations have been verified by hand calculations or visual inspection and are documented in sufficient detail to allow an independent repetition of the com putations Calculations were verifi ed by hand and graphical representations were found accurate by visual inspection
Per Software Management Microsoftreg Excel is not requir ed to be qualif ied due to its commercial availability status (Reference 211 Attachment 4 p 55 bullet 2)
43 CALCULATION APPROACH
This calculation em ploys the qualified so ftware MCNP5 version 140 (Reference 2225) a three-dimensional Monte Carlo code for pe rforming neutron and coupled neutron-gamm a calculations to estim ate dose rates at sele cted locations on and surrounding a conceptual transportation cask containing a loaded TAD canister
431 MCNP5 Program
MCNP5 a general Monte Carlo part icle transport code sim ulates particle transport through a three-dimensional representation of the nuclear system being analyzed During the random walk of particles through the system described by the geom etry the c ode collects inform ation about various events (su rface cross ing collis ions trac k leng th etc) and es timates fluxes in various geometric configurations specified as tallies by the user It also estimates the statistical precision of the results in the form of relative errors (Reference 2224 pp 1-2 to 1-8)
Per Project Design Criteria Document (Reference 2211 Section 41015) the flux estim ates are converted to dose rates using the Am erican Nuclear Society (ANS) flux-to-dose rate conversion factors for gammas and neutrons (R eference 221) The simple variance reduction techniques of Geometry SplittingRussian Roulette and source probability biasing (Sections 631 and 633) are used to enhance computational efficiency
19
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
5 LIST OF ATTACHMENTS
Number of Pages Attachment I List of Electronic Files on the CD 3 Attachment II Compact Disc NA
20
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
6 CALCULATIONS
This sectio n provides inform ation necess ary to perform the calcu lations in this docum ent Section 61 describes the configurations the type of CSNF to be analyzed the number of MCNP runs and the locations where dose rates are ca lculated Section 62 provides the calculation input that includes the details of the geom etry m odel radiation source term s and m aterial compositions Input specific to MCNP dose -rate conversion factors and relative error calculation are described in the later sections
61 DESCRIPTION OF CALCULATIONS
Dose rate calculations are perform ed with the MCNP5 version 140 com puter code (Reference 2225) Two conceptual transportation casks Cask A and Cask B (Assum ption 323) are employed Each cask contains a TAD canister that is loaded with 21 ident ical PW R SN F assemblies Three PWR source term s are analy zed they are the source term s corresponding to the maximum design basis and average PW R SN Fs The characteris tics of the P WR source terms are presented in S ection 627 Each PWR source term has neutron and ga mma radiation sources that require separate MCNP5 runs For each radiation source an axial profile source and a uniform source for the active fuel region are considered The uniform source for the active fuel region is included in this calculation because this approach was used in combination with source peaking factors in certain calculations (Reference 2216 Sections 37 and 39 and Reference 2217 Section 5242)
The total number of MCNP5 runs is 24 which re sults from a com bination of two conceptual casks three PWR source terms two radiation sources and two axia l source distributions for the active fuel region These 24 runs are categorized into four calcula tion sets Each calculation set consists of six runs that is a combination of three PWR source te rms and two radiation sources The characteristics of each calculation set are as follows
1 Cask A with axial profile sources in the active fuel region
2 Cask A with uniform axial sources in the active fuel region
3 Cask B with axial profile sources in the active fuel region
4 Cask B with uniform axial sources in the active fuel region
For each MCNP5 run dose rates are calculated at the exte rior surfaces and at distances 1 and 2 meters from the exterior surfaces Surface tallies and detector tallies (ring and point detectors) as indicated in Figure 1 are e mployed in all runs Figure 1 is used to illustrate the dep loyment of the surface and detector tallies re lative to the so urce regions and it should not be interpreted as an exact geometry of any particular run Surface tallies are deployed at all three distances while ring and point detectors are used only at 1 m and 2 m and not at the cask surfaces Using point detectors near a surface or in any scattering media is not recommended because very large scores can occur f rom collisions close ( less than a f ew centimeters) to the point detecto rs that can lead to resu lts with high r elative e rrors thus m aking the ca lculation d ifficult to o btain r eliable answers
21
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
For the radial direction surface tallies at the three distances (contact 1 m and 2 m) are computed for three su rface segments (cylindrical rings) between the planes at Z = 145 175 2 05 and 235 cm The geometric locations of the segments are shown in Figure 1 The axial locations of these segments correspond to the m iddle of the active fuel region of the PWR SNF assemblies The average dose rates for each of the segm ents are calculated for the outside surface and surfaces at 1 m and 2 m from the cask surface Two ring detectors (instead of point detectors) are deployed at 1 m and 2 m for the radial dire ction Ring detectors instead of point detectors are used in order to capitalize on the symm etry around the cask axis thus im proving the efficiency of the calculations
In the axial direction the average d ose rates within three concentric radial surfaces defined by radii of 40 80 and 120 cm (shown in Figure 1) are calculated for the top and bottom surfaces and at distances 1 m and 2 m from these surfaces Finally point detectors at 1 m and 2 m from the top and bottom axial surfaces are employed
22
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Point Detector at 2 m x
Ring Ring Detector Detector at 2 m at 1 m
x x
Z = 00 cm
Z = 145 cm
Z = 175 cm
Z = 205 cm
Z = 235 cm
R = 80 cm
R = 120 cm
R = 40 cm
Active Fuel
Shield Plug
Top End-Fitting Plenum
Bottom End-Fitting
Ring Detector at 1 m
x
Point Detector at 1 m x
Ring Detector
at 2 m x
D = 26797 cm
H =
610
845
cm
Point Detector at 1 m x
Point Detector at 2 m x
Figure 1 Geometry and Tally Scheme for the TAD Transportation Cask
23
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
62 CALCULATION INPUT
Technical product input and sources of the input used in the deve lopment of this calculation are documented in this section Tables in this docum ent and in th e associated Microsoftreg Excel spreadsheets referenced m ay present num erical values with m any significant figures these values are not to be considered as high precision values since the significant figures are results of calculated values andor unit conversions
621 TAD Canister
The TAD canis ter will contain either 21 P WR or 44 BW R (boiling water reactor) SNF assemblies (Reference 2222 Section 321) While the canister design is iden tical for both PWR and BWR SNF assemblies the internal basket structure is different depending on the SNF assemblies However the internal basket stru cture m aterial is no t in cluded in the calcu lation model (Assumption 326)
The TAD canister is a right-circu lar cylinder with a diam eter of 665 in and a height between 186 and 212 in (Reference 2222 Section 321) The average and maximum total dose rates on the top surf ace of a loaded TAD ca nister must not exceed 800 and 1000 m remhr respectively (Reference 2222 Section 314) The TAD canister used in this calculation is m ade of SS 316 with a radial wall and bottom thickness of 025 in (Assumption 321) The top of the canister has a shield plug that is 11 in thick SS 316 (Ass umption 322) A thick shield plug is needed to keep the maxim um contact dose rate of th e top surface below 1000 m remhr The overall dimensions of the TAD canister are provided in Table 3
Table 3 Dimensions of TAD Canister
Component Dimension
(in) (cm)
Maximum heighta 212 53848
Outer diametera 665 16891
Thickness of bottom lidb 025 0635
Shell thicknessb 025 0635
Lifting Featurec 6 1524
Height without Lifting Feature 206 52324
Thickness of shield plugd 110 2794
aReference 2222 Section 311 bAssumption 321 cReference 2222 p Attachment C-1 dAssumption 322
622 Conceptual TAD Transportation Casks
Two conceptual TAD transportation casks designa ted as Cask A and Cask B are em ployed in this calculation (Assumption 323) They both have a cylindrical geometry with dimensions and materials specified in Tables 1 and 2 of Section 323 Cask A will provide shielding to meet the exterior radiation standards of 10 CFR 7147(b) (Reference 231) when loaded with a TAD
24
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
canister car rying the m aximum PWR SNF Cask B will s atisfy th e sa me radiatio n standa rds when loaded with a TAD canister c arrying the average PWR SNF The reason to analyze both Casks A and B is to cover a broad range of characteristics of the CSNF
The cavity dimensions of the conceptual cask s are 53785 cm (21175 in) in height and 16891 cm (665 in) in diam eter (Tab les 1 and 2) This cav ity will accommoda te the TAD canister described in Table 3 without the lifting feature This is the geometry model used in the MCNP5 calculations
623 Fuel Assembly Selection
PWR and BWR Source Term Sensitivity Study (Reference 2211 Tables 71 through 84) shows that the source terms generated for the Bamp W 15x15 Mark B fuel assembly with 475 kg uranium loading bound the source terms of other PWR assembly types ther efore this assembly type is selected as the representative PWR fuel assembly The gamma and neutron source terms for the BampW 15x15 Mark B assembly are generated in PWR Source Term Generation and Evaluation (Reference 229) and are used in this calculation
624 BampW 15x15 Mark B PWR Fuel Assembly
BampW 15x15 Mark B fuel assembly consists of four regions top end-fitting plenum active fuel and bottom end-fitting The m aterials and ra diation sources of each assem bly region are homogenized inside a volume defined by the region height and the interior diam eter of the TAD canister (Assumption 325) The active fuel region is homogenized with fresh unirradiated fuel (Assumption 324) Since the internal structure (i e basket) design of t he TAD is currently not finalized the com position of the hom ogenized fuel does not include the basket m aterials (Assumption 326) and therefore does not take cred it for any shielding that these m aterials may provide
Table 4 provides the design param eters for the BampW 15x15 Mark B fuel assembly Data provided here are used in Attachment II PWR_fuel compxls worksheet BampWassy
25
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 4 BampW 15x15 Mark B Fuel Assembly Description
Component Material Characteristic Value Specific Reference Array Size 15 x 15
Reference 2227 Table 2-2 Fuel Pins Assembly 208 Guide Tubes Assembly 16 Instrument Tubes Assembly 1
Assembly NA Pin Pellet Diameter 0936244 cm (03686 in) Reference 2220 p 2A-34 Pin Pitch 144272 cm (0568 in)
Reference 2227 Table 2-2 Active Fuel Height 360172 cm (1418 in) Assembly Width 2168144 cm (8536 in)
Reference 2220 p 2A-31 Assembly Height 4206875 cm (165625 in) Mass U assembly 46363 kg
Guide tube Zircaloy-4 Outer Diameter 13462 cm (053 in)
Reference 2227 Table 2-2
Inner Diameter 126492 cm (0498 in)
Instrument tube Zircaloy-4 Outer Diameter 138193 cm (05441 in) Inner Diameter 112014 cm (0441 in)
Cladding` Zircaloy-4 Inner Diameter 095758 cm (0377 in) Outer Diameter 10922 cm (043 in)
Plenum region NA Length 297688 cm (11720 in) Reference 2220 p 2A-34 Top nozzle SS CF3M MassAssembly (Top) 748 kg
Reference 2220 p 2A-32
Bottom nozzle SS CF3M MassAssembly (Bottom) 816 kg Guide tubes Zircaloy-4 MassAssembly (in Core) 80 kg Instrument tube Zircaloy-4 MassAssembly (in Core) 064 kg Spacer-plenum Inconel-718 MassAssembly (Plenum) 104 kg Spacer-bottom Inconel-718 MassAssembly (Bottom) 13 kg Spacer-in core Inconel-718 MassAssembly (in Core) 49 kg Spring retainer SS CF3M MassAssembly (Top) 091 kg Holddown spring Inconel-718 MassAssembly (Top) 18 kg Upper end plug SS 304 MassAssembly (Top) 006 kg Upper nut SS 304L MassAssembly (Top) 051 kg Lower nut SS 304 MassAssembly (Bottom) 015 kg Grid supports Zircaloy-4 MassAssembly (in Core) 064 kg Plenum spring SS 302 MassAssembly (Plenum) 0042 lb (001905 kg) Reference 2220 p 2A-34
Note Som e d ata i n this tab le ar e given i n British u nits in th e r eferences thes e d ata ar e converted into metric units as the inputs to MCNP5 are in metric units
The assem bly region heights as m odeled in MC NP are presented in Table 5 utilizing values from Table 4 Table 5 is taken from Dose Rate Calculation for Exhaust Main Drifts (Reference 2213 Table 3)
26
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 5 PWR Fuel Assembly Regions
Component Height Reference
Plenum 297688 cm (11720 in) Reference 2220 p 2A-34
Active Fuel 360172 cm (1418 in) Table 3
Bottom End-Fitting 1077 cm (424 in) Calculateda
Top End-Fitting 1998 cm (787 in) Calculatedb
Source Reference 2213 Table 3 aCalculated b ased on data Reference 2227 F igures 2-3 an d 2-7
(Region 9 Height [16723 cm] + Region 10 Height [508 cm] ndash Lo wer Fuel Plenum and End Cap [11033 cm])
bCalculated (Assembly Length ndash Active Fuel Length ndash P lenum Length ndash Bottom End-fitting Length)
625 Material Compositions
The TAD transportation cask com ponent m aterial specifications are defined in Table 1 The TAD canister is constructed of SS 316 (Assumpti on 321) The PWR fuel assembly materials used to homogenize the fuel regions are defined in Table 4 Table 6 c ontains the m aterial compositions defining the TAD canister WP and fuel assemblies
27
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 6 Chemical Compositions of Materials
Material Density (gcc)
Isotopic Weight Percent Reference
SS 302 NA
C 0150 Mn 2000 P 0045 S 0030 Si 0750 Cr 18000 Ni 9000 N 0100 Fe 69925
Attachment II PWR_fuel compxls worksheet ferrous Reference 222 SEC II A SA-240 Table 1 for SS 302 SS 304 and SS 304L Reference 222 SEC II A SA-351SA -351M Table 2 for SS CF3M
SS 304 NA
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 9250 N 0100 Fe 68745
SS 304L NA
C 003 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 10000 N 0100 Fe 6804 5
SS CF3M NA
C 0030 Mn 1500 P 0040 S 0040 Si 1500 Cr 19000 Ni 11000 Mo 2500 Fe 64390
Inconel 718 NA
C 0080 Mn 0350 Si 0350 Cr 19000 Ni 52500 Co 1000 Mo 3050 Fe 16809 Nb 5125 Ti 0900 Al 0500 Cu 0300 S 0015 P 0015 B 0006
Attachment II PWR_fuel compxls worksheet alloys aReference 223 p 666 Table 6 Reference 222 SEC II B SB-637 Table 1 for Inconel 718 Reference 224 Table 2 for Zircaloy 4
Zircaloy 4 656a Cr 0100 Fe 0210 O 0125 Sn 1450 Zr 98115
SS 316 798b
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 17000 Ni 12000 Mo 2500 N 0100 Fe 65495
Attachment II PWR_fuel compxls worksheet others Reference 222 SEC II A SA-240 Table 1 for SS 316 bReference 225 Table X1
626 Homogenization Assembly Materials
The atom density of an element or isotope in atomsbmiddotcm in a homogenized region is calculated according to the following equation (Reference 2223 Appendix B)
M i times N AvogadroNi = Equation 1 Ai timesV times K
where Ni = Atom density of elementisotope i (atomsbmiddotcm) Mi = Mass of elementisotope i (g) NAvogadro = Avogadrorsquos constant 06022 x 1024 (atomsmole)
28
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Ai = Atomic weight of elementisotope i (gmole) V = Homogenization volume (cm3) K = Unit transformation constant = 1024 (bmiddotcmcm3)
Equation 1 is used in A ttachment II spreadsheet PWR_fuel compxls worksheet BampWassy to calculate th e atom dens ities for v arious elem ents and iso topes The m ass of elementsisotop es and Avogadrorsquos constant are provided in Reference 2226
Table 7 lists the com position of the hom ogenized assem bly regions (active fuel plenum top end-fitting and bottom end-fitting) for the PWR assembly The active fuel region contains fresh unirradiated fuel (Assumption 324) Since the internal structure (ie basket) design of the TAD is currently not finalized the composition of either homogenized fuel does not include the basket materials and therefore does not tak e credit for any shielding that thes e materials may provide (Assumption 326)
Table 7 Isotopic Compositions of Homogenized PWR Assembly Regions
Element Isotope
Atom Densities for Homogenized Regions (atomsbsdotcm)
Active Fuel Bottom End-Fitting Plenum Top End-Fitting
10B 861E-09 764E-08 221E-08 570E-08 11B 347E-08 307E-07 890E-08 230E-07 C 519E-07 160E-05 138E-06 993E-06 N -- 570E-07 262E-08 117E-06 O 621E-03 -- 142E-05 -- Al 144E-06 128E-05 371E-06 957E-06 Si 971E-07 243E-04 259E-06 139E-04 P 377E-08 606E-06 102E-07 360E-06 S 365E-08 581E-06 971E-08 340E-06 Ti 147E-06 130E-05 376E-06 971E-06 Cr 320E-05 187E-03 779E-05 113E-03 Mn 497E-07 126E-04 141E-06 749E-05 Fe 303E-05 531E-03 717E-05 313E-03 Co 132E-06 117E-05 340E-06 876E-06 Ni 697E-05 144E-03 180E-04 940E-04 Cu 368E-07 327E-06 945E-07 244E-06 Zr 196E-03 -- 195E-03 -- Nb 430E-06 382E-05 110E-05 285E-05 Mo 248E-06 135E-04 636E-06 791E-05 Sn 223E-05 -- 222E-05 -- 234U 139E-06 -- -- -- 235U 157E-04 -- -- -- 236U 719E-07 -- -- -- 238U 294E-03 -- -- -- Total 114E-02 924E-03 235E-03 557E-03
Source Attachment II spreadsheet PWR_fuel compxls worksheet BampWassy
29
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
The isotopic composition of commercially available 235U enriched uranium is determined by the given initial 235U enrichment using the following equations (Reference 226 p 20)
wt235U =235Uenrichment _ of _ the _ associated _ fuel _ batch Equation 2
wt234U = 0007731times (wt235U )10837 Equation 3
wt236U = 00046times (wt235U ) Equation 4
wt238U =100 minus (wt234U + wt235U + wt236U ) Equation 5
The weight percentages of uran ium isotopes for PWR fuel are ca lculated in Attachm ent II spreadsheet PWR_fuel compxls worksheet BampWassy using Equations 2 through 5
627 PWR Source Terms
This calculation uses the following three PWR source terms bull Maximum source (50 wt initial 235U enrichment 80 GWdMTU burnup and 5-year
decay time) (Reference 229 Section 55) Table 8 lists th e gamma source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Design Basis source (4 0 wt initial 235U enrichment 60 GW dMTU burnup and 10-year decay tim e) (Reference 228 Section 552) Table 9 lists the gamm a source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Average source ( 40 wt initial 235U enrichment 48 GWdMTU burnup and 25-year decay time) (Reference 229 Section 55) Table 10 lists the gamma source terms for the fuel and non-fuel regions and the neutron source term for the fuel region
These sources (ie maximum design basis and av erage) are described in this section For dose rate calculations all the fuel assemblies in a transportation cask are of the sam e characteristics Also gamma radiation source term s for the PWR assem bly are prov ided for the f our assembly regions while neutron source term is only present in the active fuel region Gamma radiation sources in the non-active fuel region are distri buted unif ormly within each source region Gamma and neutron sources in the active fuel re gion are modeled as uni form distributions or with axial source profiles
The PWR gamma and neutron axial source profiles for the active fuel region presented in Table 11 are applied to the active fuel region of all three source terms (ie maximum design basis and average) when appropriate
30
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 8 Gamma and Neutron Sources for the Maximum PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting
Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 594E+11 233E+15 528E+11 379E+11 100E-01 000E+00 100E-01 116E+11 644E+14 609E+10 743E+10 400E-01 805E+07 200E-01 283E+10 522E+14 352E+10 179E+10 900E-01 411E+08 300E-01 141E+09 148E+14 196E+09 891E+08 140E+00 376E+08 400E-01 190E+09 985E+13 586E+09 117E+09 185E+00 276E+08 600E-01 191E+09 153E+15 110E+11 741E+07 300E+00 485E+08 800E-01 435E+09 470E+15 595E+10 237E+09 643E+00 443E+08 100E+00 137E+11 708E+14 803E+09 766E+10 200E+01 393E+07 133E+00 338E+13 455E+14 174E+13 217E+13 Total 211E+09 166E+00 953E+12 130E+14 491E+12 612E+12
--
200E+00 187E+03 144E+12 919E+02 113E+03 250E+00 226E+08 249E+12 116E+08 145E+08 300E+00 351E+05 110E+11 181E+05 225E+05 400E+00 766E-08 139E+10 100E-08 416E-08 500E+00 000E+00 709E+07 000E+00 000E+00 650E+00 000E+00 286E+07 000E+00 000E+00 800E+00 000E+00 558E+06 000E+00 000E+00 100E+01 000E+00 119E+06 000E+00 000E+00
Total 442E+13 113E+16 231E+13 284E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE2R2B14cut bWasteStreamE2R1B14cut cWasteStreamE2R3B14cut dWasteStreamE2R4B14cut
31
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 9 Gamma and Neutron Sources for the Design Basis PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary
(MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 273E+11 121E+15 188E+11 175E+11 100E-01 000E+00 100E-01 528E+10 329E+14 277E+10 339E+10 400E-01 316E+07 200E-01 128E+10 245E+14 117E+10 819E+09 900E-01 161E+08 300E-01 639E+08 713E+13 633E+08 407E+08 140E+00 148E+08 400E-01 850E+08 455E+13 164E+09 533E+08 185E+00 109E+08 600E-01 492E+08 226E+14 269E+10 337E+07 300E+00 191E+08 800E-01 291E+09 237E+15 160E+10 186E+09 643E+00 174E+08 100E+00 540E+09 122E+14 248E+09 341E+09 200E+01 154E+07 133E+00 154E+13 195E+14 797E+12 990E+12 Total 830E+08 166E+00 435E+12 450E+13 225E+12 280E+12
--
200E+00 235E+00 152E+11 149E+02 215E-02 250E+00 103E+08 517E+10 534E+07 664E+07 300E+00 160E+05 379E+09 829E+04 103E+05 400E+00 943E-10 497E+08 155E-10 519E-10 500E+00 000E+00 282E+07 000E+00 000E+00 650E+00 000E+00 113E+07 000E+00 000E+00 800E+00 000E+00 222E+06 000E+00 000E+00 100E+01 000E+00 471E+05 000E+00 000E+00
Total 201E+13 486E+15 105E+13 129E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B11cut bWasteStreamE5R1B11cut cWasteStreamE5R3B11cut dWasteStreamE5R4B11cut
32
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 10 Gamma and Neutron Sources for the Average PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 336E+10 670E+14 186E+10 217E+10 100E-01 00000E+00 100E-01 602E+09 199E+14 314E+09 387E+09 400E-01 748E+06 200E-01 146E+09 126E+14 853E+08 936E+08 900E-01 382E+07 300E-01 730E+07 389E+13 439E+07 469E+07 140E+00 352E+07 400E-01 947E+07 263E+13 716E+07 607E+07 185E+00 261E+07 600E-01 141E+07 205E+13 504E+08 383E+06 300E+00 469E+07 800E-01 208E+09 124E+15 192E+09 144E+09 643E+00 418E+07 100E+00 208E+09 110E+13 164E+09 144E+09 200E+01 365E+06 133E+00 175E+12 295E+13 909E+11 112E+12 Total 199E+08 166E+00 494E+11 513E+12 257E+11 318E+11
--
200E+00 973E-01 675E+10 614E+01 872E-03 250E+00 117E+07 353E+09 609E+06 754E+06 300E+00 182E+04 288E+08 944E+03 117E+04 400E+00 186E-11 198E+07 149E-11 127E-11 500E+00 000E+00 669E+06 000E+00 000E+00 650E+00 000E+00 269E+06 000E+00 000E+00 800E+00 000E+00 527E+05 000E+00 000E+00 100E+01 000E+00 112E+05 000E+00 000E+00
Total 229E+12 237E+15 119E+12 147E+12
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B9cut bWasteStreamE5R1B9cut cWasteStreamE5R3B9cut dWasteStreamE5R4B9cut
33
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 11 Gamma and Neutron Axial Source Profiles for a PWR Assembly
Axial boundaries (From midplane)
(cm)
TOP BOTTOM
Neutron Gamma Ne utron Gamma 000 1554 1117 1554 1117 1143 1537 1114 1571 1120 2286 1521 1111 1588 1123 3429 1504 1108 1605 1126 4572 1486 1104 1622 1129 5715 1464 1100 1636 1131 6858 1438 1095 1648 1133 8001 1401 1088 1657 1135 9144 1350 1078 1654 1134
10287 1277 1063 1625 1129 11430 1165 1039 1554 1117 12573 0998 09995 1414 1091 13716 0769 09365 1172 1041 14859 0492 08375 0816 0951 16002 0220 06850 0402 0797 17145 0046 04625 0092 0551 18288 00 00 00 00
Source Reference 2219 Table S445
34
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
63 MCNP SPECIFIC INPUT
631 Source Probability
A linear radial distribution is used for all gamma and neutron sources The linear radial distribution is sam pled usi ng the built-in power function p(x) = xc a with a = 1 for the radial direction This sampling method results in a uniform source distribution over the area bounded by the outer radius of the source
The source axial distributions are unifor m for all four source regions The a xial uni form xp(x) = c distribution is sampled using the built-in power function a with a = 0 for extent
The energy distribu tions of the gamma and neutron sour ce term s are treated as energ y probabilities and are applied in MCNP5 using SISP cards
632 Dose Rate and Flux Tallies
MCNP5 dose rate calculations feature separate runs for the following calculation types
bull a photon transport calculation for prim ary ga mma contribution to the dose rates fr om photon fluxes
bull a coupled neutronphoton transport calculat ion for neutrons a nd secondary gamma (photons generated by neutron be ing captured) contributions to dose rates from neutron and gamma fluxes
The tally type F2 is us ed in th is d esign ca lculation as f lux estim ators The type F2 tally evaluates the flux averaged over a surface in particlescm2s
To generate dose ra tes in te rms of remhr the FM (tally multiplier ) and DEDF (dose energydose conversion factors) cards are used to en ter the tally multiplier f actor (source intensity in particless) energy boundaries in MeV and corresponding dose conversion factors in (remhr)(particlescm2s) respectively These factors were used in the input files
In order for the F2 tally to accum ulate flux ov er a surface a specific s urface area is requ ired The SD cards are used to enter a surface area in cm2 over which the flux will be tallied for an F2 tally
633 Variance Reduction Techniques
Variance reduction technique is usually em ployed in order to increase the efficiency of a calculation and obtain statistically m eaningful results within re asonable com puter tim e In Monte Carlo calculations when variance reduction scheme is employed the weights of particles are adjusted in order to account for the biasing and to preserve a fair game
Geometry splitting and Russian roulette techniques described in Reference 2224 (pp 2-140 ndash 2-142) are useful in shielding calculations and therefore deployed in all the MCNP5 runs
35
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
As particles migrate in an important direction (toward the detector) they are increased in number to provide better sampling by means of geometry splitting across geometric boundaries Russian roulette (the reverse process) is played when particles travel in an unimportant direction to allow termination of unim portant histories The IMP card required for every cel l ca rd is us ed to implement this technique
The other variance reduction technique deployed in the MC NP5 runs is source intensity biasing for the gamma sources from the four source regions (active fuel bottom end-fitting plenum and top end-fitting) The natural total gamma source intensity of comm ercial SNF is dom inated by the gamma source in the active fuel region This active fuel gamma source usually accounts for over 95 o f the total g amma source intens ity In order to im prove the efficiency of the axial dose rate calculations a biased source probability distribution is employed for the prim ary gamma dose rate calculations The biased gamma source probability distribution is chosen to be 005 080 010 and 005 for the bottom end-fitting the active fuel the plenum and the top end-fitting regions respectively
64 DOSE CONVERSION FACTORS
Project Design Criteria Document (Reference 2211 Se ction 41015) requires the use of flux-to-dose rate conversion fact ors from ANSIANS-611-1977 (Reference 221) for dose rate evaluations Table 16 lists the neutron and ga mma dose conversion factors used in the MCNP5 calculations
Table 12 Gamma and Neutron Flux to Dose Conversion Factors
Gamma Neutron Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
001 396E-06 140 251E-06 250E-08 367E-06 003 582E-07 180 299E-06 100E-07 367E-06 005 290E-07 220 342E-06 100E-06 446E-06 007 258E-07 260 382E-06 100E-05 454E-06 010 283E-07 280 401E-06 100E-04 418E-06 015 379E-07 325 441E-06 100E-03 376E-06 020 501E-07 375 483E-06 100E-02 356E-06 025 631E-07 425 523E-06 100E-01 217E-05 030 759E-07 475 560E-06 500E-01 926E-05 035 878E-07 500 580E-06 100E+00 132E-04 040 985E-07 525 601E-06 250E+00 125E-04 045 108E-06 575 637E-06 500E+00 156E-04 050 117E-06 625 674E-06 700E+00 147E-04 055 127E-06 675 711E-06 100E+01 147E-04 060 136E-06 750 766E-06 140E+01 208E-04 065 144E-06 900 877E-06 200E+01 227E-04 070 152E-06 1100 103E-05 080 168E-06 1300 118E-05 100 198E-06 1500 133E-05
Source Reference 221 Tables 1 and 3
36
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION
By def inition (Ref erence 2224 Equation 219) the estimated st atistic relative error of the i component is
Ri = Si
2
Equation 6Ti
where i = tally component index Ri = relative error of the i component S2
i = variance of the i component Ti = tally i component
For a result (ie dose rate) computed as a sum of different tallies the statistical relative error of the computed value is o btained from the variance of the result - S2
total which is th e sum of the estimated variances of the individual tallies S2
i n
2 2STotal = sum Si Equation 7 i=1
where S2Total = total estimated variance
n = total number of components Therefore the total tally value (dose rate) and the associated relative error are derived according to Equations 8 and 9
n TTotal = sumTi Equation 8
i=1
n n
sum (Ri timesTi )2
2 sum Si 2
STotal = i=1 = i=1 Equation 9RTotal = TTotal TTotal TTotal
where RTotal = total estimated relative error TTotal = total estimated tally
Equations 8 and 9 are utilized in Attachm ent II to ev aluate to tal dos e ra tes and their r elative errors
37
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
7 RESULTS AND CONCLUSIONS
71 RESULTS
The following sections summarize the results of this calculation Section 711 presents results for Conceptual Cask A while Section 712 for Conceptual Cask B Section 713 provides comparisons of the dose-rate reduction factors du e to the two conceptual casks and the axial source distributions in the active fuel region Do se rates and relative errors can be found in Attachment II within the output files and Excel files
711 Dose Rates of Conceptual Cask A
This section presents dose-rate results of the calculation sets 1 and 2 as described in Section 61 for Cask A Set 1 has axial p rofile sources in the active fuel region a nd consist of six runs resulting from the three PWR SNF source term s (maximum design basis and average) and the two radiation sources (gammas and neutrons) Set 2 has uniform axial sources in the active fuel region and consists of six run s r esulting f rom the th ree P WR SNF source term s and th e tw o radiation sources
As described in Section 61 dose ra tes are calculated at the three exterior surfaces (radial top and bottom) and at distances 1 m and 2 m from the exterior surfaces The total dose rates for set 1 are presented in Tables 13 14 and 15 for the ra dial top and bottom dire ctions respectively However the com ponents (primary gamma neutr on and secondary gamma) contributing to the total dose rates as well as the re lative error calculations can be found in Attachment II Excel file MCNP-Results1xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 2 are shown in Tables 16 17 and 18 The dose-rate components and the relative errors can be found in A ttachment II Excel file MCNP-Results2xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 13 and 16 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 14 and 17 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 15 and 18 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carrying th e maximum PWR SNF Based on the results in Tables 13 through 18 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask A indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these 6 tables the d ose-rate red uction f actors between the m aximum and the design basis fuels the maxim um and the averag e fuels and th e design basis and the average fuels are a lso presented
38
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 320E-02 00237 116E-02 00222 262E-03 00219 275 1223 445
1 m 133E-02 00164 494E-03 00171 106E-03 00162 269 1261 468 2 m 749E-03 00198 285E-03 00225 584E-04 00162 263 1282 488
Ring Detectors 1 m 133E-02 00116 492E-03 00115 108E-03 00124 271 1229 454 2 m 756E-03 00118 279E-03 00110 605E-04 00128 271 1250 462
Source Attachment II MCNP-Results1xls worksheet Summary
Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 142E-02 00368 628E-03 00446 934E-04 00483 226 1520 672
1 m 570E-03 00289 263E-03 00426 375E-04 00381 217 1520 701 2 m 265E-03 00364 123E-03 00547 169E-04 00374 216 1575 730
Point Detectors 1 m 598E-03 00238 274E-03 00271 402E-04 00354 219 1489 681 2 m 273E-03 00218 123E-03 00245 180E-04 00336 221 1515 684
Source Attachment II MCNP-Results1xls worksheet Summary
Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 653E-03 00298 265E-03 00276 510E-04 00341 247 1278 518
1 m 276E-03 00238 112E-03 00208 207E-04 00249 248 1334 539 2 m 125E-03 00185 508E-04 00199 933E-05 00246 246 1336 544
Point Detectors 1 m 291E-03 00227 118E-03 00203 218E-04 00242 247 1335 540 2 m 130E-03 00209 524E-04 00187 955E-05 00233 247 1357 549
Source Attachment II MCNP-Results1xls worksheet Summary
Tables 13 14 and 15 are results of calculation set 1 for conceptual Cask A with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
39
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 265E-02 00247 990E-03 00222 215E-03 00278 268 1234 461
1 m 116E-02 00178 468E-03 00549 960E-04 00189 248 1208 488 2 m 713E-03 00273 265E-03 00161 602E-04 00360 269 1184 439
Ring Detectors 1 m 117E-02 00120 454E-03 00132 979E-04 00141 259 1199 463 2 m 722E-03 00130 276E-03 00141 589E-04 00153 261 1226 469
Source Attachment II MCNP-Results2xls worksheet Summary
Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 199E-02 00461 827E-03 00455 147E-03 00536 241 1359 564
1 m 849E-03 00564 323E-03 00314 563E-04 00418 263 1507 574 2 m 415E-03 00832 158E-03 00603 253E-04 00501 263 1641 623
Point Detectors 1 m 877E-03 00348 353E-03 00275 615E-04 00391 248 1426 574 2 m 393E-03 00341 160E-03 00278 270E-04 00378 246 1454 590
Source Attachment II MCNP-Results2xls worksheet Summary
Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 879E-03 00374 356E-03 00333 669E-04 00406 247 1315 533
1 m 365E-03 00223 147E-03 00209 269E-04 00253 248 1358 548 2 m 164E-03 00229 674E-04 00205 120E-04 00248 243 1364 560
Point Detectors 1 m 383E-03 00217 155E-03 00204 285E-04 00248 247 1347 546 2 m 172E-03 00197 689E-04 00186 124E-04 00225 249 1391 558
Source Attachment II MCNP-Results2xls worksheet Summary
Tables 16 17 and 18 ar e results of calculation set 2 for conceptual Cask A with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
40
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
FIGURES
Page
Figure 1 Geometry and Tally Scheme for the TAD Transportation Cask 23
5
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
TABLES
Page
Table 1 Geometry and Materials of Conceptual TAD Transportation Cask A 15 Table 2 Geometry and Materials of Conceptual TAD Transportation Cask B 16 Table 3 Dimensions of TAD Canister 24 Table 4 BampW 15x15 Mark B Fuel Assembly Description 26 Table 5 PWR Fuel Assembly Regions 27 Table 6 Chemical Compositions of Materials 28 Table 7 Isotopic Compositions of Homogenized PWR Assembly Regions 29 Table 8 Gamma and Neutron Sources for the Maximum PWR SNF Assembly 31 Table 9 Gamma and Neutron Sources for the Design Basis PWR SNF Assembly 32 Table 10 Gamma and Neutron Sources for the Average PWR SNF Assembly 33 Table 11 Gamma and Neutron Axial Source Profiles for a PWR Assembly 34 Table 12 Gamma and Neutron Flux to Dose Conversion Factors 36 Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources 39 Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources 39 Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources 39 Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources 40 Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources 40 Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources 40 Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources 42 Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources 42 Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources 42 Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources 43 Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources 43 Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources 43 Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources 44 Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources 45 Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources 45 Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources 45 Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources 45 Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial
Sources 46 Table 31 Recommended Average Radial Dose-Rate Reduction Factors 46 Table 32 Recommended Average Top Dose-Rate Reduction Factors 46 Table 33 Recommended Average Bottom Dose-Rate Reduction Factors 46 Table I-1 Listing of Electronic Files on Compact DiscI-1
6
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ACRONYMS AND ABBREVIATIONS
ACRONYMS
ANS American Nuclear Society
ANSI American National Standards Institute
ASTM American Society for Testing and Materials
BSC Bechtel SAIC Company LLC
BWR Boiling Water Reactor
CD Compact disc
CSNF Commercial Spent Nuclear Fuel
DB Design Basis
DOE U S Department of Energy
DPC Dual Purpose Canister
NRC U S Nuclear Regulatory Commission
PCSA Preclosure Safety Analysis
PWR Pressurized Water Reactor
RPM Repository Project Management
SNF Spent Nuclear Fuel
SS 316 Stainless Steel 316
TAD Transportation Aging and Disposal
WP Waste Package
YMP Yucca Mountain Project
ABBREVIATIONS and UNITS
b barn
cm centimeter
7
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
g gram
GWd gigawatt-day
hr hour
in inch
kg kilogram
m meter
mrem millirem
MeV million electron volt
MTU metric ton uranium
s second
8
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
1 PURPOSE
The purpose of this calculation is to calcu late th e dose ra tes of two conceptua l tr ansportation casks each carrying a Transportation Aging and Disposal (TAD) canister separately loaded with the average design basis (DB) and m aximum comm ercial spent nuc lear fuel (CSNF) assemblies Then the dose-ra te reduction f actors between the m aximum and the design basis fuels the d esign bas is and the average fuels and the m aximum and the averag e fuels are computed
The results of this calculation may be used to substantiate the dose-rate reduction factors such as those in the engineering study Repository ALARA Goal Compliance (Reference 227) which is cited as a reference in a Preclosure Safety Analyses (PCSA) calculation that supports the License Application
The calculations contained in this docum ent are developed by Nuclear and Radiological Engineering of the Repository Project Mana gement (RPM) organization Yucca Mountain Project (YMP) personnel from Nuclear and Radiological Engineering should be consulted before use of the calculations for purposes other than those stated herein or use by individuals other than personnel in Nuclear and Radiological Engineering
9
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
2 REFERENCES
21 PROJECT PROCEDURESDIRECTIVES
211 IT-PRO-0011 Rev 0010 Software Management Las Vegas Nevada Bechtel SAIC Company
212 EG-PRO-3DP-G04B-00037 Rev 14 Calculations and Analyses Las Vegas Nevada Bechtel SAIC Company
213 IT-PRO-0012 Rev 007 Qualification of Software Las Vegas Nevada Bechtel SAIC Company
22 DESIGN INPUTS
221 ANSIANS-611-1977 Neutron and Gamma-Ray Flux-to-Dose-Rate Factors La Grange Park Illinois American Nuclear Society TIC 239401
222 ASME (American Society of Mechanical Engineers) 2004 2004 ASME Boiler and Pressure Vessel Code 2004 Edition New York New York American Society of Mechanical Engineers TIC 256479 ISBN 0-7918-2899-9
223 ASM International 1990 Properties and Selection Nonferrous Alloys and Special-Purpose Materials Specific Metals and Alloys Volume 2 of Metals Handbook 10th Edition Page 666 [Materials Park Ohio] American Society for Metals TIC 239807
224 ASTM (American Society for Testing and Materials) B 811-90 1991 Standard Specification for Wrought Zirconium Alloy Seamless Tubes for Nuclear Reactor Fuel Cladding Philadelphia Pennsylvania American Society for Testing and Materials TIC 239780
225 ASTM G 1-90 (Reapproved 1999) 1999 Standard Practice for Preparing Cleaning and Evaluating Corrosion Test Specimens West Conshohocken Pennsylvania American Society for Testing and Materials TIC 238771
226 Bowman SM Hermann OW and Brady MC 1995 Sequoyah Unit 2 Cycle 3 Volume 2 of Scale-4 Analysis of Pressurized Water Reactor Critical Configurations ORNLTM-12294V2 Oak Ridge Tennessee Oak Ridge National Laboratory TIC 244397 [DIRS 123796]
227 BSC (Bechtel SAIC Company LLC) 2008 Repository ALARA Goal Compliance 000-30R-MGR0-04000-000 REV 000 Las Vegas Nevada Bechtel SAIC Company ACC ENG200802050014 [DIRS 184957]
228 BSC 2002 Subsurface Shielding Source Term Specification Calculation 000-00C-WER0-00100-000-00A Las Vegas Nevada Bechtel SAIC Company ACC MOL200212160076 ENG200508150022
10
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
229 BSC 2004 PWR Source Term Generation and Evaluation 000-00C-MGR0-00100-000-00B Las Vegas Nevada Bechtel SAIC Company ACC ENG200405240007
2210 BSC 2008 Basis of Design for the TAD Canister-Based Repository Design Concept 000-3DR-MGR0-00300-000-003 Las Vegas Nevada Bechtel SAIC Company ACC ENG200810060001
2211 BSC 2007 Project Design Criteria Document 000-3DR-MGR0-00100-000-007 Las Vegas Nevada Bechtel SAIC Company ACC ENG200710160005 ENG200711080001 ENG200712200003 ENG200801070001 ENG200801070002 ENG200801070016 ENG200801070017 ENG200801310006 ENG200803050002 ENG200803050011 ENG200803050012 ENG200803060009 ENG200803130004 ENG200807100001 ENG200811120006 ENG200811140004
2212 BSC 2004 PWR and BWR Source Term Sensitivity Study 000-00C-MGR0-00300-000-00A Las Vegas Nevada Bechtel SAIC Company ACC ENG200401140003 ENG200508150023
2213 BSC 2007 Dose Rate Calculation for Exhaust Main Drifts 800-00C-SS00-00700-000-00B Las Vegas Nevada Bechtel SAIC Company ACC ENG200711050017 ENG200803060001
2214 BSC 2006 Dual Purpose Canister Opening Study 050-30R-WHS0-00600-000-000 Las Vegas Nevada Bechtel SAIC Company ACC ENG200612200023
2215 BSC 2007 GROA Shielding Requirements Calculation 000-00C-MGR0-03300-000-00B Las Vegas Nevada Bechtel SAIC Company ACC ENG200705290037
2216 BSC 2002 Concrete Shielding Calculation for Dry Facility 1 110-00C-CS10-00100-000-00A Las Vegas Nevada Bechtel SAIC Company ACC MOL200301140075
2217 BSC 2003 Shielding Design Calculations for Dry Facility 1 110-00C-CS10-00200-000-00A Las Vegas Nevada Bechtel SAIC Company ACC ENG200306020003
2218 CRWMS MampO 1998 Calculation of the Effect of Source Geometry on the 21-PWR WP Dose Rates BBAC00000-01717-0210-00004 REV 00 Las Vegas Nevada CRWMS MampO ACC MOL199902220059 [DIRS 102134]
2219 CRWMS MampO 2000 Users Manual for SCALE-44A 10129-UM-44A-00 Las Vegas Nevada CRWMS MampO ACC MOL200011300136 MOL200108220084 MOL200108220085 MOL200108220086 MOL200108220087 [DIRS 153872]
2220 DOE (US Department of Energy) 1987 Appendix 2A Physical Descriptions of LWR Fuel Assemblies Volume 3 of Characteristics of Spent Fuel High-Level Waste and Other Radioactive Wastes Which May Require Long-Term Isolation DOERW-0184 Washington DC US Department of Energy Office of Civilian Radioactive Waste Management ACC HQX198804050024 [DIRS 132333]
11
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
2221 DOE 2007 Software Validation Report for MCNP5 v140 Document ID 11199-SVR-140-00-WINXP Las Vegas Nevada US Department of Energy Office of Repository Development ACC MOL200702280252 [DIRS 180516]
2222 DOE 2008 Transportation Aging and Disposal Canister System Performance Specification WMO-TADCS-000001 Rev 1 ICN 1 Washington DC US Department of Energy Office of Civilian Radioactive Waste Management ACC DOC200803310001 [DIRS 185304]
2223 Harmon CD II Busch RD Briesmeister JF and Forster RA 1994 Criticality Calculations with MCNPtrade A Primer LA-12827-M Los Alamos New Mexico Los Alamos National Laboratory TIC 234014 [DIRS 154532]
2224 LANL (Los Alamos National Laboratory) 2004 MCNP mdash A General Monte Carlo N-Particle Transport Code Version 5 (Appendix H is not included) LA-UR-03-1987 Volume I Los Alamos [New Mexico] Los Alamos National Laboratory ACC MOL200510240126 [DIRS 176521]
2225 MCNP5 V 140 2007 Windows XP STN 11199-140-00 [DIRS 180515]
2226 Parrington JR Knox HD Breneman SL Baum EM and Feiner F 1996 Nuclides and Isotopes Chart of the Nuclides 15th Edition San Jose California General Electric Company and KAPL Inc TIC 233705 LC Call Number QC7935 N8622 1996
2227 Punatar MK 2001 Summary Report of Commercial Reactor Criticality Data for Crystal River Unit 3 TDR-UDC-NU-000001 REV 02 Las Vegas Nevada Bechtel SAIC Company ACC MOL200107020087 [DIRS 155635]
2228 Sisley SE 2002 Transportation License Application for the FuelSolutionstrade System (TAC No L23311) Submittal of the FuelSolutiontrade Transportation SARs Revision 3 Letter from SE Sisley (BNFL) to the NRC April 11 2002 BFSNRC 02-011 with enclosures TIC 255245 [DIRS 171545]
NOTE Reference 2220 is a direct input but is not QA QA It is justified as acceptable for the intended use as it is directly from the DOE and is considered the best available data on the subject The referenced values cited in Tables 3 and 4 are valid for use since they are reliable and reasonable based on engineering judgment
23 DESIGN CONSTRAINTS
231 10 CFR 71 2008 Energy Packaging and Transportation of Radioactive Material Internet Accessible [DIRS 185678]
12
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
24 DESIGN OUTPUTS
The resu lts of this calculation will be us ed to substan tiate th e dose reduc tion f actor in the Repository ALARA Goal Compliance (Reference 227) which is cited as a reference in a PCSA calculation that supports the License Application
13
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
3 ASSUMPTIONS
31 ASSUMPTIONS REQUIRING VERIFICATION
None
32 ASSUMPTIONS NOT REQUIRING VERIFICATION
Assumptions 321 322 and 323 are m odeling assum ptions and do not require further verification The m aterials and dim ensions for the TAD canister and for the conceptu al transportation casks are only selected to charac terize two tr ansportation casks th at m eet 10 CFR7147 (Reference 231) dose rates when lo aded with the ldquom aximumrdquo and ldquoaveragerdquo pressurized water re actor (PW R) assem blies re spectively There is n o need to v erify those dimensions or m aterials at a later date The ca lculated results in Sect ion 711 verify that the conceptual casks would meet 10 CFR 7147 (Reference 231) dose rates
321 Material and Wall Thickness of TAD Canister
Assumption It is assumed that the TAD canister is made of stainless steel 316 (SS 316) and has a wall thickness of 025 in for the radial and bottom shells
Rationale Currently the design of the TAD canis ter d oes not ex ist Based on a survey of existing m ultipurpose a nd dual purpose caniste rs (DPC) (Ref erence 2214 p 56) a 025 in thickness is below the wall thick ness of any existing c anisters For the purp ose of this calculation this assumption leads to higher and conservative external dose rates Since SS 316 is the sam e material used for the waste pack age inner shell it is a l ogical cho ice f or the TAD canister
Although Reference 2214 is an engineering study with a QA N A status it is used here as an indirect input to support the assumption which is conservative for dose rate calculations
Usage This assumption is used in Sections 621 and 625
322 Material and Thickness of TAD Shield Plug
Assumption It is assu med that the TAD shield plug is made of SS 316 and has a thickness of 11 in
Rationale Currently the design of the TAD canister doe s not exist A thick shield plug of 11 in (Reference 2215 Table 12) is needed to keep the m aximum contact dose rate of the top surface below 1000 mrem hr (Reference 2222 Section 314) Since SS 316 is the sam e material used for the waste package inner shell it is a logical choice for the TAD shield plug
Usage This assumption is used in Section 621
14
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
323 Geometry and Materials of Conceptual TAD Transportation Casks
Assumption Two conceptual TAD transpo rtation casks designated as Cask A and Cask B are assumed to have a cylindrical geom etry and m aterials specified in Tab les 1 and 2 respectively The casks are basically construc ted of an inner layer of SS 316 for ga mma shielding a m iddle layer of 5-borated polyethylen e for neutron shielding and a th in outer layer of SS 316 whic h serves a structural function as well as shielding secondary gamma rays
Both Cask A and Cask B have a cavity height of 53785 cm (21175 in) and a cavity diameter of 16891 cm (6650 in) However Cask A has a total height of 610845 cm (24049 in) and an outside diameter of 26797 cm (10550 in) while the total height and outside diameter of Cask B are 58885 cm (23183 in) and 24765 cm (9750) respectively
Cask A will provide shielding to m eet the exterior radiat ion standards of 10 C FR 7147(b) (Reference 231) when loaded w ith a TAD canister carrying th e maximum PWR spent nuclear fuel (SNF) Cask B will satisf y the same radiation standards when loade d with a TAD caniste r carrying the average PWR SNF
Table 1 Geometry and Materials of Conceptual TAD Transportation Cask A
Component Dimension
Material (cm) (in)
Total Height 61085 2404 9 NA
Outside Diameter 26797 1055 0 NA
Cask Cavity Height 53785 2117 5 NA
Cask Cavity Diameter (Radius) 16891 (8446) 6650 (3325) NA
Radial Gamma Shield Thickness (Radius)a 3302 (11748)a 1300 (4625)a SS 316
Radial Neutron Shield Thickness (Radius)b 1524 (13272)b 600 (5225)b 5-borated polyethylene
Radial Outer Shell Thickness (Radius)c 127 (13399)c 050 (5275)c SS 316
Top Gamma Shield Thickness (Axial Position)d 600 (54385)d 236 (21411)d SS 316
Top Neutron Shield Thickness (Axial Position)d 1000 (55385)d 394 (21805)d 5-borated polyethylene
Top Outer Shell Thickness (Axial Position)d 200 (55585)d 079 (21884)d SS 316
Bottom Gamma Shield Thickness (Axial Position)d 35365 (-360)d 1392 (-1417)d SS 316
Bottom Neutron Shield Thickness (Axial Position)d 15 (-510)d 591 (-2008)d 5-borated polyethylene
Bottom Outer Shell Thickness (Axial Position)d 4 (-550)d 157 (-2165)d SS 316 a11748 = 3302 + 8446 and 4625 = 1300 + 3325 b13272 = 1524 + 11748 and 5225 = 600 + 4625 c13399 = 127 + 13272 and 5275 = 050 + 5225 dCoordinate relative to the bottom of the fuel assembly as modeled in MCNP5
15
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 2 Geometry and Materials of Conceptual TAD Transportation Cask B
Component Dimension
Material (cm) (in)
Total Height 58885 2318 3 NA
Outside Diameter 24765 9750 NA
Cask Cavity Height 53785 2117 5 NA
Cask Cavity Diameter (Radius) 16891 (8446) 6650 (3325) NA
Radial Gamma Shield Thickness (Radius)a 254 (10986)a 1000 (4325)a SS 316
Radial Neutron Shield Thickness (Radius)b 127 (12256)b 500 (4825)b 5-borated polyethylene
Radial Outer Shell Thickness (Radius)c 127 (12383)c 050 (4875)c SS 316
Top Gamma Shield Thickness (Axial Position)d 8 (54585)d 315 (21490)d SS 316
Top Neutron Shield Thickness (Axial Position)d None Non e NA
Top Outer Shell Thickness (Axial Position)d None Non e NA
Bottom Gamma Shield Thickness (Axial Position)d 3837 (-390)d 1510 (-1535)d SS 316
Bottom Neutron Shield Thickness (Axial Position)d 300 (-420)d 118 (-1654)d 5-borated polyethylene
Bottom Outer Shell Thickness (Axial Position)d 100 (-430)d 039 (-1693)d SS 316 a10986 = 254 + 8446 and 4325 = 1000 + 3325 b12256= 127 + 10986 and 4825 = 500+ 4325 c12383 = 127 + 12256 and 4875 = 050 + 4825 dCoordinate relative to the bottom of the fuel assembly as modeled in MCNP5
Rationale Currently a design for the TAD transporta tion cask does not exist The casks assumed for this calculation are so lely for estim ation of the dose reduction due to different source terms This is a conceptual repres entation only used in this calculation to estim ate the parameters of interest
Usage This assumption is used in Sections 61 and 622
324 Usage of Unirradiated Fuel for Commercial SNF
Assumption It is assumed that the active fuel region of the commercial SNF assembly contains the same isotopic concentrations as the fresh uni rradiated fuel and that the concentrations of fresh fuel with 5 initial enrichm ent corresp onding to m aximum SNF are used for all other SNFs
Rationale This assumption is a standard practice for shielding calculations throughout the industry accepted by the U S Nucle ar Regulatory Commission (NRC) (Reference 2228 Table 53-5) It sh ould be noted that this assumption applies to material composition only it does no t apply to source terms which are based on the characteristics of spent fuel
Usage This assumption is used in Sections 624 and 626
325 Homogenization of Radiation Source Regions
Assumption It is assu med that a commercial SNF assembly consis ts of four distinct reg ions (active fuel bottom end-fitting plenum and top end-fitting) The materials and radiation sources
16
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
of each assembly region are homogenized inside a volume defined by the TAD cavity radius and region height
Rationale The assembly representation is consistent with the industry practice for shielding calculations accepted by NRC (Reference 2228 Figure 53-6) The effec t of source homogenization is twofold (1) it d ecreases th e m ass de nsity of the source region and (2) it places source points slightly closer to detector locations thus reducing radiation attenuation The resu lts of Calculation of the Effect of Source Geometry on the 21-PWR WP Dose Rates (Reference 2218 pp 22-26) indicate that th e effect of assem bly homogenization gives nearly the same or conservative dose rates as the explicit fuel assembly model
Usage This assumption is used in Section 624
326 Ignoring Internal Fuel Basket Materials
Assumption It is assumed that the internal fuel basket materials are ignored
Rationale Inclusion of fuel basket m aterials in the smeared m aterial com position would increase the overall density and consequently increase the attenuati on of the radiation Therefore this assumption is conservative
Usage This assumption is used in Sections 621 624 and 626
17
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
4 METHODOLOGY
41 QUALITY ASSURANCE
This calculation was prepared in accordance with EG-PRO-3DP-G04B-00037 Calculations and Analyses (Reference 212) The results of th is calculation provides worker dose assessm ent adjustments and this will id entify radio logical hazards f or f acilities im portant to saf ety Therefore the approved version is designated as QA QA
42 USE OF COMPUTER SOFTWARE
421 Baseline Software
The Monte Carlo N-Particle com puter pr ogram (MCNP5) version 140 (Reference 2225) is used to calculate the dose rates (neutron pr imary gamm a and secondary gamm a) at various locations around a transportation cask and an aging overpack
The software specifications are as follows
bull Program Name MCNP5 bull VersionRevision Number Version 140 bull Operating Systems Windows XP bull Software Tracking Number 11199-140-00 bull Computer Type Dell OPTIPLEX GX620
MCNP5 which is Level 1 software is (a) appropriate for three-dim ensional neutron gamma and coupled neutrongamma shielding calculations (b) used within th e range of validation as documented in Software Validation Report for MCNP5 v140 (Reference 2221) and (c) obtained from Software C onfiguration Managem ent and qualified in accordance with procedure IT-PRO-0012 Qualification of Software (Reference 213) Therefore MCNP5 code is suitable for use in this design calculation All MCNP5 input and output files docum ented in this calculation are provided on a compact disc (CD) as Attachment II
All MCNP cases are executed on one of the following Q com puters QNW -004184 QNW -004187 QNW-004194 and QNW-004196 as shown in the output files
422 Commercial off the Shelf Software
The Excel sof tware is used to c alculate var ious inpu t values (i e atom densities weight percentages geometrical dimensions normalized source spectra and probabilities etc) Standard functions of Excel are also used in this desi gn calculation to display results (ie gamma and neutron dose rates) in tabular and graphic forms and to perform relative error calculations
The software specifications are as follows
bull Program Name Excel bull VersionRevision Number Microsoftreg Excel 2003
18
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
bull This software is installed on a persona l com puter running Microsoft W indows XP (central processing unit number 151834)
The user defined for mulas inputs results and gr aphical representations have been verified by hand calculations or visual inspection and are documented in sufficient detail to allow an independent repetition of the com putations Calculations were verifi ed by hand and graphical representations were found accurate by visual inspection
Per Software Management Microsoftreg Excel is not requir ed to be qualif ied due to its commercial availability status (Reference 211 Attachment 4 p 55 bullet 2)
43 CALCULATION APPROACH
This calculation em ploys the qualified so ftware MCNP5 version 140 (Reference 2225) a three-dimensional Monte Carlo code for pe rforming neutron and coupled neutron-gamm a calculations to estim ate dose rates at sele cted locations on and surrounding a conceptual transportation cask containing a loaded TAD canister
431 MCNP5 Program
MCNP5 a general Monte Carlo part icle transport code sim ulates particle transport through a three-dimensional representation of the nuclear system being analyzed During the random walk of particles through the system described by the geom etry the c ode collects inform ation about various events (su rface cross ing collis ions trac k leng th etc) and es timates fluxes in various geometric configurations specified as tallies by the user It also estimates the statistical precision of the results in the form of relative errors (Reference 2224 pp 1-2 to 1-8)
Per Project Design Criteria Document (Reference 2211 Section 41015) the flux estim ates are converted to dose rates using the Am erican Nuclear Society (ANS) flux-to-dose rate conversion factors for gammas and neutrons (R eference 221) The simple variance reduction techniques of Geometry SplittingRussian Roulette and source probability biasing (Sections 631 and 633) are used to enhance computational efficiency
19
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
5 LIST OF ATTACHMENTS
Number of Pages Attachment I List of Electronic Files on the CD 3 Attachment II Compact Disc NA
20
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
6 CALCULATIONS
This sectio n provides inform ation necess ary to perform the calcu lations in this docum ent Section 61 describes the configurations the type of CSNF to be analyzed the number of MCNP runs and the locations where dose rates are ca lculated Section 62 provides the calculation input that includes the details of the geom etry m odel radiation source term s and m aterial compositions Input specific to MCNP dose -rate conversion factors and relative error calculation are described in the later sections
61 DESCRIPTION OF CALCULATIONS
Dose rate calculations are perform ed with the MCNP5 version 140 com puter code (Reference 2225) Two conceptual transportation casks Cask A and Cask B (Assum ption 323) are employed Each cask contains a TAD canister that is loaded with 21 ident ical PW R SN F assemblies Three PWR source term s are analy zed they are the source term s corresponding to the maximum design basis and average PW R SN Fs The characteris tics of the P WR source terms are presented in S ection 627 Each PWR source term has neutron and ga mma radiation sources that require separate MCNP5 runs For each radiation source an axial profile source and a uniform source for the active fuel region are considered The uniform source for the active fuel region is included in this calculation because this approach was used in combination with source peaking factors in certain calculations (Reference 2216 Sections 37 and 39 and Reference 2217 Section 5242)
The total number of MCNP5 runs is 24 which re sults from a com bination of two conceptual casks three PWR source terms two radiation sources and two axia l source distributions for the active fuel region These 24 runs are categorized into four calcula tion sets Each calculation set consists of six runs that is a combination of three PWR source te rms and two radiation sources The characteristics of each calculation set are as follows
1 Cask A with axial profile sources in the active fuel region
2 Cask A with uniform axial sources in the active fuel region
3 Cask B with axial profile sources in the active fuel region
4 Cask B with uniform axial sources in the active fuel region
For each MCNP5 run dose rates are calculated at the exte rior surfaces and at distances 1 and 2 meters from the exterior surfaces Surface tallies and detector tallies (ring and point detectors) as indicated in Figure 1 are e mployed in all runs Figure 1 is used to illustrate the dep loyment of the surface and detector tallies re lative to the so urce regions and it should not be interpreted as an exact geometry of any particular run Surface tallies are deployed at all three distances while ring and point detectors are used only at 1 m and 2 m and not at the cask surfaces Using point detectors near a surface or in any scattering media is not recommended because very large scores can occur f rom collisions close ( less than a f ew centimeters) to the point detecto rs that can lead to resu lts with high r elative e rrors thus m aking the ca lculation d ifficult to o btain r eliable answers
21
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
For the radial direction surface tallies at the three distances (contact 1 m and 2 m) are computed for three su rface segments (cylindrical rings) between the planes at Z = 145 175 2 05 and 235 cm The geometric locations of the segments are shown in Figure 1 The axial locations of these segments correspond to the m iddle of the active fuel region of the PWR SNF assemblies The average dose rates for each of the segm ents are calculated for the outside surface and surfaces at 1 m and 2 m from the cask surface Two ring detectors (instead of point detectors) are deployed at 1 m and 2 m for the radial dire ction Ring detectors instead of point detectors are used in order to capitalize on the symm etry around the cask axis thus im proving the efficiency of the calculations
In the axial direction the average d ose rates within three concentric radial surfaces defined by radii of 40 80 and 120 cm (shown in Figure 1) are calculated for the top and bottom surfaces and at distances 1 m and 2 m from these surfaces Finally point detectors at 1 m and 2 m from the top and bottom axial surfaces are employed
22
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Point Detector at 2 m x
Ring Ring Detector Detector at 2 m at 1 m
x x
Z = 00 cm
Z = 145 cm
Z = 175 cm
Z = 205 cm
Z = 235 cm
R = 80 cm
R = 120 cm
R = 40 cm
Active Fuel
Shield Plug
Top End-Fitting Plenum
Bottom End-Fitting
Ring Detector at 1 m
x
Point Detector at 1 m x
Ring Detector
at 2 m x
D = 26797 cm
H =
610
845
cm
Point Detector at 1 m x
Point Detector at 2 m x
Figure 1 Geometry and Tally Scheme for the TAD Transportation Cask
23
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
62 CALCULATION INPUT
Technical product input and sources of the input used in the deve lopment of this calculation are documented in this section Tables in this docum ent and in th e associated Microsoftreg Excel spreadsheets referenced m ay present num erical values with m any significant figures these values are not to be considered as high precision values since the significant figures are results of calculated values andor unit conversions
621 TAD Canister
The TAD canis ter will contain either 21 P WR or 44 BW R (boiling water reactor) SNF assemblies (Reference 2222 Section 321) While the canister design is iden tical for both PWR and BWR SNF assemblies the internal basket structure is different depending on the SNF assemblies However the internal basket stru cture m aterial is no t in cluded in the calcu lation model (Assumption 326)
The TAD canister is a right-circu lar cylinder with a diam eter of 665 in and a height between 186 and 212 in (Reference 2222 Section 321) The average and maximum total dose rates on the top surf ace of a loaded TAD ca nister must not exceed 800 and 1000 m remhr respectively (Reference 2222 Section 314) The TAD canister used in this calculation is m ade of SS 316 with a radial wall and bottom thickness of 025 in (Assumption 321) The top of the canister has a shield plug that is 11 in thick SS 316 (Ass umption 322) A thick shield plug is needed to keep the maxim um contact dose rate of th e top surface below 1000 m remhr The overall dimensions of the TAD canister are provided in Table 3
Table 3 Dimensions of TAD Canister
Component Dimension
(in) (cm)
Maximum heighta 212 53848
Outer diametera 665 16891
Thickness of bottom lidb 025 0635
Shell thicknessb 025 0635
Lifting Featurec 6 1524
Height without Lifting Feature 206 52324
Thickness of shield plugd 110 2794
aReference 2222 Section 311 bAssumption 321 cReference 2222 p Attachment C-1 dAssumption 322
622 Conceptual TAD Transportation Casks
Two conceptual TAD transportation casks designa ted as Cask A and Cask B are em ployed in this calculation (Assumption 323) They both have a cylindrical geometry with dimensions and materials specified in Tables 1 and 2 of Section 323 Cask A will provide shielding to meet the exterior radiation standards of 10 CFR 7147(b) (Reference 231) when loaded with a TAD
24
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
canister car rying the m aximum PWR SNF Cask B will s atisfy th e sa me radiatio n standa rds when loaded with a TAD canister c arrying the average PWR SNF The reason to analyze both Casks A and B is to cover a broad range of characteristics of the CSNF
The cavity dimensions of the conceptual cask s are 53785 cm (21175 in) in height and 16891 cm (665 in) in diam eter (Tab les 1 and 2) This cav ity will accommoda te the TAD canister described in Table 3 without the lifting feature This is the geometry model used in the MCNP5 calculations
623 Fuel Assembly Selection
PWR and BWR Source Term Sensitivity Study (Reference 2211 Tables 71 through 84) shows that the source terms generated for the Bamp W 15x15 Mark B fuel assembly with 475 kg uranium loading bound the source terms of other PWR assembly types ther efore this assembly type is selected as the representative PWR fuel assembly The gamma and neutron source terms for the BampW 15x15 Mark B assembly are generated in PWR Source Term Generation and Evaluation (Reference 229) and are used in this calculation
624 BampW 15x15 Mark B PWR Fuel Assembly
BampW 15x15 Mark B fuel assembly consists of four regions top end-fitting plenum active fuel and bottom end-fitting The m aterials and ra diation sources of each assem bly region are homogenized inside a volume defined by the region height and the interior diam eter of the TAD canister (Assumption 325) The active fuel region is homogenized with fresh unirradiated fuel (Assumption 324) Since the internal structure (i e basket) design of t he TAD is currently not finalized the com position of the hom ogenized fuel does not include the basket m aterials (Assumption 326) and therefore does not take cred it for any shielding that these m aterials may provide
Table 4 provides the design param eters for the BampW 15x15 Mark B fuel assembly Data provided here are used in Attachment II PWR_fuel compxls worksheet BampWassy
25
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 4 BampW 15x15 Mark B Fuel Assembly Description
Component Material Characteristic Value Specific Reference Array Size 15 x 15
Reference 2227 Table 2-2 Fuel Pins Assembly 208 Guide Tubes Assembly 16 Instrument Tubes Assembly 1
Assembly NA Pin Pellet Diameter 0936244 cm (03686 in) Reference 2220 p 2A-34 Pin Pitch 144272 cm (0568 in)
Reference 2227 Table 2-2 Active Fuel Height 360172 cm (1418 in) Assembly Width 2168144 cm (8536 in)
Reference 2220 p 2A-31 Assembly Height 4206875 cm (165625 in) Mass U assembly 46363 kg
Guide tube Zircaloy-4 Outer Diameter 13462 cm (053 in)
Reference 2227 Table 2-2
Inner Diameter 126492 cm (0498 in)
Instrument tube Zircaloy-4 Outer Diameter 138193 cm (05441 in) Inner Diameter 112014 cm (0441 in)
Cladding` Zircaloy-4 Inner Diameter 095758 cm (0377 in) Outer Diameter 10922 cm (043 in)
Plenum region NA Length 297688 cm (11720 in) Reference 2220 p 2A-34 Top nozzle SS CF3M MassAssembly (Top) 748 kg
Reference 2220 p 2A-32
Bottom nozzle SS CF3M MassAssembly (Bottom) 816 kg Guide tubes Zircaloy-4 MassAssembly (in Core) 80 kg Instrument tube Zircaloy-4 MassAssembly (in Core) 064 kg Spacer-plenum Inconel-718 MassAssembly (Plenum) 104 kg Spacer-bottom Inconel-718 MassAssembly (Bottom) 13 kg Spacer-in core Inconel-718 MassAssembly (in Core) 49 kg Spring retainer SS CF3M MassAssembly (Top) 091 kg Holddown spring Inconel-718 MassAssembly (Top) 18 kg Upper end plug SS 304 MassAssembly (Top) 006 kg Upper nut SS 304L MassAssembly (Top) 051 kg Lower nut SS 304 MassAssembly (Bottom) 015 kg Grid supports Zircaloy-4 MassAssembly (in Core) 064 kg Plenum spring SS 302 MassAssembly (Plenum) 0042 lb (001905 kg) Reference 2220 p 2A-34
Note Som e d ata i n this tab le ar e given i n British u nits in th e r eferences thes e d ata ar e converted into metric units as the inputs to MCNP5 are in metric units
The assem bly region heights as m odeled in MC NP are presented in Table 5 utilizing values from Table 4 Table 5 is taken from Dose Rate Calculation for Exhaust Main Drifts (Reference 2213 Table 3)
26
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 5 PWR Fuel Assembly Regions
Component Height Reference
Plenum 297688 cm (11720 in) Reference 2220 p 2A-34
Active Fuel 360172 cm (1418 in) Table 3
Bottom End-Fitting 1077 cm (424 in) Calculateda
Top End-Fitting 1998 cm (787 in) Calculatedb
Source Reference 2213 Table 3 aCalculated b ased on data Reference 2227 F igures 2-3 an d 2-7
(Region 9 Height [16723 cm] + Region 10 Height [508 cm] ndash Lo wer Fuel Plenum and End Cap [11033 cm])
bCalculated (Assembly Length ndash Active Fuel Length ndash P lenum Length ndash Bottom End-fitting Length)
625 Material Compositions
The TAD transportation cask com ponent m aterial specifications are defined in Table 1 The TAD canister is constructed of SS 316 (Assumpti on 321) The PWR fuel assembly materials used to homogenize the fuel regions are defined in Table 4 Table 6 c ontains the m aterial compositions defining the TAD canister WP and fuel assemblies
27
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 6 Chemical Compositions of Materials
Material Density (gcc)
Isotopic Weight Percent Reference
SS 302 NA
C 0150 Mn 2000 P 0045 S 0030 Si 0750 Cr 18000 Ni 9000 N 0100 Fe 69925
Attachment II PWR_fuel compxls worksheet ferrous Reference 222 SEC II A SA-240 Table 1 for SS 302 SS 304 and SS 304L Reference 222 SEC II A SA-351SA -351M Table 2 for SS CF3M
SS 304 NA
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 9250 N 0100 Fe 68745
SS 304L NA
C 003 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 10000 N 0100 Fe 6804 5
SS CF3M NA
C 0030 Mn 1500 P 0040 S 0040 Si 1500 Cr 19000 Ni 11000 Mo 2500 Fe 64390
Inconel 718 NA
C 0080 Mn 0350 Si 0350 Cr 19000 Ni 52500 Co 1000 Mo 3050 Fe 16809 Nb 5125 Ti 0900 Al 0500 Cu 0300 S 0015 P 0015 B 0006
Attachment II PWR_fuel compxls worksheet alloys aReference 223 p 666 Table 6 Reference 222 SEC II B SB-637 Table 1 for Inconel 718 Reference 224 Table 2 for Zircaloy 4
Zircaloy 4 656a Cr 0100 Fe 0210 O 0125 Sn 1450 Zr 98115
SS 316 798b
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 17000 Ni 12000 Mo 2500 N 0100 Fe 65495
Attachment II PWR_fuel compxls worksheet others Reference 222 SEC II A SA-240 Table 1 for SS 316 bReference 225 Table X1
626 Homogenization Assembly Materials
The atom density of an element or isotope in atomsbmiddotcm in a homogenized region is calculated according to the following equation (Reference 2223 Appendix B)
M i times N AvogadroNi = Equation 1 Ai timesV times K
where Ni = Atom density of elementisotope i (atomsbmiddotcm) Mi = Mass of elementisotope i (g) NAvogadro = Avogadrorsquos constant 06022 x 1024 (atomsmole)
28
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Ai = Atomic weight of elementisotope i (gmole) V = Homogenization volume (cm3) K = Unit transformation constant = 1024 (bmiddotcmcm3)
Equation 1 is used in A ttachment II spreadsheet PWR_fuel compxls worksheet BampWassy to calculate th e atom dens ities for v arious elem ents and iso topes The m ass of elementsisotop es and Avogadrorsquos constant are provided in Reference 2226
Table 7 lists the com position of the hom ogenized assem bly regions (active fuel plenum top end-fitting and bottom end-fitting) for the PWR assembly The active fuel region contains fresh unirradiated fuel (Assumption 324) Since the internal structure (ie basket) design of the TAD is currently not finalized the composition of either homogenized fuel does not include the basket materials and therefore does not tak e credit for any shielding that thes e materials may provide (Assumption 326)
Table 7 Isotopic Compositions of Homogenized PWR Assembly Regions
Element Isotope
Atom Densities for Homogenized Regions (atomsbsdotcm)
Active Fuel Bottom End-Fitting Plenum Top End-Fitting
10B 861E-09 764E-08 221E-08 570E-08 11B 347E-08 307E-07 890E-08 230E-07 C 519E-07 160E-05 138E-06 993E-06 N -- 570E-07 262E-08 117E-06 O 621E-03 -- 142E-05 -- Al 144E-06 128E-05 371E-06 957E-06 Si 971E-07 243E-04 259E-06 139E-04 P 377E-08 606E-06 102E-07 360E-06 S 365E-08 581E-06 971E-08 340E-06 Ti 147E-06 130E-05 376E-06 971E-06 Cr 320E-05 187E-03 779E-05 113E-03 Mn 497E-07 126E-04 141E-06 749E-05 Fe 303E-05 531E-03 717E-05 313E-03 Co 132E-06 117E-05 340E-06 876E-06 Ni 697E-05 144E-03 180E-04 940E-04 Cu 368E-07 327E-06 945E-07 244E-06 Zr 196E-03 -- 195E-03 -- Nb 430E-06 382E-05 110E-05 285E-05 Mo 248E-06 135E-04 636E-06 791E-05 Sn 223E-05 -- 222E-05 -- 234U 139E-06 -- -- -- 235U 157E-04 -- -- -- 236U 719E-07 -- -- -- 238U 294E-03 -- -- -- Total 114E-02 924E-03 235E-03 557E-03
Source Attachment II spreadsheet PWR_fuel compxls worksheet BampWassy
29
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
The isotopic composition of commercially available 235U enriched uranium is determined by the given initial 235U enrichment using the following equations (Reference 226 p 20)
wt235U =235Uenrichment _ of _ the _ associated _ fuel _ batch Equation 2
wt234U = 0007731times (wt235U )10837 Equation 3
wt236U = 00046times (wt235U ) Equation 4
wt238U =100 minus (wt234U + wt235U + wt236U ) Equation 5
The weight percentages of uran ium isotopes for PWR fuel are ca lculated in Attachm ent II spreadsheet PWR_fuel compxls worksheet BampWassy using Equations 2 through 5
627 PWR Source Terms
This calculation uses the following three PWR source terms bull Maximum source (50 wt initial 235U enrichment 80 GWdMTU burnup and 5-year
decay time) (Reference 229 Section 55) Table 8 lists th e gamma source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Design Basis source (4 0 wt initial 235U enrichment 60 GW dMTU burnup and 10-year decay tim e) (Reference 228 Section 552) Table 9 lists the gamm a source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Average source ( 40 wt initial 235U enrichment 48 GWdMTU burnup and 25-year decay time) (Reference 229 Section 55) Table 10 lists the gamma source terms for the fuel and non-fuel regions and the neutron source term for the fuel region
These sources (ie maximum design basis and av erage) are described in this section For dose rate calculations all the fuel assemblies in a transportation cask are of the sam e characteristics Also gamma radiation source term s for the PWR assem bly are prov ided for the f our assembly regions while neutron source term is only present in the active fuel region Gamma radiation sources in the non-active fuel region are distri buted unif ormly within each source region Gamma and neutron sources in the active fuel re gion are modeled as uni form distributions or with axial source profiles
The PWR gamma and neutron axial source profiles for the active fuel region presented in Table 11 are applied to the active fuel region of all three source terms (ie maximum design basis and average) when appropriate
30
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 8 Gamma and Neutron Sources for the Maximum PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting
Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 594E+11 233E+15 528E+11 379E+11 100E-01 000E+00 100E-01 116E+11 644E+14 609E+10 743E+10 400E-01 805E+07 200E-01 283E+10 522E+14 352E+10 179E+10 900E-01 411E+08 300E-01 141E+09 148E+14 196E+09 891E+08 140E+00 376E+08 400E-01 190E+09 985E+13 586E+09 117E+09 185E+00 276E+08 600E-01 191E+09 153E+15 110E+11 741E+07 300E+00 485E+08 800E-01 435E+09 470E+15 595E+10 237E+09 643E+00 443E+08 100E+00 137E+11 708E+14 803E+09 766E+10 200E+01 393E+07 133E+00 338E+13 455E+14 174E+13 217E+13 Total 211E+09 166E+00 953E+12 130E+14 491E+12 612E+12
--
200E+00 187E+03 144E+12 919E+02 113E+03 250E+00 226E+08 249E+12 116E+08 145E+08 300E+00 351E+05 110E+11 181E+05 225E+05 400E+00 766E-08 139E+10 100E-08 416E-08 500E+00 000E+00 709E+07 000E+00 000E+00 650E+00 000E+00 286E+07 000E+00 000E+00 800E+00 000E+00 558E+06 000E+00 000E+00 100E+01 000E+00 119E+06 000E+00 000E+00
Total 442E+13 113E+16 231E+13 284E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE2R2B14cut bWasteStreamE2R1B14cut cWasteStreamE2R3B14cut dWasteStreamE2R4B14cut
31
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 9 Gamma and Neutron Sources for the Design Basis PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary
(MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 273E+11 121E+15 188E+11 175E+11 100E-01 000E+00 100E-01 528E+10 329E+14 277E+10 339E+10 400E-01 316E+07 200E-01 128E+10 245E+14 117E+10 819E+09 900E-01 161E+08 300E-01 639E+08 713E+13 633E+08 407E+08 140E+00 148E+08 400E-01 850E+08 455E+13 164E+09 533E+08 185E+00 109E+08 600E-01 492E+08 226E+14 269E+10 337E+07 300E+00 191E+08 800E-01 291E+09 237E+15 160E+10 186E+09 643E+00 174E+08 100E+00 540E+09 122E+14 248E+09 341E+09 200E+01 154E+07 133E+00 154E+13 195E+14 797E+12 990E+12 Total 830E+08 166E+00 435E+12 450E+13 225E+12 280E+12
--
200E+00 235E+00 152E+11 149E+02 215E-02 250E+00 103E+08 517E+10 534E+07 664E+07 300E+00 160E+05 379E+09 829E+04 103E+05 400E+00 943E-10 497E+08 155E-10 519E-10 500E+00 000E+00 282E+07 000E+00 000E+00 650E+00 000E+00 113E+07 000E+00 000E+00 800E+00 000E+00 222E+06 000E+00 000E+00 100E+01 000E+00 471E+05 000E+00 000E+00
Total 201E+13 486E+15 105E+13 129E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B11cut bWasteStreamE5R1B11cut cWasteStreamE5R3B11cut dWasteStreamE5R4B11cut
32
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 10 Gamma and Neutron Sources for the Average PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 336E+10 670E+14 186E+10 217E+10 100E-01 00000E+00 100E-01 602E+09 199E+14 314E+09 387E+09 400E-01 748E+06 200E-01 146E+09 126E+14 853E+08 936E+08 900E-01 382E+07 300E-01 730E+07 389E+13 439E+07 469E+07 140E+00 352E+07 400E-01 947E+07 263E+13 716E+07 607E+07 185E+00 261E+07 600E-01 141E+07 205E+13 504E+08 383E+06 300E+00 469E+07 800E-01 208E+09 124E+15 192E+09 144E+09 643E+00 418E+07 100E+00 208E+09 110E+13 164E+09 144E+09 200E+01 365E+06 133E+00 175E+12 295E+13 909E+11 112E+12 Total 199E+08 166E+00 494E+11 513E+12 257E+11 318E+11
--
200E+00 973E-01 675E+10 614E+01 872E-03 250E+00 117E+07 353E+09 609E+06 754E+06 300E+00 182E+04 288E+08 944E+03 117E+04 400E+00 186E-11 198E+07 149E-11 127E-11 500E+00 000E+00 669E+06 000E+00 000E+00 650E+00 000E+00 269E+06 000E+00 000E+00 800E+00 000E+00 527E+05 000E+00 000E+00 100E+01 000E+00 112E+05 000E+00 000E+00
Total 229E+12 237E+15 119E+12 147E+12
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B9cut bWasteStreamE5R1B9cut cWasteStreamE5R3B9cut dWasteStreamE5R4B9cut
33
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 11 Gamma and Neutron Axial Source Profiles for a PWR Assembly
Axial boundaries (From midplane)
(cm)
TOP BOTTOM
Neutron Gamma Ne utron Gamma 000 1554 1117 1554 1117 1143 1537 1114 1571 1120 2286 1521 1111 1588 1123 3429 1504 1108 1605 1126 4572 1486 1104 1622 1129 5715 1464 1100 1636 1131 6858 1438 1095 1648 1133 8001 1401 1088 1657 1135 9144 1350 1078 1654 1134
10287 1277 1063 1625 1129 11430 1165 1039 1554 1117 12573 0998 09995 1414 1091 13716 0769 09365 1172 1041 14859 0492 08375 0816 0951 16002 0220 06850 0402 0797 17145 0046 04625 0092 0551 18288 00 00 00 00
Source Reference 2219 Table S445
34
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
63 MCNP SPECIFIC INPUT
631 Source Probability
A linear radial distribution is used for all gamma and neutron sources The linear radial distribution is sam pled usi ng the built-in power function p(x) = xc a with a = 1 for the radial direction This sampling method results in a uniform source distribution over the area bounded by the outer radius of the source
The source axial distributions are unifor m for all four source regions The a xial uni form xp(x) = c distribution is sampled using the built-in power function a with a = 0 for extent
The energy distribu tions of the gamma and neutron sour ce term s are treated as energ y probabilities and are applied in MCNP5 using SISP cards
632 Dose Rate and Flux Tallies
MCNP5 dose rate calculations feature separate runs for the following calculation types
bull a photon transport calculation for prim ary ga mma contribution to the dose rates fr om photon fluxes
bull a coupled neutronphoton transport calculat ion for neutrons a nd secondary gamma (photons generated by neutron be ing captured) contributions to dose rates from neutron and gamma fluxes
The tally type F2 is us ed in th is d esign ca lculation as f lux estim ators The type F2 tally evaluates the flux averaged over a surface in particlescm2s
To generate dose ra tes in te rms of remhr the FM (tally multiplier ) and DEDF (dose energydose conversion factors) cards are used to en ter the tally multiplier f actor (source intensity in particless) energy boundaries in MeV and corresponding dose conversion factors in (remhr)(particlescm2s) respectively These factors were used in the input files
In order for the F2 tally to accum ulate flux ov er a surface a specific s urface area is requ ired The SD cards are used to enter a surface area in cm2 over which the flux will be tallied for an F2 tally
633 Variance Reduction Techniques
Variance reduction technique is usually em ployed in order to increase the efficiency of a calculation and obtain statistically m eaningful results within re asonable com puter tim e In Monte Carlo calculations when variance reduction scheme is employed the weights of particles are adjusted in order to account for the biasing and to preserve a fair game
Geometry splitting and Russian roulette techniques described in Reference 2224 (pp 2-140 ndash 2-142) are useful in shielding calculations and therefore deployed in all the MCNP5 runs
35
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
As particles migrate in an important direction (toward the detector) they are increased in number to provide better sampling by means of geometry splitting across geometric boundaries Russian roulette (the reverse process) is played when particles travel in an unimportant direction to allow termination of unim portant histories The IMP card required for every cel l ca rd is us ed to implement this technique
The other variance reduction technique deployed in the MC NP5 runs is source intensity biasing for the gamma sources from the four source regions (active fuel bottom end-fitting plenum and top end-fitting) The natural total gamma source intensity of comm ercial SNF is dom inated by the gamma source in the active fuel region This active fuel gamma source usually accounts for over 95 o f the total g amma source intens ity In order to im prove the efficiency of the axial dose rate calculations a biased source probability distribution is employed for the prim ary gamma dose rate calculations The biased gamma source probability distribution is chosen to be 005 080 010 and 005 for the bottom end-fitting the active fuel the plenum and the top end-fitting regions respectively
64 DOSE CONVERSION FACTORS
Project Design Criteria Document (Reference 2211 Se ction 41015) requires the use of flux-to-dose rate conversion fact ors from ANSIANS-611-1977 (Reference 221) for dose rate evaluations Table 16 lists the neutron and ga mma dose conversion factors used in the MCNP5 calculations
Table 12 Gamma and Neutron Flux to Dose Conversion Factors
Gamma Neutron Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
001 396E-06 140 251E-06 250E-08 367E-06 003 582E-07 180 299E-06 100E-07 367E-06 005 290E-07 220 342E-06 100E-06 446E-06 007 258E-07 260 382E-06 100E-05 454E-06 010 283E-07 280 401E-06 100E-04 418E-06 015 379E-07 325 441E-06 100E-03 376E-06 020 501E-07 375 483E-06 100E-02 356E-06 025 631E-07 425 523E-06 100E-01 217E-05 030 759E-07 475 560E-06 500E-01 926E-05 035 878E-07 500 580E-06 100E+00 132E-04 040 985E-07 525 601E-06 250E+00 125E-04 045 108E-06 575 637E-06 500E+00 156E-04 050 117E-06 625 674E-06 700E+00 147E-04 055 127E-06 675 711E-06 100E+01 147E-04 060 136E-06 750 766E-06 140E+01 208E-04 065 144E-06 900 877E-06 200E+01 227E-04 070 152E-06 1100 103E-05 080 168E-06 1300 118E-05 100 198E-06 1500 133E-05
Source Reference 221 Tables 1 and 3
36
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION
By def inition (Ref erence 2224 Equation 219) the estimated st atistic relative error of the i component is
Ri = Si
2
Equation 6Ti
where i = tally component index Ri = relative error of the i component S2
i = variance of the i component Ti = tally i component
For a result (ie dose rate) computed as a sum of different tallies the statistical relative error of the computed value is o btained from the variance of the result - S2
total which is th e sum of the estimated variances of the individual tallies S2
i n
2 2STotal = sum Si Equation 7 i=1
where S2Total = total estimated variance
n = total number of components Therefore the total tally value (dose rate) and the associated relative error are derived according to Equations 8 and 9
n TTotal = sumTi Equation 8
i=1
n n
sum (Ri timesTi )2
2 sum Si 2
STotal = i=1 = i=1 Equation 9RTotal = TTotal TTotal TTotal
where RTotal = total estimated relative error TTotal = total estimated tally
Equations 8 and 9 are utilized in Attachm ent II to ev aluate to tal dos e ra tes and their r elative errors
37
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
7 RESULTS AND CONCLUSIONS
71 RESULTS
The following sections summarize the results of this calculation Section 711 presents results for Conceptual Cask A while Section 712 for Conceptual Cask B Section 713 provides comparisons of the dose-rate reduction factors du e to the two conceptual casks and the axial source distributions in the active fuel region Do se rates and relative errors can be found in Attachment II within the output files and Excel files
711 Dose Rates of Conceptual Cask A
This section presents dose-rate results of the calculation sets 1 and 2 as described in Section 61 for Cask A Set 1 has axial p rofile sources in the active fuel region a nd consist of six runs resulting from the three PWR SNF source term s (maximum design basis and average) and the two radiation sources (gammas and neutrons) Set 2 has uniform axial sources in the active fuel region and consists of six run s r esulting f rom the th ree P WR SNF source term s and th e tw o radiation sources
As described in Section 61 dose ra tes are calculated at the three exterior surfaces (radial top and bottom) and at distances 1 m and 2 m from the exterior surfaces The total dose rates for set 1 are presented in Tables 13 14 and 15 for the ra dial top and bottom dire ctions respectively However the com ponents (primary gamma neutr on and secondary gamma) contributing to the total dose rates as well as the re lative error calculations can be found in Attachment II Excel file MCNP-Results1xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 2 are shown in Tables 16 17 and 18 The dose-rate components and the relative errors can be found in A ttachment II Excel file MCNP-Results2xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 13 and 16 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 14 and 17 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 15 and 18 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carrying th e maximum PWR SNF Based on the results in Tables 13 through 18 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask A indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these 6 tables the d ose-rate red uction f actors between the m aximum and the design basis fuels the maxim um and the averag e fuels and th e design basis and the average fuels are a lso presented
38
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 320E-02 00237 116E-02 00222 262E-03 00219 275 1223 445
1 m 133E-02 00164 494E-03 00171 106E-03 00162 269 1261 468 2 m 749E-03 00198 285E-03 00225 584E-04 00162 263 1282 488
Ring Detectors 1 m 133E-02 00116 492E-03 00115 108E-03 00124 271 1229 454 2 m 756E-03 00118 279E-03 00110 605E-04 00128 271 1250 462
Source Attachment II MCNP-Results1xls worksheet Summary
Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 142E-02 00368 628E-03 00446 934E-04 00483 226 1520 672
1 m 570E-03 00289 263E-03 00426 375E-04 00381 217 1520 701 2 m 265E-03 00364 123E-03 00547 169E-04 00374 216 1575 730
Point Detectors 1 m 598E-03 00238 274E-03 00271 402E-04 00354 219 1489 681 2 m 273E-03 00218 123E-03 00245 180E-04 00336 221 1515 684
Source Attachment II MCNP-Results1xls worksheet Summary
Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 653E-03 00298 265E-03 00276 510E-04 00341 247 1278 518
1 m 276E-03 00238 112E-03 00208 207E-04 00249 248 1334 539 2 m 125E-03 00185 508E-04 00199 933E-05 00246 246 1336 544
Point Detectors 1 m 291E-03 00227 118E-03 00203 218E-04 00242 247 1335 540 2 m 130E-03 00209 524E-04 00187 955E-05 00233 247 1357 549
Source Attachment II MCNP-Results1xls worksheet Summary
Tables 13 14 and 15 are results of calculation set 1 for conceptual Cask A with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
39
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 265E-02 00247 990E-03 00222 215E-03 00278 268 1234 461
1 m 116E-02 00178 468E-03 00549 960E-04 00189 248 1208 488 2 m 713E-03 00273 265E-03 00161 602E-04 00360 269 1184 439
Ring Detectors 1 m 117E-02 00120 454E-03 00132 979E-04 00141 259 1199 463 2 m 722E-03 00130 276E-03 00141 589E-04 00153 261 1226 469
Source Attachment II MCNP-Results2xls worksheet Summary
Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 199E-02 00461 827E-03 00455 147E-03 00536 241 1359 564
1 m 849E-03 00564 323E-03 00314 563E-04 00418 263 1507 574 2 m 415E-03 00832 158E-03 00603 253E-04 00501 263 1641 623
Point Detectors 1 m 877E-03 00348 353E-03 00275 615E-04 00391 248 1426 574 2 m 393E-03 00341 160E-03 00278 270E-04 00378 246 1454 590
Source Attachment II MCNP-Results2xls worksheet Summary
Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 879E-03 00374 356E-03 00333 669E-04 00406 247 1315 533
1 m 365E-03 00223 147E-03 00209 269E-04 00253 248 1358 548 2 m 164E-03 00229 674E-04 00205 120E-04 00248 243 1364 560
Point Detectors 1 m 383E-03 00217 155E-03 00204 285E-04 00248 247 1347 546 2 m 172E-03 00197 689E-04 00186 124E-04 00225 249 1391 558
Source Attachment II MCNP-Results2xls worksheet Summary
Tables 16 17 and 18 ar e results of calculation set 2 for conceptual Cask A with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
40
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
TABLES
Page
Table 1 Geometry and Materials of Conceptual TAD Transportation Cask A 15 Table 2 Geometry and Materials of Conceptual TAD Transportation Cask B 16 Table 3 Dimensions of TAD Canister 24 Table 4 BampW 15x15 Mark B Fuel Assembly Description 26 Table 5 PWR Fuel Assembly Regions 27 Table 6 Chemical Compositions of Materials 28 Table 7 Isotopic Compositions of Homogenized PWR Assembly Regions 29 Table 8 Gamma and Neutron Sources for the Maximum PWR SNF Assembly 31 Table 9 Gamma and Neutron Sources for the Design Basis PWR SNF Assembly 32 Table 10 Gamma and Neutron Sources for the Average PWR SNF Assembly 33 Table 11 Gamma and Neutron Axial Source Profiles for a PWR Assembly 34 Table 12 Gamma and Neutron Flux to Dose Conversion Factors 36 Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources 39 Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources 39 Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources 39 Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources 40 Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources 40 Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources 40 Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources 42 Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources 42 Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources 42 Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources 43 Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources 43 Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources 43 Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources 44 Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources 45 Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources 45 Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources 45 Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources 45 Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial
Sources 46 Table 31 Recommended Average Radial Dose-Rate Reduction Factors 46 Table 32 Recommended Average Top Dose-Rate Reduction Factors 46 Table 33 Recommended Average Bottom Dose-Rate Reduction Factors 46 Table I-1 Listing of Electronic Files on Compact DiscI-1
6
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ACRONYMS AND ABBREVIATIONS
ACRONYMS
ANS American Nuclear Society
ANSI American National Standards Institute
ASTM American Society for Testing and Materials
BSC Bechtel SAIC Company LLC
BWR Boiling Water Reactor
CD Compact disc
CSNF Commercial Spent Nuclear Fuel
DB Design Basis
DOE U S Department of Energy
DPC Dual Purpose Canister
NRC U S Nuclear Regulatory Commission
PCSA Preclosure Safety Analysis
PWR Pressurized Water Reactor
RPM Repository Project Management
SNF Spent Nuclear Fuel
SS 316 Stainless Steel 316
TAD Transportation Aging and Disposal
WP Waste Package
YMP Yucca Mountain Project
ABBREVIATIONS and UNITS
b barn
cm centimeter
7
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
g gram
GWd gigawatt-day
hr hour
in inch
kg kilogram
m meter
mrem millirem
MeV million electron volt
MTU metric ton uranium
s second
8
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
1 PURPOSE
The purpose of this calculation is to calcu late th e dose ra tes of two conceptua l tr ansportation casks each carrying a Transportation Aging and Disposal (TAD) canister separately loaded with the average design basis (DB) and m aximum comm ercial spent nuc lear fuel (CSNF) assemblies Then the dose-ra te reduction f actors between the m aximum and the design basis fuels the d esign bas is and the average fuels and the m aximum and the averag e fuels are computed
The results of this calculation may be used to substantiate the dose-rate reduction factors such as those in the engineering study Repository ALARA Goal Compliance (Reference 227) which is cited as a reference in a Preclosure Safety Analyses (PCSA) calculation that supports the License Application
The calculations contained in this docum ent are developed by Nuclear and Radiological Engineering of the Repository Project Mana gement (RPM) organization Yucca Mountain Project (YMP) personnel from Nuclear and Radiological Engineering should be consulted before use of the calculations for purposes other than those stated herein or use by individuals other than personnel in Nuclear and Radiological Engineering
9
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
2 REFERENCES
21 PROJECT PROCEDURESDIRECTIVES
211 IT-PRO-0011 Rev 0010 Software Management Las Vegas Nevada Bechtel SAIC Company
212 EG-PRO-3DP-G04B-00037 Rev 14 Calculations and Analyses Las Vegas Nevada Bechtel SAIC Company
213 IT-PRO-0012 Rev 007 Qualification of Software Las Vegas Nevada Bechtel SAIC Company
22 DESIGN INPUTS
221 ANSIANS-611-1977 Neutron and Gamma-Ray Flux-to-Dose-Rate Factors La Grange Park Illinois American Nuclear Society TIC 239401
222 ASME (American Society of Mechanical Engineers) 2004 2004 ASME Boiler and Pressure Vessel Code 2004 Edition New York New York American Society of Mechanical Engineers TIC 256479 ISBN 0-7918-2899-9
223 ASM International 1990 Properties and Selection Nonferrous Alloys and Special-Purpose Materials Specific Metals and Alloys Volume 2 of Metals Handbook 10th Edition Page 666 [Materials Park Ohio] American Society for Metals TIC 239807
224 ASTM (American Society for Testing and Materials) B 811-90 1991 Standard Specification for Wrought Zirconium Alloy Seamless Tubes for Nuclear Reactor Fuel Cladding Philadelphia Pennsylvania American Society for Testing and Materials TIC 239780
225 ASTM G 1-90 (Reapproved 1999) 1999 Standard Practice for Preparing Cleaning and Evaluating Corrosion Test Specimens West Conshohocken Pennsylvania American Society for Testing and Materials TIC 238771
226 Bowman SM Hermann OW and Brady MC 1995 Sequoyah Unit 2 Cycle 3 Volume 2 of Scale-4 Analysis of Pressurized Water Reactor Critical Configurations ORNLTM-12294V2 Oak Ridge Tennessee Oak Ridge National Laboratory TIC 244397 [DIRS 123796]
227 BSC (Bechtel SAIC Company LLC) 2008 Repository ALARA Goal Compliance 000-30R-MGR0-04000-000 REV 000 Las Vegas Nevada Bechtel SAIC Company ACC ENG200802050014 [DIRS 184957]
228 BSC 2002 Subsurface Shielding Source Term Specification Calculation 000-00C-WER0-00100-000-00A Las Vegas Nevada Bechtel SAIC Company ACC MOL200212160076 ENG200508150022
10
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
229 BSC 2004 PWR Source Term Generation and Evaluation 000-00C-MGR0-00100-000-00B Las Vegas Nevada Bechtel SAIC Company ACC ENG200405240007
2210 BSC 2008 Basis of Design for the TAD Canister-Based Repository Design Concept 000-3DR-MGR0-00300-000-003 Las Vegas Nevada Bechtel SAIC Company ACC ENG200810060001
2211 BSC 2007 Project Design Criteria Document 000-3DR-MGR0-00100-000-007 Las Vegas Nevada Bechtel SAIC Company ACC ENG200710160005 ENG200711080001 ENG200712200003 ENG200801070001 ENG200801070002 ENG200801070016 ENG200801070017 ENG200801310006 ENG200803050002 ENG200803050011 ENG200803050012 ENG200803060009 ENG200803130004 ENG200807100001 ENG200811120006 ENG200811140004
2212 BSC 2004 PWR and BWR Source Term Sensitivity Study 000-00C-MGR0-00300-000-00A Las Vegas Nevada Bechtel SAIC Company ACC ENG200401140003 ENG200508150023
2213 BSC 2007 Dose Rate Calculation for Exhaust Main Drifts 800-00C-SS00-00700-000-00B Las Vegas Nevada Bechtel SAIC Company ACC ENG200711050017 ENG200803060001
2214 BSC 2006 Dual Purpose Canister Opening Study 050-30R-WHS0-00600-000-000 Las Vegas Nevada Bechtel SAIC Company ACC ENG200612200023
2215 BSC 2007 GROA Shielding Requirements Calculation 000-00C-MGR0-03300-000-00B Las Vegas Nevada Bechtel SAIC Company ACC ENG200705290037
2216 BSC 2002 Concrete Shielding Calculation for Dry Facility 1 110-00C-CS10-00100-000-00A Las Vegas Nevada Bechtel SAIC Company ACC MOL200301140075
2217 BSC 2003 Shielding Design Calculations for Dry Facility 1 110-00C-CS10-00200-000-00A Las Vegas Nevada Bechtel SAIC Company ACC ENG200306020003
2218 CRWMS MampO 1998 Calculation of the Effect of Source Geometry on the 21-PWR WP Dose Rates BBAC00000-01717-0210-00004 REV 00 Las Vegas Nevada CRWMS MampO ACC MOL199902220059 [DIRS 102134]
2219 CRWMS MampO 2000 Users Manual for SCALE-44A 10129-UM-44A-00 Las Vegas Nevada CRWMS MampO ACC MOL200011300136 MOL200108220084 MOL200108220085 MOL200108220086 MOL200108220087 [DIRS 153872]
2220 DOE (US Department of Energy) 1987 Appendix 2A Physical Descriptions of LWR Fuel Assemblies Volume 3 of Characteristics of Spent Fuel High-Level Waste and Other Radioactive Wastes Which May Require Long-Term Isolation DOERW-0184 Washington DC US Department of Energy Office of Civilian Radioactive Waste Management ACC HQX198804050024 [DIRS 132333]
11
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
2221 DOE 2007 Software Validation Report for MCNP5 v140 Document ID 11199-SVR-140-00-WINXP Las Vegas Nevada US Department of Energy Office of Repository Development ACC MOL200702280252 [DIRS 180516]
2222 DOE 2008 Transportation Aging and Disposal Canister System Performance Specification WMO-TADCS-000001 Rev 1 ICN 1 Washington DC US Department of Energy Office of Civilian Radioactive Waste Management ACC DOC200803310001 [DIRS 185304]
2223 Harmon CD II Busch RD Briesmeister JF and Forster RA 1994 Criticality Calculations with MCNPtrade A Primer LA-12827-M Los Alamos New Mexico Los Alamos National Laboratory TIC 234014 [DIRS 154532]
2224 LANL (Los Alamos National Laboratory) 2004 MCNP mdash A General Monte Carlo N-Particle Transport Code Version 5 (Appendix H is not included) LA-UR-03-1987 Volume I Los Alamos [New Mexico] Los Alamos National Laboratory ACC MOL200510240126 [DIRS 176521]
2225 MCNP5 V 140 2007 Windows XP STN 11199-140-00 [DIRS 180515]
2226 Parrington JR Knox HD Breneman SL Baum EM and Feiner F 1996 Nuclides and Isotopes Chart of the Nuclides 15th Edition San Jose California General Electric Company and KAPL Inc TIC 233705 LC Call Number QC7935 N8622 1996
2227 Punatar MK 2001 Summary Report of Commercial Reactor Criticality Data for Crystal River Unit 3 TDR-UDC-NU-000001 REV 02 Las Vegas Nevada Bechtel SAIC Company ACC MOL200107020087 [DIRS 155635]
2228 Sisley SE 2002 Transportation License Application for the FuelSolutionstrade System (TAC No L23311) Submittal of the FuelSolutiontrade Transportation SARs Revision 3 Letter from SE Sisley (BNFL) to the NRC April 11 2002 BFSNRC 02-011 with enclosures TIC 255245 [DIRS 171545]
NOTE Reference 2220 is a direct input but is not QA QA It is justified as acceptable for the intended use as it is directly from the DOE and is considered the best available data on the subject The referenced values cited in Tables 3 and 4 are valid for use since they are reliable and reasonable based on engineering judgment
23 DESIGN CONSTRAINTS
231 10 CFR 71 2008 Energy Packaging and Transportation of Radioactive Material Internet Accessible [DIRS 185678]
12
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
24 DESIGN OUTPUTS
The resu lts of this calculation will be us ed to substan tiate th e dose reduc tion f actor in the Repository ALARA Goal Compliance (Reference 227) which is cited as a reference in a PCSA calculation that supports the License Application
13
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
3 ASSUMPTIONS
31 ASSUMPTIONS REQUIRING VERIFICATION
None
32 ASSUMPTIONS NOT REQUIRING VERIFICATION
Assumptions 321 322 and 323 are m odeling assum ptions and do not require further verification The m aterials and dim ensions for the TAD canister and for the conceptu al transportation casks are only selected to charac terize two tr ansportation casks th at m eet 10 CFR7147 (Reference 231) dose rates when lo aded with the ldquom aximumrdquo and ldquoaveragerdquo pressurized water re actor (PW R) assem blies re spectively There is n o need to v erify those dimensions or m aterials at a later date The ca lculated results in Sect ion 711 verify that the conceptual casks would meet 10 CFR 7147 (Reference 231) dose rates
321 Material and Wall Thickness of TAD Canister
Assumption It is assumed that the TAD canister is made of stainless steel 316 (SS 316) and has a wall thickness of 025 in for the radial and bottom shells
Rationale Currently the design of the TAD canis ter d oes not ex ist Based on a survey of existing m ultipurpose a nd dual purpose caniste rs (DPC) (Ref erence 2214 p 56) a 025 in thickness is below the wall thick ness of any existing c anisters For the purp ose of this calculation this assumption leads to higher and conservative external dose rates Since SS 316 is the sam e material used for the waste pack age inner shell it is a l ogical cho ice f or the TAD canister
Although Reference 2214 is an engineering study with a QA N A status it is used here as an indirect input to support the assumption which is conservative for dose rate calculations
Usage This assumption is used in Sections 621 and 625
322 Material and Thickness of TAD Shield Plug
Assumption It is assu med that the TAD shield plug is made of SS 316 and has a thickness of 11 in
Rationale Currently the design of the TAD canister doe s not exist A thick shield plug of 11 in (Reference 2215 Table 12) is needed to keep the m aximum contact dose rate of the top surface below 1000 mrem hr (Reference 2222 Section 314) Since SS 316 is the sam e material used for the waste package inner shell it is a logical choice for the TAD shield plug
Usage This assumption is used in Section 621
14
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
323 Geometry and Materials of Conceptual TAD Transportation Casks
Assumption Two conceptual TAD transpo rtation casks designated as Cask A and Cask B are assumed to have a cylindrical geom etry and m aterials specified in Tab les 1 and 2 respectively The casks are basically construc ted of an inner layer of SS 316 for ga mma shielding a m iddle layer of 5-borated polyethylen e for neutron shielding and a th in outer layer of SS 316 whic h serves a structural function as well as shielding secondary gamma rays
Both Cask A and Cask B have a cavity height of 53785 cm (21175 in) and a cavity diameter of 16891 cm (6650 in) However Cask A has a total height of 610845 cm (24049 in) and an outside diameter of 26797 cm (10550 in) while the total height and outside diameter of Cask B are 58885 cm (23183 in) and 24765 cm (9750) respectively
Cask A will provide shielding to m eet the exterior radiat ion standards of 10 C FR 7147(b) (Reference 231) when loaded w ith a TAD canister carrying th e maximum PWR spent nuclear fuel (SNF) Cask B will satisf y the same radiation standards when loade d with a TAD caniste r carrying the average PWR SNF
Table 1 Geometry and Materials of Conceptual TAD Transportation Cask A
Component Dimension
Material (cm) (in)
Total Height 61085 2404 9 NA
Outside Diameter 26797 1055 0 NA
Cask Cavity Height 53785 2117 5 NA
Cask Cavity Diameter (Radius) 16891 (8446) 6650 (3325) NA
Radial Gamma Shield Thickness (Radius)a 3302 (11748)a 1300 (4625)a SS 316
Radial Neutron Shield Thickness (Radius)b 1524 (13272)b 600 (5225)b 5-borated polyethylene
Radial Outer Shell Thickness (Radius)c 127 (13399)c 050 (5275)c SS 316
Top Gamma Shield Thickness (Axial Position)d 600 (54385)d 236 (21411)d SS 316
Top Neutron Shield Thickness (Axial Position)d 1000 (55385)d 394 (21805)d 5-borated polyethylene
Top Outer Shell Thickness (Axial Position)d 200 (55585)d 079 (21884)d SS 316
Bottom Gamma Shield Thickness (Axial Position)d 35365 (-360)d 1392 (-1417)d SS 316
Bottom Neutron Shield Thickness (Axial Position)d 15 (-510)d 591 (-2008)d 5-borated polyethylene
Bottom Outer Shell Thickness (Axial Position)d 4 (-550)d 157 (-2165)d SS 316 a11748 = 3302 + 8446 and 4625 = 1300 + 3325 b13272 = 1524 + 11748 and 5225 = 600 + 4625 c13399 = 127 + 13272 and 5275 = 050 + 5225 dCoordinate relative to the bottom of the fuel assembly as modeled in MCNP5
15
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 2 Geometry and Materials of Conceptual TAD Transportation Cask B
Component Dimension
Material (cm) (in)
Total Height 58885 2318 3 NA
Outside Diameter 24765 9750 NA
Cask Cavity Height 53785 2117 5 NA
Cask Cavity Diameter (Radius) 16891 (8446) 6650 (3325) NA
Radial Gamma Shield Thickness (Radius)a 254 (10986)a 1000 (4325)a SS 316
Radial Neutron Shield Thickness (Radius)b 127 (12256)b 500 (4825)b 5-borated polyethylene
Radial Outer Shell Thickness (Radius)c 127 (12383)c 050 (4875)c SS 316
Top Gamma Shield Thickness (Axial Position)d 8 (54585)d 315 (21490)d SS 316
Top Neutron Shield Thickness (Axial Position)d None Non e NA
Top Outer Shell Thickness (Axial Position)d None Non e NA
Bottom Gamma Shield Thickness (Axial Position)d 3837 (-390)d 1510 (-1535)d SS 316
Bottom Neutron Shield Thickness (Axial Position)d 300 (-420)d 118 (-1654)d 5-borated polyethylene
Bottom Outer Shell Thickness (Axial Position)d 100 (-430)d 039 (-1693)d SS 316 a10986 = 254 + 8446 and 4325 = 1000 + 3325 b12256= 127 + 10986 and 4825 = 500+ 4325 c12383 = 127 + 12256 and 4875 = 050 + 4825 dCoordinate relative to the bottom of the fuel assembly as modeled in MCNP5
Rationale Currently a design for the TAD transporta tion cask does not exist The casks assumed for this calculation are so lely for estim ation of the dose reduction due to different source terms This is a conceptual repres entation only used in this calculation to estim ate the parameters of interest
Usage This assumption is used in Sections 61 and 622
324 Usage of Unirradiated Fuel for Commercial SNF
Assumption It is assumed that the active fuel region of the commercial SNF assembly contains the same isotopic concentrations as the fresh uni rradiated fuel and that the concentrations of fresh fuel with 5 initial enrichm ent corresp onding to m aximum SNF are used for all other SNFs
Rationale This assumption is a standard practice for shielding calculations throughout the industry accepted by the U S Nucle ar Regulatory Commission (NRC) (Reference 2228 Table 53-5) It sh ould be noted that this assumption applies to material composition only it does no t apply to source terms which are based on the characteristics of spent fuel
Usage This assumption is used in Sections 624 and 626
325 Homogenization of Radiation Source Regions
Assumption It is assu med that a commercial SNF assembly consis ts of four distinct reg ions (active fuel bottom end-fitting plenum and top end-fitting) The materials and radiation sources
16
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
of each assembly region are homogenized inside a volume defined by the TAD cavity radius and region height
Rationale The assembly representation is consistent with the industry practice for shielding calculations accepted by NRC (Reference 2228 Figure 53-6) The effec t of source homogenization is twofold (1) it d ecreases th e m ass de nsity of the source region and (2) it places source points slightly closer to detector locations thus reducing radiation attenuation The resu lts of Calculation of the Effect of Source Geometry on the 21-PWR WP Dose Rates (Reference 2218 pp 22-26) indicate that th e effect of assem bly homogenization gives nearly the same or conservative dose rates as the explicit fuel assembly model
Usage This assumption is used in Section 624
326 Ignoring Internal Fuel Basket Materials
Assumption It is assumed that the internal fuel basket materials are ignored
Rationale Inclusion of fuel basket m aterials in the smeared m aterial com position would increase the overall density and consequently increase the attenuati on of the radiation Therefore this assumption is conservative
Usage This assumption is used in Sections 621 624 and 626
17
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
4 METHODOLOGY
41 QUALITY ASSURANCE
This calculation was prepared in accordance with EG-PRO-3DP-G04B-00037 Calculations and Analyses (Reference 212) The results of th is calculation provides worker dose assessm ent adjustments and this will id entify radio logical hazards f or f acilities im portant to saf ety Therefore the approved version is designated as QA QA
42 USE OF COMPUTER SOFTWARE
421 Baseline Software
The Monte Carlo N-Particle com puter pr ogram (MCNP5) version 140 (Reference 2225) is used to calculate the dose rates (neutron pr imary gamm a and secondary gamm a) at various locations around a transportation cask and an aging overpack
The software specifications are as follows
bull Program Name MCNP5 bull VersionRevision Number Version 140 bull Operating Systems Windows XP bull Software Tracking Number 11199-140-00 bull Computer Type Dell OPTIPLEX GX620
MCNP5 which is Level 1 software is (a) appropriate for three-dim ensional neutron gamma and coupled neutrongamma shielding calculations (b) used within th e range of validation as documented in Software Validation Report for MCNP5 v140 (Reference 2221) and (c) obtained from Software C onfiguration Managem ent and qualified in accordance with procedure IT-PRO-0012 Qualification of Software (Reference 213) Therefore MCNP5 code is suitable for use in this design calculation All MCNP5 input and output files docum ented in this calculation are provided on a compact disc (CD) as Attachment II
All MCNP cases are executed on one of the following Q com puters QNW -004184 QNW -004187 QNW-004194 and QNW-004196 as shown in the output files
422 Commercial off the Shelf Software
The Excel sof tware is used to c alculate var ious inpu t values (i e atom densities weight percentages geometrical dimensions normalized source spectra and probabilities etc) Standard functions of Excel are also used in this desi gn calculation to display results (ie gamma and neutron dose rates) in tabular and graphic forms and to perform relative error calculations
The software specifications are as follows
bull Program Name Excel bull VersionRevision Number Microsoftreg Excel 2003
18
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
bull This software is installed on a persona l com puter running Microsoft W indows XP (central processing unit number 151834)
The user defined for mulas inputs results and gr aphical representations have been verified by hand calculations or visual inspection and are documented in sufficient detail to allow an independent repetition of the com putations Calculations were verifi ed by hand and graphical representations were found accurate by visual inspection
Per Software Management Microsoftreg Excel is not requir ed to be qualif ied due to its commercial availability status (Reference 211 Attachment 4 p 55 bullet 2)
43 CALCULATION APPROACH
This calculation em ploys the qualified so ftware MCNP5 version 140 (Reference 2225) a three-dimensional Monte Carlo code for pe rforming neutron and coupled neutron-gamm a calculations to estim ate dose rates at sele cted locations on and surrounding a conceptual transportation cask containing a loaded TAD canister
431 MCNP5 Program
MCNP5 a general Monte Carlo part icle transport code sim ulates particle transport through a three-dimensional representation of the nuclear system being analyzed During the random walk of particles through the system described by the geom etry the c ode collects inform ation about various events (su rface cross ing collis ions trac k leng th etc) and es timates fluxes in various geometric configurations specified as tallies by the user It also estimates the statistical precision of the results in the form of relative errors (Reference 2224 pp 1-2 to 1-8)
Per Project Design Criteria Document (Reference 2211 Section 41015) the flux estim ates are converted to dose rates using the Am erican Nuclear Society (ANS) flux-to-dose rate conversion factors for gammas and neutrons (R eference 221) The simple variance reduction techniques of Geometry SplittingRussian Roulette and source probability biasing (Sections 631 and 633) are used to enhance computational efficiency
19
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
5 LIST OF ATTACHMENTS
Number of Pages Attachment I List of Electronic Files on the CD 3 Attachment II Compact Disc NA
20
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
6 CALCULATIONS
This sectio n provides inform ation necess ary to perform the calcu lations in this docum ent Section 61 describes the configurations the type of CSNF to be analyzed the number of MCNP runs and the locations where dose rates are ca lculated Section 62 provides the calculation input that includes the details of the geom etry m odel radiation source term s and m aterial compositions Input specific to MCNP dose -rate conversion factors and relative error calculation are described in the later sections
61 DESCRIPTION OF CALCULATIONS
Dose rate calculations are perform ed with the MCNP5 version 140 com puter code (Reference 2225) Two conceptual transportation casks Cask A and Cask B (Assum ption 323) are employed Each cask contains a TAD canister that is loaded with 21 ident ical PW R SN F assemblies Three PWR source term s are analy zed they are the source term s corresponding to the maximum design basis and average PW R SN Fs The characteris tics of the P WR source terms are presented in S ection 627 Each PWR source term has neutron and ga mma radiation sources that require separate MCNP5 runs For each radiation source an axial profile source and a uniform source for the active fuel region are considered The uniform source for the active fuel region is included in this calculation because this approach was used in combination with source peaking factors in certain calculations (Reference 2216 Sections 37 and 39 and Reference 2217 Section 5242)
The total number of MCNP5 runs is 24 which re sults from a com bination of two conceptual casks three PWR source terms two radiation sources and two axia l source distributions for the active fuel region These 24 runs are categorized into four calcula tion sets Each calculation set consists of six runs that is a combination of three PWR source te rms and two radiation sources The characteristics of each calculation set are as follows
1 Cask A with axial profile sources in the active fuel region
2 Cask A with uniform axial sources in the active fuel region
3 Cask B with axial profile sources in the active fuel region
4 Cask B with uniform axial sources in the active fuel region
For each MCNP5 run dose rates are calculated at the exte rior surfaces and at distances 1 and 2 meters from the exterior surfaces Surface tallies and detector tallies (ring and point detectors) as indicated in Figure 1 are e mployed in all runs Figure 1 is used to illustrate the dep loyment of the surface and detector tallies re lative to the so urce regions and it should not be interpreted as an exact geometry of any particular run Surface tallies are deployed at all three distances while ring and point detectors are used only at 1 m and 2 m and not at the cask surfaces Using point detectors near a surface or in any scattering media is not recommended because very large scores can occur f rom collisions close ( less than a f ew centimeters) to the point detecto rs that can lead to resu lts with high r elative e rrors thus m aking the ca lculation d ifficult to o btain r eliable answers
21
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
For the radial direction surface tallies at the three distances (contact 1 m and 2 m) are computed for three su rface segments (cylindrical rings) between the planes at Z = 145 175 2 05 and 235 cm The geometric locations of the segments are shown in Figure 1 The axial locations of these segments correspond to the m iddle of the active fuel region of the PWR SNF assemblies The average dose rates for each of the segm ents are calculated for the outside surface and surfaces at 1 m and 2 m from the cask surface Two ring detectors (instead of point detectors) are deployed at 1 m and 2 m for the radial dire ction Ring detectors instead of point detectors are used in order to capitalize on the symm etry around the cask axis thus im proving the efficiency of the calculations
In the axial direction the average d ose rates within three concentric radial surfaces defined by radii of 40 80 and 120 cm (shown in Figure 1) are calculated for the top and bottom surfaces and at distances 1 m and 2 m from these surfaces Finally point detectors at 1 m and 2 m from the top and bottom axial surfaces are employed
22
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Point Detector at 2 m x
Ring Ring Detector Detector at 2 m at 1 m
x x
Z = 00 cm
Z = 145 cm
Z = 175 cm
Z = 205 cm
Z = 235 cm
R = 80 cm
R = 120 cm
R = 40 cm
Active Fuel
Shield Plug
Top End-Fitting Plenum
Bottom End-Fitting
Ring Detector at 1 m
x
Point Detector at 1 m x
Ring Detector
at 2 m x
D = 26797 cm
H =
610
845
cm
Point Detector at 1 m x
Point Detector at 2 m x
Figure 1 Geometry and Tally Scheme for the TAD Transportation Cask
23
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
62 CALCULATION INPUT
Technical product input and sources of the input used in the deve lopment of this calculation are documented in this section Tables in this docum ent and in th e associated Microsoftreg Excel spreadsheets referenced m ay present num erical values with m any significant figures these values are not to be considered as high precision values since the significant figures are results of calculated values andor unit conversions
621 TAD Canister
The TAD canis ter will contain either 21 P WR or 44 BW R (boiling water reactor) SNF assemblies (Reference 2222 Section 321) While the canister design is iden tical for both PWR and BWR SNF assemblies the internal basket structure is different depending on the SNF assemblies However the internal basket stru cture m aterial is no t in cluded in the calcu lation model (Assumption 326)
The TAD canister is a right-circu lar cylinder with a diam eter of 665 in and a height between 186 and 212 in (Reference 2222 Section 321) The average and maximum total dose rates on the top surf ace of a loaded TAD ca nister must not exceed 800 and 1000 m remhr respectively (Reference 2222 Section 314) The TAD canister used in this calculation is m ade of SS 316 with a radial wall and bottom thickness of 025 in (Assumption 321) The top of the canister has a shield plug that is 11 in thick SS 316 (Ass umption 322) A thick shield plug is needed to keep the maxim um contact dose rate of th e top surface below 1000 m remhr The overall dimensions of the TAD canister are provided in Table 3
Table 3 Dimensions of TAD Canister
Component Dimension
(in) (cm)
Maximum heighta 212 53848
Outer diametera 665 16891
Thickness of bottom lidb 025 0635
Shell thicknessb 025 0635
Lifting Featurec 6 1524
Height without Lifting Feature 206 52324
Thickness of shield plugd 110 2794
aReference 2222 Section 311 bAssumption 321 cReference 2222 p Attachment C-1 dAssumption 322
622 Conceptual TAD Transportation Casks
Two conceptual TAD transportation casks designa ted as Cask A and Cask B are em ployed in this calculation (Assumption 323) They both have a cylindrical geometry with dimensions and materials specified in Tables 1 and 2 of Section 323 Cask A will provide shielding to meet the exterior radiation standards of 10 CFR 7147(b) (Reference 231) when loaded with a TAD
24
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
canister car rying the m aximum PWR SNF Cask B will s atisfy th e sa me radiatio n standa rds when loaded with a TAD canister c arrying the average PWR SNF The reason to analyze both Casks A and B is to cover a broad range of characteristics of the CSNF
The cavity dimensions of the conceptual cask s are 53785 cm (21175 in) in height and 16891 cm (665 in) in diam eter (Tab les 1 and 2) This cav ity will accommoda te the TAD canister described in Table 3 without the lifting feature This is the geometry model used in the MCNP5 calculations
623 Fuel Assembly Selection
PWR and BWR Source Term Sensitivity Study (Reference 2211 Tables 71 through 84) shows that the source terms generated for the Bamp W 15x15 Mark B fuel assembly with 475 kg uranium loading bound the source terms of other PWR assembly types ther efore this assembly type is selected as the representative PWR fuel assembly The gamma and neutron source terms for the BampW 15x15 Mark B assembly are generated in PWR Source Term Generation and Evaluation (Reference 229) and are used in this calculation
624 BampW 15x15 Mark B PWR Fuel Assembly
BampW 15x15 Mark B fuel assembly consists of four regions top end-fitting plenum active fuel and bottom end-fitting The m aterials and ra diation sources of each assem bly region are homogenized inside a volume defined by the region height and the interior diam eter of the TAD canister (Assumption 325) The active fuel region is homogenized with fresh unirradiated fuel (Assumption 324) Since the internal structure (i e basket) design of t he TAD is currently not finalized the com position of the hom ogenized fuel does not include the basket m aterials (Assumption 326) and therefore does not take cred it for any shielding that these m aterials may provide
Table 4 provides the design param eters for the BampW 15x15 Mark B fuel assembly Data provided here are used in Attachment II PWR_fuel compxls worksheet BampWassy
25
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 4 BampW 15x15 Mark B Fuel Assembly Description
Component Material Characteristic Value Specific Reference Array Size 15 x 15
Reference 2227 Table 2-2 Fuel Pins Assembly 208 Guide Tubes Assembly 16 Instrument Tubes Assembly 1
Assembly NA Pin Pellet Diameter 0936244 cm (03686 in) Reference 2220 p 2A-34 Pin Pitch 144272 cm (0568 in)
Reference 2227 Table 2-2 Active Fuel Height 360172 cm (1418 in) Assembly Width 2168144 cm (8536 in)
Reference 2220 p 2A-31 Assembly Height 4206875 cm (165625 in) Mass U assembly 46363 kg
Guide tube Zircaloy-4 Outer Diameter 13462 cm (053 in)
Reference 2227 Table 2-2
Inner Diameter 126492 cm (0498 in)
Instrument tube Zircaloy-4 Outer Diameter 138193 cm (05441 in) Inner Diameter 112014 cm (0441 in)
Cladding` Zircaloy-4 Inner Diameter 095758 cm (0377 in) Outer Diameter 10922 cm (043 in)
Plenum region NA Length 297688 cm (11720 in) Reference 2220 p 2A-34 Top nozzle SS CF3M MassAssembly (Top) 748 kg
Reference 2220 p 2A-32
Bottom nozzle SS CF3M MassAssembly (Bottom) 816 kg Guide tubes Zircaloy-4 MassAssembly (in Core) 80 kg Instrument tube Zircaloy-4 MassAssembly (in Core) 064 kg Spacer-plenum Inconel-718 MassAssembly (Plenum) 104 kg Spacer-bottom Inconel-718 MassAssembly (Bottom) 13 kg Spacer-in core Inconel-718 MassAssembly (in Core) 49 kg Spring retainer SS CF3M MassAssembly (Top) 091 kg Holddown spring Inconel-718 MassAssembly (Top) 18 kg Upper end plug SS 304 MassAssembly (Top) 006 kg Upper nut SS 304L MassAssembly (Top) 051 kg Lower nut SS 304 MassAssembly (Bottom) 015 kg Grid supports Zircaloy-4 MassAssembly (in Core) 064 kg Plenum spring SS 302 MassAssembly (Plenum) 0042 lb (001905 kg) Reference 2220 p 2A-34
Note Som e d ata i n this tab le ar e given i n British u nits in th e r eferences thes e d ata ar e converted into metric units as the inputs to MCNP5 are in metric units
The assem bly region heights as m odeled in MC NP are presented in Table 5 utilizing values from Table 4 Table 5 is taken from Dose Rate Calculation for Exhaust Main Drifts (Reference 2213 Table 3)
26
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 5 PWR Fuel Assembly Regions
Component Height Reference
Plenum 297688 cm (11720 in) Reference 2220 p 2A-34
Active Fuel 360172 cm (1418 in) Table 3
Bottom End-Fitting 1077 cm (424 in) Calculateda
Top End-Fitting 1998 cm (787 in) Calculatedb
Source Reference 2213 Table 3 aCalculated b ased on data Reference 2227 F igures 2-3 an d 2-7
(Region 9 Height [16723 cm] + Region 10 Height [508 cm] ndash Lo wer Fuel Plenum and End Cap [11033 cm])
bCalculated (Assembly Length ndash Active Fuel Length ndash P lenum Length ndash Bottom End-fitting Length)
625 Material Compositions
The TAD transportation cask com ponent m aterial specifications are defined in Table 1 The TAD canister is constructed of SS 316 (Assumpti on 321) The PWR fuel assembly materials used to homogenize the fuel regions are defined in Table 4 Table 6 c ontains the m aterial compositions defining the TAD canister WP and fuel assemblies
27
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 6 Chemical Compositions of Materials
Material Density (gcc)
Isotopic Weight Percent Reference
SS 302 NA
C 0150 Mn 2000 P 0045 S 0030 Si 0750 Cr 18000 Ni 9000 N 0100 Fe 69925
Attachment II PWR_fuel compxls worksheet ferrous Reference 222 SEC II A SA-240 Table 1 for SS 302 SS 304 and SS 304L Reference 222 SEC II A SA-351SA -351M Table 2 for SS CF3M
SS 304 NA
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 9250 N 0100 Fe 68745
SS 304L NA
C 003 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 10000 N 0100 Fe 6804 5
SS CF3M NA
C 0030 Mn 1500 P 0040 S 0040 Si 1500 Cr 19000 Ni 11000 Mo 2500 Fe 64390
Inconel 718 NA
C 0080 Mn 0350 Si 0350 Cr 19000 Ni 52500 Co 1000 Mo 3050 Fe 16809 Nb 5125 Ti 0900 Al 0500 Cu 0300 S 0015 P 0015 B 0006
Attachment II PWR_fuel compxls worksheet alloys aReference 223 p 666 Table 6 Reference 222 SEC II B SB-637 Table 1 for Inconel 718 Reference 224 Table 2 for Zircaloy 4
Zircaloy 4 656a Cr 0100 Fe 0210 O 0125 Sn 1450 Zr 98115
SS 316 798b
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 17000 Ni 12000 Mo 2500 N 0100 Fe 65495
Attachment II PWR_fuel compxls worksheet others Reference 222 SEC II A SA-240 Table 1 for SS 316 bReference 225 Table X1
626 Homogenization Assembly Materials
The atom density of an element or isotope in atomsbmiddotcm in a homogenized region is calculated according to the following equation (Reference 2223 Appendix B)
M i times N AvogadroNi = Equation 1 Ai timesV times K
where Ni = Atom density of elementisotope i (atomsbmiddotcm) Mi = Mass of elementisotope i (g) NAvogadro = Avogadrorsquos constant 06022 x 1024 (atomsmole)
28
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Ai = Atomic weight of elementisotope i (gmole) V = Homogenization volume (cm3) K = Unit transformation constant = 1024 (bmiddotcmcm3)
Equation 1 is used in A ttachment II spreadsheet PWR_fuel compxls worksheet BampWassy to calculate th e atom dens ities for v arious elem ents and iso topes The m ass of elementsisotop es and Avogadrorsquos constant are provided in Reference 2226
Table 7 lists the com position of the hom ogenized assem bly regions (active fuel plenum top end-fitting and bottom end-fitting) for the PWR assembly The active fuel region contains fresh unirradiated fuel (Assumption 324) Since the internal structure (ie basket) design of the TAD is currently not finalized the composition of either homogenized fuel does not include the basket materials and therefore does not tak e credit for any shielding that thes e materials may provide (Assumption 326)
Table 7 Isotopic Compositions of Homogenized PWR Assembly Regions
Element Isotope
Atom Densities for Homogenized Regions (atomsbsdotcm)
Active Fuel Bottom End-Fitting Plenum Top End-Fitting
10B 861E-09 764E-08 221E-08 570E-08 11B 347E-08 307E-07 890E-08 230E-07 C 519E-07 160E-05 138E-06 993E-06 N -- 570E-07 262E-08 117E-06 O 621E-03 -- 142E-05 -- Al 144E-06 128E-05 371E-06 957E-06 Si 971E-07 243E-04 259E-06 139E-04 P 377E-08 606E-06 102E-07 360E-06 S 365E-08 581E-06 971E-08 340E-06 Ti 147E-06 130E-05 376E-06 971E-06 Cr 320E-05 187E-03 779E-05 113E-03 Mn 497E-07 126E-04 141E-06 749E-05 Fe 303E-05 531E-03 717E-05 313E-03 Co 132E-06 117E-05 340E-06 876E-06 Ni 697E-05 144E-03 180E-04 940E-04 Cu 368E-07 327E-06 945E-07 244E-06 Zr 196E-03 -- 195E-03 -- Nb 430E-06 382E-05 110E-05 285E-05 Mo 248E-06 135E-04 636E-06 791E-05 Sn 223E-05 -- 222E-05 -- 234U 139E-06 -- -- -- 235U 157E-04 -- -- -- 236U 719E-07 -- -- -- 238U 294E-03 -- -- -- Total 114E-02 924E-03 235E-03 557E-03
Source Attachment II spreadsheet PWR_fuel compxls worksheet BampWassy
29
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
The isotopic composition of commercially available 235U enriched uranium is determined by the given initial 235U enrichment using the following equations (Reference 226 p 20)
wt235U =235Uenrichment _ of _ the _ associated _ fuel _ batch Equation 2
wt234U = 0007731times (wt235U )10837 Equation 3
wt236U = 00046times (wt235U ) Equation 4
wt238U =100 minus (wt234U + wt235U + wt236U ) Equation 5
The weight percentages of uran ium isotopes for PWR fuel are ca lculated in Attachm ent II spreadsheet PWR_fuel compxls worksheet BampWassy using Equations 2 through 5
627 PWR Source Terms
This calculation uses the following three PWR source terms bull Maximum source (50 wt initial 235U enrichment 80 GWdMTU burnup and 5-year
decay time) (Reference 229 Section 55) Table 8 lists th e gamma source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Design Basis source (4 0 wt initial 235U enrichment 60 GW dMTU burnup and 10-year decay tim e) (Reference 228 Section 552) Table 9 lists the gamm a source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Average source ( 40 wt initial 235U enrichment 48 GWdMTU burnup and 25-year decay time) (Reference 229 Section 55) Table 10 lists the gamma source terms for the fuel and non-fuel regions and the neutron source term for the fuel region
These sources (ie maximum design basis and av erage) are described in this section For dose rate calculations all the fuel assemblies in a transportation cask are of the sam e characteristics Also gamma radiation source term s for the PWR assem bly are prov ided for the f our assembly regions while neutron source term is only present in the active fuel region Gamma radiation sources in the non-active fuel region are distri buted unif ormly within each source region Gamma and neutron sources in the active fuel re gion are modeled as uni form distributions or with axial source profiles
The PWR gamma and neutron axial source profiles for the active fuel region presented in Table 11 are applied to the active fuel region of all three source terms (ie maximum design basis and average) when appropriate
30
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 8 Gamma and Neutron Sources for the Maximum PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting
Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 594E+11 233E+15 528E+11 379E+11 100E-01 000E+00 100E-01 116E+11 644E+14 609E+10 743E+10 400E-01 805E+07 200E-01 283E+10 522E+14 352E+10 179E+10 900E-01 411E+08 300E-01 141E+09 148E+14 196E+09 891E+08 140E+00 376E+08 400E-01 190E+09 985E+13 586E+09 117E+09 185E+00 276E+08 600E-01 191E+09 153E+15 110E+11 741E+07 300E+00 485E+08 800E-01 435E+09 470E+15 595E+10 237E+09 643E+00 443E+08 100E+00 137E+11 708E+14 803E+09 766E+10 200E+01 393E+07 133E+00 338E+13 455E+14 174E+13 217E+13 Total 211E+09 166E+00 953E+12 130E+14 491E+12 612E+12
--
200E+00 187E+03 144E+12 919E+02 113E+03 250E+00 226E+08 249E+12 116E+08 145E+08 300E+00 351E+05 110E+11 181E+05 225E+05 400E+00 766E-08 139E+10 100E-08 416E-08 500E+00 000E+00 709E+07 000E+00 000E+00 650E+00 000E+00 286E+07 000E+00 000E+00 800E+00 000E+00 558E+06 000E+00 000E+00 100E+01 000E+00 119E+06 000E+00 000E+00
Total 442E+13 113E+16 231E+13 284E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE2R2B14cut bWasteStreamE2R1B14cut cWasteStreamE2R3B14cut dWasteStreamE2R4B14cut
31
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 9 Gamma and Neutron Sources for the Design Basis PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary
(MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 273E+11 121E+15 188E+11 175E+11 100E-01 000E+00 100E-01 528E+10 329E+14 277E+10 339E+10 400E-01 316E+07 200E-01 128E+10 245E+14 117E+10 819E+09 900E-01 161E+08 300E-01 639E+08 713E+13 633E+08 407E+08 140E+00 148E+08 400E-01 850E+08 455E+13 164E+09 533E+08 185E+00 109E+08 600E-01 492E+08 226E+14 269E+10 337E+07 300E+00 191E+08 800E-01 291E+09 237E+15 160E+10 186E+09 643E+00 174E+08 100E+00 540E+09 122E+14 248E+09 341E+09 200E+01 154E+07 133E+00 154E+13 195E+14 797E+12 990E+12 Total 830E+08 166E+00 435E+12 450E+13 225E+12 280E+12
--
200E+00 235E+00 152E+11 149E+02 215E-02 250E+00 103E+08 517E+10 534E+07 664E+07 300E+00 160E+05 379E+09 829E+04 103E+05 400E+00 943E-10 497E+08 155E-10 519E-10 500E+00 000E+00 282E+07 000E+00 000E+00 650E+00 000E+00 113E+07 000E+00 000E+00 800E+00 000E+00 222E+06 000E+00 000E+00 100E+01 000E+00 471E+05 000E+00 000E+00
Total 201E+13 486E+15 105E+13 129E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B11cut bWasteStreamE5R1B11cut cWasteStreamE5R3B11cut dWasteStreamE5R4B11cut
32
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 10 Gamma and Neutron Sources for the Average PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 336E+10 670E+14 186E+10 217E+10 100E-01 00000E+00 100E-01 602E+09 199E+14 314E+09 387E+09 400E-01 748E+06 200E-01 146E+09 126E+14 853E+08 936E+08 900E-01 382E+07 300E-01 730E+07 389E+13 439E+07 469E+07 140E+00 352E+07 400E-01 947E+07 263E+13 716E+07 607E+07 185E+00 261E+07 600E-01 141E+07 205E+13 504E+08 383E+06 300E+00 469E+07 800E-01 208E+09 124E+15 192E+09 144E+09 643E+00 418E+07 100E+00 208E+09 110E+13 164E+09 144E+09 200E+01 365E+06 133E+00 175E+12 295E+13 909E+11 112E+12 Total 199E+08 166E+00 494E+11 513E+12 257E+11 318E+11
--
200E+00 973E-01 675E+10 614E+01 872E-03 250E+00 117E+07 353E+09 609E+06 754E+06 300E+00 182E+04 288E+08 944E+03 117E+04 400E+00 186E-11 198E+07 149E-11 127E-11 500E+00 000E+00 669E+06 000E+00 000E+00 650E+00 000E+00 269E+06 000E+00 000E+00 800E+00 000E+00 527E+05 000E+00 000E+00 100E+01 000E+00 112E+05 000E+00 000E+00
Total 229E+12 237E+15 119E+12 147E+12
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B9cut bWasteStreamE5R1B9cut cWasteStreamE5R3B9cut dWasteStreamE5R4B9cut
33
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 11 Gamma and Neutron Axial Source Profiles for a PWR Assembly
Axial boundaries (From midplane)
(cm)
TOP BOTTOM
Neutron Gamma Ne utron Gamma 000 1554 1117 1554 1117 1143 1537 1114 1571 1120 2286 1521 1111 1588 1123 3429 1504 1108 1605 1126 4572 1486 1104 1622 1129 5715 1464 1100 1636 1131 6858 1438 1095 1648 1133 8001 1401 1088 1657 1135 9144 1350 1078 1654 1134
10287 1277 1063 1625 1129 11430 1165 1039 1554 1117 12573 0998 09995 1414 1091 13716 0769 09365 1172 1041 14859 0492 08375 0816 0951 16002 0220 06850 0402 0797 17145 0046 04625 0092 0551 18288 00 00 00 00
Source Reference 2219 Table S445
34
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
63 MCNP SPECIFIC INPUT
631 Source Probability
A linear radial distribution is used for all gamma and neutron sources The linear radial distribution is sam pled usi ng the built-in power function p(x) = xc a with a = 1 for the radial direction This sampling method results in a uniform source distribution over the area bounded by the outer radius of the source
The source axial distributions are unifor m for all four source regions The a xial uni form xp(x) = c distribution is sampled using the built-in power function a with a = 0 for extent
The energy distribu tions of the gamma and neutron sour ce term s are treated as energ y probabilities and are applied in MCNP5 using SISP cards
632 Dose Rate and Flux Tallies
MCNP5 dose rate calculations feature separate runs for the following calculation types
bull a photon transport calculation for prim ary ga mma contribution to the dose rates fr om photon fluxes
bull a coupled neutronphoton transport calculat ion for neutrons a nd secondary gamma (photons generated by neutron be ing captured) contributions to dose rates from neutron and gamma fluxes
The tally type F2 is us ed in th is d esign ca lculation as f lux estim ators The type F2 tally evaluates the flux averaged over a surface in particlescm2s
To generate dose ra tes in te rms of remhr the FM (tally multiplier ) and DEDF (dose energydose conversion factors) cards are used to en ter the tally multiplier f actor (source intensity in particless) energy boundaries in MeV and corresponding dose conversion factors in (remhr)(particlescm2s) respectively These factors were used in the input files
In order for the F2 tally to accum ulate flux ov er a surface a specific s urface area is requ ired The SD cards are used to enter a surface area in cm2 over which the flux will be tallied for an F2 tally
633 Variance Reduction Techniques
Variance reduction technique is usually em ployed in order to increase the efficiency of a calculation and obtain statistically m eaningful results within re asonable com puter tim e In Monte Carlo calculations when variance reduction scheme is employed the weights of particles are adjusted in order to account for the biasing and to preserve a fair game
Geometry splitting and Russian roulette techniques described in Reference 2224 (pp 2-140 ndash 2-142) are useful in shielding calculations and therefore deployed in all the MCNP5 runs
35
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
As particles migrate in an important direction (toward the detector) they are increased in number to provide better sampling by means of geometry splitting across geometric boundaries Russian roulette (the reverse process) is played when particles travel in an unimportant direction to allow termination of unim portant histories The IMP card required for every cel l ca rd is us ed to implement this technique
The other variance reduction technique deployed in the MC NP5 runs is source intensity biasing for the gamma sources from the four source regions (active fuel bottom end-fitting plenum and top end-fitting) The natural total gamma source intensity of comm ercial SNF is dom inated by the gamma source in the active fuel region This active fuel gamma source usually accounts for over 95 o f the total g amma source intens ity In order to im prove the efficiency of the axial dose rate calculations a biased source probability distribution is employed for the prim ary gamma dose rate calculations The biased gamma source probability distribution is chosen to be 005 080 010 and 005 for the bottom end-fitting the active fuel the plenum and the top end-fitting regions respectively
64 DOSE CONVERSION FACTORS
Project Design Criteria Document (Reference 2211 Se ction 41015) requires the use of flux-to-dose rate conversion fact ors from ANSIANS-611-1977 (Reference 221) for dose rate evaluations Table 16 lists the neutron and ga mma dose conversion factors used in the MCNP5 calculations
Table 12 Gamma and Neutron Flux to Dose Conversion Factors
Gamma Neutron Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
001 396E-06 140 251E-06 250E-08 367E-06 003 582E-07 180 299E-06 100E-07 367E-06 005 290E-07 220 342E-06 100E-06 446E-06 007 258E-07 260 382E-06 100E-05 454E-06 010 283E-07 280 401E-06 100E-04 418E-06 015 379E-07 325 441E-06 100E-03 376E-06 020 501E-07 375 483E-06 100E-02 356E-06 025 631E-07 425 523E-06 100E-01 217E-05 030 759E-07 475 560E-06 500E-01 926E-05 035 878E-07 500 580E-06 100E+00 132E-04 040 985E-07 525 601E-06 250E+00 125E-04 045 108E-06 575 637E-06 500E+00 156E-04 050 117E-06 625 674E-06 700E+00 147E-04 055 127E-06 675 711E-06 100E+01 147E-04 060 136E-06 750 766E-06 140E+01 208E-04 065 144E-06 900 877E-06 200E+01 227E-04 070 152E-06 1100 103E-05 080 168E-06 1300 118E-05 100 198E-06 1500 133E-05
Source Reference 221 Tables 1 and 3
36
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION
By def inition (Ref erence 2224 Equation 219) the estimated st atistic relative error of the i component is
Ri = Si
2
Equation 6Ti
where i = tally component index Ri = relative error of the i component S2
i = variance of the i component Ti = tally i component
For a result (ie dose rate) computed as a sum of different tallies the statistical relative error of the computed value is o btained from the variance of the result - S2
total which is th e sum of the estimated variances of the individual tallies S2
i n
2 2STotal = sum Si Equation 7 i=1
where S2Total = total estimated variance
n = total number of components Therefore the total tally value (dose rate) and the associated relative error are derived according to Equations 8 and 9
n TTotal = sumTi Equation 8
i=1
n n
sum (Ri timesTi )2
2 sum Si 2
STotal = i=1 = i=1 Equation 9RTotal = TTotal TTotal TTotal
where RTotal = total estimated relative error TTotal = total estimated tally
Equations 8 and 9 are utilized in Attachm ent II to ev aluate to tal dos e ra tes and their r elative errors
37
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
7 RESULTS AND CONCLUSIONS
71 RESULTS
The following sections summarize the results of this calculation Section 711 presents results for Conceptual Cask A while Section 712 for Conceptual Cask B Section 713 provides comparisons of the dose-rate reduction factors du e to the two conceptual casks and the axial source distributions in the active fuel region Do se rates and relative errors can be found in Attachment II within the output files and Excel files
711 Dose Rates of Conceptual Cask A
This section presents dose-rate results of the calculation sets 1 and 2 as described in Section 61 for Cask A Set 1 has axial p rofile sources in the active fuel region a nd consist of six runs resulting from the three PWR SNF source term s (maximum design basis and average) and the two radiation sources (gammas and neutrons) Set 2 has uniform axial sources in the active fuel region and consists of six run s r esulting f rom the th ree P WR SNF source term s and th e tw o radiation sources
As described in Section 61 dose ra tes are calculated at the three exterior surfaces (radial top and bottom) and at distances 1 m and 2 m from the exterior surfaces The total dose rates for set 1 are presented in Tables 13 14 and 15 for the ra dial top and bottom dire ctions respectively However the com ponents (primary gamma neutr on and secondary gamma) contributing to the total dose rates as well as the re lative error calculations can be found in Attachment II Excel file MCNP-Results1xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 2 are shown in Tables 16 17 and 18 The dose-rate components and the relative errors can be found in A ttachment II Excel file MCNP-Results2xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 13 and 16 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 14 and 17 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 15 and 18 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carrying th e maximum PWR SNF Based on the results in Tables 13 through 18 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask A indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these 6 tables the d ose-rate red uction f actors between the m aximum and the design basis fuels the maxim um and the averag e fuels and th e design basis and the average fuels are a lso presented
38
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 320E-02 00237 116E-02 00222 262E-03 00219 275 1223 445
1 m 133E-02 00164 494E-03 00171 106E-03 00162 269 1261 468 2 m 749E-03 00198 285E-03 00225 584E-04 00162 263 1282 488
Ring Detectors 1 m 133E-02 00116 492E-03 00115 108E-03 00124 271 1229 454 2 m 756E-03 00118 279E-03 00110 605E-04 00128 271 1250 462
Source Attachment II MCNP-Results1xls worksheet Summary
Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 142E-02 00368 628E-03 00446 934E-04 00483 226 1520 672
1 m 570E-03 00289 263E-03 00426 375E-04 00381 217 1520 701 2 m 265E-03 00364 123E-03 00547 169E-04 00374 216 1575 730
Point Detectors 1 m 598E-03 00238 274E-03 00271 402E-04 00354 219 1489 681 2 m 273E-03 00218 123E-03 00245 180E-04 00336 221 1515 684
Source Attachment II MCNP-Results1xls worksheet Summary
Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 653E-03 00298 265E-03 00276 510E-04 00341 247 1278 518
1 m 276E-03 00238 112E-03 00208 207E-04 00249 248 1334 539 2 m 125E-03 00185 508E-04 00199 933E-05 00246 246 1336 544
Point Detectors 1 m 291E-03 00227 118E-03 00203 218E-04 00242 247 1335 540 2 m 130E-03 00209 524E-04 00187 955E-05 00233 247 1357 549
Source Attachment II MCNP-Results1xls worksheet Summary
Tables 13 14 and 15 are results of calculation set 1 for conceptual Cask A with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
39
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 265E-02 00247 990E-03 00222 215E-03 00278 268 1234 461
1 m 116E-02 00178 468E-03 00549 960E-04 00189 248 1208 488 2 m 713E-03 00273 265E-03 00161 602E-04 00360 269 1184 439
Ring Detectors 1 m 117E-02 00120 454E-03 00132 979E-04 00141 259 1199 463 2 m 722E-03 00130 276E-03 00141 589E-04 00153 261 1226 469
Source Attachment II MCNP-Results2xls worksheet Summary
Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 199E-02 00461 827E-03 00455 147E-03 00536 241 1359 564
1 m 849E-03 00564 323E-03 00314 563E-04 00418 263 1507 574 2 m 415E-03 00832 158E-03 00603 253E-04 00501 263 1641 623
Point Detectors 1 m 877E-03 00348 353E-03 00275 615E-04 00391 248 1426 574 2 m 393E-03 00341 160E-03 00278 270E-04 00378 246 1454 590
Source Attachment II MCNP-Results2xls worksheet Summary
Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 879E-03 00374 356E-03 00333 669E-04 00406 247 1315 533
1 m 365E-03 00223 147E-03 00209 269E-04 00253 248 1358 548 2 m 164E-03 00229 674E-04 00205 120E-04 00248 243 1364 560
Point Detectors 1 m 383E-03 00217 155E-03 00204 285E-04 00248 247 1347 546 2 m 172E-03 00197 689E-04 00186 124E-04 00225 249 1391 558
Source Attachment II MCNP-Results2xls worksheet Summary
Tables 16 17 and 18 ar e results of calculation set 2 for conceptual Cask A with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
40
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ACRONYMS AND ABBREVIATIONS
ACRONYMS
ANS American Nuclear Society
ANSI American National Standards Institute
ASTM American Society for Testing and Materials
BSC Bechtel SAIC Company LLC
BWR Boiling Water Reactor
CD Compact disc
CSNF Commercial Spent Nuclear Fuel
DB Design Basis
DOE U S Department of Energy
DPC Dual Purpose Canister
NRC U S Nuclear Regulatory Commission
PCSA Preclosure Safety Analysis
PWR Pressurized Water Reactor
RPM Repository Project Management
SNF Spent Nuclear Fuel
SS 316 Stainless Steel 316
TAD Transportation Aging and Disposal
WP Waste Package
YMP Yucca Mountain Project
ABBREVIATIONS and UNITS
b barn
cm centimeter
7
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
g gram
GWd gigawatt-day
hr hour
in inch
kg kilogram
m meter
mrem millirem
MeV million electron volt
MTU metric ton uranium
s second
8
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
1 PURPOSE
The purpose of this calculation is to calcu late th e dose ra tes of two conceptua l tr ansportation casks each carrying a Transportation Aging and Disposal (TAD) canister separately loaded with the average design basis (DB) and m aximum comm ercial spent nuc lear fuel (CSNF) assemblies Then the dose-ra te reduction f actors between the m aximum and the design basis fuels the d esign bas is and the average fuels and the m aximum and the averag e fuels are computed
The results of this calculation may be used to substantiate the dose-rate reduction factors such as those in the engineering study Repository ALARA Goal Compliance (Reference 227) which is cited as a reference in a Preclosure Safety Analyses (PCSA) calculation that supports the License Application
The calculations contained in this docum ent are developed by Nuclear and Radiological Engineering of the Repository Project Mana gement (RPM) organization Yucca Mountain Project (YMP) personnel from Nuclear and Radiological Engineering should be consulted before use of the calculations for purposes other than those stated herein or use by individuals other than personnel in Nuclear and Radiological Engineering
9
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
2 REFERENCES
21 PROJECT PROCEDURESDIRECTIVES
211 IT-PRO-0011 Rev 0010 Software Management Las Vegas Nevada Bechtel SAIC Company
212 EG-PRO-3DP-G04B-00037 Rev 14 Calculations and Analyses Las Vegas Nevada Bechtel SAIC Company
213 IT-PRO-0012 Rev 007 Qualification of Software Las Vegas Nevada Bechtel SAIC Company
22 DESIGN INPUTS
221 ANSIANS-611-1977 Neutron and Gamma-Ray Flux-to-Dose-Rate Factors La Grange Park Illinois American Nuclear Society TIC 239401
222 ASME (American Society of Mechanical Engineers) 2004 2004 ASME Boiler and Pressure Vessel Code 2004 Edition New York New York American Society of Mechanical Engineers TIC 256479 ISBN 0-7918-2899-9
223 ASM International 1990 Properties and Selection Nonferrous Alloys and Special-Purpose Materials Specific Metals and Alloys Volume 2 of Metals Handbook 10th Edition Page 666 [Materials Park Ohio] American Society for Metals TIC 239807
224 ASTM (American Society for Testing and Materials) B 811-90 1991 Standard Specification for Wrought Zirconium Alloy Seamless Tubes for Nuclear Reactor Fuel Cladding Philadelphia Pennsylvania American Society for Testing and Materials TIC 239780
225 ASTM G 1-90 (Reapproved 1999) 1999 Standard Practice for Preparing Cleaning and Evaluating Corrosion Test Specimens West Conshohocken Pennsylvania American Society for Testing and Materials TIC 238771
226 Bowman SM Hermann OW and Brady MC 1995 Sequoyah Unit 2 Cycle 3 Volume 2 of Scale-4 Analysis of Pressurized Water Reactor Critical Configurations ORNLTM-12294V2 Oak Ridge Tennessee Oak Ridge National Laboratory TIC 244397 [DIRS 123796]
227 BSC (Bechtel SAIC Company LLC) 2008 Repository ALARA Goal Compliance 000-30R-MGR0-04000-000 REV 000 Las Vegas Nevada Bechtel SAIC Company ACC ENG200802050014 [DIRS 184957]
228 BSC 2002 Subsurface Shielding Source Term Specification Calculation 000-00C-WER0-00100-000-00A Las Vegas Nevada Bechtel SAIC Company ACC MOL200212160076 ENG200508150022
10
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
229 BSC 2004 PWR Source Term Generation and Evaluation 000-00C-MGR0-00100-000-00B Las Vegas Nevada Bechtel SAIC Company ACC ENG200405240007
2210 BSC 2008 Basis of Design for the TAD Canister-Based Repository Design Concept 000-3DR-MGR0-00300-000-003 Las Vegas Nevada Bechtel SAIC Company ACC ENG200810060001
2211 BSC 2007 Project Design Criteria Document 000-3DR-MGR0-00100-000-007 Las Vegas Nevada Bechtel SAIC Company ACC ENG200710160005 ENG200711080001 ENG200712200003 ENG200801070001 ENG200801070002 ENG200801070016 ENG200801070017 ENG200801310006 ENG200803050002 ENG200803050011 ENG200803050012 ENG200803060009 ENG200803130004 ENG200807100001 ENG200811120006 ENG200811140004
2212 BSC 2004 PWR and BWR Source Term Sensitivity Study 000-00C-MGR0-00300-000-00A Las Vegas Nevada Bechtel SAIC Company ACC ENG200401140003 ENG200508150023
2213 BSC 2007 Dose Rate Calculation for Exhaust Main Drifts 800-00C-SS00-00700-000-00B Las Vegas Nevada Bechtel SAIC Company ACC ENG200711050017 ENG200803060001
2214 BSC 2006 Dual Purpose Canister Opening Study 050-30R-WHS0-00600-000-000 Las Vegas Nevada Bechtel SAIC Company ACC ENG200612200023
2215 BSC 2007 GROA Shielding Requirements Calculation 000-00C-MGR0-03300-000-00B Las Vegas Nevada Bechtel SAIC Company ACC ENG200705290037
2216 BSC 2002 Concrete Shielding Calculation for Dry Facility 1 110-00C-CS10-00100-000-00A Las Vegas Nevada Bechtel SAIC Company ACC MOL200301140075
2217 BSC 2003 Shielding Design Calculations for Dry Facility 1 110-00C-CS10-00200-000-00A Las Vegas Nevada Bechtel SAIC Company ACC ENG200306020003
2218 CRWMS MampO 1998 Calculation of the Effect of Source Geometry on the 21-PWR WP Dose Rates BBAC00000-01717-0210-00004 REV 00 Las Vegas Nevada CRWMS MampO ACC MOL199902220059 [DIRS 102134]
2219 CRWMS MampO 2000 Users Manual for SCALE-44A 10129-UM-44A-00 Las Vegas Nevada CRWMS MampO ACC MOL200011300136 MOL200108220084 MOL200108220085 MOL200108220086 MOL200108220087 [DIRS 153872]
2220 DOE (US Department of Energy) 1987 Appendix 2A Physical Descriptions of LWR Fuel Assemblies Volume 3 of Characteristics of Spent Fuel High-Level Waste and Other Radioactive Wastes Which May Require Long-Term Isolation DOERW-0184 Washington DC US Department of Energy Office of Civilian Radioactive Waste Management ACC HQX198804050024 [DIRS 132333]
11
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
2221 DOE 2007 Software Validation Report for MCNP5 v140 Document ID 11199-SVR-140-00-WINXP Las Vegas Nevada US Department of Energy Office of Repository Development ACC MOL200702280252 [DIRS 180516]
2222 DOE 2008 Transportation Aging and Disposal Canister System Performance Specification WMO-TADCS-000001 Rev 1 ICN 1 Washington DC US Department of Energy Office of Civilian Radioactive Waste Management ACC DOC200803310001 [DIRS 185304]
2223 Harmon CD II Busch RD Briesmeister JF and Forster RA 1994 Criticality Calculations with MCNPtrade A Primer LA-12827-M Los Alamos New Mexico Los Alamos National Laboratory TIC 234014 [DIRS 154532]
2224 LANL (Los Alamos National Laboratory) 2004 MCNP mdash A General Monte Carlo N-Particle Transport Code Version 5 (Appendix H is not included) LA-UR-03-1987 Volume I Los Alamos [New Mexico] Los Alamos National Laboratory ACC MOL200510240126 [DIRS 176521]
2225 MCNP5 V 140 2007 Windows XP STN 11199-140-00 [DIRS 180515]
2226 Parrington JR Knox HD Breneman SL Baum EM and Feiner F 1996 Nuclides and Isotopes Chart of the Nuclides 15th Edition San Jose California General Electric Company and KAPL Inc TIC 233705 LC Call Number QC7935 N8622 1996
2227 Punatar MK 2001 Summary Report of Commercial Reactor Criticality Data for Crystal River Unit 3 TDR-UDC-NU-000001 REV 02 Las Vegas Nevada Bechtel SAIC Company ACC MOL200107020087 [DIRS 155635]
2228 Sisley SE 2002 Transportation License Application for the FuelSolutionstrade System (TAC No L23311) Submittal of the FuelSolutiontrade Transportation SARs Revision 3 Letter from SE Sisley (BNFL) to the NRC April 11 2002 BFSNRC 02-011 with enclosures TIC 255245 [DIRS 171545]
NOTE Reference 2220 is a direct input but is not QA QA It is justified as acceptable for the intended use as it is directly from the DOE and is considered the best available data on the subject The referenced values cited in Tables 3 and 4 are valid for use since they are reliable and reasonable based on engineering judgment
23 DESIGN CONSTRAINTS
231 10 CFR 71 2008 Energy Packaging and Transportation of Radioactive Material Internet Accessible [DIRS 185678]
12
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
24 DESIGN OUTPUTS
The resu lts of this calculation will be us ed to substan tiate th e dose reduc tion f actor in the Repository ALARA Goal Compliance (Reference 227) which is cited as a reference in a PCSA calculation that supports the License Application
13
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
3 ASSUMPTIONS
31 ASSUMPTIONS REQUIRING VERIFICATION
None
32 ASSUMPTIONS NOT REQUIRING VERIFICATION
Assumptions 321 322 and 323 are m odeling assum ptions and do not require further verification The m aterials and dim ensions for the TAD canister and for the conceptu al transportation casks are only selected to charac terize two tr ansportation casks th at m eet 10 CFR7147 (Reference 231) dose rates when lo aded with the ldquom aximumrdquo and ldquoaveragerdquo pressurized water re actor (PW R) assem blies re spectively There is n o need to v erify those dimensions or m aterials at a later date The ca lculated results in Sect ion 711 verify that the conceptual casks would meet 10 CFR 7147 (Reference 231) dose rates
321 Material and Wall Thickness of TAD Canister
Assumption It is assumed that the TAD canister is made of stainless steel 316 (SS 316) and has a wall thickness of 025 in for the radial and bottom shells
Rationale Currently the design of the TAD canis ter d oes not ex ist Based on a survey of existing m ultipurpose a nd dual purpose caniste rs (DPC) (Ref erence 2214 p 56) a 025 in thickness is below the wall thick ness of any existing c anisters For the purp ose of this calculation this assumption leads to higher and conservative external dose rates Since SS 316 is the sam e material used for the waste pack age inner shell it is a l ogical cho ice f or the TAD canister
Although Reference 2214 is an engineering study with a QA N A status it is used here as an indirect input to support the assumption which is conservative for dose rate calculations
Usage This assumption is used in Sections 621 and 625
322 Material and Thickness of TAD Shield Plug
Assumption It is assu med that the TAD shield plug is made of SS 316 and has a thickness of 11 in
Rationale Currently the design of the TAD canister doe s not exist A thick shield plug of 11 in (Reference 2215 Table 12) is needed to keep the m aximum contact dose rate of the top surface below 1000 mrem hr (Reference 2222 Section 314) Since SS 316 is the sam e material used for the waste package inner shell it is a logical choice for the TAD shield plug
Usage This assumption is used in Section 621
14
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
323 Geometry and Materials of Conceptual TAD Transportation Casks
Assumption Two conceptual TAD transpo rtation casks designated as Cask A and Cask B are assumed to have a cylindrical geom etry and m aterials specified in Tab les 1 and 2 respectively The casks are basically construc ted of an inner layer of SS 316 for ga mma shielding a m iddle layer of 5-borated polyethylen e for neutron shielding and a th in outer layer of SS 316 whic h serves a structural function as well as shielding secondary gamma rays
Both Cask A and Cask B have a cavity height of 53785 cm (21175 in) and a cavity diameter of 16891 cm (6650 in) However Cask A has a total height of 610845 cm (24049 in) and an outside diameter of 26797 cm (10550 in) while the total height and outside diameter of Cask B are 58885 cm (23183 in) and 24765 cm (9750) respectively
Cask A will provide shielding to m eet the exterior radiat ion standards of 10 C FR 7147(b) (Reference 231) when loaded w ith a TAD canister carrying th e maximum PWR spent nuclear fuel (SNF) Cask B will satisf y the same radiation standards when loade d with a TAD caniste r carrying the average PWR SNF
Table 1 Geometry and Materials of Conceptual TAD Transportation Cask A
Component Dimension
Material (cm) (in)
Total Height 61085 2404 9 NA
Outside Diameter 26797 1055 0 NA
Cask Cavity Height 53785 2117 5 NA
Cask Cavity Diameter (Radius) 16891 (8446) 6650 (3325) NA
Radial Gamma Shield Thickness (Radius)a 3302 (11748)a 1300 (4625)a SS 316
Radial Neutron Shield Thickness (Radius)b 1524 (13272)b 600 (5225)b 5-borated polyethylene
Radial Outer Shell Thickness (Radius)c 127 (13399)c 050 (5275)c SS 316
Top Gamma Shield Thickness (Axial Position)d 600 (54385)d 236 (21411)d SS 316
Top Neutron Shield Thickness (Axial Position)d 1000 (55385)d 394 (21805)d 5-borated polyethylene
Top Outer Shell Thickness (Axial Position)d 200 (55585)d 079 (21884)d SS 316
Bottom Gamma Shield Thickness (Axial Position)d 35365 (-360)d 1392 (-1417)d SS 316
Bottom Neutron Shield Thickness (Axial Position)d 15 (-510)d 591 (-2008)d 5-borated polyethylene
Bottom Outer Shell Thickness (Axial Position)d 4 (-550)d 157 (-2165)d SS 316 a11748 = 3302 + 8446 and 4625 = 1300 + 3325 b13272 = 1524 + 11748 and 5225 = 600 + 4625 c13399 = 127 + 13272 and 5275 = 050 + 5225 dCoordinate relative to the bottom of the fuel assembly as modeled in MCNP5
15
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 2 Geometry and Materials of Conceptual TAD Transportation Cask B
Component Dimension
Material (cm) (in)
Total Height 58885 2318 3 NA
Outside Diameter 24765 9750 NA
Cask Cavity Height 53785 2117 5 NA
Cask Cavity Diameter (Radius) 16891 (8446) 6650 (3325) NA
Radial Gamma Shield Thickness (Radius)a 254 (10986)a 1000 (4325)a SS 316
Radial Neutron Shield Thickness (Radius)b 127 (12256)b 500 (4825)b 5-borated polyethylene
Radial Outer Shell Thickness (Radius)c 127 (12383)c 050 (4875)c SS 316
Top Gamma Shield Thickness (Axial Position)d 8 (54585)d 315 (21490)d SS 316
Top Neutron Shield Thickness (Axial Position)d None Non e NA
Top Outer Shell Thickness (Axial Position)d None Non e NA
Bottom Gamma Shield Thickness (Axial Position)d 3837 (-390)d 1510 (-1535)d SS 316
Bottom Neutron Shield Thickness (Axial Position)d 300 (-420)d 118 (-1654)d 5-borated polyethylene
Bottom Outer Shell Thickness (Axial Position)d 100 (-430)d 039 (-1693)d SS 316 a10986 = 254 + 8446 and 4325 = 1000 + 3325 b12256= 127 + 10986 and 4825 = 500+ 4325 c12383 = 127 + 12256 and 4875 = 050 + 4825 dCoordinate relative to the bottom of the fuel assembly as modeled in MCNP5
Rationale Currently a design for the TAD transporta tion cask does not exist The casks assumed for this calculation are so lely for estim ation of the dose reduction due to different source terms This is a conceptual repres entation only used in this calculation to estim ate the parameters of interest
Usage This assumption is used in Sections 61 and 622
324 Usage of Unirradiated Fuel for Commercial SNF
Assumption It is assumed that the active fuel region of the commercial SNF assembly contains the same isotopic concentrations as the fresh uni rradiated fuel and that the concentrations of fresh fuel with 5 initial enrichm ent corresp onding to m aximum SNF are used for all other SNFs
Rationale This assumption is a standard practice for shielding calculations throughout the industry accepted by the U S Nucle ar Regulatory Commission (NRC) (Reference 2228 Table 53-5) It sh ould be noted that this assumption applies to material composition only it does no t apply to source terms which are based on the characteristics of spent fuel
Usage This assumption is used in Sections 624 and 626
325 Homogenization of Radiation Source Regions
Assumption It is assu med that a commercial SNF assembly consis ts of four distinct reg ions (active fuel bottom end-fitting plenum and top end-fitting) The materials and radiation sources
16
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
of each assembly region are homogenized inside a volume defined by the TAD cavity radius and region height
Rationale The assembly representation is consistent with the industry practice for shielding calculations accepted by NRC (Reference 2228 Figure 53-6) The effec t of source homogenization is twofold (1) it d ecreases th e m ass de nsity of the source region and (2) it places source points slightly closer to detector locations thus reducing radiation attenuation The resu lts of Calculation of the Effect of Source Geometry on the 21-PWR WP Dose Rates (Reference 2218 pp 22-26) indicate that th e effect of assem bly homogenization gives nearly the same or conservative dose rates as the explicit fuel assembly model
Usage This assumption is used in Section 624
326 Ignoring Internal Fuel Basket Materials
Assumption It is assumed that the internal fuel basket materials are ignored
Rationale Inclusion of fuel basket m aterials in the smeared m aterial com position would increase the overall density and consequently increase the attenuati on of the radiation Therefore this assumption is conservative
Usage This assumption is used in Sections 621 624 and 626
17
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
4 METHODOLOGY
41 QUALITY ASSURANCE
This calculation was prepared in accordance with EG-PRO-3DP-G04B-00037 Calculations and Analyses (Reference 212) The results of th is calculation provides worker dose assessm ent adjustments and this will id entify radio logical hazards f or f acilities im portant to saf ety Therefore the approved version is designated as QA QA
42 USE OF COMPUTER SOFTWARE
421 Baseline Software
The Monte Carlo N-Particle com puter pr ogram (MCNP5) version 140 (Reference 2225) is used to calculate the dose rates (neutron pr imary gamm a and secondary gamm a) at various locations around a transportation cask and an aging overpack
The software specifications are as follows
bull Program Name MCNP5 bull VersionRevision Number Version 140 bull Operating Systems Windows XP bull Software Tracking Number 11199-140-00 bull Computer Type Dell OPTIPLEX GX620
MCNP5 which is Level 1 software is (a) appropriate for three-dim ensional neutron gamma and coupled neutrongamma shielding calculations (b) used within th e range of validation as documented in Software Validation Report for MCNP5 v140 (Reference 2221) and (c) obtained from Software C onfiguration Managem ent and qualified in accordance with procedure IT-PRO-0012 Qualification of Software (Reference 213) Therefore MCNP5 code is suitable for use in this design calculation All MCNP5 input and output files docum ented in this calculation are provided on a compact disc (CD) as Attachment II
All MCNP cases are executed on one of the following Q com puters QNW -004184 QNW -004187 QNW-004194 and QNW-004196 as shown in the output files
422 Commercial off the Shelf Software
The Excel sof tware is used to c alculate var ious inpu t values (i e atom densities weight percentages geometrical dimensions normalized source spectra and probabilities etc) Standard functions of Excel are also used in this desi gn calculation to display results (ie gamma and neutron dose rates) in tabular and graphic forms and to perform relative error calculations
The software specifications are as follows
bull Program Name Excel bull VersionRevision Number Microsoftreg Excel 2003
18
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
bull This software is installed on a persona l com puter running Microsoft W indows XP (central processing unit number 151834)
The user defined for mulas inputs results and gr aphical representations have been verified by hand calculations or visual inspection and are documented in sufficient detail to allow an independent repetition of the com putations Calculations were verifi ed by hand and graphical representations were found accurate by visual inspection
Per Software Management Microsoftreg Excel is not requir ed to be qualif ied due to its commercial availability status (Reference 211 Attachment 4 p 55 bullet 2)
43 CALCULATION APPROACH
This calculation em ploys the qualified so ftware MCNP5 version 140 (Reference 2225) a three-dimensional Monte Carlo code for pe rforming neutron and coupled neutron-gamm a calculations to estim ate dose rates at sele cted locations on and surrounding a conceptual transportation cask containing a loaded TAD canister
431 MCNP5 Program
MCNP5 a general Monte Carlo part icle transport code sim ulates particle transport through a three-dimensional representation of the nuclear system being analyzed During the random walk of particles through the system described by the geom etry the c ode collects inform ation about various events (su rface cross ing collis ions trac k leng th etc) and es timates fluxes in various geometric configurations specified as tallies by the user It also estimates the statistical precision of the results in the form of relative errors (Reference 2224 pp 1-2 to 1-8)
Per Project Design Criteria Document (Reference 2211 Section 41015) the flux estim ates are converted to dose rates using the Am erican Nuclear Society (ANS) flux-to-dose rate conversion factors for gammas and neutrons (R eference 221) The simple variance reduction techniques of Geometry SplittingRussian Roulette and source probability biasing (Sections 631 and 633) are used to enhance computational efficiency
19
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
5 LIST OF ATTACHMENTS
Number of Pages Attachment I List of Electronic Files on the CD 3 Attachment II Compact Disc NA
20
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
6 CALCULATIONS
This sectio n provides inform ation necess ary to perform the calcu lations in this docum ent Section 61 describes the configurations the type of CSNF to be analyzed the number of MCNP runs and the locations where dose rates are ca lculated Section 62 provides the calculation input that includes the details of the geom etry m odel radiation source term s and m aterial compositions Input specific to MCNP dose -rate conversion factors and relative error calculation are described in the later sections
61 DESCRIPTION OF CALCULATIONS
Dose rate calculations are perform ed with the MCNP5 version 140 com puter code (Reference 2225) Two conceptual transportation casks Cask A and Cask B (Assum ption 323) are employed Each cask contains a TAD canister that is loaded with 21 ident ical PW R SN F assemblies Three PWR source term s are analy zed they are the source term s corresponding to the maximum design basis and average PW R SN Fs The characteris tics of the P WR source terms are presented in S ection 627 Each PWR source term has neutron and ga mma radiation sources that require separate MCNP5 runs For each radiation source an axial profile source and a uniform source for the active fuel region are considered The uniform source for the active fuel region is included in this calculation because this approach was used in combination with source peaking factors in certain calculations (Reference 2216 Sections 37 and 39 and Reference 2217 Section 5242)
The total number of MCNP5 runs is 24 which re sults from a com bination of two conceptual casks three PWR source terms two radiation sources and two axia l source distributions for the active fuel region These 24 runs are categorized into four calcula tion sets Each calculation set consists of six runs that is a combination of three PWR source te rms and two radiation sources The characteristics of each calculation set are as follows
1 Cask A with axial profile sources in the active fuel region
2 Cask A with uniform axial sources in the active fuel region
3 Cask B with axial profile sources in the active fuel region
4 Cask B with uniform axial sources in the active fuel region
For each MCNP5 run dose rates are calculated at the exte rior surfaces and at distances 1 and 2 meters from the exterior surfaces Surface tallies and detector tallies (ring and point detectors) as indicated in Figure 1 are e mployed in all runs Figure 1 is used to illustrate the dep loyment of the surface and detector tallies re lative to the so urce regions and it should not be interpreted as an exact geometry of any particular run Surface tallies are deployed at all three distances while ring and point detectors are used only at 1 m and 2 m and not at the cask surfaces Using point detectors near a surface or in any scattering media is not recommended because very large scores can occur f rom collisions close ( less than a f ew centimeters) to the point detecto rs that can lead to resu lts with high r elative e rrors thus m aking the ca lculation d ifficult to o btain r eliable answers
21
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
For the radial direction surface tallies at the three distances (contact 1 m and 2 m) are computed for three su rface segments (cylindrical rings) between the planes at Z = 145 175 2 05 and 235 cm The geometric locations of the segments are shown in Figure 1 The axial locations of these segments correspond to the m iddle of the active fuel region of the PWR SNF assemblies The average dose rates for each of the segm ents are calculated for the outside surface and surfaces at 1 m and 2 m from the cask surface Two ring detectors (instead of point detectors) are deployed at 1 m and 2 m for the radial dire ction Ring detectors instead of point detectors are used in order to capitalize on the symm etry around the cask axis thus im proving the efficiency of the calculations
In the axial direction the average d ose rates within three concentric radial surfaces defined by radii of 40 80 and 120 cm (shown in Figure 1) are calculated for the top and bottom surfaces and at distances 1 m and 2 m from these surfaces Finally point detectors at 1 m and 2 m from the top and bottom axial surfaces are employed
22
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Point Detector at 2 m x
Ring Ring Detector Detector at 2 m at 1 m
x x
Z = 00 cm
Z = 145 cm
Z = 175 cm
Z = 205 cm
Z = 235 cm
R = 80 cm
R = 120 cm
R = 40 cm
Active Fuel
Shield Plug
Top End-Fitting Plenum
Bottom End-Fitting
Ring Detector at 1 m
x
Point Detector at 1 m x
Ring Detector
at 2 m x
D = 26797 cm
H =
610
845
cm
Point Detector at 1 m x
Point Detector at 2 m x
Figure 1 Geometry and Tally Scheme for the TAD Transportation Cask
23
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
62 CALCULATION INPUT
Technical product input and sources of the input used in the deve lopment of this calculation are documented in this section Tables in this docum ent and in th e associated Microsoftreg Excel spreadsheets referenced m ay present num erical values with m any significant figures these values are not to be considered as high precision values since the significant figures are results of calculated values andor unit conversions
621 TAD Canister
The TAD canis ter will contain either 21 P WR or 44 BW R (boiling water reactor) SNF assemblies (Reference 2222 Section 321) While the canister design is iden tical for both PWR and BWR SNF assemblies the internal basket structure is different depending on the SNF assemblies However the internal basket stru cture m aterial is no t in cluded in the calcu lation model (Assumption 326)
The TAD canister is a right-circu lar cylinder with a diam eter of 665 in and a height between 186 and 212 in (Reference 2222 Section 321) The average and maximum total dose rates on the top surf ace of a loaded TAD ca nister must not exceed 800 and 1000 m remhr respectively (Reference 2222 Section 314) The TAD canister used in this calculation is m ade of SS 316 with a radial wall and bottom thickness of 025 in (Assumption 321) The top of the canister has a shield plug that is 11 in thick SS 316 (Ass umption 322) A thick shield plug is needed to keep the maxim um contact dose rate of th e top surface below 1000 m remhr The overall dimensions of the TAD canister are provided in Table 3
Table 3 Dimensions of TAD Canister
Component Dimension
(in) (cm)
Maximum heighta 212 53848
Outer diametera 665 16891
Thickness of bottom lidb 025 0635
Shell thicknessb 025 0635
Lifting Featurec 6 1524
Height without Lifting Feature 206 52324
Thickness of shield plugd 110 2794
aReference 2222 Section 311 bAssumption 321 cReference 2222 p Attachment C-1 dAssumption 322
622 Conceptual TAD Transportation Casks
Two conceptual TAD transportation casks designa ted as Cask A and Cask B are em ployed in this calculation (Assumption 323) They both have a cylindrical geometry with dimensions and materials specified in Tables 1 and 2 of Section 323 Cask A will provide shielding to meet the exterior radiation standards of 10 CFR 7147(b) (Reference 231) when loaded with a TAD
24
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
canister car rying the m aximum PWR SNF Cask B will s atisfy th e sa me radiatio n standa rds when loaded with a TAD canister c arrying the average PWR SNF The reason to analyze both Casks A and B is to cover a broad range of characteristics of the CSNF
The cavity dimensions of the conceptual cask s are 53785 cm (21175 in) in height and 16891 cm (665 in) in diam eter (Tab les 1 and 2) This cav ity will accommoda te the TAD canister described in Table 3 without the lifting feature This is the geometry model used in the MCNP5 calculations
623 Fuel Assembly Selection
PWR and BWR Source Term Sensitivity Study (Reference 2211 Tables 71 through 84) shows that the source terms generated for the Bamp W 15x15 Mark B fuel assembly with 475 kg uranium loading bound the source terms of other PWR assembly types ther efore this assembly type is selected as the representative PWR fuel assembly The gamma and neutron source terms for the BampW 15x15 Mark B assembly are generated in PWR Source Term Generation and Evaluation (Reference 229) and are used in this calculation
624 BampW 15x15 Mark B PWR Fuel Assembly
BampW 15x15 Mark B fuel assembly consists of four regions top end-fitting plenum active fuel and bottom end-fitting The m aterials and ra diation sources of each assem bly region are homogenized inside a volume defined by the region height and the interior diam eter of the TAD canister (Assumption 325) The active fuel region is homogenized with fresh unirradiated fuel (Assumption 324) Since the internal structure (i e basket) design of t he TAD is currently not finalized the com position of the hom ogenized fuel does not include the basket m aterials (Assumption 326) and therefore does not take cred it for any shielding that these m aterials may provide
Table 4 provides the design param eters for the BampW 15x15 Mark B fuel assembly Data provided here are used in Attachment II PWR_fuel compxls worksheet BampWassy
25
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 4 BampW 15x15 Mark B Fuel Assembly Description
Component Material Characteristic Value Specific Reference Array Size 15 x 15
Reference 2227 Table 2-2 Fuel Pins Assembly 208 Guide Tubes Assembly 16 Instrument Tubes Assembly 1
Assembly NA Pin Pellet Diameter 0936244 cm (03686 in) Reference 2220 p 2A-34 Pin Pitch 144272 cm (0568 in)
Reference 2227 Table 2-2 Active Fuel Height 360172 cm (1418 in) Assembly Width 2168144 cm (8536 in)
Reference 2220 p 2A-31 Assembly Height 4206875 cm (165625 in) Mass U assembly 46363 kg
Guide tube Zircaloy-4 Outer Diameter 13462 cm (053 in)
Reference 2227 Table 2-2
Inner Diameter 126492 cm (0498 in)
Instrument tube Zircaloy-4 Outer Diameter 138193 cm (05441 in) Inner Diameter 112014 cm (0441 in)
Cladding` Zircaloy-4 Inner Diameter 095758 cm (0377 in) Outer Diameter 10922 cm (043 in)
Plenum region NA Length 297688 cm (11720 in) Reference 2220 p 2A-34 Top nozzle SS CF3M MassAssembly (Top) 748 kg
Reference 2220 p 2A-32
Bottom nozzle SS CF3M MassAssembly (Bottom) 816 kg Guide tubes Zircaloy-4 MassAssembly (in Core) 80 kg Instrument tube Zircaloy-4 MassAssembly (in Core) 064 kg Spacer-plenum Inconel-718 MassAssembly (Plenum) 104 kg Spacer-bottom Inconel-718 MassAssembly (Bottom) 13 kg Spacer-in core Inconel-718 MassAssembly (in Core) 49 kg Spring retainer SS CF3M MassAssembly (Top) 091 kg Holddown spring Inconel-718 MassAssembly (Top) 18 kg Upper end plug SS 304 MassAssembly (Top) 006 kg Upper nut SS 304L MassAssembly (Top) 051 kg Lower nut SS 304 MassAssembly (Bottom) 015 kg Grid supports Zircaloy-4 MassAssembly (in Core) 064 kg Plenum spring SS 302 MassAssembly (Plenum) 0042 lb (001905 kg) Reference 2220 p 2A-34
Note Som e d ata i n this tab le ar e given i n British u nits in th e r eferences thes e d ata ar e converted into metric units as the inputs to MCNP5 are in metric units
The assem bly region heights as m odeled in MC NP are presented in Table 5 utilizing values from Table 4 Table 5 is taken from Dose Rate Calculation for Exhaust Main Drifts (Reference 2213 Table 3)
26
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 5 PWR Fuel Assembly Regions
Component Height Reference
Plenum 297688 cm (11720 in) Reference 2220 p 2A-34
Active Fuel 360172 cm (1418 in) Table 3
Bottom End-Fitting 1077 cm (424 in) Calculateda
Top End-Fitting 1998 cm (787 in) Calculatedb
Source Reference 2213 Table 3 aCalculated b ased on data Reference 2227 F igures 2-3 an d 2-7
(Region 9 Height [16723 cm] + Region 10 Height [508 cm] ndash Lo wer Fuel Plenum and End Cap [11033 cm])
bCalculated (Assembly Length ndash Active Fuel Length ndash P lenum Length ndash Bottom End-fitting Length)
625 Material Compositions
The TAD transportation cask com ponent m aterial specifications are defined in Table 1 The TAD canister is constructed of SS 316 (Assumpti on 321) The PWR fuel assembly materials used to homogenize the fuel regions are defined in Table 4 Table 6 c ontains the m aterial compositions defining the TAD canister WP and fuel assemblies
27
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 6 Chemical Compositions of Materials
Material Density (gcc)
Isotopic Weight Percent Reference
SS 302 NA
C 0150 Mn 2000 P 0045 S 0030 Si 0750 Cr 18000 Ni 9000 N 0100 Fe 69925
Attachment II PWR_fuel compxls worksheet ferrous Reference 222 SEC II A SA-240 Table 1 for SS 302 SS 304 and SS 304L Reference 222 SEC II A SA-351SA -351M Table 2 for SS CF3M
SS 304 NA
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 9250 N 0100 Fe 68745
SS 304L NA
C 003 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 10000 N 0100 Fe 6804 5
SS CF3M NA
C 0030 Mn 1500 P 0040 S 0040 Si 1500 Cr 19000 Ni 11000 Mo 2500 Fe 64390
Inconel 718 NA
C 0080 Mn 0350 Si 0350 Cr 19000 Ni 52500 Co 1000 Mo 3050 Fe 16809 Nb 5125 Ti 0900 Al 0500 Cu 0300 S 0015 P 0015 B 0006
Attachment II PWR_fuel compxls worksheet alloys aReference 223 p 666 Table 6 Reference 222 SEC II B SB-637 Table 1 for Inconel 718 Reference 224 Table 2 for Zircaloy 4
Zircaloy 4 656a Cr 0100 Fe 0210 O 0125 Sn 1450 Zr 98115
SS 316 798b
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 17000 Ni 12000 Mo 2500 N 0100 Fe 65495
Attachment II PWR_fuel compxls worksheet others Reference 222 SEC II A SA-240 Table 1 for SS 316 bReference 225 Table X1
626 Homogenization Assembly Materials
The atom density of an element or isotope in atomsbmiddotcm in a homogenized region is calculated according to the following equation (Reference 2223 Appendix B)
M i times N AvogadroNi = Equation 1 Ai timesV times K
where Ni = Atom density of elementisotope i (atomsbmiddotcm) Mi = Mass of elementisotope i (g) NAvogadro = Avogadrorsquos constant 06022 x 1024 (atomsmole)
28
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Ai = Atomic weight of elementisotope i (gmole) V = Homogenization volume (cm3) K = Unit transformation constant = 1024 (bmiddotcmcm3)
Equation 1 is used in A ttachment II spreadsheet PWR_fuel compxls worksheet BampWassy to calculate th e atom dens ities for v arious elem ents and iso topes The m ass of elementsisotop es and Avogadrorsquos constant are provided in Reference 2226
Table 7 lists the com position of the hom ogenized assem bly regions (active fuel plenum top end-fitting and bottom end-fitting) for the PWR assembly The active fuel region contains fresh unirradiated fuel (Assumption 324) Since the internal structure (ie basket) design of the TAD is currently not finalized the composition of either homogenized fuel does not include the basket materials and therefore does not tak e credit for any shielding that thes e materials may provide (Assumption 326)
Table 7 Isotopic Compositions of Homogenized PWR Assembly Regions
Element Isotope
Atom Densities for Homogenized Regions (atomsbsdotcm)
Active Fuel Bottom End-Fitting Plenum Top End-Fitting
10B 861E-09 764E-08 221E-08 570E-08 11B 347E-08 307E-07 890E-08 230E-07 C 519E-07 160E-05 138E-06 993E-06 N -- 570E-07 262E-08 117E-06 O 621E-03 -- 142E-05 -- Al 144E-06 128E-05 371E-06 957E-06 Si 971E-07 243E-04 259E-06 139E-04 P 377E-08 606E-06 102E-07 360E-06 S 365E-08 581E-06 971E-08 340E-06 Ti 147E-06 130E-05 376E-06 971E-06 Cr 320E-05 187E-03 779E-05 113E-03 Mn 497E-07 126E-04 141E-06 749E-05 Fe 303E-05 531E-03 717E-05 313E-03 Co 132E-06 117E-05 340E-06 876E-06 Ni 697E-05 144E-03 180E-04 940E-04 Cu 368E-07 327E-06 945E-07 244E-06 Zr 196E-03 -- 195E-03 -- Nb 430E-06 382E-05 110E-05 285E-05 Mo 248E-06 135E-04 636E-06 791E-05 Sn 223E-05 -- 222E-05 -- 234U 139E-06 -- -- -- 235U 157E-04 -- -- -- 236U 719E-07 -- -- -- 238U 294E-03 -- -- -- Total 114E-02 924E-03 235E-03 557E-03
Source Attachment II spreadsheet PWR_fuel compxls worksheet BampWassy
29
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
The isotopic composition of commercially available 235U enriched uranium is determined by the given initial 235U enrichment using the following equations (Reference 226 p 20)
wt235U =235Uenrichment _ of _ the _ associated _ fuel _ batch Equation 2
wt234U = 0007731times (wt235U )10837 Equation 3
wt236U = 00046times (wt235U ) Equation 4
wt238U =100 minus (wt234U + wt235U + wt236U ) Equation 5
The weight percentages of uran ium isotopes for PWR fuel are ca lculated in Attachm ent II spreadsheet PWR_fuel compxls worksheet BampWassy using Equations 2 through 5
627 PWR Source Terms
This calculation uses the following three PWR source terms bull Maximum source (50 wt initial 235U enrichment 80 GWdMTU burnup and 5-year
decay time) (Reference 229 Section 55) Table 8 lists th e gamma source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Design Basis source (4 0 wt initial 235U enrichment 60 GW dMTU burnup and 10-year decay tim e) (Reference 228 Section 552) Table 9 lists the gamm a source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Average source ( 40 wt initial 235U enrichment 48 GWdMTU burnup and 25-year decay time) (Reference 229 Section 55) Table 10 lists the gamma source terms for the fuel and non-fuel regions and the neutron source term for the fuel region
These sources (ie maximum design basis and av erage) are described in this section For dose rate calculations all the fuel assemblies in a transportation cask are of the sam e characteristics Also gamma radiation source term s for the PWR assem bly are prov ided for the f our assembly regions while neutron source term is only present in the active fuel region Gamma radiation sources in the non-active fuel region are distri buted unif ormly within each source region Gamma and neutron sources in the active fuel re gion are modeled as uni form distributions or with axial source profiles
The PWR gamma and neutron axial source profiles for the active fuel region presented in Table 11 are applied to the active fuel region of all three source terms (ie maximum design basis and average) when appropriate
30
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 8 Gamma and Neutron Sources for the Maximum PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting
Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 594E+11 233E+15 528E+11 379E+11 100E-01 000E+00 100E-01 116E+11 644E+14 609E+10 743E+10 400E-01 805E+07 200E-01 283E+10 522E+14 352E+10 179E+10 900E-01 411E+08 300E-01 141E+09 148E+14 196E+09 891E+08 140E+00 376E+08 400E-01 190E+09 985E+13 586E+09 117E+09 185E+00 276E+08 600E-01 191E+09 153E+15 110E+11 741E+07 300E+00 485E+08 800E-01 435E+09 470E+15 595E+10 237E+09 643E+00 443E+08 100E+00 137E+11 708E+14 803E+09 766E+10 200E+01 393E+07 133E+00 338E+13 455E+14 174E+13 217E+13 Total 211E+09 166E+00 953E+12 130E+14 491E+12 612E+12
--
200E+00 187E+03 144E+12 919E+02 113E+03 250E+00 226E+08 249E+12 116E+08 145E+08 300E+00 351E+05 110E+11 181E+05 225E+05 400E+00 766E-08 139E+10 100E-08 416E-08 500E+00 000E+00 709E+07 000E+00 000E+00 650E+00 000E+00 286E+07 000E+00 000E+00 800E+00 000E+00 558E+06 000E+00 000E+00 100E+01 000E+00 119E+06 000E+00 000E+00
Total 442E+13 113E+16 231E+13 284E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE2R2B14cut bWasteStreamE2R1B14cut cWasteStreamE2R3B14cut dWasteStreamE2R4B14cut
31
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 9 Gamma and Neutron Sources for the Design Basis PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary
(MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 273E+11 121E+15 188E+11 175E+11 100E-01 000E+00 100E-01 528E+10 329E+14 277E+10 339E+10 400E-01 316E+07 200E-01 128E+10 245E+14 117E+10 819E+09 900E-01 161E+08 300E-01 639E+08 713E+13 633E+08 407E+08 140E+00 148E+08 400E-01 850E+08 455E+13 164E+09 533E+08 185E+00 109E+08 600E-01 492E+08 226E+14 269E+10 337E+07 300E+00 191E+08 800E-01 291E+09 237E+15 160E+10 186E+09 643E+00 174E+08 100E+00 540E+09 122E+14 248E+09 341E+09 200E+01 154E+07 133E+00 154E+13 195E+14 797E+12 990E+12 Total 830E+08 166E+00 435E+12 450E+13 225E+12 280E+12
--
200E+00 235E+00 152E+11 149E+02 215E-02 250E+00 103E+08 517E+10 534E+07 664E+07 300E+00 160E+05 379E+09 829E+04 103E+05 400E+00 943E-10 497E+08 155E-10 519E-10 500E+00 000E+00 282E+07 000E+00 000E+00 650E+00 000E+00 113E+07 000E+00 000E+00 800E+00 000E+00 222E+06 000E+00 000E+00 100E+01 000E+00 471E+05 000E+00 000E+00
Total 201E+13 486E+15 105E+13 129E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B11cut bWasteStreamE5R1B11cut cWasteStreamE5R3B11cut dWasteStreamE5R4B11cut
32
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 10 Gamma and Neutron Sources for the Average PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 336E+10 670E+14 186E+10 217E+10 100E-01 00000E+00 100E-01 602E+09 199E+14 314E+09 387E+09 400E-01 748E+06 200E-01 146E+09 126E+14 853E+08 936E+08 900E-01 382E+07 300E-01 730E+07 389E+13 439E+07 469E+07 140E+00 352E+07 400E-01 947E+07 263E+13 716E+07 607E+07 185E+00 261E+07 600E-01 141E+07 205E+13 504E+08 383E+06 300E+00 469E+07 800E-01 208E+09 124E+15 192E+09 144E+09 643E+00 418E+07 100E+00 208E+09 110E+13 164E+09 144E+09 200E+01 365E+06 133E+00 175E+12 295E+13 909E+11 112E+12 Total 199E+08 166E+00 494E+11 513E+12 257E+11 318E+11
--
200E+00 973E-01 675E+10 614E+01 872E-03 250E+00 117E+07 353E+09 609E+06 754E+06 300E+00 182E+04 288E+08 944E+03 117E+04 400E+00 186E-11 198E+07 149E-11 127E-11 500E+00 000E+00 669E+06 000E+00 000E+00 650E+00 000E+00 269E+06 000E+00 000E+00 800E+00 000E+00 527E+05 000E+00 000E+00 100E+01 000E+00 112E+05 000E+00 000E+00
Total 229E+12 237E+15 119E+12 147E+12
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B9cut bWasteStreamE5R1B9cut cWasteStreamE5R3B9cut dWasteStreamE5R4B9cut
33
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 11 Gamma and Neutron Axial Source Profiles for a PWR Assembly
Axial boundaries (From midplane)
(cm)
TOP BOTTOM
Neutron Gamma Ne utron Gamma 000 1554 1117 1554 1117 1143 1537 1114 1571 1120 2286 1521 1111 1588 1123 3429 1504 1108 1605 1126 4572 1486 1104 1622 1129 5715 1464 1100 1636 1131 6858 1438 1095 1648 1133 8001 1401 1088 1657 1135 9144 1350 1078 1654 1134
10287 1277 1063 1625 1129 11430 1165 1039 1554 1117 12573 0998 09995 1414 1091 13716 0769 09365 1172 1041 14859 0492 08375 0816 0951 16002 0220 06850 0402 0797 17145 0046 04625 0092 0551 18288 00 00 00 00
Source Reference 2219 Table S445
34
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
63 MCNP SPECIFIC INPUT
631 Source Probability
A linear radial distribution is used for all gamma and neutron sources The linear radial distribution is sam pled usi ng the built-in power function p(x) = xc a with a = 1 for the radial direction This sampling method results in a uniform source distribution over the area bounded by the outer radius of the source
The source axial distributions are unifor m for all four source regions The a xial uni form xp(x) = c distribution is sampled using the built-in power function a with a = 0 for extent
The energy distribu tions of the gamma and neutron sour ce term s are treated as energ y probabilities and are applied in MCNP5 using SISP cards
632 Dose Rate and Flux Tallies
MCNP5 dose rate calculations feature separate runs for the following calculation types
bull a photon transport calculation for prim ary ga mma contribution to the dose rates fr om photon fluxes
bull a coupled neutronphoton transport calculat ion for neutrons a nd secondary gamma (photons generated by neutron be ing captured) contributions to dose rates from neutron and gamma fluxes
The tally type F2 is us ed in th is d esign ca lculation as f lux estim ators The type F2 tally evaluates the flux averaged over a surface in particlescm2s
To generate dose ra tes in te rms of remhr the FM (tally multiplier ) and DEDF (dose energydose conversion factors) cards are used to en ter the tally multiplier f actor (source intensity in particless) energy boundaries in MeV and corresponding dose conversion factors in (remhr)(particlescm2s) respectively These factors were used in the input files
In order for the F2 tally to accum ulate flux ov er a surface a specific s urface area is requ ired The SD cards are used to enter a surface area in cm2 over which the flux will be tallied for an F2 tally
633 Variance Reduction Techniques
Variance reduction technique is usually em ployed in order to increase the efficiency of a calculation and obtain statistically m eaningful results within re asonable com puter tim e In Monte Carlo calculations when variance reduction scheme is employed the weights of particles are adjusted in order to account for the biasing and to preserve a fair game
Geometry splitting and Russian roulette techniques described in Reference 2224 (pp 2-140 ndash 2-142) are useful in shielding calculations and therefore deployed in all the MCNP5 runs
35
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
As particles migrate in an important direction (toward the detector) they are increased in number to provide better sampling by means of geometry splitting across geometric boundaries Russian roulette (the reverse process) is played when particles travel in an unimportant direction to allow termination of unim portant histories The IMP card required for every cel l ca rd is us ed to implement this technique
The other variance reduction technique deployed in the MC NP5 runs is source intensity biasing for the gamma sources from the four source regions (active fuel bottom end-fitting plenum and top end-fitting) The natural total gamma source intensity of comm ercial SNF is dom inated by the gamma source in the active fuel region This active fuel gamma source usually accounts for over 95 o f the total g amma source intens ity In order to im prove the efficiency of the axial dose rate calculations a biased source probability distribution is employed for the prim ary gamma dose rate calculations The biased gamma source probability distribution is chosen to be 005 080 010 and 005 for the bottom end-fitting the active fuel the plenum and the top end-fitting regions respectively
64 DOSE CONVERSION FACTORS
Project Design Criteria Document (Reference 2211 Se ction 41015) requires the use of flux-to-dose rate conversion fact ors from ANSIANS-611-1977 (Reference 221) for dose rate evaluations Table 16 lists the neutron and ga mma dose conversion factors used in the MCNP5 calculations
Table 12 Gamma and Neutron Flux to Dose Conversion Factors
Gamma Neutron Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
001 396E-06 140 251E-06 250E-08 367E-06 003 582E-07 180 299E-06 100E-07 367E-06 005 290E-07 220 342E-06 100E-06 446E-06 007 258E-07 260 382E-06 100E-05 454E-06 010 283E-07 280 401E-06 100E-04 418E-06 015 379E-07 325 441E-06 100E-03 376E-06 020 501E-07 375 483E-06 100E-02 356E-06 025 631E-07 425 523E-06 100E-01 217E-05 030 759E-07 475 560E-06 500E-01 926E-05 035 878E-07 500 580E-06 100E+00 132E-04 040 985E-07 525 601E-06 250E+00 125E-04 045 108E-06 575 637E-06 500E+00 156E-04 050 117E-06 625 674E-06 700E+00 147E-04 055 127E-06 675 711E-06 100E+01 147E-04 060 136E-06 750 766E-06 140E+01 208E-04 065 144E-06 900 877E-06 200E+01 227E-04 070 152E-06 1100 103E-05 080 168E-06 1300 118E-05 100 198E-06 1500 133E-05
Source Reference 221 Tables 1 and 3
36
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION
By def inition (Ref erence 2224 Equation 219) the estimated st atistic relative error of the i component is
Ri = Si
2
Equation 6Ti
where i = tally component index Ri = relative error of the i component S2
i = variance of the i component Ti = tally i component
For a result (ie dose rate) computed as a sum of different tallies the statistical relative error of the computed value is o btained from the variance of the result - S2
total which is th e sum of the estimated variances of the individual tallies S2
i n
2 2STotal = sum Si Equation 7 i=1
where S2Total = total estimated variance
n = total number of components Therefore the total tally value (dose rate) and the associated relative error are derived according to Equations 8 and 9
n TTotal = sumTi Equation 8
i=1
n n
sum (Ri timesTi )2
2 sum Si 2
STotal = i=1 = i=1 Equation 9RTotal = TTotal TTotal TTotal
where RTotal = total estimated relative error TTotal = total estimated tally
Equations 8 and 9 are utilized in Attachm ent II to ev aluate to tal dos e ra tes and their r elative errors
37
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
7 RESULTS AND CONCLUSIONS
71 RESULTS
The following sections summarize the results of this calculation Section 711 presents results for Conceptual Cask A while Section 712 for Conceptual Cask B Section 713 provides comparisons of the dose-rate reduction factors du e to the two conceptual casks and the axial source distributions in the active fuel region Do se rates and relative errors can be found in Attachment II within the output files and Excel files
711 Dose Rates of Conceptual Cask A
This section presents dose-rate results of the calculation sets 1 and 2 as described in Section 61 for Cask A Set 1 has axial p rofile sources in the active fuel region a nd consist of six runs resulting from the three PWR SNF source term s (maximum design basis and average) and the two radiation sources (gammas and neutrons) Set 2 has uniform axial sources in the active fuel region and consists of six run s r esulting f rom the th ree P WR SNF source term s and th e tw o radiation sources
As described in Section 61 dose ra tes are calculated at the three exterior surfaces (radial top and bottom) and at distances 1 m and 2 m from the exterior surfaces The total dose rates for set 1 are presented in Tables 13 14 and 15 for the ra dial top and bottom dire ctions respectively However the com ponents (primary gamma neutr on and secondary gamma) contributing to the total dose rates as well as the re lative error calculations can be found in Attachment II Excel file MCNP-Results1xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 2 are shown in Tables 16 17 and 18 The dose-rate components and the relative errors can be found in A ttachment II Excel file MCNP-Results2xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 13 and 16 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 14 and 17 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 15 and 18 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carrying th e maximum PWR SNF Based on the results in Tables 13 through 18 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask A indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these 6 tables the d ose-rate red uction f actors between the m aximum and the design basis fuels the maxim um and the averag e fuels and th e design basis and the average fuels are a lso presented
38
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 320E-02 00237 116E-02 00222 262E-03 00219 275 1223 445
1 m 133E-02 00164 494E-03 00171 106E-03 00162 269 1261 468 2 m 749E-03 00198 285E-03 00225 584E-04 00162 263 1282 488
Ring Detectors 1 m 133E-02 00116 492E-03 00115 108E-03 00124 271 1229 454 2 m 756E-03 00118 279E-03 00110 605E-04 00128 271 1250 462
Source Attachment II MCNP-Results1xls worksheet Summary
Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 142E-02 00368 628E-03 00446 934E-04 00483 226 1520 672
1 m 570E-03 00289 263E-03 00426 375E-04 00381 217 1520 701 2 m 265E-03 00364 123E-03 00547 169E-04 00374 216 1575 730
Point Detectors 1 m 598E-03 00238 274E-03 00271 402E-04 00354 219 1489 681 2 m 273E-03 00218 123E-03 00245 180E-04 00336 221 1515 684
Source Attachment II MCNP-Results1xls worksheet Summary
Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 653E-03 00298 265E-03 00276 510E-04 00341 247 1278 518
1 m 276E-03 00238 112E-03 00208 207E-04 00249 248 1334 539 2 m 125E-03 00185 508E-04 00199 933E-05 00246 246 1336 544
Point Detectors 1 m 291E-03 00227 118E-03 00203 218E-04 00242 247 1335 540 2 m 130E-03 00209 524E-04 00187 955E-05 00233 247 1357 549
Source Attachment II MCNP-Results1xls worksheet Summary
Tables 13 14 and 15 are results of calculation set 1 for conceptual Cask A with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
39
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 265E-02 00247 990E-03 00222 215E-03 00278 268 1234 461
1 m 116E-02 00178 468E-03 00549 960E-04 00189 248 1208 488 2 m 713E-03 00273 265E-03 00161 602E-04 00360 269 1184 439
Ring Detectors 1 m 117E-02 00120 454E-03 00132 979E-04 00141 259 1199 463 2 m 722E-03 00130 276E-03 00141 589E-04 00153 261 1226 469
Source Attachment II MCNP-Results2xls worksheet Summary
Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 199E-02 00461 827E-03 00455 147E-03 00536 241 1359 564
1 m 849E-03 00564 323E-03 00314 563E-04 00418 263 1507 574 2 m 415E-03 00832 158E-03 00603 253E-04 00501 263 1641 623
Point Detectors 1 m 877E-03 00348 353E-03 00275 615E-04 00391 248 1426 574 2 m 393E-03 00341 160E-03 00278 270E-04 00378 246 1454 590
Source Attachment II MCNP-Results2xls worksheet Summary
Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 879E-03 00374 356E-03 00333 669E-04 00406 247 1315 533
1 m 365E-03 00223 147E-03 00209 269E-04 00253 248 1358 548 2 m 164E-03 00229 674E-04 00205 120E-04 00248 243 1364 560
Point Detectors 1 m 383E-03 00217 155E-03 00204 285E-04 00248 247 1347 546 2 m 172E-03 00197 689E-04 00186 124E-04 00225 249 1391 558
Source Attachment II MCNP-Results2xls worksheet Summary
Tables 16 17 and 18 ar e results of calculation set 2 for conceptual Cask A with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
40
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
g gram
GWd gigawatt-day
hr hour
in inch
kg kilogram
m meter
mrem millirem
MeV million electron volt
MTU metric ton uranium
s second
8
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
1 PURPOSE
The purpose of this calculation is to calcu late th e dose ra tes of two conceptua l tr ansportation casks each carrying a Transportation Aging and Disposal (TAD) canister separately loaded with the average design basis (DB) and m aximum comm ercial spent nuc lear fuel (CSNF) assemblies Then the dose-ra te reduction f actors between the m aximum and the design basis fuels the d esign bas is and the average fuels and the m aximum and the averag e fuels are computed
The results of this calculation may be used to substantiate the dose-rate reduction factors such as those in the engineering study Repository ALARA Goal Compliance (Reference 227) which is cited as a reference in a Preclosure Safety Analyses (PCSA) calculation that supports the License Application
The calculations contained in this docum ent are developed by Nuclear and Radiological Engineering of the Repository Project Mana gement (RPM) organization Yucca Mountain Project (YMP) personnel from Nuclear and Radiological Engineering should be consulted before use of the calculations for purposes other than those stated herein or use by individuals other than personnel in Nuclear and Radiological Engineering
9
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
2 REFERENCES
21 PROJECT PROCEDURESDIRECTIVES
211 IT-PRO-0011 Rev 0010 Software Management Las Vegas Nevada Bechtel SAIC Company
212 EG-PRO-3DP-G04B-00037 Rev 14 Calculations and Analyses Las Vegas Nevada Bechtel SAIC Company
213 IT-PRO-0012 Rev 007 Qualification of Software Las Vegas Nevada Bechtel SAIC Company
22 DESIGN INPUTS
221 ANSIANS-611-1977 Neutron and Gamma-Ray Flux-to-Dose-Rate Factors La Grange Park Illinois American Nuclear Society TIC 239401
222 ASME (American Society of Mechanical Engineers) 2004 2004 ASME Boiler and Pressure Vessel Code 2004 Edition New York New York American Society of Mechanical Engineers TIC 256479 ISBN 0-7918-2899-9
223 ASM International 1990 Properties and Selection Nonferrous Alloys and Special-Purpose Materials Specific Metals and Alloys Volume 2 of Metals Handbook 10th Edition Page 666 [Materials Park Ohio] American Society for Metals TIC 239807
224 ASTM (American Society for Testing and Materials) B 811-90 1991 Standard Specification for Wrought Zirconium Alloy Seamless Tubes for Nuclear Reactor Fuel Cladding Philadelphia Pennsylvania American Society for Testing and Materials TIC 239780
225 ASTM G 1-90 (Reapproved 1999) 1999 Standard Practice for Preparing Cleaning and Evaluating Corrosion Test Specimens West Conshohocken Pennsylvania American Society for Testing and Materials TIC 238771
226 Bowman SM Hermann OW and Brady MC 1995 Sequoyah Unit 2 Cycle 3 Volume 2 of Scale-4 Analysis of Pressurized Water Reactor Critical Configurations ORNLTM-12294V2 Oak Ridge Tennessee Oak Ridge National Laboratory TIC 244397 [DIRS 123796]
227 BSC (Bechtel SAIC Company LLC) 2008 Repository ALARA Goal Compliance 000-30R-MGR0-04000-000 REV 000 Las Vegas Nevada Bechtel SAIC Company ACC ENG200802050014 [DIRS 184957]
228 BSC 2002 Subsurface Shielding Source Term Specification Calculation 000-00C-WER0-00100-000-00A Las Vegas Nevada Bechtel SAIC Company ACC MOL200212160076 ENG200508150022
10
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
229 BSC 2004 PWR Source Term Generation and Evaluation 000-00C-MGR0-00100-000-00B Las Vegas Nevada Bechtel SAIC Company ACC ENG200405240007
2210 BSC 2008 Basis of Design for the TAD Canister-Based Repository Design Concept 000-3DR-MGR0-00300-000-003 Las Vegas Nevada Bechtel SAIC Company ACC ENG200810060001
2211 BSC 2007 Project Design Criteria Document 000-3DR-MGR0-00100-000-007 Las Vegas Nevada Bechtel SAIC Company ACC ENG200710160005 ENG200711080001 ENG200712200003 ENG200801070001 ENG200801070002 ENG200801070016 ENG200801070017 ENG200801310006 ENG200803050002 ENG200803050011 ENG200803050012 ENG200803060009 ENG200803130004 ENG200807100001 ENG200811120006 ENG200811140004
2212 BSC 2004 PWR and BWR Source Term Sensitivity Study 000-00C-MGR0-00300-000-00A Las Vegas Nevada Bechtel SAIC Company ACC ENG200401140003 ENG200508150023
2213 BSC 2007 Dose Rate Calculation for Exhaust Main Drifts 800-00C-SS00-00700-000-00B Las Vegas Nevada Bechtel SAIC Company ACC ENG200711050017 ENG200803060001
2214 BSC 2006 Dual Purpose Canister Opening Study 050-30R-WHS0-00600-000-000 Las Vegas Nevada Bechtel SAIC Company ACC ENG200612200023
2215 BSC 2007 GROA Shielding Requirements Calculation 000-00C-MGR0-03300-000-00B Las Vegas Nevada Bechtel SAIC Company ACC ENG200705290037
2216 BSC 2002 Concrete Shielding Calculation for Dry Facility 1 110-00C-CS10-00100-000-00A Las Vegas Nevada Bechtel SAIC Company ACC MOL200301140075
2217 BSC 2003 Shielding Design Calculations for Dry Facility 1 110-00C-CS10-00200-000-00A Las Vegas Nevada Bechtel SAIC Company ACC ENG200306020003
2218 CRWMS MampO 1998 Calculation of the Effect of Source Geometry on the 21-PWR WP Dose Rates BBAC00000-01717-0210-00004 REV 00 Las Vegas Nevada CRWMS MampO ACC MOL199902220059 [DIRS 102134]
2219 CRWMS MampO 2000 Users Manual for SCALE-44A 10129-UM-44A-00 Las Vegas Nevada CRWMS MampO ACC MOL200011300136 MOL200108220084 MOL200108220085 MOL200108220086 MOL200108220087 [DIRS 153872]
2220 DOE (US Department of Energy) 1987 Appendix 2A Physical Descriptions of LWR Fuel Assemblies Volume 3 of Characteristics of Spent Fuel High-Level Waste and Other Radioactive Wastes Which May Require Long-Term Isolation DOERW-0184 Washington DC US Department of Energy Office of Civilian Radioactive Waste Management ACC HQX198804050024 [DIRS 132333]
11
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
2221 DOE 2007 Software Validation Report for MCNP5 v140 Document ID 11199-SVR-140-00-WINXP Las Vegas Nevada US Department of Energy Office of Repository Development ACC MOL200702280252 [DIRS 180516]
2222 DOE 2008 Transportation Aging and Disposal Canister System Performance Specification WMO-TADCS-000001 Rev 1 ICN 1 Washington DC US Department of Energy Office of Civilian Radioactive Waste Management ACC DOC200803310001 [DIRS 185304]
2223 Harmon CD II Busch RD Briesmeister JF and Forster RA 1994 Criticality Calculations with MCNPtrade A Primer LA-12827-M Los Alamos New Mexico Los Alamos National Laboratory TIC 234014 [DIRS 154532]
2224 LANL (Los Alamos National Laboratory) 2004 MCNP mdash A General Monte Carlo N-Particle Transport Code Version 5 (Appendix H is not included) LA-UR-03-1987 Volume I Los Alamos [New Mexico] Los Alamos National Laboratory ACC MOL200510240126 [DIRS 176521]
2225 MCNP5 V 140 2007 Windows XP STN 11199-140-00 [DIRS 180515]
2226 Parrington JR Knox HD Breneman SL Baum EM and Feiner F 1996 Nuclides and Isotopes Chart of the Nuclides 15th Edition San Jose California General Electric Company and KAPL Inc TIC 233705 LC Call Number QC7935 N8622 1996
2227 Punatar MK 2001 Summary Report of Commercial Reactor Criticality Data for Crystal River Unit 3 TDR-UDC-NU-000001 REV 02 Las Vegas Nevada Bechtel SAIC Company ACC MOL200107020087 [DIRS 155635]
2228 Sisley SE 2002 Transportation License Application for the FuelSolutionstrade System (TAC No L23311) Submittal of the FuelSolutiontrade Transportation SARs Revision 3 Letter from SE Sisley (BNFL) to the NRC April 11 2002 BFSNRC 02-011 with enclosures TIC 255245 [DIRS 171545]
NOTE Reference 2220 is a direct input but is not QA QA It is justified as acceptable for the intended use as it is directly from the DOE and is considered the best available data on the subject The referenced values cited in Tables 3 and 4 are valid for use since they are reliable and reasonable based on engineering judgment
23 DESIGN CONSTRAINTS
231 10 CFR 71 2008 Energy Packaging and Transportation of Radioactive Material Internet Accessible [DIRS 185678]
12
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
24 DESIGN OUTPUTS
The resu lts of this calculation will be us ed to substan tiate th e dose reduc tion f actor in the Repository ALARA Goal Compliance (Reference 227) which is cited as a reference in a PCSA calculation that supports the License Application
13
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
3 ASSUMPTIONS
31 ASSUMPTIONS REQUIRING VERIFICATION
None
32 ASSUMPTIONS NOT REQUIRING VERIFICATION
Assumptions 321 322 and 323 are m odeling assum ptions and do not require further verification The m aterials and dim ensions for the TAD canister and for the conceptu al transportation casks are only selected to charac terize two tr ansportation casks th at m eet 10 CFR7147 (Reference 231) dose rates when lo aded with the ldquom aximumrdquo and ldquoaveragerdquo pressurized water re actor (PW R) assem blies re spectively There is n o need to v erify those dimensions or m aterials at a later date The ca lculated results in Sect ion 711 verify that the conceptual casks would meet 10 CFR 7147 (Reference 231) dose rates
321 Material and Wall Thickness of TAD Canister
Assumption It is assumed that the TAD canister is made of stainless steel 316 (SS 316) and has a wall thickness of 025 in for the radial and bottom shells
Rationale Currently the design of the TAD canis ter d oes not ex ist Based on a survey of existing m ultipurpose a nd dual purpose caniste rs (DPC) (Ref erence 2214 p 56) a 025 in thickness is below the wall thick ness of any existing c anisters For the purp ose of this calculation this assumption leads to higher and conservative external dose rates Since SS 316 is the sam e material used for the waste pack age inner shell it is a l ogical cho ice f or the TAD canister
Although Reference 2214 is an engineering study with a QA N A status it is used here as an indirect input to support the assumption which is conservative for dose rate calculations
Usage This assumption is used in Sections 621 and 625
322 Material and Thickness of TAD Shield Plug
Assumption It is assu med that the TAD shield plug is made of SS 316 and has a thickness of 11 in
Rationale Currently the design of the TAD canister doe s not exist A thick shield plug of 11 in (Reference 2215 Table 12) is needed to keep the m aximum contact dose rate of the top surface below 1000 mrem hr (Reference 2222 Section 314) Since SS 316 is the sam e material used for the waste package inner shell it is a logical choice for the TAD shield plug
Usage This assumption is used in Section 621
14
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
323 Geometry and Materials of Conceptual TAD Transportation Casks
Assumption Two conceptual TAD transpo rtation casks designated as Cask A and Cask B are assumed to have a cylindrical geom etry and m aterials specified in Tab les 1 and 2 respectively The casks are basically construc ted of an inner layer of SS 316 for ga mma shielding a m iddle layer of 5-borated polyethylen e for neutron shielding and a th in outer layer of SS 316 whic h serves a structural function as well as shielding secondary gamma rays
Both Cask A and Cask B have a cavity height of 53785 cm (21175 in) and a cavity diameter of 16891 cm (6650 in) However Cask A has a total height of 610845 cm (24049 in) and an outside diameter of 26797 cm (10550 in) while the total height and outside diameter of Cask B are 58885 cm (23183 in) and 24765 cm (9750) respectively
Cask A will provide shielding to m eet the exterior radiat ion standards of 10 C FR 7147(b) (Reference 231) when loaded w ith a TAD canister carrying th e maximum PWR spent nuclear fuel (SNF) Cask B will satisf y the same radiation standards when loade d with a TAD caniste r carrying the average PWR SNF
Table 1 Geometry and Materials of Conceptual TAD Transportation Cask A
Component Dimension
Material (cm) (in)
Total Height 61085 2404 9 NA
Outside Diameter 26797 1055 0 NA
Cask Cavity Height 53785 2117 5 NA
Cask Cavity Diameter (Radius) 16891 (8446) 6650 (3325) NA
Radial Gamma Shield Thickness (Radius)a 3302 (11748)a 1300 (4625)a SS 316
Radial Neutron Shield Thickness (Radius)b 1524 (13272)b 600 (5225)b 5-borated polyethylene
Radial Outer Shell Thickness (Radius)c 127 (13399)c 050 (5275)c SS 316
Top Gamma Shield Thickness (Axial Position)d 600 (54385)d 236 (21411)d SS 316
Top Neutron Shield Thickness (Axial Position)d 1000 (55385)d 394 (21805)d 5-borated polyethylene
Top Outer Shell Thickness (Axial Position)d 200 (55585)d 079 (21884)d SS 316
Bottom Gamma Shield Thickness (Axial Position)d 35365 (-360)d 1392 (-1417)d SS 316
Bottom Neutron Shield Thickness (Axial Position)d 15 (-510)d 591 (-2008)d 5-borated polyethylene
Bottom Outer Shell Thickness (Axial Position)d 4 (-550)d 157 (-2165)d SS 316 a11748 = 3302 + 8446 and 4625 = 1300 + 3325 b13272 = 1524 + 11748 and 5225 = 600 + 4625 c13399 = 127 + 13272 and 5275 = 050 + 5225 dCoordinate relative to the bottom of the fuel assembly as modeled in MCNP5
15
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 2 Geometry and Materials of Conceptual TAD Transportation Cask B
Component Dimension
Material (cm) (in)
Total Height 58885 2318 3 NA
Outside Diameter 24765 9750 NA
Cask Cavity Height 53785 2117 5 NA
Cask Cavity Diameter (Radius) 16891 (8446) 6650 (3325) NA
Radial Gamma Shield Thickness (Radius)a 254 (10986)a 1000 (4325)a SS 316
Radial Neutron Shield Thickness (Radius)b 127 (12256)b 500 (4825)b 5-borated polyethylene
Radial Outer Shell Thickness (Radius)c 127 (12383)c 050 (4875)c SS 316
Top Gamma Shield Thickness (Axial Position)d 8 (54585)d 315 (21490)d SS 316
Top Neutron Shield Thickness (Axial Position)d None Non e NA
Top Outer Shell Thickness (Axial Position)d None Non e NA
Bottom Gamma Shield Thickness (Axial Position)d 3837 (-390)d 1510 (-1535)d SS 316
Bottom Neutron Shield Thickness (Axial Position)d 300 (-420)d 118 (-1654)d 5-borated polyethylene
Bottom Outer Shell Thickness (Axial Position)d 100 (-430)d 039 (-1693)d SS 316 a10986 = 254 + 8446 and 4325 = 1000 + 3325 b12256= 127 + 10986 and 4825 = 500+ 4325 c12383 = 127 + 12256 and 4875 = 050 + 4825 dCoordinate relative to the bottom of the fuel assembly as modeled in MCNP5
Rationale Currently a design for the TAD transporta tion cask does not exist The casks assumed for this calculation are so lely for estim ation of the dose reduction due to different source terms This is a conceptual repres entation only used in this calculation to estim ate the parameters of interest
Usage This assumption is used in Sections 61 and 622
324 Usage of Unirradiated Fuel for Commercial SNF
Assumption It is assumed that the active fuel region of the commercial SNF assembly contains the same isotopic concentrations as the fresh uni rradiated fuel and that the concentrations of fresh fuel with 5 initial enrichm ent corresp onding to m aximum SNF are used for all other SNFs
Rationale This assumption is a standard practice for shielding calculations throughout the industry accepted by the U S Nucle ar Regulatory Commission (NRC) (Reference 2228 Table 53-5) It sh ould be noted that this assumption applies to material composition only it does no t apply to source terms which are based on the characteristics of spent fuel
Usage This assumption is used in Sections 624 and 626
325 Homogenization of Radiation Source Regions
Assumption It is assu med that a commercial SNF assembly consis ts of four distinct reg ions (active fuel bottom end-fitting plenum and top end-fitting) The materials and radiation sources
16
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
of each assembly region are homogenized inside a volume defined by the TAD cavity radius and region height
Rationale The assembly representation is consistent with the industry practice for shielding calculations accepted by NRC (Reference 2228 Figure 53-6) The effec t of source homogenization is twofold (1) it d ecreases th e m ass de nsity of the source region and (2) it places source points slightly closer to detector locations thus reducing radiation attenuation The resu lts of Calculation of the Effect of Source Geometry on the 21-PWR WP Dose Rates (Reference 2218 pp 22-26) indicate that th e effect of assem bly homogenization gives nearly the same or conservative dose rates as the explicit fuel assembly model
Usage This assumption is used in Section 624
326 Ignoring Internal Fuel Basket Materials
Assumption It is assumed that the internal fuel basket materials are ignored
Rationale Inclusion of fuel basket m aterials in the smeared m aterial com position would increase the overall density and consequently increase the attenuati on of the radiation Therefore this assumption is conservative
Usage This assumption is used in Sections 621 624 and 626
17
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
4 METHODOLOGY
41 QUALITY ASSURANCE
This calculation was prepared in accordance with EG-PRO-3DP-G04B-00037 Calculations and Analyses (Reference 212) The results of th is calculation provides worker dose assessm ent adjustments and this will id entify radio logical hazards f or f acilities im portant to saf ety Therefore the approved version is designated as QA QA
42 USE OF COMPUTER SOFTWARE
421 Baseline Software
The Monte Carlo N-Particle com puter pr ogram (MCNP5) version 140 (Reference 2225) is used to calculate the dose rates (neutron pr imary gamm a and secondary gamm a) at various locations around a transportation cask and an aging overpack
The software specifications are as follows
bull Program Name MCNP5 bull VersionRevision Number Version 140 bull Operating Systems Windows XP bull Software Tracking Number 11199-140-00 bull Computer Type Dell OPTIPLEX GX620
MCNP5 which is Level 1 software is (a) appropriate for three-dim ensional neutron gamma and coupled neutrongamma shielding calculations (b) used within th e range of validation as documented in Software Validation Report for MCNP5 v140 (Reference 2221) and (c) obtained from Software C onfiguration Managem ent and qualified in accordance with procedure IT-PRO-0012 Qualification of Software (Reference 213) Therefore MCNP5 code is suitable for use in this design calculation All MCNP5 input and output files docum ented in this calculation are provided on a compact disc (CD) as Attachment II
All MCNP cases are executed on one of the following Q com puters QNW -004184 QNW -004187 QNW-004194 and QNW-004196 as shown in the output files
422 Commercial off the Shelf Software
The Excel sof tware is used to c alculate var ious inpu t values (i e atom densities weight percentages geometrical dimensions normalized source spectra and probabilities etc) Standard functions of Excel are also used in this desi gn calculation to display results (ie gamma and neutron dose rates) in tabular and graphic forms and to perform relative error calculations
The software specifications are as follows
bull Program Name Excel bull VersionRevision Number Microsoftreg Excel 2003
18
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
bull This software is installed on a persona l com puter running Microsoft W indows XP (central processing unit number 151834)
The user defined for mulas inputs results and gr aphical representations have been verified by hand calculations or visual inspection and are documented in sufficient detail to allow an independent repetition of the com putations Calculations were verifi ed by hand and graphical representations were found accurate by visual inspection
Per Software Management Microsoftreg Excel is not requir ed to be qualif ied due to its commercial availability status (Reference 211 Attachment 4 p 55 bullet 2)
43 CALCULATION APPROACH
This calculation em ploys the qualified so ftware MCNP5 version 140 (Reference 2225) a three-dimensional Monte Carlo code for pe rforming neutron and coupled neutron-gamm a calculations to estim ate dose rates at sele cted locations on and surrounding a conceptual transportation cask containing a loaded TAD canister
431 MCNP5 Program
MCNP5 a general Monte Carlo part icle transport code sim ulates particle transport through a three-dimensional representation of the nuclear system being analyzed During the random walk of particles through the system described by the geom etry the c ode collects inform ation about various events (su rface cross ing collis ions trac k leng th etc) and es timates fluxes in various geometric configurations specified as tallies by the user It also estimates the statistical precision of the results in the form of relative errors (Reference 2224 pp 1-2 to 1-8)
Per Project Design Criteria Document (Reference 2211 Section 41015) the flux estim ates are converted to dose rates using the Am erican Nuclear Society (ANS) flux-to-dose rate conversion factors for gammas and neutrons (R eference 221) The simple variance reduction techniques of Geometry SplittingRussian Roulette and source probability biasing (Sections 631 and 633) are used to enhance computational efficiency
19
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
5 LIST OF ATTACHMENTS
Number of Pages Attachment I List of Electronic Files on the CD 3 Attachment II Compact Disc NA
20
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
6 CALCULATIONS
This sectio n provides inform ation necess ary to perform the calcu lations in this docum ent Section 61 describes the configurations the type of CSNF to be analyzed the number of MCNP runs and the locations where dose rates are ca lculated Section 62 provides the calculation input that includes the details of the geom etry m odel radiation source term s and m aterial compositions Input specific to MCNP dose -rate conversion factors and relative error calculation are described in the later sections
61 DESCRIPTION OF CALCULATIONS
Dose rate calculations are perform ed with the MCNP5 version 140 com puter code (Reference 2225) Two conceptual transportation casks Cask A and Cask B (Assum ption 323) are employed Each cask contains a TAD canister that is loaded with 21 ident ical PW R SN F assemblies Three PWR source term s are analy zed they are the source term s corresponding to the maximum design basis and average PW R SN Fs The characteris tics of the P WR source terms are presented in S ection 627 Each PWR source term has neutron and ga mma radiation sources that require separate MCNP5 runs For each radiation source an axial profile source and a uniform source for the active fuel region are considered The uniform source for the active fuel region is included in this calculation because this approach was used in combination with source peaking factors in certain calculations (Reference 2216 Sections 37 and 39 and Reference 2217 Section 5242)
The total number of MCNP5 runs is 24 which re sults from a com bination of two conceptual casks three PWR source terms two radiation sources and two axia l source distributions for the active fuel region These 24 runs are categorized into four calcula tion sets Each calculation set consists of six runs that is a combination of three PWR source te rms and two radiation sources The characteristics of each calculation set are as follows
1 Cask A with axial profile sources in the active fuel region
2 Cask A with uniform axial sources in the active fuel region
3 Cask B with axial profile sources in the active fuel region
4 Cask B with uniform axial sources in the active fuel region
For each MCNP5 run dose rates are calculated at the exte rior surfaces and at distances 1 and 2 meters from the exterior surfaces Surface tallies and detector tallies (ring and point detectors) as indicated in Figure 1 are e mployed in all runs Figure 1 is used to illustrate the dep loyment of the surface and detector tallies re lative to the so urce regions and it should not be interpreted as an exact geometry of any particular run Surface tallies are deployed at all three distances while ring and point detectors are used only at 1 m and 2 m and not at the cask surfaces Using point detectors near a surface or in any scattering media is not recommended because very large scores can occur f rom collisions close ( less than a f ew centimeters) to the point detecto rs that can lead to resu lts with high r elative e rrors thus m aking the ca lculation d ifficult to o btain r eliable answers
21
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
For the radial direction surface tallies at the three distances (contact 1 m and 2 m) are computed for three su rface segments (cylindrical rings) between the planes at Z = 145 175 2 05 and 235 cm The geometric locations of the segments are shown in Figure 1 The axial locations of these segments correspond to the m iddle of the active fuel region of the PWR SNF assemblies The average dose rates for each of the segm ents are calculated for the outside surface and surfaces at 1 m and 2 m from the cask surface Two ring detectors (instead of point detectors) are deployed at 1 m and 2 m for the radial dire ction Ring detectors instead of point detectors are used in order to capitalize on the symm etry around the cask axis thus im proving the efficiency of the calculations
In the axial direction the average d ose rates within three concentric radial surfaces defined by radii of 40 80 and 120 cm (shown in Figure 1) are calculated for the top and bottom surfaces and at distances 1 m and 2 m from these surfaces Finally point detectors at 1 m and 2 m from the top and bottom axial surfaces are employed
22
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Point Detector at 2 m x
Ring Ring Detector Detector at 2 m at 1 m
x x
Z = 00 cm
Z = 145 cm
Z = 175 cm
Z = 205 cm
Z = 235 cm
R = 80 cm
R = 120 cm
R = 40 cm
Active Fuel
Shield Plug
Top End-Fitting Plenum
Bottom End-Fitting
Ring Detector at 1 m
x
Point Detector at 1 m x
Ring Detector
at 2 m x
D = 26797 cm
H =
610
845
cm
Point Detector at 1 m x
Point Detector at 2 m x
Figure 1 Geometry and Tally Scheme for the TAD Transportation Cask
23
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
62 CALCULATION INPUT
Technical product input and sources of the input used in the deve lopment of this calculation are documented in this section Tables in this docum ent and in th e associated Microsoftreg Excel spreadsheets referenced m ay present num erical values with m any significant figures these values are not to be considered as high precision values since the significant figures are results of calculated values andor unit conversions
621 TAD Canister
The TAD canis ter will contain either 21 P WR or 44 BW R (boiling water reactor) SNF assemblies (Reference 2222 Section 321) While the canister design is iden tical for both PWR and BWR SNF assemblies the internal basket structure is different depending on the SNF assemblies However the internal basket stru cture m aterial is no t in cluded in the calcu lation model (Assumption 326)
The TAD canister is a right-circu lar cylinder with a diam eter of 665 in and a height between 186 and 212 in (Reference 2222 Section 321) The average and maximum total dose rates on the top surf ace of a loaded TAD ca nister must not exceed 800 and 1000 m remhr respectively (Reference 2222 Section 314) The TAD canister used in this calculation is m ade of SS 316 with a radial wall and bottom thickness of 025 in (Assumption 321) The top of the canister has a shield plug that is 11 in thick SS 316 (Ass umption 322) A thick shield plug is needed to keep the maxim um contact dose rate of th e top surface below 1000 m remhr The overall dimensions of the TAD canister are provided in Table 3
Table 3 Dimensions of TAD Canister
Component Dimension
(in) (cm)
Maximum heighta 212 53848
Outer diametera 665 16891
Thickness of bottom lidb 025 0635
Shell thicknessb 025 0635
Lifting Featurec 6 1524
Height without Lifting Feature 206 52324
Thickness of shield plugd 110 2794
aReference 2222 Section 311 bAssumption 321 cReference 2222 p Attachment C-1 dAssumption 322
622 Conceptual TAD Transportation Casks
Two conceptual TAD transportation casks designa ted as Cask A and Cask B are em ployed in this calculation (Assumption 323) They both have a cylindrical geometry with dimensions and materials specified in Tables 1 and 2 of Section 323 Cask A will provide shielding to meet the exterior radiation standards of 10 CFR 7147(b) (Reference 231) when loaded with a TAD
24
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
canister car rying the m aximum PWR SNF Cask B will s atisfy th e sa me radiatio n standa rds when loaded with a TAD canister c arrying the average PWR SNF The reason to analyze both Casks A and B is to cover a broad range of characteristics of the CSNF
The cavity dimensions of the conceptual cask s are 53785 cm (21175 in) in height and 16891 cm (665 in) in diam eter (Tab les 1 and 2) This cav ity will accommoda te the TAD canister described in Table 3 without the lifting feature This is the geometry model used in the MCNP5 calculations
623 Fuel Assembly Selection
PWR and BWR Source Term Sensitivity Study (Reference 2211 Tables 71 through 84) shows that the source terms generated for the Bamp W 15x15 Mark B fuel assembly with 475 kg uranium loading bound the source terms of other PWR assembly types ther efore this assembly type is selected as the representative PWR fuel assembly The gamma and neutron source terms for the BampW 15x15 Mark B assembly are generated in PWR Source Term Generation and Evaluation (Reference 229) and are used in this calculation
624 BampW 15x15 Mark B PWR Fuel Assembly
BampW 15x15 Mark B fuel assembly consists of four regions top end-fitting plenum active fuel and bottom end-fitting The m aterials and ra diation sources of each assem bly region are homogenized inside a volume defined by the region height and the interior diam eter of the TAD canister (Assumption 325) The active fuel region is homogenized with fresh unirradiated fuel (Assumption 324) Since the internal structure (i e basket) design of t he TAD is currently not finalized the com position of the hom ogenized fuel does not include the basket m aterials (Assumption 326) and therefore does not take cred it for any shielding that these m aterials may provide
Table 4 provides the design param eters for the BampW 15x15 Mark B fuel assembly Data provided here are used in Attachment II PWR_fuel compxls worksheet BampWassy
25
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 4 BampW 15x15 Mark B Fuel Assembly Description
Component Material Characteristic Value Specific Reference Array Size 15 x 15
Reference 2227 Table 2-2 Fuel Pins Assembly 208 Guide Tubes Assembly 16 Instrument Tubes Assembly 1
Assembly NA Pin Pellet Diameter 0936244 cm (03686 in) Reference 2220 p 2A-34 Pin Pitch 144272 cm (0568 in)
Reference 2227 Table 2-2 Active Fuel Height 360172 cm (1418 in) Assembly Width 2168144 cm (8536 in)
Reference 2220 p 2A-31 Assembly Height 4206875 cm (165625 in) Mass U assembly 46363 kg
Guide tube Zircaloy-4 Outer Diameter 13462 cm (053 in)
Reference 2227 Table 2-2
Inner Diameter 126492 cm (0498 in)
Instrument tube Zircaloy-4 Outer Diameter 138193 cm (05441 in) Inner Diameter 112014 cm (0441 in)
Cladding` Zircaloy-4 Inner Diameter 095758 cm (0377 in) Outer Diameter 10922 cm (043 in)
Plenum region NA Length 297688 cm (11720 in) Reference 2220 p 2A-34 Top nozzle SS CF3M MassAssembly (Top) 748 kg
Reference 2220 p 2A-32
Bottom nozzle SS CF3M MassAssembly (Bottom) 816 kg Guide tubes Zircaloy-4 MassAssembly (in Core) 80 kg Instrument tube Zircaloy-4 MassAssembly (in Core) 064 kg Spacer-plenum Inconel-718 MassAssembly (Plenum) 104 kg Spacer-bottom Inconel-718 MassAssembly (Bottom) 13 kg Spacer-in core Inconel-718 MassAssembly (in Core) 49 kg Spring retainer SS CF3M MassAssembly (Top) 091 kg Holddown spring Inconel-718 MassAssembly (Top) 18 kg Upper end plug SS 304 MassAssembly (Top) 006 kg Upper nut SS 304L MassAssembly (Top) 051 kg Lower nut SS 304 MassAssembly (Bottom) 015 kg Grid supports Zircaloy-4 MassAssembly (in Core) 064 kg Plenum spring SS 302 MassAssembly (Plenum) 0042 lb (001905 kg) Reference 2220 p 2A-34
Note Som e d ata i n this tab le ar e given i n British u nits in th e r eferences thes e d ata ar e converted into metric units as the inputs to MCNP5 are in metric units
The assem bly region heights as m odeled in MC NP are presented in Table 5 utilizing values from Table 4 Table 5 is taken from Dose Rate Calculation for Exhaust Main Drifts (Reference 2213 Table 3)
26
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 5 PWR Fuel Assembly Regions
Component Height Reference
Plenum 297688 cm (11720 in) Reference 2220 p 2A-34
Active Fuel 360172 cm (1418 in) Table 3
Bottom End-Fitting 1077 cm (424 in) Calculateda
Top End-Fitting 1998 cm (787 in) Calculatedb
Source Reference 2213 Table 3 aCalculated b ased on data Reference 2227 F igures 2-3 an d 2-7
(Region 9 Height [16723 cm] + Region 10 Height [508 cm] ndash Lo wer Fuel Plenum and End Cap [11033 cm])
bCalculated (Assembly Length ndash Active Fuel Length ndash P lenum Length ndash Bottom End-fitting Length)
625 Material Compositions
The TAD transportation cask com ponent m aterial specifications are defined in Table 1 The TAD canister is constructed of SS 316 (Assumpti on 321) The PWR fuel assembly materials used to homogenize the fuel regions are defined in Table 4 Table 6 c ontains the m aterial compositions defining the TAD canister WP and fuel assemblies
27
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 6 Chemical Compositions of Materials
Material Density (gcc)
Isotopic Weight Percent Reference
SS 302 NA
C 0150 Mn 2000 P 0045 S 0030 Si 0750 Cr 18000 Ni 9000 N 0100 Fe 69925
Attachment II PWR_fuel compxls worksheet ferrous Reference 222 SEC II A SA-240 Table 1 for SS 302 SS 304 and SS 304L Reference 222 SEC II A SA-351SA -351M Table 2 for SS CF3M
SS 304 NA
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 9250 N 0100 Fe 68745
SS 304L NA
C 003 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 10000 N 0100 Fe 6804 5
SS CF3M NA
C 0030 Mn 1500 P 0040 S 0040 Si 1500 Cr 19000 Ni 11000 Mo 2500 Fe 64390
Inconel 718 NA
C 0080 Mn 0350 Si 0350 Cr 19000 Ni 52500 Co 1000 Mo 3050 Fe 16809 Nb 5125 Ti 0900 Al 0500 Cu 0300 S 0015 P 0015 B 0006
Attachment II PWR_fuel compxls worksheet alloys aReference 223 p 666 Table 6 Reference 222 SEC II B SB-637 Table 1 for Inconel 718 Reference 224 Table 2 for Zircaloy 4
Zircaloy 4 656a Cr 0100 Fe 0210 O 0125 Sn 1450 Zr 98115
SS 316 798b
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 17000 Ni 12000 Mo 2500 N 0100 Fe 65495
Attachment II PWR_fuel compxls worksheet others Reference 222 SEC II A SA-240 Table 1 for SS 316 bReference 225 Table X1
626 Homogenization Assembly Materials
The atom density of an element or isotope in atomsbmiddotcm in a homogenized region is calculated according to the following equation (Reference 2223 Appendix B)
M i times N AvogadroNi = Equation 1 Ai timesV times K
where Ni = Atom density of elementisotope i (atomsbmiddotcm) Mi = Mass of elementisotope i (g) NAvogadro = Avogadrorsquos constant 06022 x 1024 (atomsmole)
28
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Ai = Atomic weight of elementisotope i (gmole) V = Homogenization volume (cm3) K = Unit transformation constant = 1024 (bmiddotcmcm3)
Equation 1 is used in A ttachment II spreadsheet PWR_fuel compxls worksheet BampWassy to calculate th e atom dens ities for v arious elem ents and iso topes The m ass of elementsisotop es and Avogadrorsquos constant are provided in Reference 2226
Table 7 lists the com position of the hom ogenized assem bly regions (active fuel plenum top end-fitting and bottom end-fitting) for the PWR assembly The active fuel region contains fresh unirradiated fuel (Assumption 324) Since the internal structure (ie basket) design of the TAD is currently not finalized the composition of either homogenized fuel does not include the basket materials and therefore does not tak e credit for any shielding that thes e materials may provide (Assumption 326)
Table 7 Isotopic Compositions of Homogenized PWR Assembly Regions
Element Isotope
Atom Densities for Homogenized Regions (atomsbsdotcm)
Active Fuel Bottom End-Fitting Plenum Top End-Fitting
10B 861E-09 764E-08 221E-08 570E-08 11B 347E-08 307E-07 890E-08 230E-07 C 519E-07 160E-05 138E-06 993E-06 N -- 570E-07 262E-08 117E-06 O 621E-03 -- 142E-05 -- Al 144E-06 128E-05 371E-06 957E-06 Si 971E-07 243E-04 259E-06 139E-04 P 377E-08 606E-06 102E-07 360E-06 S 365E-08 581E-06 971E-08 340E-06 Ti 147E-06 130E-05 376E-06 971E-06 Cr 320E-05 187E-03 779E-05 113E-03 Mn 497E-07 126E-04 141E-06 749E-05 Fe 303E-05 531E-03 717E-05 313E-03 Co 132E-06 117E-05 340E-06 876E-06 Ni 697E-05 144E-03 180E-04 940E-04 Cu 368E-07 327E-06 945E-07 244E-06 Zr 196E-03 -- 195E-03 -- Nb 430E-06 382E-05 110E-05 285E-05 Mo 248E-06 135E-04 636E-06 791E-05 Sn 223E-05 -- 222E-05 -- 234U 139E-06 -- -- -- 235U 157E-04 -- -- -- 236U 719E-07 -- -- -- 238U 294E-03 -- -- -- Total 114E-02 924E-03 235E-03 557E-03
Source Attachment II spreadsheet PWR_fuel compxls worksheet BampWassy
29
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
The isotopic composition of commercially available 235U enriched uranium is determined by the given initial 235U enrichment using the following equations (Reference 226 p 20)
wt235U =235Uenrichment _ of _ the _ associated _ fuel _ batch Equation 2
wt234U = 0007731times (wt235U )10837 Equation 3
wt236U = 00046times (wt235U ) Equation 4
wt238U =100 minus (wt234U + wt235U + wt236U ) Equation 5
The weight percentages of uran ium isotopes for PWR fuel are ca lculated in Attachm ent II spreadsheet PWR_fuel compxls worksheet BampWassy using Equations 2 through 5
627 PWR Source Terms
This calculation uses the following three PWR source terms bull Maximum source (50 wt initial 235U enrichment 80 GWdMTU burnup and 5-year
decay time) (Reference 229 Section 55) Table 8 lists th e gamma source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Design Basis source (4 0 wt initial 235U enrichment 60 GW dMTU burnup and 10-year decay tim e) (Reference 228 Section 552) Table 9 lists the gamm a source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Average source ( 40 wt initial 235U enrichment 48 GWdMTU burnup and 25-year decay time) (Reference 229 Section 55) Table 10 lists the gamma source terms for the fuel and non-fuel regions and the neutron source term for the fuel region
These sources (ie maximum design basis and av erage) are described in this section For dose rate calculations all the fuel assemblies in a transportation cask are of the sam e characteristics Also gamma radiation source term s for the PWR assem bly are prov ided for the f our assembly regions while neutron source term is only present in the active fuel region Gamma radiation sources in the non-active fuel region are distri buted unif ormly within each source region Gamma and neutron sources in the active fuel re gion are modeled as uni form distributions or with axial source profiles
The PWR gamma and neutron axial source profiles for the active fuel region presented in Table 11 are applied to the active fuel region of all three source terms (ie maximum design basis and average) when appropriate
30
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 8 Gamma and Neutron Sources for the Maximum PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting
Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 594E+11 233E+15 528E+11 379E+11 100E-01 000E+00 100E-01 116E+11 644E+14 609E+10 743E+10 400E-01 805E+07 200E-01 283E+10 522E+14 352E+10 179E+10 900E-01 411E+08 300E-01 141E+09 148E+14 196E+09 891E+08 140E+00 376E+08 400E-01 190E+09 985E+13 586E+09 117E+09 185E+00 276E+08 600E-01 191E+09 153E+15 110E+11 741E+07 300E+00 485E+08 800E-01 435E+09 470E+15 595E+10 237E+09 643E+00 443E+08 100E+00 137E+11 708E+14 803E+09 766E+10 200E+01 393E+07 133E+00 338E+13 455E+14 174E+13 217E+13 Total 211E+09 166E+00 953E+12 130E+14 491E+12 612E+12
--
200E+00 187E+03 144E+12 919E+02 113E+03 250E+00 226E+08 249E+12 116E+08 145E+08 300E+00 351E+05 110E+11 181E+05 225E+05 400E+00 766E-08 139E+10 100E-08 416E-08 500E+00 000E+00 709E+07 000E+00 000E+00 650E+00 000E+00 286E+07 000E+00 000E+00 800E+00 000E+00 558E+06 000E+00 000E+00 100E+01 000E+00 119E+06 000E+00 000E+00
Total 442E+13 113E+16 231E+13 284E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE2R2B14cut bWasteStreamE2R1B14cut cWasteStreamE2R3B14cut dWasteStreamE2R4B14cut
31
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 9 Gamma and Neutron Sources for the Design Basis PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary
(MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 273E+11 121E+15 188E+11 175E+11 100E-01 000E+00 100E-01 528E+10 329E+14 277E+10 339E+10 400E-01 316E+07 200E-01 128E+10 245E+14 117E+10 819E+09 900E-01 161E+08 300E-01 639E+08 713E+13 633E+08 407E+08 140E+00 148E+08 400E-01 850E+08 455E+13 164E+09 533E+08 185E+00 109E+08 600E-01 492E+08 226E+14 269E+10 337E+07 300E+00 191E+08 800E-01 291E+09 237E+15 160E+10 186E+09 643E+00 174E+08 100E+00 540E+09 122E+14 248E+09 341E+09 200E+01 154E+07 133E+00 154E+13 195E+14 797E+12 990E+12 Total 830E+08 166E+00 435E+12 450E+13 225E+12 280E+12
--
200E+00 235E+00 152E+11 149E+02 215E-02 250E+00 103E+08 517E+10 534E+07 664E+07 300E+00 160E+05 379E+09 829E+04 103E+05 400E+00 943E-10 497E+08 155E-10 519E-10 500E+00 000E+00 282E+07 000E+00 000E+00 650E+00 000E+00 113E+07 000E+00 000E+00 800E+00 000E+00 222E+06 000E+00 000E+00 100E+01 000E+00 471E+05 000E+00 000E+00
Total 201E+13 486E+15 105E+13 129E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B11cut bWasteStreamE5R1B11cut cWasteStreamE5R3B11cut dWasteStreamE5R4B11cut
32
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 10 Gamma and Neutron Sources for the Average PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 336E+10 670E+14 186E+10 217E+10 100E-01 00000E+00 100E-01 602E+09 199E+14 314E+09 387E+09 400E-01 748E+06 200E-01 146E+09 126E+14 853E+08 936E+08 900E-01 382E+07 300E-01 730E+07 389E+13 439E+07 469E+07 140E+00 352E+07 400E-01 947E+07 263E+13 716E+07 607E+07 185E+00 261E+07 600E-01 141E+07 205E+13 504E+08 383E+06 300E+00 469E+07 800E-01 208E+09 124E+15 192E+09 144E+09 643E+00 418E+07 100E+00 208E+09 110E+13 164E+09 144E+09 200E+01 365E+06 133E+00 175E+12 295E+13 909E+11 112E+12 Total 199E+08 166E+00 494E+11 513E+12 257E+11 318E+11
--
200E+00 973E-01 675E+10 614E+01 872E-03 250E+00 117E+07 353E+09 609E+06 754E+06 300E+00 182E+04 288E+08 944E+03 117E+04 400E+00 186E-11 198E+07 149E-11 127E-11 500E+00 000E+00 669E+06 000E+00 000E+00 650E+00 000E+00 269E+06 000E+00 000E+00 800E+00 000E+00 527E+05 000E+00 000E+00 100E+01 000E+00 112E+05 000E+00 000E+00
Total 229E+12 237E+15 119E+12 147E+12
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B9cut bWasteStreamE5R1B9cut cWasteStreamE5R3B9cut dWasteStreamE5R4B9cut
33
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 11 Gamma and Neutron Axial Source Profiles for a PWR Assembly
Axial boundaries (From midplane)
(cm)
TOP BOTTOM
Neutron Gamma Ne utron Gamma 000 1554 1117 1554 1117 1143 1537 1114 1571 1120 2286 1521 1111 1588 1123 3429 1504 1108 1605 1126 4572 1486 1104 1622 1129 5715 1464 1100 1636 1131 6858 1438 1095 1648 1133 8001 1401 1088 1657 1135 9144 1350 1078 1654 1134
10287 1277 1063 1625 1129 11430 1165 1039 1554 1117 12573 0998 09995 1414 1091 13716 0769 09365 1172 1041 14859 0492 08375 0816 0951 16002 0220 06850 0402 0797 17145 0046 04625 0092 0551 18288 00 00 00 00
Source Reference 2219 Table S445
34
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
63 MCNP SPECIFIC INPUT
631 Source Probability
A linear radial distribution is used for all gamma and neutron sources The linear radial distribution is sam pled usi ng the built-in power function p(x) = xc a with a = 1 for the radial direction This sampling method results in a uniform source distribution over the area bounded by the outer radius of the source
The source axial distributions are unifor m for all four source regions The a xial uni form xp(x) = c distribution is sampled using the built-in power function a with a = 0 for extent
The energy distribu tions of the gamma and neutron sour ce term s are treated as energ y probabilities and are applied in MCNP5 using SISP cards
632 Dose Rate and Flux Tallies
MCNP5 dose rate calculations feature separate runs for the following calculation types
bull a photon transport calculation for prim ary ga mma contribution to the dose rates fr om photon fluxes
bull a coupled neutronphoton transport calculat ion for neutrons a nd secondary gamma (photons generated by neutron be ing captured) contributions to dose rates from neutron and gamma fluxes
The tally type F2 is us ed in th is d esign ca lculation as f lux estim ators The type F2 tally evaluates the flux averaged over a surface in particlescm2s
To generate dose ra tes in te rms of remhr the FM (tally multiplier ) and DEDF (dose energydose conversion factors) cards are used to en ter the tally multiplier f actor (source intensity in particless) energy boundaries in MeV and corresponding dose conversion factors in (remhr)(particlescm2s) respectively These factors were used in the input files
In order for the F2 tally to accum ulate flux ov er a surface a specific s urface area is requ ired The SD cards are used to enter a surface area in cm2 over which the flux will be tallied for an F2 tally
633 Variance Reduction Techniques
Variance reduction technique is usually em ployed in order to increase the efficiency of a calculation and obtain statistically m eaningful results within re asonable com puter tim e In Monte Carlo calculations when variance reduction scheme is employed the weights of particles are adjusted in order to account for the biasing and to preserve a fair game
Geometry splitting and Russian roulette techniques described in Reference 2224 (pp 2-140 ndash 2-142) are useful in shielding calculations and therefore deployed in all the MCNP5 runs
35
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
As particles migrate in an important direction (toward the detector) they are increased in number to provide better sampling by means of geometry splitting across geometric boundaries Russian roulette (the reverse process) is played when particles travel in an unimportant direction to allow termination of unim portant histories The IMP card required for every cel l ca rd is us ed to implement this technique
The other variance reduction technique deployed in the MC NP5 runs is source intensity biasing for the gamma sources from the four source regions (active fuel bottom end-fitting plenum and top end-fitting) The natural total gamma source intensity of comm ercial SNF is dom inated by the gamma source in the active fuel region This active fuel gamma source usually accounts for over 95 o f the total g amma source intens ity In order to im prove the efficiency of the axial dose rate calculations a biased source probability distribution is employed for the prim ary gamma dose rate calculations The biased gamma source probability distribution is chosen to be 005 080 010 and 005 for the bottom end-fitting the active fuel the plenum and the top end-fitting regions respectively
64 DOSE CONVERSION FACTORS
Project Design Criteria Document (Reference 2211 Se ction 41015) requires the use of flux-to-dose rate conversion fact ors from ANSIANS-611-1977 (Reference 221) for dose rate evaluations Table 16 lists the neutron and ga mma dose conversion factors used in the MCNP5 calculations
Table 12 Gamma and Neutron Flux to Dose Conversion Factors
Gamma Neutron Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
001 396E-06 140 251E-06 250E-08 367E-06 003 582E-07 180 299E-06 100E-07 367E-06 005 290E-07 220 342E-06 100E-06 446E-06 007 258E-07 260 382E-06 100E-05 454E-06 010 283E-07 280 401E-06 100E-04 418E-06 015 379E-07 325 441E-06 100E-03 376E-06 020 501E-07 375 483E-06 100E-02 356E-06 025 631E-07 425 523E-06 100E-01 217E-05 030 759E-07 475 560E-06 500E-01 926E-05 035 878E-07 500 580E-06 100E+00 132E-04 040 985E-07 525 601E-06 250E+00 125E-04 045 108E-06 575 637E-06 500E+00 156E-04 050 117E-06 625 674E-06 700E+00 147E-04 055 127E-06 675 711E-06 100E+01 147E-04 060 136E-06 750 766E-06 140E+01 208E-04 065 144E-06 900 877E-06 200E+01 227E-04 070 152E-06 1100 103E-05 080 168E-06 1300 118E-05 100 198E-06 1500 133E-05
Source Reference 221 Tables 1 and 3
36
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION
By def inition (Ref erence 2224 Equation 219) the estimated st atistic relative error of the i component is
Ri = Si
2
Equation 6Ti
where i = tally component index Ri = relative error of the i component S2
i = variance of the i component Ti = tally i component
For a result (ie dose rate) computed as a sum of different tallies the statistical relative error of the computed value is o btained from the variance of the result - S2
total which is th e sum of the estimated variances of the individual tallies S2
i n
2 2STotal = sum Si Equation 7 i=1
where S2Total = total estimated variance
n = total number of components Therefore the total tally value (dose rate) and the associated relative error are derived according to Equations 8 and 9
n TTotal = sumTi Equation 8
i=1
n n
sum (Ri timesTi )2
2 sum Si 2
STotal = i=1 = i=1 Equation 9RTotal = TTotal TTotal TTotal
where RTotal = total estimated relative error TTotal = total estimated tally
Equations 8 and 9 are utilized in Attachm ent II to ev aluate to tal dos e ra tes and their r elative errors
37
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
7 RESULTS AND CONCLUSIONS
71 RESULTS
The following sections summarize the results of this calculation Section 711 presents results for Conceptual Cask A while Section 712 for Conceptual Cask B Section 713 provides comparisons of the dose-rate reduction factors du e to the two conceptual casks and the axial source distributions in the active fuel region Do se rates and relative errors can be found in Attachment II within the output files and Excel files
711 Dose Rates of Conceptual Cask A
This section presents dose-rate results of the calculation sets 1 and 2 as described in Section 61 for Cask A Set 1 has axial p rofile sources in the active fuel region a nd consist of six runs resulting from the three PWR SNF source term s (maximum design basis and average) and the two radiation sources (gammas and neutrons) Set 2 has uniform axial sources in the active fuel region and consists of six run s r esulting f rom the th ree P WR SNF source term s and th e tw o radiation sources
As described in Section 61 dose ra tes are calculated at the three exterior surfaces (radial top and bottom) and at distances 1 m and 2 m from the exterior surfaces The total dose rates for set 1 are presented in Tables 13 14 and 15 for the ra dial top and bottom dire ctions respectively However the com ponents (primary gamma neutr on and secondary gamma) contributing to the total dose rates as well as the re lative error calculations can be found in Attachment II Excel file MCNP-Results1xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 2 are shown in Tables 16 17 and 18 The dose-rate components and the relative errors can be found in A ttachment II Excel file MCNP-Results2xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 13 and 16 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 14 and 17 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 15 and 18 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carrying th e maximum PWR SNF Based on the results in Tables 13 through 18 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask A indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these 6 tables the d ose-rate red uction f actors between the m aximum and the design basis fuels the maxim um and the averag e fuels and th e design basis and the average fuels are a lso presented
38
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 320E-02 00237 116E-02 00222 262E-03 00219 275 1223 445
1 m 133E-02 00164 494E-03 00171 106E-03 00162 269 1261 468 2 m 749E-03 00198 285E-03 00225 584E-04 00162 263 1282 488
Ring Detectors 1 m 133E-02 00116 492E-03 00115 108E-03 00124 271 1229 454 2 m 756E-03 00118 279E-03 00110 605E-04 00128 271 1250 462
Source Attachment II MCNP-Results1xls worksheet Summary
Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 142E-02 00368 628E-03 00446 934E-04 00483 226 1520 672
1 m 570E-03 00289 263E-03 00426 375E-04 00381 217 1520 701 2 m 265E-03 00364 123E-03 00547 169E-04 00374 216 1575 730
Point Detectors 1 m 598E-03 00238 274E-03 00271 402E-04 00354 219 1489 681 2 m 273E-03 00218 123E-03 00245 180E-04 00336 221 1515 684
Source Attachment II MCNP-Results1xls worksheet Summary
Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 653E-03 00298 265E-03 00276 510E-04 00341 247 1278 518
1 m 276E-03 00238 112E-03 00208 207E-04 00249 248 1334 539 2 m 125E-03 00185 508E-04 00199 933E-05 00246 246 1336 544
Point Detectors 1 m 291E-03 00227 118E-03 00203 218E-04 00242 247 1335 540 2 m 130E-03 00209 524E-04 00187 955E-05 00233 247 1357 549
Source Attachment II MCNP-Results1xls worksheet Summary
Tables 13 14 and 15 are results of calculation set 1 for conceptual Cask A with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
39
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 265E-02 00247 990E-03 00222 215E-03 00278 268 1234 461
1 m 116E-02 00178 468E-03 00549 960E-04 00189 248 1208 488 2 m 713E-03 00273 265E-03 00161 602E-04 00360 269 1184 439
Ring Detectors 1 m 117E-02 00120 454E-03 00132 979E-04 00141 259 1199 463 2 m 722E-03 00130 276E-03 00141 589E-04 00153 261 1226 469
Source Attachment II MCNP-Results2xls worksheet Summary
Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 199E-02 00461 827E-03 00455 147E-03 00536 241 1359 564
1 m 849E-03 00564 323E-03 00314 563E-04 00418 263 1507 574 2 m 415E-03 00832 158E-03 00603 253E-04 00501 263 1641 623
Point Detectors 1 m 877E-03 00348 353E-03 00275 615E-04 00391 248 1426 574 2 m 393E-03 00341 160E-03 00278 270E-04 00378 246 1454 590
Source Attachment II MCNP-Results2xls worksheet Summary
Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 879E-03 00374 356E-03 00333 669E-04 00406 247 1315 533
1 m 365E-03 00223 147E-03 00209 269E-04 00253 248 1358 548 2 m 164E-03 00229 674E-04 00205 120E-04 00248 243 1364 560
Point Detectors 1 m 383E-03 00217 155E-03 00204 285E-04 00248 247 1347 546 2 m 172E-03 00197 689E-04 00186 124E-04 00225 249 1391 558
Source Attachment II MCNP-Results2xls worksheet Summary
Tables 16 17 and 18 ar e results of calculation set 2 for conceptual Cask A with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
40
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
1 PURPOSE
The purpose of this calculation is to calcu late th e dose ra tes of two conceptua l tr ansportation casks each carrying a Transportation Aging and Disposal (TAD) canister separately loaded with the average design basis (DB) and m aximum comm ercial spent nuc lear fuel (CSNF) assemblies Then the dose-ra te reduction f actors between the m aximum and the design basis fuels the d esign bas is and the average fuels and the m aximum and the averag e fuels are computed
The results of this calculation may be used to substantiate the dose-rate reduction factors such as those in the engineering study Repository ALARA Goal Compliance (Reference 227) which is cited as a reference in a Preclosure Safety Analyses (PCSA) calculation that supports the License Application
The calculations contained in this docum ent are developed by Nuclear and Radiological Engineering of the Repository Project Mana gement (RPM) organization Yucca Mountain Project (YMP) personnel from Nuclear and Radiological Engineering should be consulted before use of the calculations for purposes other than those stated herein or use by individuals other than personnel in Nuclear and Radiological Engineering
9
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
2 REFERENCES
21 PROJECT PROCEDURESDIRECTIVES
211 IT-PRO-0011 Rev 0010 Software Management Las Vegas Nevada Bechtel SAIC Company
212 EG-PRO-3DP-G04B-00037 Rev 14 Calculations and Analyses Las Vegas Nevada Bechtel SAIC Company
213 IT-PRO-0012 Rev 007 Qualification of Software Las Vegas Nevada Bechtel SAIC Company
22 DESIGN INPUTS
221 ANSIANS-611-1977 Neutron and Gamma-Ray Flux-to-Dose-Rate Factors La Grange Park Illinois American Nuclear Society TIC 239401
222 ASME (American Society of Mechanical Engineers) 2004 2004 ASME Boiler and Pressure Vessel Code 2004 Edition New York New York American Society of Mechanical Engineers TIC 256479 ISBN 0-7918-2899-9
223 ASM International 1990 Properties and Selection Nonferrous Alloys and Special-Purpose Materials Specific Metals and Alloys Volume 2 of Metals Handbook 10th Edition Page 666 [Materials Park Ohio] American Society for Metals TIC 239807
224 ASTM (American Society for Testing and Materials) B 811-90 1991 Standard Specification for Wrought Zirconium Alloy Seamless Tubes for Nuclear Reactor Fuel Cladding Philadelphia Pennsylvania American Society for Testing and Materials TIC 239780
225 ASTM G 1-90 (Reapproved 1999) 1999 Standard Practice for Preparing Cleaning and Evaluating Corrosion Test Specimens West Conshohocken Pennsylvania American Society for Testing and Materials TIC 238771
226 Bowman SM Hermann OW and Brady MC 1995 Sequoyah Unit 2 Cycle 3 Volume 2 of Scale-4 Analysis of Pressurized Water Reactor Critical Configurations ORNLTM-12294V2 Oak Ridge Tennessee Oak Ridge National Laboratory TIC 244397 [DIRS 123796]
227 BSC (Bechtel SAIC Company LLC) 2008 Repository ALARA Goal Compliance 000-30R-MGR0-04000-000 REV 000 Las Vegas Nevada Bechtel SAIC Company ACC ENG200802050014 [DIRS 184957]
228 BSC 2002 Subsurface Shielding Source Term Specification Calculation 000-00C-WER0-00100-000-00A Las Vegas Nevada Bechtel SAIC Company ACC MOL200212160076 ENG200508150022
10
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
229 BSC 2004 PWR Source Term Generation and Evaluation 000-00C-MGR0-00100-000-00B Las Vegas Nevada Bechtel SAIC Company ACC ENG200405240007
2210 BSC 2008 Basis of Design for the TAD Canister-Based Repository Design Concept 000-3DR-MGR0-00300-000-003 Las Vegas Nevada Bechtel SAIC Company ACC ENG200810060001
2211 BSC 2007 Project Design Criteria Document 000-3DR-MGR0-00100-000-007 Las Vegas Nevada Bechtel SAIC Company ACC ENG200710160005 ENG200711080001 ENG200712200003 ENG200801070001 ENG200801070002 ENG200801070016 ENG200801070017 ENG200801310006 ENG200803050002 ENG200803050011 ENG200803050012 ENG200803060009 ENG200803130004 ENG200807100001 ENG200811120006 ENG200811140004
2212 BSC 2004 PWR and BWR Source Term Sensitivity Study 000-00C-MGR0-00300-000-00A Las Vegas Nevada Bechtel SAIC Company ACC ENG200401140003 ENG200508150023
2213 BSC 2007 Dose Rate Calculation for Exhaust Main Drifts 800-00C-SS00-00700-000-00B Las Vegas Nevada Bechtel SAIC Company ACC ENG200711050017 ENG200803060001
2214 BSC 2006 Dual Purpose Canister Opening Study 050-30R-WHS0-00600-000-000 Las Vegas Nevada Bechtel SAIC Company ACC ENG200612200023
2215 BSC 2007 GROA Shielding Requirements Calculation 000-00C-MGR0-03300-000-00B Las Vegas Nevada Bechtel SAIC Company ACC ENG200705290037
2216 BSC 2002 Concrete Shielding Calculation for Dry Facility 1 110-00C-CS10-00100-000-00A Las Vegas Nevada Bechtel SAIC Company ACC MOL200301140075
2217 BSC 2003 Shielding Design Calculations for Dry Facility 1 110-00C-CS10-00200-000-00A Las Vegas Nevada Bechtel SAIC Company ACC ENG200306020003
2218 CRWMS MampO 1998 Calculation of the Effect of Source Geometry on the 21-PWR WP Dose Rates BBAC00000-01717-0210-00004 REV 00 Las Vegas Nevada CRWMS MampO ACC MOL199902220059 [DIRS 102134]
2219 CRWMS MampO 2000 Users Manual for SCALE-44A 10129-UM-44A-00 Las Vegas Nevada CRWMS MampO ACC MOL200011300136 MOL200108220084 MOL200108220085 MOL200108220086 MOL200108220087 [DIRS 153872]
2220 DOE (US Department of Energy) 1987 Appendix 2A Physical Descriptions of LWR Fuel Assemblies Volume 3 of Characteristics of Spent Fuel High-Level Waste and Other Radioactive Wastes Which May Require Long-Term Isolation DOERW-0184 Washington DC US Department of Energy Office of Civilian Radioactive Waste Management ACC HQX198804050024 [DIRS 132333]
11
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
2221 DOE 2007 Software Validation Report for MCNP5 v140 Document ID 11199-SVR-140-00-WINXP Las Vegas Nevada US Department of Energy Office of Repository Development ACC MOL200702280252 [DIRS 180516]
2222 DOE 2008 Transportation Aging and Disposal Canister System Performance Specification WMO-TADCS-000001 Rev 1 ICN 1 Washington DC US Department of Energy Office of Civilian Radioactive Waste Management ACC DOC200803310001 [DIRS 185304]
2223 Harmon CD II Busch RD Briesmeister JF and Forster RA 1994 Criticality Calculations with MCNPtrade A Primer LA-12827-M Los Alamos New Mexico Los Alamos National Laboratory TIC 234014 [DIRS 154532]
2224 LANL (Los Alamos National Laboratory) 2004 MCNP mdash A General Monte Carlo N-Particle Transport Code Version 5 (Appendix H is not included) LA-UR-03-1987 Volume I Los Alamos [New Mexico] Los Alamos National Laboratory ACC MOL200510240126 [DIRS 176521]
2225 MCNP5 V 140 2007 Windows XP STN 11199-140-00 [DIRS 180515]
2226 Parrington JR Knox HD Breneman SL Baum EM and Feiner F 1996 Nuclides and Isotopes Chart of the Nuclides 15th Edition San Jose California General Electric Company and KAPL Inc TIC 233705 LC Call Number QC7935 N8622 1996
2227 Punatar MK 2001 Summary Report of Commercial Reactor Criticality Data for Crystal River Unit 3 TDR-UDC-NU-000001 REV 02 Las Vegas Nevada Bechtel SAIC Company ACC MOL200107020087 [DIRS 155635]
2228 Sisley SE 2002 Transportation License Application for the FuelSolutionstrade System (TAC No L23311) Submittal of the FuelSolutiontrade Transportation SARs Revision 3 Letter from SE Sisley (BNFL) to the NRC April 11 2002 BFSNRC 02-011 with enclosures TIC 255245 [DIRS 171545]
NOTE Reference 2220 is a direct input but is not QA QA It is justified as acceptable for the intended use as it is directly from the DOE and is considered the best available data on the subject The referenced values cited in Tables 3 and 4 are valid for use since they are reliable and reasonable based on engineering judgment
23 DESIGN CONSTRAINTS
231 10 CFR 71 2008 Energy Packaging and Transportation of Radioactive Material Internet Accessible [DIRS 185678]
12
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
24 DESIGN OUTPUTS
The resu lts of this calculation will be us ed to substan tiate th e dose reduc tion f actor in the Repository ALARA Goal Compliance (Reference 227) which is cited as a reference in a PCSA calculation that supports the License Application
13
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
3 ASSUMPTIONS
31 ASSUMPTIONS REQUIRING VERIFICATION
None
32 ASSUMPTIONS NOT REQUIRING VERIFICATION
Assumptions 321 322 and 323 are m odeling assum ptions and do not require further verification The m aterials and dim ensions for the TAD canister and for the conceptu al transportation casks are only selected to charac terize two tr ansportation casks th at m eet 10 CFR7147 (Reference 231) dose rates when lo aded with the ldquom aximumrdquo and ldquoaveragerdquo pressurized water re actor (PW R) assem blies re spectively There is n o need to v erify those dimensions or m aterials at a later date The ca lculated results in Sect ion 711 verify that the conceptual casks would meet 10 CFR 7147 (Reference 231) dose rates
321 Material and Wall Thickness of TAD Canister
Assumption It is assumed that the TAD canister is made of stainless steel 316 (SS 316) and has a wall thickness of 025 in for the radial and bottom shells
Rationale Currently the design of the TAD canis ter d oes not ex ist Based on a survey of existing m ultipurpose a nd dual purpose caniste rs (DPC) (Ref erence 2214 p 56) a 025 in thickness is below the wall thick ness of any existing c anisters For the purp ose of this calculation this assumption leads to higher and conservative external dose rates Since SS 316 is the sam e material used for the waste pack age inner shell it is a l ogical cho ice f or the TAD canister
Although Reference 2214 is an engineering study with a QA N A status it is used here as an indirect input to support the assumption which is conservative for dose rate calculations
Usage This assumption is used in Sections 621 and 625
322 Material and Thickness of TAD Shield Plug
Assumption It is assu med that the TAD shield plug is made of SS 316 and has a thickness of 11 in
Rationale Currently the design of the TAD canister doe s not exist A thick shield plug of 11 in (Reference 2215 Table 12) is needed to keep the m aximum contact dose rate of the top surface below 1000 mrem hr (Reference 2222 Section 314) Since SS 316 is the sam e material used for the waste package inner shell it is a logical choice for the TAD shield plug
Usage This assumption is used in Section 621
14
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
323 Geometry and Materials of Conceptual TAD Transportation Casks
Assumption Two conceptual TAD transpo rtation casks designated as Cask A and Cask B are assumed to have a cylindrical geom etry and m aterials specified in Tab les 1 and 2 respectively The casks are basically construc ted of an inner layer of SS 316 for ga mma shielding a m iddle layer of 5-borated polyethylen e for neutron shielding and a th in outer layer of SS 316 whic h serves a structural function as well as shielding secondary gamma rays
Both Cask A and Cask B have a cavity height of 53785 cm (21175 in) and a cavity diameter of 16891 cm (6650 in) However Cask A has a total height of 610845 cm (24049 in) and an outside diameter of 26797 cm (10550 in) while the total height and outside diameter of Cask B are 58885 cm (23183 in) and 24765 cm (9750) respectively
Cask A will provide shielding to m eet the exterior radiat ion standards of 10 C FR 7147(b) (Reference 231) when loaded w ith a TAD canister carrying th e maximum PWR spent nuclear fuel (SNF) Cask B will satisf y the same radiation standards when loade d with a TAD caniste r carrying the average PWR SNF
Table 1 Geometry and Materials of Conceptual TAD Transportation Cask A
Component Dimension
Material (cm) (in)
Total Height 61085 2404 9 NA
Outside Diameter 26797 1055 0 NA
Cask Cavity Height 53785 2117 5 NA
Cask Cavity Diameter (Radius) 16891 (8446) 6650 (3325) NA
Radial Gamma Shield Thickness (Radius)a 3302 (11748)a 1300 (4625)a SS 316
Radial Neutron Shield Thickness (Radius)b 1524 (13272)b 600 (5225)b 5-borated polyethylene
Radial Outer Shell Thickness (Radius)c 127 (13399)c 050 (5275)c SS 316
Top Gamma Shield Thickness (Axial Position)d 600 (54385)d 236 (21411)d SS 316
Top Neutron Shield Thickness (Axial Position)d 1000 (55385)d 394 (21805)d 5-borated polyethylene
Top Outer Shell Thickness (Axial Position)d 200 (55585)d 079 (21884)d SS 316
Bottom Gamma Shield Thickness (Axial Position)d 35365 (-360)d 1392 (-1417)d SS 316
Bottom Neutron Shield Thickness (Axial Position)d 15 (-510)d 591 (-2008)d 5-borated polyethylene
Bottom Outer Shell Thickness (Axial Position)d 4 (-550)d 157 (-2165)d SS 316 a11748 = 3302 + 8446 and 4625 = 1300 + 3325 b13272 = 1524 + 11748 and 5225 = 600 + 4625 c13399 = 127 + 13272 and 5275 = 050 + 5225 dCoordinate relative to the bottom of the fuel assembly as modeled in MCNP5
15
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 2 Geometry and Materials of Conceptual TAD Transportation Cask B
Component Dimension
Material (cm) (in)
Total Height 58885 2318 3 NA
Outside Diameter 24765 9750 NA
Cask Cavity Height 53785 2117 5 NA
Cask Cavity Diameter (Radius) 16891 (8446) 6650 (3325) NA
Radial Gamma Shield Thickness (Radius)a 254 (10986)a 1000 (4325)a SS 316
Radial Neutron Shield Thickness (Radius)b 127 (12256)b 500 (4825)b 5-borated polyethylene
Radial Outer Shell Thickness (Radius)c 127 (12383)c 050 (4875)c SS 316
Top Gamma Shield Thickness (Axial Position)d 8 (54585)d 315 (21490)d SS 316
Top Neutron Shield Thickness (Axial Position)d None Non e NA
Top Outer Shell Thickness (Axial Position)d None Non e NA
Bottom Gamma Shield Thickness (Axial Position)d 3837 (-390)d 1510 (-1535)d SS 316
Bottom Neutron Shield Thickness (Axial Position)d 300 (-420)d 118 (-1654)d 5-borated polyethylene
Bottom Outer Shell Thickness (Axial Position)d 100 (-430)d 039 (-1693)d SS 316 a10986 = 254 + 8446 and 4325 = 1000 + 3325 b12256= 127 + 10986 and 4825 = 500+ 4325 c12383 = 127 + 12256 and 4875 = 050 + 4825 dCoordinate relative to the bottom of the fuel assembly as modeled in MCNP5
Rationale Currently a design for the TAD transporta tion cask does not exist The casks assumed for this calculation are so lely for estim ation of the dose reduction due to different source terms This is a conceptual repres entation only used in this calculation to estim ate the parameters of interest
Usage This assumption is used in Sections 61 and 622
324 Usage of Unirradiated Fuel for Commercial SNF
Assumption It is assumed that the active fuel region of the commercial SNF assembly contains the same isotopic concentrations as the fresh uni rradiated fuel and that the concentrations of fresh fuel with 5 initial enrichm ent corresp onding to m aximum SNF are used for all other SNFs
Rationale This assumption is a standard practice for shielding calculations throughout the industry accepted by the U S Nucle ar Regulatory Commission (NRC) (Reference 2228 Table 53-5) It sh ould be noted that this assumption applies to material composition only it does no t apply to source terms which are based on the characteristics of spent fuel
Usage This assumption is used in Sections 624 and 626
325 Homogenization of Radiation Source Regions
Assumption It is assu med that a commercial SNF assembly consis ts of four distinct reg ions (active fuel bottom end-fitting plenum and top end-fitting) The materials and radiation sources
16
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
of each assembly region are homogenized inside a volume defined by the TAD cavity radius and region height
Rationale The assembly representation is consistent with the industry practice for shielding calculations accepted by NRC (Reference 2228 Figure 53-6) The effec t of source homogenization is twofold (1) it d ecreases th e m ass de nsity of the source region and (2) it places source points slightly closer to detector locations thus reducing radiation attenuation The resu lts of Calculation of the Effect of Source Geometry on the 21-PWR WP Dose Rates (Reference 2218 pp 22-26) indicate that th e effect of assem bly homogenization gives nearly the same or conservative dose rates as the explicit fuel assembly model
Usage This assumption is used in Section 624
326 Ignoring Internal Fuel Basket Materials
Assumption It is assumed that the internal fuel basket materials are ignored
Rationale Inclusion of fuel basket m aterials in the smeared m aterial com position would increase the overall density and consequently increase the attenuati on of the radiation Therefore this assumption is conservative
Usage This assumption is used in Sections 621 624 and 626
17
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
4 METHODOLOGY
41 QUALITY ASSURANCE
This calculation was prepared in accordance with EG-PRO-3DP-G04B-00037 Calculations and Analyses (Reference 212) The results of th is calculation provides worker dose assessm ent adjustments and this will id entify radio logical hazards f or f acilities im portant to saf ety Therefore the approved version is designated as QA QA
42 USE OF COMPUTER SOFTWARE
421 Baseline Software
The Monte Carlo N-Particle com puter pr ogram (MCNP5) version 140 (Reference 2225) is used to calculate the dose rates (neutron pr imary gamm a and secondary gamm a) at various locations around a transportation cask and an aging overpack
The software specifications are as follows
bull Program Name MCNP5 bull VersionRevision Number Version 140 bull Operating Systems Windows XP bull Software Tracking Number 11199-140-00 bull Computer Type Dell OPTIPLEX GX620
MCNP5 which is Level 1 software is (a) appropriate for three-dim ensional neutron gamma and coupled neutrongamma shielding calculations (b) used within th e range of validation as documented in Software Validation Report for MCNP5 v140 (Reference 2221) and (c) obtained from Software C onfiguration Managem ent and qualified in accordance with procedure IT-PRO-0012 Qualification of Software (Reference 213) Therefore MCNP5 code is suitable for use in this design calculation All MCNP5 input and output files docum ented in this calculation are provided on a compact disc (CD) as Attachment II
All MCNP cases are executed on one of the following Q com puters QNW -004184 QNW -004187 QNW-004194 and QNW-004196 as shown in the output files
422 Commercial off the Shelf Software
The Excel sof tware is used to c alculate var ious inpu t values (i e atom densities weight percentages geometrical dimensions normalized source spectra and probabilities etc) Standard functions of Excel are also used in this desi gn calculation to display results (ie gamma and neutron dose rates) in tabular and graphic forms and to perform relative error calculations
The software specifications are as follows
bull Program Name Excel bull VersionRevision Number Microsoftreg Excel 2003
18
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
bull This software is installed on a persona l com puter running Microsoft W indows XP (central processing unit number 151834)
The user defined for mulas inputs results and gr aphical representations have been verified by hand calculations or visual inspection and are documented in sufficient detail to allow an independent repetition of the com putations Calculations were verifi ed by hand and graphical representations were found accurate by visual inspection
Per Software Management Microsoftreg Excel is not requir ed to be qualif ied due to its commercial availability status (Reference 211 Attachment 4 p 55 bullet 2)
43 CALCULATION APPROACH
This calculation em ploys the qualified so ftware MCNP5 version 140 (Reference 2225) a three-dimensional Monte Carlo code for pe rforming neutron and coupled neutron-gamm a calculations to estim ate dose rates at sele cted locations on and surrounding a conceptual transportation cask containing a loaded TAD canister
431 MCNP5 Program
MCNP5 a general Monte Carlo part icle transport code sim ulates particle transport through a three-dimensional representation of the nuclear system being analyzed During the random walk of particles through the system described by the geom etry the c ode collects inform ation about various events (su rface cross ing collis ions trac k leng th etc) and es timates fluxes in various geometric configurations specified as tallies by the user It also estimates the statistical precision of the results in the form of relative errors (Reference 2224 pp 1-2 to 1-8)
Per Project Design Criteria Document (Reference 2211 Section 41015) the flux estim ates are converted to dose rates using the Am erican Nuclear Society (ANS) flux-to-dose rate conversion factors for gammas and neutrons (R eference 221) The simple variance reduction techniques of Geometry SplittingRussian Roulette and source probability biasing (Sections 631 and 633) are used to enhance computational efficiency
19
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
5 LIST OF ATTACHMENTS
Number of Pages Attachment I List of Electronic Files on the CD 3 Attachment II Compact Disc NA
20
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
6 CALCULATIONS
This sectio n provides inform ation necess ary to perform the calcu lations in this docum ent Section 61 describes the configurations the type of CSNF to be analyzed the number of MCNP runs and the locations where dose rates are ca lculated Section 62 provides the calculation input that includes the details of the geom etry m odel radiation source term s and m aterial compositions Input specific to MCNP dose -rate conversion factors and relative error calculation are described in the later sections
61 DESCRIPTION OF CALCULATIONS
Dose rate calculations are perform ed with the MCNP5 version 140 com puter code (Reference 2225) Two conceptual transportation casks Cask A and Cask B (Assum ption 323) are employed Each cask contains a TAD canister that is loaded with 21 ident ical PW R SN F assemblies Three PWR source term s are analy zed they are the source term s corresponding to the maximum design basis and average PW R SN Fs The characteris tics of the P WR source terms are presented in S ection 627 Each PWR source term has neutron and ga mma radiation sources that require separate MCNP5 runs For each radiation source an axial profile source and a uniform source for the active fuel region are considered The uniform source for the active fuel region is included in this calculation because this approach was used in combination with source peaking factors in certain calculations (Reference 2216 Sections 37 and 39 and Reference 2217 Section 5242)
The total number of MCNP5 runs is 24 which re sults from a com bination of two conceptual casks three PWR source terms two radiation sources and two axia l source distributions for the active fuel region These 24 runs are categorized into four calcula tion sets Each calculation set consists of six runs that is a combination of three PWR source te rms and two radiation sources The characteristics of each calculation set are as follows
1 Cask A with axial profile sources in the active fuel region
2 Cask A with uniform axial sources in the active fuel region
3 Cask B with axial profile sources in the active fuel region
4 Cask B with uniform axial sources in the active fuel region
For each MCNP5 run dose rates are calculated at the exte rior surfaces and at distances 1 and 2 meters from the exterior surfaces Surface tallies and detector tallies (ring and point detectors) as indicated in Figure 1 are e mployed in all runs Figure 1 is used to illustrate the dep loyment of the surface and detector tallies re lative to the so urce regions and it should not be interpreted as an exact geometry of any particular run Surface tallies are deployed at all three distances while ring and point detectors are used only at 1 m and 2 m and not at the cask surfaces Using point detectors near a surface or in any scattering media is not recommended because very large scores can occur f rom collisions close ( less than a f ew centimeters) to the point detecto rs that can lead to resu lts with high r elative e rrors thus m aking the ca lculation d ifficult to o btain r eliable answers
21
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
For the radial direction surface tallies at the three distances (contact 1 m and 2 m) are computed for three su rface segments (cylindrical rings) between the planes at Z = 145 175 2 05 and 235 cm The geometric locations of the segments are shown in Figure 1 The axial locations of these segments correspond to the m iddle of the active fuel region of the PWR SNF assemblies The average dose rates for each of the segm ents are calculated for the outside surface and surfaces at 1 m and 2 m from the cask surface Two ring detectors (instead of point detectors) are deployed at 1 m and 2 m for the radial dire ction Ring detectors instead of point detectors are used in order to capitalize on the symm etry around the cask axis thus im proving the efficiency of the calculations
In the axial direction the average d ose rates within three concentric radial surfaces defined by radii of 40 80 and 120 cm (shown in Figure 1) are calculated for the top and bottom surfaces and at distances 1 m and 2 m from these surfaces Finally point detectors at 1 m and 2 m from the top and bottom axial surfaces are employed
22
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Point Detector at 2 m x
Ring Ring Detector Detector at 2 m at 1 m
x x
Z = 00 cm
Z = 145 cm
Z = 175 cm
Z = 205 cm
Z = 235 cm
R = 80 cm
R = 120 cm
R = 40 cm
Active Fuel
Shield Plug
Top End-Fitting Plenum
Bottom End-Fitting
Ring Detector at 1 m
x
Point Detector at 1 m x
Ring Detector
at 2 m x
D = 26797 cm
H =
610
845
cm
Point Detector at 1 m x
Point Detector at 2 m x
Figure 1 Geometry and Tally Scheme for the TAD Transportation Cask
23
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
62 CALCULATION INPUT
Technical product input and sources of the input used in the deve lopment of this calculation are documented in this section Tables in this docum ent and in th e associated Microsoftreg Excel spreadsheets referenced m ay present num erical values with m any significant figures these values are not to be considered as high precision values since the significant figures are results of calculated values andor unit conversions
621 TAD Canister
The TAD canis ter will contain either 21 P WR or 44 BW R (boiling water reactor) SNF assemblies (Reference 2222 Section 321) While the canister design is iden tical for both PWR and BWR SNF assemblies the internal basket structure is different depending on the SNF assemblies However the internal basket stru cture m aterial is no t in cluded in the calcu lation model (Assumption 326)
The TAD canister is a right-circu lar cylinder with a diam eter of 665 in and a height between 186 and 212 in (Reference 2222 Section 321) The average and maximum total dose rates on the top surf ace of a loaded TAD ca nister must not exceed 800 and 1000 m remhr respectively (Reference 2222 Section 314) The TAD canister used in this calculation is m ade of SS 316 with a radial wall and bottom thickness of 025 in (Assumption 321) The top of the canister has a shield plug that is 11 in thick SS 316 (Ass umption 322) A thick shield plug is needed to keep the maxim um contact dose rate of th e top surface below 1000 m remhr The overall dimensions of the TAD canister are provided in Table 3
Table 3 Dimensions of TAD Canister
Component Dimension
(in) (cm)
Maximum heighta 212 53848
Outer diametera 665 16891
Thickness of bottom lidb 025 0635
Shell thicknessb 025 0635
Lifting Featurec 6 1524
Height without Lifting Feature 206 52324
Thickness of shield plugd 110 2794
aReference 2222 Section 311 bAssumption 321 cReference 2222 p Attachment C-1 dAssumption 322
622 Conceptual TAD Transportation Casks
Two conceptual TAD transportation casks designa ted as Cask A and Cask B are em ployed in this calculation (Assumption 323) They both have a cylindrical geometry with dimensions and materials specified in Tables 1 and 2 of Section 323 Cask A will provide shielding to meet the exterior radiation standards of 10 CFR 7147(b) (Reference 231) when loaded with a TAD
24
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
canister car rying the m aximum PWR SNF Cask B will s atisfy th e sa me radiatio n standa rds when loaded with a TAD canister c arrying the average PWR SNF The reason to analyze both Casks A and B is to cover a broad range of characteristics of the CSNF
The cavity dimensions of the conceptual cask s are 53785 cm (21175 in) in height and 16891 cm (665 in) in diam eter (Tab les 1 and 2) This cav ity will accommoda te the TAD canister described in Table 3 without the lifting feature This is the geometry model used in the MCNP5 calculations
623 Fuel Assembly Selection
PWR and BWR Source Term Sensitivity Study (Reference 2211 Tables 71 through 84) shows that the source terms generated for the Bamp W 15x15 Mark B fuel assembly with 475 kg uranium loading bound the source terms of other PWR assembly types ther efore this assembly type is selected as the representative PWR fuel assembly The gamma and neutron source terms for the BampW 15x15 Mark B assembly are generated in PWR Source Term Generation and Evaluation (Reference 229) and are used in this calculation
624 BampW 15x15 Mark B PWR Fuel Assembly
BampW 15x15 Mark B fuel assembly consists of four regions top end-fitting plenum active fuel and bottom end-fitting The m aterials and ra diation sources of each assem bly region are homogenized inside a volume defined by the region height and the interior diam eter of the TAD canister (Assumption 325) The active fuel region is homogenized with fresh unirradiated fuel (Assumption 324) Since the internal structure (i e basket) design of t he TAD is currently not finalized the com position of the hom ogenized fuel does not include the basket m aterials (Assumption 326) and therefore does not take cred it for any shielding that these m aterials may provide
Table 4 provides the design param eters for the BampW 15x15 Mark B fuel assembly Data provided here are used in Attachment II PWR_fuel compxls worksheet BampWassy
25
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 4 BampW 15x15 Mark B Fuel Assembly Description
Component Material Characteristic Value Specific Reference Array Size 15 x 15
Reference 2227 Table 2-2 Fuel Pins Assembly 208 Guide Tubes Assembly 16 Instrument Tubes Assembly 1
Assembly NA Pin Pellet Diameter 0936244 cm (03686 in) Reference 2220 p 2A-34 Pin Pitch 144272 cm (0568 in)
Reference 2227 Table 2-2 Active Fuel Height 360172 cm (1418 in) Assembly Width 2168144 cm (8536 in)
Reference 2220 p 2A-31 Assembly Height 4206875 cm (165625 in) Mass U assembly 46363 kg
Guide tube Zircaloy-4 Outer Diameter 13462 cm (053 in)
Reference 2227 Table 2-2
Inner Diameter 126492 cm (0498 in)
Instrument tube Zircaloy-4 Outer Diameter 138193 cm (05441 in) Inner Diameter 112014 cm (0441 in)
Cladding` Zircaloy-4 Inner Diameter 095758 cm (0377 in) Outer Diameter 10922 cm (043 in)
Plenum region NA Length 297688 cm (11720 in) Reference 2220 p 2A-34 Top nozzle SS CF3M MassAssembly (Top) 748 kg
Reference 2220 p 2A-32
Bottom nozzle SS CF3M MassAssembly (Bottom) 816 kg Guide tubes Zircaloy-4 MassAssembly (in Core) 80 kg Instrument tube Zircaloy-4 MassAssembly (in Core) 064 kg Spacer-plenum Inconel-718 MassAssembly (Plenum) 104 kg Spacer-bottom Inconel-718 MassAssembly (Bottom) 13 kg Spacer-in core Inconel-718 MassAssembly (in Core) 49 kg Spring retainer SS CF3M MassAssembly (Top) 091 kg Holddown spring Inconel-718 MassAssembly (Top) 18 kg Upper end plug SS 304 MassAssembly (Top) 006 kg Upper nut SS 304L MassAssembly (Top) 051 kg Lower nut SS 304 MassAssembly (Bottom) 015 kg Grid supports Zircaloy-4 MassAssembly (in Core) 064 kg Plenum spring SS 302 MassAssembly (Plenum) 0042 lb (001905 kg) Reference 2220 p 2A-34
Note Som e d ata i n this tab le ar e given i n British u nits in th e r eferences thes e d ata ar e converted into metric units as the inputs to MCNP5 are in metric units
The assem bly region heights as m odeled in MC NP are presented in Table 5 utilizing values from Table 4 Table 5 is taken from Dose Rate Calculation for Exhaust Main Drifts (Reference 2213 Table 3)
26
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 5 PWR Fuel Assembly Regions
Component Height Reference
Plenum 297688 cm (11720 in) Reference 2220 p 2A-34
Active Fuel 360172 cm (1418 in) Table 3
Bottom End-Fitting 1077 cm (424 in) Calculateda
Top End-Fitting 1998 cm (787 in) Calculatedb
Source Reference 2213 Table 3 aCalculated b ased on data Reference 2227 F igures 2-3 an d 2-7
(Region 9 Height [16723 cm] + Region 10 Height [508 cm] ndash Lo wer Fuel Plenum and End Cap [11033 cm])
bCalculated (Assembly Length ndash Active Fuel Length ndash P lenum Length ndash Bottom End-fitting Length)
625 Material Compositions
The TAD transportation cask com ponent m aterial specifications are defined in Table 1 The TAD canister is constructed of SS 316 (Assumpti on 321) The PWR fuel assembly materials used to homogenize the fuel regions are defined in Table 4 Table 6 c ontains the m aterial compositions defining the TAD canister WP and fuel assemblies
27
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 6 Chemical Compositions of Materials
Material Density (gcc)
Isotopic Weight Percent Reference
SS 302 NA
C 0150 Mn 2000 P 0045 S 0030 Si 0750 Cr 18000 Ni 9000 N 0100 Fe 69925
Attachment II PWR_fuel compxls worksheet ferrous Reference 222 SEC II A SA-240 Table 1 for SS 302 SS 304 and SS 304L Reference 222 SEC II A SA-351SA -351M Table 2 for SS CF3M
SS 304 NA
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 9250 N 0100 Fe 68745
SS 304L NA
C 003 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 10000 N 0100 Fe 6804 5
SS CF3M NA
C 0030 Mn 1500 P 0040 S 0040 Si 1500 Cr 19000 Ni 11000 Mo 2500 Fe 64390
Inconel 718 NA
C 0080 Mn 0350 Si 0350 Cr 19000 Ni 52500 Co 1000 Mo 3050 Fe 16809 Nb 5125 Ti 0900 Al 0500 Cu 0300 S 0015 P 0015 B 0006
Attachment II PWR_fuel compxls worksheet alloys aReference 223 p 666 Table 6 Reference 222 SEC II B SB-637 Table 1 for Inconel 718 Reference 224 Table 2 for Zircaloy 4
Zircaloy 4 656a Cr 0100 Fe 0210 O 0125 Sn 1450 Zr 98115
SS 316 798b
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 17000 Ni 12000 Mo 2500 N 0100 Fe 65495
Attachment II PWR_fuel compxls worksheet others Reference 222 SEC II A SA-240 Table 1 for SS 316 bReference 225 Table X1
626 Homogenization Assembly Materials
The atom density of an element or isotope in atomsbmiddotcm in a homogenized region is calculated according to the following equation (Reference 2223 Appendix B)
M i times N AvogadroNi = Equation 1 Ai timesV times K
where Ni = Atom density of elementisotope i (atomsbmiddotcm) Mi = Mass of elementisotope i (g) NAvogadro = Avogadrorsquos constant 06022 x 1024 (atomsmole)
28
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Ai = Atomic weight of elementisotope i (gmole) V = Homogenization volume (cm3) K = Unit transformation constant = 1024 (bmiddotcmcm3)
Equation 1 is used in A ttachment II spreadsheet PWR_fuel compxls worksheet BampWassy to calculate th e atom dens ities for v arious elem ents and iso topes The m ass of elementsisotop es and Avogadrorsquos constant are provided in Reference 2226
Table 7 lists the com position of the hom ogenized assem bly regions (active fuel plenum top end-fitting and bottom end-fitting) for the PWR assembly The active fuel region contains fresh unirradiated fuel (Assumption 324) Since the internal structure (ie basket) design of the TAD is currently not finalized the composition of either homogenized fuel does not include the basket materials and therefore does not tak e credit for any shielding that thes e materials may provide (Assumption 326)
Table 7 Isotopic Compositions of Homogenized PWR Assembly Regions
Element Isotope
Atom Densities for Homogenized Regions (atomsbsdotcm)
Active Fuel Bottom End-Fitting Plenum Top End-Fitting
10B 861E-09 764E-08 221E-08 570E-08 11B 347E-08 307E-07 890E-08 230E-07 C 519E-07 160E-05 138E-06 993E-06 N -- 570E-07 262E-08 117E-06 O 621E-03 -- 142E-05 -- Al 144E-06 128E-05 371E-06 957E-06 Si 971E-07 243E-04 259E-06 139E-04 P 377E-08 606E-06 102E-07 360E-06 S 365E-08 581E-06 971E-08 340E-06 Ti 147E-06 130E-05 376E-06 971E-06 Cr 320E-05 187E-03 779E-05 113E-03 Mn 497E-07 126E-04 141E-06 749E-05 Fe 303E-05 531E-03 717E-05 313E-03 Co 132E-06 117E-05 340E-06 876E-06 Ni 697E-05 144E-03 180E-04 940E-04 Cu 368E-07 327E-06 945E-07 244E-06 Zr 196E-03 -- 195E-03 -- Nb 430E-06 382E-05 110E-05 285E-05 Mo 248E-06 135E-04 636E-06 791E-05 Sn 223E-05 -- 222E-05 -- 234U 139E-06 -- -- -- 235U 157E-04 -- -- -- 236U 719E-07 -- -- -- 238U 294E-03 -- -- -- Total 114E-02 924E-03 235E-03 557E-03
Source Attachment II spreadsheet PWR_fuel compxls worksheet BampWassy
29
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
The isotopic composition of commercially available 235U enriched uranium is determined by the given initial 235U enrichment using the following equations (Reference 226 p 20)
wt235U =235Uenrichment _ of _ the _ associated _ fuel _ batch Equation 2
wt234U = 0007731times (wt235U )10837 Equation 3
wt236U = 00046times (wt235U ) Equation 4
wt238U =100 minus (wt234U + wt235U + wt236U ) Equation 5
The weight percentages of uran ium isotopes for PWR fuel are ca lculated in Attachm ent II spreadsheet PWR_fuel compxls worksheet BampWassy using Equations 2 through 5
627 PWR Source Terms
This calculation uses the following three PWR source terms bull Maximum source (50 wt initial 235U enrichment 80 GWdMTU burnup and 5-year
decay time) (Reference 229 Section 55) Table 8 lists th e gamma source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Design Basis source (4 0 wt initial 235U enrichment 60 GW dMTU burnup and 10-year decay tim e) (Reference 228 Section 552) Table 9 lists the gamm a source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Average source ( 40 wt initial 235U enrichment 48 GWdMTU burnup and 25-year decay time) (Reference 229 Section 55) Table 10 lists the gamma source terms for the fuel and non-fuel regions and the neutron source term for the fuel region
These sources (ie maximum design basis and av erage) are described in this section For dose rate calculations all the fuel assemblies in a transportation cask are of the sam e characteristics Also gamma radiation source term s for the PWR assem bly are prov ided for the f our assembly regions while neutron source term is only present in the active fuel region Gamma radiation sources in the non-active fuel region are distri buted unif ormly within each source region Gamma and neutron sources in the active fuel re gion are modeled as uni form distributions or with axial source profiles
The PWR gamma and neutron axial source profiles for the active fuel region presented in Table 11 are applied to the active fuel region of all three source terms (ie maximum design basis and average) when appropriate
30
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 8 Gamma and Neutron Sources for the Maximum PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting
Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 594E+11 233E+15 528E+11 379E+11 100E-01 000E+00 100E-01 116E+11 644E+14 609E+10 743E+10 400E-01 805E+07 200E-01 283E+10 522E+14 352E+10 179E+10 900E-01 411E+08 300E-01 141E+09 148E+14 196E+09 891E+08 140E+00 376E+08 400E-01 190E+09 985E+13 586E+09 117E+09 185E+00 276E+08 600E-01 191E+09 153E+15 110E+11 741E+07 300E+00 485E+08 800E-01 435E+09 470E+15 595E+10 237E+09 643E+00 443E+08 100E+00 137E+11 708E+14 803E+09 766E+10 200E+01 393E+07 133E+00 338E+13 455E+14 174E+13 217E+13 Total 211E+09 166E+00 953E+12 130E+14 491E+12 612E+12
--
200E+00 187E+03 144E+12 919E+02 113E+03 250E+00 226E+08 249E+12 116E+08 145E+08 300E+00 351E+05 110E+11 181E+05 225E+05 400E+00 766E-08 139E+10 100E-08 416E-08 500E+00 000E+00 709E+07 000E+00 000E+00 650E+00 000E+00 286E+07 000E+00 000E+00 800E+00 000E+00 558E+06 000E+00 000E+00 100E+01 000E+00 119E+06 000E+00 000E+00
Total 442E+13 113E+16 231E+13 284E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE2R2B14cut bWasteStreamE2R1B14cut cWasteStreamE2R3B14cut dWasteStreamE2R4B14cut
31
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 9 Gamma and Neutron Sources for the Design Basis PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary
(MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 273E+11 121E+15 188E+11 175E+11 100E-01 000E+00 100E-01 528E+10 329E+14 277E+10 339E+10 400E-01 316E+07 200E-01 128E+10 245E+14 117E+10 819E+09 900E-01 161E+08 300E-01 639E+08 713E+13 633E+08 407E+08 140E+00 148E+08 400E-01 850E+08 455E+13 164E+09 533E+08 185E+00 109E+08 600E-01 492E+08 226E+14 269E+10 337E+07 300E+00 191E+08 800E-01 291E+09 237E+15 160E+10 186E+09 643E+00 174E+08 100E+00 540E+09 122E+14 248E+09 341E+09 200E+01 154E+07 133E+00 154E+13 195E+14 797E+12 990E+12 Total 830E+08 166E+00 435E+12 450E+13 225E+12 280E+12
--
200E+00 235E+00 152E+11 149E+02 215E-02 250E+00 103E+08 517E+10 534E+07 664E+07 300E+00 160E+05 379E+09 829E+04 103E+05 400E+00 943E-10 497E+08 155E-10 519E-10 500E+00 000E+00 282E+07 000E+00 000E+00 650E+00 000E+00 113E+07 000E+00 000E+00 800E+00 000E+00 222E+06 000E+00 000E+00 100E+01 000E+00 471E+05 000E+00 000E+00
Total 201E+13 486E+15 105E+13 129E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B11cut bWasteStreamE5R1B11cut cWasteStreamE5R3B11cut dWasteStreamE5R4B11cut
32
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 10 Gamma and Neutron Sources for the Average PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 336E+10 670E+14 186E+10 217E+10 100E-01 00000E+00 100E-01 602E+09 199E+14 314E+09 387E+09 400E-01 748E+06 200E-01 146E+09 126E+14 853E+08 936E+08 900E-01 382E+07 300E-01 730E+07 389E+13 439E+07 469E+07 140E+00 352E+07 400E-01 947E+07 263E+13 716E+07 607E+07 185E+00 261E+07 600E-01 141E+07 205E+13 504E+08 383E+06 300E+00 469E+07 800E-01 208E+09 124E+15 192E+09 144E+09 643E+00 418E+07 100E+00 208E+09 110E+13 164E+09 144E+09 200E+01 365E+06 133E+00 175E+12 295E+13 909E+11 112E+12 Total 199E+08 166E+00 494E+11 513E+12 257E+11 318E+11
--
200E+00 973E-01 675E+10 614E+01 872E-03 250E+00 117E+07 353E+09 609E+06 754E+06 300E+00 182E+04 288E+08 944E+03 117E+04 400E+00 186E-11 198E+07 149E-11 127E-11 500E+00 000E+00 669E+06 000E+00 000E+00 650E+00 000E+00 269E+06 000E+00 000E+00 800E+00 000E+00 527E+05 000E+00 000E+00 100E+01 000E+00 112E+05 000E+00 000E+00
Total 229E+12 237E+15 119E+12 147E+12
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B9cut bWasteStreamE5R1B9cut cWasteStreamE5R3B9cut dWasteStreamE5R4B9cut
33
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 11 Gamma and Neutron Axial Source Profiles for a PWR Assembly
Axial boundaries (From midplane)
(cm)
TOP BOTTOM
Neutron Gamma Ne utron Gamma 000 1554 1117 1554 1117 1143 1537 1114 1571 1120 2286 1521 1111 1588 1123 3429 1504 1108 1605 1126 4572 1486 1104 1622 1129 5715 1464 1100 1636 1131 6858 1438 1095 1648 1133 8001 1401 1088 1657 1135 9144 1350 1078 1654 1134
10287 1277 1063 1625 1129 11430 1165 1039 1554 1117 12573 0998 09995 1414 1091 13716 0769 09365 1172 1041 14859 0492 08375 0816 0951 16002 0220 06850 0402 0797 17145 0046 04625 0092 0551 18288 00 00 00 00
Source Reference 2219 Table S445
34
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
63 MCNP SPECIFIC INPUT
631 Source Probability
A linear radial distribution is used for all gamma and neutron sources The linear radial distribution is sam pled usi ng the built-in power function p(x) = xc a with a = 1 for the radial direction This sampling method results in a uniform source distribution over the area bounded by the outer radius of the source
The source axial distributions are unifor m for all four source regions The a xial uni form xp(x) = c distribution is sampled using the built-in power function a with a = 0 for extent
The energy distribu tions of the gamma and neutron sour ce term s are treated as energ y probabilities and are applied in MCNP5 using SISP cards
632 Dose Rate and Flux Tallies
MCNP5 dose rate calculations feature separate runs for the following calculation types
bull a photon transport calculation for prim ary ga mma contribution to the dose rates fr om photon fluxes
bull a coupled neutronphoton transport calculat ion for neutrons a nd secondary gamma (photons generated by neutron be ing captured) contributions to dose rates from neutron and gamma fluxes
The tally type F2 is us ed in th is d esign ca lculation as f lux estim ators The type F2 tally evaluates the flux averaged over a surface in particlescm2s
To generate dose ra tes in te rms of remhr the FM (tally multiplier ) and DEDF (dose energydose conversion factors) cards are used to en ter the tally multiplier f actor (source intensity in particless) energy boundaries in MeV and corresponding dose conversion factors in (remhr)(particlescm2s) respectively These factors were used in the input files
In order for the F2 tally to accum ulate flux ov er a surface a specific s urface area is requ ired The SD cards are used to enter a surface area in cm2 over which the flux will be tallied for an F2 tally
633 Variance Reduction Techniques
Variance reduction technique is usually em ployed in order to increase the efficiency of a calculation and obtain statistically m eaningful results within re asonable com puter tim e In Monte Carlo calculations when variance reduction scheme is employed the weights of particles are adjusted in order to account for the biasing and to preserve a fair game
Geometry splitting and Russian roulette techniques described in Reference 2224 (pp 2-140 ndash 2-142) are useful in shielding calculations and therefore deployed in all the MCNP5 runs
35
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
As particles migrate in an important direction (toward the detector) they are increased in number to provide better sampling by means of geometry splitting across geometric boundaries Russian roulette (the reverse process) is played when particles travel in an unimportant direction to allow termination of unim portant histories The IMP card required for every cel l ca rd is us ed to implement this technique
The other variance reduction technique deployed in the MC NP5 runs is source intensity biasing for the gamma sources from the four source regions (active fuel bottom end-fitting plenum and top end-fitting) The natural total gamma source intensity of comm ercial SNF is dom inated by the gamma source in the active fuel region This active fuel gamma source usually accounts for over 95 o f the total g amma source intens ity In order to im prove the efficiency of the axial dose rate calculations a biased source probability distribution is employed for the prim ary gamma dose rate calculations The biased gamma source probability distribution is chosen to be 005 080 010 and 005 for the bottom end-fitting the active fuel the plenum and the top end-fitting regions respectively
64 DOSE CONVERSION FACTORS
Project Design Criteria Document (Reference 2211 Se ction 41015) requires the use of flux-to-dose rate conversion fact ors from ANSIANS-611-1977 (Reference 221) for dose rate evaluations Table 16 lists the neutron and ga mma dose conversion factors used in the MCNP5 calculations
Table 12 Gamma and Neutron Flux to Dose Conversion Factors
Gamma Neutron Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
001 396E-06 140 251E-06 250E-08 367E-06 003 582E-07 180 299E-06 100E-07 367E-06 005 290E-07 220 342E-06 100E-06 446E-06 007 258E-07 260 382E-06 100E-05 454E-06 010 283E-07 280 401E-06 100E-04 418E-06 015 379E-07 325 441E-06 100E-03 376E-06 020 501E-07 375 483E-06 100E-02 356E-06 025 631E-07 425 523E-06 100E-01 217E-05 030 759E-07 475 560E-06 500E-01 926E-05 035 878E-07 500 580E-06 100E+00 132E-04 040 985E-07 525 601E-06 250E+00 125E-04 045 108E-06 575 637E-06 500E+00 156E-04 050 117E-06 625 674E-06 700E+00 147E-04 055 127E-06 675 711E-06 100E+01 147E-04 060 136E-06 750 766E-06 140E+01 208E-04 065 144E-06 900 877E-06 200E+01 227E-04 070 152E-06 1100 103E-05 080 168E-06 1300 118E-05 100 198E-06 1500 133E-05
Source Reference 221 Tables 1 and 3
36
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION
By def inition (Ref erence 2224 Equation 219) the estimated st atistic relative error of the i component is
Ri = Si
2
Equation 6Ti
where i = tally component index Ri = relative error of the i component S2
i = variance of the i component Ti = tally i component
For a result (ie dose rate) computed as a sum of different tallies the statistical relative error of the computed value is o btained from the variance of the result - S2
total which is th e sum of the estimated variances of the individual tallies S2
i n
2 2STotal = sum Si Equation 7 i=1
where S2Total = total estimated variance
n = total number of components Therefore the total tally value (dose rate) and the associated relative error are derived according to Equations 8 and 9
n TTotal = sumTi Equation 8
i=1
n n
sum (Ri timesTi )2
2 sum Si 2
STotal = i=1 = i=1 Equation 9RTotal = TTotal TTotal TTotal
where RTotal = total estimated relative error TTotal = total estimated tally
Equations 8 and 9 are utilized in Attachm ent II to ev aluate to tal dos e ra tes and their r elative errors
37
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
7 RESULTS AND CONCLUSIONS
71 RESULTS
The following sections summarize the results of this calculation Section 711 presents results for Conceptual Cask A while Section 712 for Conceptual Cask B Section 713 provides comparisons of the dose-rate reduction factors du e to the two conceptual casks and the axial source distributions in the active fuel region Do se rates and relative errors can be found in Attachment II within the output files and Excel files
711 Dose Rates of Conceptual Cask A
This section presents dose-rate results of the calculation sets 1 and 2 as described in Section 61 for Cask A Set 1 has axial p rofile sources in the active fuel region a nd consist of six runs resulting from the three PWR SNF source term s (maximum design basis and average) and the two radiation sources (gammas and neutrons) Set 2 has uniform axial sources in the active fuel region and consists of six run s r esulting f rom the th ree P WR SNF source term s and th e tw o radiation sources
As described in Section 61 dose ra tes are calculated at the three exterior surfaces (radial top and bottom) and at distances 1 m and 2 m from the exterior surfaces The total dose rates for set 1 are presented in Tables 13 14 and 15 for the ra dial top and bottom dire ctions respectively However the com ponents (primary gamma neutr on and secondary gamma) contributing to the total dose rates as well as the re lative error calculations can be found in Attachment II Excel file MCNP-Results1xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 2 are shown in Tables 16 17 and 18 The dose-rate components and the relative errors can be found in A ttachment II Excel file MCNP-Results2xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 13 and 16 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 14 and 17 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 15 and 18 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carrying th e maximum PWR SNF Based on the results in Tables 13 through 18 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask A indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these 6 tables the d ose-rate red uction f actors between the m aximum and the design basis fuels the maxim um and the averag e fuels and th e design basis and the average fuels are a lso presented
38
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 320E-02 00237 116E-02 00222 262E-03 00219 275 1223 445
1 m 133E-02 00164 494E-03 00171 106E-03 00162 269 1261 468 2 m 749E-03 00198 285E-03 00225 584E-04 00162 263 1282 488
Ring Detectors 1 m 133E-02 00116 492E-03 00115 108E-03 00124 271 1229 454 2 m 756E-03 00118 279E-03 00110 605E-04 00128 271 1250 462
Source Attachment II MCNP-Results1xls worksheet Summary
Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 142E-02 00368 628E-03 00446 934E-04 00483 226 1520 672
1 m 570E-03 00289 263E-03 00426 375E-04 00381 217 1520 701 2 m 265E-03 00364 123E-03 00547 169E-04 00374 216 1575 730
Point Detectors 1 m 598E-03 00238 274E-03 00271 402E-04 00354 219 1489 681 2 m 273E-03 00218 123E-03 00245 180E-04 00336 221 1515 684
Source Attachment II MCNP-Results1xls worksheet Summary
Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 653E-03 00298 265E-03 00276 510E-04 00341 247 1278 518
1 m 276E-03 00238 112E-03 00208 207E-04 00249 248 1334 539 2 m 125E-03 00185 508E-04 00199 933E-05 00246 246 1336 544
Point Detectors 1 m 291E-03 00227 118E-03 00203 218E-04 00242 247 1335 540 2 m 130E-03 00209 524E-04 00187 955E-05 00233 247 1357 549
Source Attachment II MCNP-Results1xls worksheet Summary
Tables 13 14 and 15 are results of calculation set 1 for conceptual Cask A with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
39
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 265E-02 00247 990E-03 00222 215E-03 00278 268 1234 461
1 m 116E-02 00178 468E-03 00549 960E-04 00189 248 1208 488 2 m 713E-03 00273 265E-03 00161 602E-04 00360 269 1184 439
Ring Detectors 1 m 117E-02 00120 454E-03 00132 979E-04 00141 259 1199 463 2 m 722E-03 00130 276E-03 00141 589E-04 00153 261 1226 469
Source Attachment II MCNP-Results2xls worksheet Summary
Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 199E-02 00461 827E-03 00455 147E-03 00536 241 1359 564
1 m 849E-03 00564 323E-03 00314 563E-04 00418 263 1507 574 2 m 415E-03 00832 158E-03 00603 253E-04 00501 263 1641 623
Point Detectors 1 m 877E-03 00348 353E-03 00275 615E-04 00391 248 1426 574 2 m 393E-03 00341 160E-03 00278 270E-04 00378 246 1454 590
Source Attachment II MCNP-Results2xls worksheet Summary
Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 879E-03 00374 356E-03 00333 669E-04 00406 247 1315 533
1 m 365E-03 00223 147E-03 00209 269E-04 00253 248 1358 548 2 m 164E-03 00229 674E-04 00205 120E-04 00248 243 1364 560
Point Detectors 1 m 383E-03 00217 155E-03 00204 285E-04 00248 247 1347 546 2 m 172E-03 00197 689E-04 00186 124E-04 00225 249 1391 558
Source Attachment II MCNP-Results2xls worksheet Summary
Tables 16 17 and 18 ar e results of calculation set 2 for conceptual Cask A with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
40
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
2 REFERENCES
21 PROJECT PROCEDURESDIRECTIVES
211 IT-PRO-0011 Rev 0010 Software Management Las Vegas Nevada Bechtel SAIC Company
212 EG-PRO-3DP-G04B-00037 Rev 14 Calculations and Analyses Las Vegas Nevada Bechtel SAIC Company
213 IT-PRO-0012 Rev 007 Qualification of Software Las Vegas Nevada Bechtel SAIC Company
22 DESIGN INPUTS
221 ANSIANS-611-1977 Neutron and Gamma-Ray Flux-to-Dose-Rate Factors La Grange Park Illinois American Nuclear Society TIC 239401
222 ASME (American Society of Mechanical Engineers) 2004 2004 ASME Boiler and Pressure Vessel Code 2004 Edition New York New York American Society of Mechanical Engineers TIC 256479 ISBN 0-7918-2899-9
223 ASM International 1990 Properties and Selection Nonferrous Alloys and Special-Purpose Materials Specific Metals and Alloys Volume 2 of Metals Handbook 10th Edition Page 666 [Materials Park Ohio] American Society for Metals TIC 239807
224 ASTM (American Society for Testing and Materials) B 811-90 1991 Standard Specification for Wrought Zirconium Alloy Seamless Tubes for Nuclear Reactor Fuel Cladding Philadelphia Pennsylvania American Society for Testing and Materials TIC 239780
225 ASTM G 1-90 (Reapproved 1999) 1999 Standard Practice for Preparing Cleaning and Evaluating Corrosion Test Specimens West Conshohocken Pennsylvania American Society for Testing and Materials TIC 238771
226 Bowman SM Hermann OW and Brady MC 1995 Sequoyah Unit 2 Cycle 3 Volume 2 of Scale-4 Analysis of Pressurized Water Reactor Critical Configurations ORNLTM-12294V2 Oak Ridge Tennessee Oak Ridge National Laboratory TIC 244397 [DIRS 123796]
227 BSC (Bechtel SAIC Company LLC) 2008 Repository ALARA Goal Compliance 000-30R-MGR0-04000-000 REV 000 Las Vegas Nevada Bechtel SAIC Company ACC ENG200802050014 [DIRS 184957]
228 BSC 2002 Subsurface Shielding Source Term Specification Calculation 000-00C-WER0-00100-000-00A Las Vegas Nevada Bechtel SAIC Company ACC MOL200212160076 ENG200508150022
10
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
229 BSC 2004 PWR Source Term Generation and Evaluation 000-00C-MGR0-00100-000-00B Las Vegas Nevada Bechtel SAIC Company ACC ENG200405240007
2210 BSC 2008 Basis of Design for the TAD Canister-Based Repository Design Concept 000-3DR-MGR0-00300-000-003 Las Vegas Nevada Bechtel SAIC Company ACC ENG200810060001
2211 BSC 2007 Project Design Criteria Document 000-3DR-MGR0-00100-000-007 Las Vegas Nevada Bechtel SAIC Company ACC ENG200710160005 ENG200711080001 ENG200712200003 ENG200801070001 ENG200801070002 ENG200801070016 ENG200801070017 ENG200801310006 ENG200803050002 ENG200803050011 ENG200803050012 ENG200803060009 ENG200803130004 ENG200807100001 ENG200811120006 ENG200811140004
2212 BSC 2004 PWR and BWR Source Term Sensitivity Study 000-00C-MGR0-00300-000-00A Las Vegas Nevada Bechtel SAIC Company ACC ENG200401140003 ENG200508150023
2213 BSC 2007 Dose Rate Calculation for Exhaust Main Drifts 800-00C-SS00-00700-000-00B Las Vegas Nevada Bechtel SAIC Company ACC ENG200711050017 ENG200803060001
2214 BSC 2006 Dual Purpose Canister Opening Study 050-30R-WHS0-00600-000-000 Las Vegas Nevada Bechtel SAIC Company ACC ENG200612200023
2215 BSC 2007 GROA Shielding Requirements Calculation 000-00C-MGR0-03300-000-00B Las Vegas Nevada Bechtel SAIC Company ACC ENG200705290037
2216 BSC 2002 Concrete Shielding Calculation for Dry Facility 1 110-00C-CS10-00100-000-00A Las Vegas Nevada Bechtel SAIC Company ACC MOL200301140075
2217 BSC 2003 Shielding Design Calculations for Dry Facility 1 110-00C-CS10-00200-000-00A Las Vegas Nevada Bechtel SAIC Company ACC ENG200306020003
2218 CRWMS MampO 1998 Calculation of the Effect of Source Geometry on the 21-PWR WP Dose Rates BBAC00000-01717-0210-00004 REV 00 Las Vegas Nevada CRWMS MampO ACC MOL199902220059 [DIRS 102134]
2219 CRWMS MampO 2000 Users Manual for SCALE-44A 10129-UM-44A-00 Las Vegas Nevada CRWMS MampO ACC MOL200011300136 MOL200108220084 MOL200108220085 MOL200108220086 MOL200108220087 [DIRS 153872]
2220 DOE (US Department of Energy) 1987 Appendix 2A Physical Descriptions of LWR Fuel Assemblies Volume 3 of Characteristics of Spent Fuel High-Level Waste and Other Radioactive Wastes Which May Require Long-Term Isolation DOERW-0184 Washington DC US Department of Energy Office of Civilian Radioactive Waste Management ACC HQX198804050024 [DIRS 132333]
11
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
2221 DOE 2007 Software Validation Report for MCNP5 v140 Document ID 11199-SVR-140-00-WINXP Las Vegas Nevada US Department of Energy Office of Repository Development ACC MOL200702280252 [DIRS 180516]
2222 DOE 2008 Transportation Aging and Disposal Canister System Performance Specification WMO-TADCS-000001 Rev 1 ICN 1 Washington DC US Department of Energy Office of Civilian Radioactive Waste Management ACC DOC200803310001 [DIRS 185304]
2223 Harmon CD II Busch RD Briesmeister JF and Forster RA 1994 Criticality Calculations with MCNPtrade A Primer LA-12827-M Los Alamos New Mexico Los Alamos National Laboratory TIC 234014 [DIRS 154532]
2224 LANL (Los Alamos National Laboratory) 2004 MCNP mdash A General Monte Carlo N-Particle Transport Code Version 5 (Appendix H is not included) LA-UR-03-1987 Volume I Los Alamos [New Mexico] Los Alamos National Laboratory ACC MOL200510240126 [DIRS 176521]
2225 MCNP5 V 140 2007 Windows XP STN 11199-140-00 [DIRS 180515]
2226 Parrington JR Knox HD Breneman SL Baum EM and Feiner F 1996 Nuclides and Isotopes Chart of the Nuclides 15th Edition San Jose California General Electric Company and KAPL Inc TIC 233705 LC Call Number QC7935 N8622 1996
2227 Punatar MK 2001 Summary Report of Commercial Reactor Criticality Data for Crystal River Unit 3 TDR-UDC-NU-000001 REV 02 Las Vegas Nevada Bechtel SAIC Company ACC MOL200107020087 [DIRS 155635]
2228 Sisley SE 2002 Transportation License Application for the FuelSolutionstrade System (TAC No L23311) Submittal of the FuelSolutiontrade Transportation SARs Revision 3 Letter from SE Sisley (BNFL) to the NRC April 11 2002 BFSNRC 02-011 with enclosures TIC 255245 [DIRS 171545]
NOTE Reference 2220 is a direct input but is not QA QA It is justified as acceptable for the intended use as it is directly from the DOE and is considered the best available data on the subject The referenced values cited in Tables 3 and 4 are valid for use since they are reliable and reasonable based on engineering judgment
23 DESIGN CONSTRAINTS
231 10 CFR 71 2008 Energy Packaging and Transportation of Radioactive Material Internet Accessible [DIRS 185678]
12
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
24 DESIGN OUTPUTS
The resu lts of this calculation will be us ed to substan tiate th e dose reduc tion f actor in the Repository ALARA Goal Compliance (Reference 227) which is cited as a reference in a PCSA calculation that supports the License Application
13
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
3 ASSUMPTIONS
31 ASSUMPTIONS REQUIRING VERIFICATION
None
32 ASSUMPTIONS NOT REQUIRING VERIFICATION
Assumptions 321 322 and 323 are m odeling assum ptions and do not require further verification The m aterials and dim ensions for the TAD canister and for the conceptu al transportation casks are only selected to charac terize two tr ansportation casks th at m eet 10 CFR7147 (Reference 231) dose rates when lo aded with the ldquom aximumrdquo and ldquoaveragerdquo pressurized water re actor (PW R) assem blies re spectively There is n o need to v erify those dimensions or m aterials at a later date The ca lculated results in Sect ion 711 verify that the conceptual casks would meet 10 CFR 7147 (Reference 231) dose rates
321 Material and Wall Thickness of TAD Canister
Assumption It is assumed that the TAD canister is made of stainless steel 316 (SS 316) and has a wall thickness of 025 in for the radial and bottom shells
Rationale Currently the design of the TAD canis ter d oes not ex ist Based on a survey of existing m ultipurpose a nd dual purpose caniste rs (DPC) (Ref erence 2214 p 56) a 025 in thickness is below the wall thick ness of any existing c anisters For the purp ose of this calculation this assumption leads to higher and conservative external dose rates Since SS 316 is the sam e material used for the waste pack age inner shell it is a l ogical cho ice f or the TAD canister
Although Reference 2214 is an engineering study with a QA N A status it is used here as an indirect input to support the assumption which is conservative for dose rate calculations
Usage This assumption is used in Sections 621 and 625
322 Material and Thickness of TAD Shield Plug
Assumption It is assu med that the TAD shield plug is made of SS 316 and has a thickness of 11 in
Rationale Currently the design of the TAD canister doe s not exist A thick shield plug of 11 in (Reference 2215 Table 12) is needed to keep the m aximum contact dose rate of the top surface below 1000 mrem hr (Reference 2222 Section 314) Since SS 316 is the sam e material used for the waste package inner shell it is a logical choice for the TAD shield plug
Usage This assumption is used in Section 621
14
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
323 Geometry and Materials of Conceptual TAD Transportation Casks
Assumption Two conceptual TAD transpo rtation casks designated as Cask A and Cask B are assumed to have a cylindrical geom etry and m aterials specified in Tab les 1 and 2 respectively The casks are basically construc ted of an inner layer of SS 316 for ga mma shielding a m iddle layer of 5-borated polyethylen e for neutron shielding and a th in outer layer of SS 316 whic h serves a structural function as well as shielding secondary gamma rays
Both Cask A and Cask B have a cavity height of 53785 cm (21175 in) and a cavity diameter of 16891 cm (6650 in) However Cask A has a total height of 610845 cm (24049 in) and an outside diameter of 26797 cm (10550 in) while the total height and outside diameter of Cask B are 58885 cm (23183 in) and 24765 cm (9750) respectively
Cask A will provide shielding to m eet the exterior radiat ion standards of 10 C FR 7147(b) (Reference 231) when loaded w ith a TAD canister carrying th e maximum PWR spent nuclear fuel (SNF) Cask B will satisf y the same radiation standards when loade d with a TAD caniste r carrying the average PWR SNF
Table 1 Geometry and Materials of Conceptual TAD Transportation Cask A
Component Dimension
Material (cm) (in)
Total Height 61085 2404 9 NA
Outside Diameter 26797 1055 0 NA
Cask Cavity Height 53785 2117 5 NA
Cask Cavity Diameter (Radius) 16891 (8446) 6650 (3325) NA
Radial Gamma Shield Thickness (Radius)a 3302 (11748)a 1300 (4625)a SS 316
Radial Neutron Shield Thickness (Radius)b 1524 (13272)b 600 (5225)b 5-borated polyethylene
Radial Outer Shell Thickness (Radius)c 127 (13399)c 050 (5275)c SS 316
Top Gamma Shield Thickness (Axial Position)d 600 (54385)d 236 (21411)d SS 316
Top Neutron Shield Thickness (Axial Position)d 1000 (55385)d 394 (21805)d 5-borated polyethylene
Top Outer Shell Thickness (Axial Position)d 200 (55585)d 079 (21884)d SS 316
Bottom Gamma Shield Thickness (Axial Position)d 35365 (-360)d 1392 (-1417)d SS 316
Bottom Neutron Shield Thickness (Axial Position)d 15 (-510)d 591 (-2008)d 5-borated polyethylene
Bottom Outer Shell Thickness (Axial Position)d 4 (-550)d 157 (-2165)d SS 316 a11748 = 3302 + 8446 and 4625 = 1300 + 3325 b13272 = 1524 + 11748 and 5225 = 600 + 4625 c13399 = 127 + 13272 and 5275 = 050 + 5225 dCoordinate relative to the bottom of the fuel assembly as modeled in MCNP5
15
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 2 Geometry and Materials of Conceptual TAD Transportation Cask B
Component Dimension
Material (cm) (in)
Total Height 58885 2318 3 NA
Outside Diameter 24765 9750 NA
Cask Cavity Height 53785 2117 5 NA
Cask Cavity Diameter (Radius) 16891 (8446) 6650 (3325) NA
Radial Gamma Shield Thickness (Radius)a 254 (10986)a 1000 (4325)a SS 316
Radial Neutron Shield Thickness (Radius)b 127 (12256)b 500 (4825)b 5-borated polyethylene
Radial Outer Shell Thickness (Radius)c 127 (12383)c 050 (4875)c SS 316
Top Gamma Shield Thickness (Axial Position)d 8 (54585)d 315 (21490)d SS 316
Top Neutron Shield Thickness (Axial Position)d None Non e NA
Top Outer Shell Thickness (Axial Position)d None Non e NA
Bottom Gamma Shield Thickness (Axial Position)d 3837 (-390)d 1510 (-1535)d SS 316
Bottom Neutron Shield Thickness (Axial Position)d 300 (-420)d 118 (-1654)d 5-borated polyethylene
Bottom Outer Shell Thickness (Axial Position)d 100 (-430)d 039 (-1693)d SS 316 a10986 = 254 + 8446 and 4325 = 1000 + 3325 b12256= 127 + 10986 and 4825 = 500+ 4325 c12383 = 127 + 12256 and 4875 = 050 + 4825 dCoordinate relative to the bottom of the fuel assembly as modeled in MCNP5
Rationale Currently a design for the TAD transporta tion cask does not exist The casks assumed for this calculation are so lely for estim ation of the dose reduction due to different source terms This is a conceptual repres entation only used in this calculation to estim ate the parameters of interest
Usage This assumption is used in Sections 61 and 622
324 Usage of Unirradiated Fuel for Commercial SNF
Assumption It is assumed that the active fuel region of the commercial SNF assembly contains the same isotopic concentrations as the fresh uni rradiated fuel and that the concentrations of fresh fuel with 5 initial enrichm ent corresp onding to m aximum SNF are used for all other SNFs
Rationale This assumption is a standard practice for shielding calculations throughout the industry accepted by the U S Nucle ar Regulatory Commission (NRC) (Reference 2228 Table 53-5) It sh ould be noted that this assumption applies to material composition only it does no t apply to source terms which are based on the characteristics of spent fuel
Usage This assumption is used in Sections 624 and 626
325 Homogenization of Radiation Source Regions
Assumption It is assu med that a commercial SNF assembly consis ts of four distinct reg ions (active fuel bottom end-fitting plenum and top end-fitting) The materials and radiation sources
16
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
of each assembly region are homogenized inside a volume defined by the TAD cavity radius and region height
Rationale The assembly representation is consistent with the industry practice for shielding calculations accepted by NRC (Reference 2228 Figure 53-6) The effec t of source homogenization is twofold (1) it d ecreases th e m ass de nsity of the source region and (2) it places source points slightly closer to detector locations thus reducing radiation attenuation The resu lts of Calculation of the Effect of Source Geometry on the 21-PWR WP Dose Rates (Reference 2218 pp 22-26) indicate that th e effect of assem bly homogenization gives nearly the same or conservative dose rates as the explicit fuel assembly model
Usage This assumption is used in Section 624
326 Ignoring Internal Fuel Basket Materials
Assumption It is assumed that the internal fuel basket materials are ignored
Rationale Inclusion of fuel basket m aterials in the smeared m aterial com position would increase the overall density and consequently increase the attenuati on of the radiation Therefore this assumption is conservative
Usage This assumption is used in Sections 621 624 and 626
17
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
4 METHODOLOGY
41 QUALITY ASSURANCE
This calculation was prepared in accordance with EG-PRO-3DP-G04B-00037 Calculations and Analyses (Reference 212) The results of th is calculation provides worker dose assessm ent adjustments and this will id entify radio logical hazards f or f acilities im portant to saf ety Therefore the approved version is designated as QA QA
42 USE OF COMPUTER SOFTWARE
421 Baseline Software
The Monte Carlo N-Particle com puter pr ogram (MCNP5) version 140 (Reference 2225) is used to calculate the dose rates (neutron pr imary gamm a and secondary gamm a) at various locations around a transportation cask and an aging overpack
The software specifications are as follows
bull Program Name MCNP5 bull VersionRevision Number Version 140 bull Operating Systems Windows XP bull Software Tracking Number 11199-140-00 bull Computer Type Dell OPTIPLEX GX620
MCNP5 which is Level 1 software is (a) appropriate for three-dim ensional neutron gamma and coupled neutrongamma shielding calculations (b) used within th e range of validation as documented in Software Validation Report for MCNP5 v140 (Reference 2221) and (c) obtained from Software C onfiguration Managem ent and qualified in accordance with procedure IT-PRO-0012 Qualification of Software (Reference 213) Therefore MCNP5 code is suitable for use in this design calculation All MCNP5 input and output files docum ented in this calculation are provided on a compact disc (CD) as Attachment II
All MCNP cases are executed on one of the following Q com puters QNW -004184 QNW -004187 QNW-004194 and QNW-004196 as shown in the output files
422 Commercial off the Shelf Software
The Excel sof tware is used to c alculate var ious inpu t values (i e atom densities weight percentages geometrical dimensions normalized source spectra and probabilities etc) Standard functions of Excel are also used in this desi gn calculation to display results (ie gamma and neutron dose rates) in tabular and graphic forms and to perform relative error calculations
The software specifications are as follows
bull Program Name Excel bull VersionRevision Number Microsoftreg Excel 2003
18
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
bull This software is installed on a persona l com puter running Microsoft W indows XP (central processing unit number 151834)
The user defined for mulas inputs results and gr aphical representations have been verified by hand calculations or visual inspection and are documented in sufficient detail to allow an independent repetition of the com putations Calculations were verifi ed by hand and graphical representations were found accurate by visual inspection
Per Software Management Microsoftreg Excel is not requir ed to be qualif ied due to its commercial availability status (Reference 211 Attachment 4 p 55 bullet 2)
43 CALCULATION APPROACH
This calculation em ploys the qualified so ftware MCNP5 version 140 (Reference 2225) a three-dimensional Monte Carlo code for pe rforming neutron and coupled neutron-gamm a calculations to estim ate dose rates at sele cted locations on and surrounding a conceptual transportation cask containing a loaded TAD canister
431 MCNP5 Program
MCNP5 a general Monte Carlo part icle transport code sim ulates particle transport through a three-dimensional representation of the nuclear system being analyzed During the random walk of particles through the system described by the geom etry the c ode collects inform ation about various events (su rface cross ing collis ions trac k leng th etc) and es timates fluxes in various geometric configurations specified as tallies by the user It also estimates the statistical precision of the results in the form of relative errors (Reference 2224 pp 1-2 to 1-8)
Per Project Design Criteria Document (Reference 2211 Section 41015) the flux estim ates are converted to dose rates using the Am erican Nuclear Society (ANS) flux-to-dose rate conversion factors for gammas and neutrons (R eference 221) The simple variance reduction techniques of Geometry SplittingRussian Roulette and source probability biasing (Sections 631 and 633) are used to enhance computational efficiency
19
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
5 LIST OF ATTACHMENTS
Number of Pages Attachment I List of Electronic Files on the CD 3 Attachment II Compact Disc NA
20
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
6 CALCULATIONS
This sectio n provides inform ation necess ary to perform the calcu lations in this docum ent Section 61 describes the configurations the type of CSNF to be analyzed the number of MCNP runs and the locations where dose rates are ca lculated Section 62 provides the calculation input that includes the details of the geom etry m odel radiation source term s and m aterial compositions Input specific to MCNP dose -rate conversion factors and relative error calculation are described in the later sections
61 DESCRIPTION OF CALCULATIONS
Dose rate calculations are perform ed with the MCNP5 version 140 com puter code (Reference 2225) Two conceptual transportation casks Cask A and Cask B (Assum ption 323) are employed Each cask contains a TAD canister that is loaded with 21 ident ical PW R SN F assemblies Three PWR source term s are analy zed they are the source term s corresponding to the maximum design basis and average PW R SN Fs The characteris tics of the P WR source terms are presented in S ection 627 Each PWR source term has neutron and ga mma radiation sources that require separate MCNP5 runs For each radiation source an axial profile source and a uniform source for the active fuel region are considered The uniform source for the active fuel region is included in this calculation because this approach was used in combination with source peaking factors in certain calculations (Reference 2216 Sections 37 and 39 and Reference 2217 Section 5242)
The total number of MCNP5 runs is 24 which re sults from a com bination of two conceptual casks three PWR source terms two radiation sources and two axia l source distributions for the active fuel region These 24 runs are categorized into four calcula tion sets Each calculation set consists of six runs that is a combination of three PWR source te rms and two radiation sources The characteristics of each calculation set are as follows
1 Cask A with axial profile sources in the active fuel region
2 Cask A with uniform axial sources in the active fuel region
3 Cask B with axial profile sources in the active fuel region
4 Cask B with uniform axial sources in the active fuel region
For each MCNP5 run dose rates are calculated at the exte rior surfaces and at distances 1 and 2 meters from the exterior surfaces Surface tallies and detector tallies (ring and point detectors) as indicated in Figure 1 are e mployed in all runs Figure 1 is used to illustrate the dep loyment of the surface and detector tallies re lative to the so urce regions and it should not be interpreted as an exact geometry of any particular run Surface tallies are deployed at all three distances while ring and point detectors are used only at 1 m and 2 m and not at the cask surfaces Using point detectors near a surface or in any scattering media is not recommended because very large scores can occur f rom collisions close ( less than a f ew centimeters) to the point detecto rs that can lead to resu lts with high r elative e rrors thus m aking the ca lculation d ifficult to o btain r eliable answers
21
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
For the radial direction surface tallies at the three distances (contact 1 m and 2 m) are computed for three su rface segments (cylindrical rings) between the planes at Z = 145 175 2 05 and 235 cm The geometric locations of the segments are shown in Figure 1 The axial locations of these segments correspond to the m iddle of the active fuel region of the PWR SNF assemblies The average dose rates for each of the segm ents are calculated for the outside surface and surfaces at 1 m and 2 m from the cask surface Two ring detectors (instead of point detectors) are deployed at 1 m and 2 m for the radial dire ction Ring detectors instead of point detectors are used in order to capitalize on the symm etry around the cask axis thus im proving the efficiency of the calculations
In the axial direction the average d ose rates within three concentric radial surfaces defined by radii of 40 80 and 120 cm (shown in Figure 1) are calculated for the top and bottom surfaces and at distances 1 m and 2 m from these surfaces Finally point detectors at 1 m and 2 m from the top and bottom axial surfaces are employed
22
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Point Detector at 2 m x
Ring Ring Detector Detector at 2 m at 1 m
x x
Z = 00 cm
Z = 145 cm
Z = 175 cm
Z = 205 cm
Z = 235 cm
R = 80 cm
R = 120 cm
R = 40 cm
Active Fuel
Shield Plug
Top End-Fitting Plenum
Bottom End-Fitting
Ring Detector at 1 m
x
Point Detector at 1 m x
Ring Detector
at 2 m x
D = 26797 cm
H =
610
845
cm
Point Detector at 1 m x
Point Detector at 2 m x
Figure 1 Geometry and Tally Scheme for the TAD Transportation Cask
23
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
62 CALCULATION INPUT
Technical product input and sources of the input used in the deve lopment of this calculation are documented in this section Tables in this docum ent and in th e associated Microsoftreg Excel spreadsheets referenced m ay present num erical values with m any significant figures these values are not to be considered as high precision values since the significant figures are results of calculated values andor unit conversions
621 TAD Canister
The TAD canis ter will contain either 21 P WR or 44 BW R (boiling water reactor) SNF assemblies (Reference 2222 Section 321) While the canister design is iden tical for both PWR and BWR SNF assemblies the internal basket structure is different depending on the SNF assemblies However the internal basket stru cture m aterial is no t in cluded in the calcu lation model (Assumption 326)
The TAD canister is a right-circu lar cylinder with a diam eter of 665 in and a height between 186 and 212 in (Reference 2222 Section 321) The average and maximum total dose rates on the top surf ace of a loaded TAD ca nister must not exceed 800 and 1000 m remhr respectively (Reference 2222 Section 314) The TAD canister used in this calculation is m ade of SS 316 with a radial wall and bottom thickness of 025 in (Assumption 321) The top of the canister has a shield plug that is 11 in thick SS 316 (Ass umption 322) A thick shield plug is needed to keep the maxim um contact dose rate of th e top surface below 1000 m remhr The overall dimensions of the TAD canister are provided in Table 3
Table 3 Dimensions of TAD Canister
Component Dimension
(in) (cm)
Maximum heighta 212 53848
Outer diametera 665 16891
Thickness of bottom lidb 025 0635
Shell thicknessb 025 0635
Lifting Featurec 6 1524
Height without Lifting Feature 206 52324
Thickness of shield plugd 110 2794
aReference 2222 Section 311 bAssumption 321 cReference 2222 p Attachment C-1 dAssumption 322
622 Conceptual TAD Transportation Casks
Two conceptual TAD transportation casks designa ted as Cask A and Cask B are em ployed in this calculation (Assumption 323) They both have a cylindrical geometry with dimensions and materials specified in Tables 1 and 2 of Section 323 Cask A will provide shielding to meet the exterior radiation standards of 10 CFR 7147(b) (Reference 231) when loaded with a TAD
24
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
canister car rying the m aximum PWR SNF Cask B will s atisfy th e sa me radiatio n standa rds when loaded with a TAD canister c arrying the average PWR SNF The reason to analyze both Casks A and B is to cover a broad range of characteristics of the CSNF
The cavity dimensions of the conceptual cask s are 53785 cm (21175 in) in height and 16891 cm (665 in) in diam eter (Tab les 1 and 2) This cav ity will accommoda te the TAD canister described in Table 3 without the lifting feature This is the geometry model used in the MCNP5 calculations
623 Fuel Assembly Selection
PWR and BWR Source Term Sensitivity Study (Reference 2211 Tables 71 through 84) shows that the source terms generated for the Bamp W 15x15 Mark B fuel assembly with 475 kg uranium loading bound the source terms of other PWR assembly types ther efore this assembly type is selected as the representative PWR fuel assembly The gamma and neutron source terms for the BampW 15x15 Mark B assembly are generated in PWR Source Term Generation and Evaluation (Reference 229) and are used in this calculation
624 BampW 15x15 Mark B PWR Fuel Assembly
BampW 15x15 Mark B fuel assembly consists of four regions top end-fitting plenum active fuel and bottom end-fitting The m aterials and ra diation sources of each assem bly region are homogenized inside a volume defined by the region height and the interior diam eter of the TAD canister (Assumption 325) The active fuel region is homogenized with fresh unirradiated fuel (Assumption 324) Since the internal structure (i e basket) design of t he TAD is currently not finalized the com position of the hom ogenized fuel does not include the basket m aterials (Assumption 326) and therefore does not take cred it for any shielding that these m aterials may provide
Table 4 provides the design param eters for the BampW 15x15 Mark B fuel assembly Data provided here are used in Attachment II PWR_fuel compxls worksheet BampWassy
25
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 4 BampW 15x15 Mark B Fuel Assembly Description
Component Material Characteristic Value Specific Reference Array Size 15 x 15
Reference 2227 Table 2-2 Fuel Pins Assembly 208 Guide Tubes Assembly 16 Instrument Tubes Assembly 1
Assembly NA Pin Pellet Diameter 0936244 cm (03686 in) Reference 2220 p 2A-34 Pin Pitch 144272 cm (0568 in)
Reference 2227 Table 2-2 Active Fuel Height 360172 cm (1418 in) Assembly Width 2168144 cm (8536 in)
Reference 2220 p 2A-31 Assembly Height 4206875 cm (165625 in) Mass U assembly 46363 kg
Guide tube Zircaloy-4 Outer Diameter 13462 cm (053 in)
Reference 2227 Table 2-2
Inner Diameter 126492 cm (0498 in)
Instrument tube Zircaloy-4 Outer Diameter 138193 cm (05441 in) Inner Diameter 112014 cm (0441 in)
Cladding` Zircaloy-4 Inner Diameter 095758 cm (0377 in) Outer Diameter 10922 cm (043 in)
Plenum region NA Length 297688 cm (11720 in) Reference 2220 p 2A-34 Top nozzle SS CF3M MassAssembly (Top) 748 kg
Reference 2220 p 2A-32
Bottom nozzle SS CF3M MassAssembly (Bottom) 816 kg Guide tubes Zircaloy-4 MassAssembly (in Core) 80 kg Instrument tube Zircaloy-4 MassAssembly (in Core) 064 kg Spacer-plenum Inconel-718 MassAssembly (Plenum) 104 kg Spacer-bottom Inconel-718 MassAssembly (Bottom) 13 kg Spacer-in core Inconel-718 MassAssembly (in Core) 49 kg Spring retainer SS CF3M MassAssembly (Top) 091 kg Holddown spring Inconel-718 MassAssembly (Top) 18 kg Upper end plug SS 304 MassAssembly (Top) 006 kg Upper nut SS 304L MassAssembly (Top) 051 kg Lower nut SS 304 MassAssembly (Bottom) 015 kg Grid supports Zircaloy-4 MassAssembly (in Core) 064 kg Plenum spring SS 302 MassAssembly (Plenum) 0042 lb (001905 kg) Reference 2220 p 2A-34
Note Som e d ata i n this tab le ar e given i n British u nits in th e r eferences thes e d ata ar e converted into metric units as the inputs to MCNP5 are in metric units
The assem bly region heights as m odeled in MC NP are presented in Table 5 utilizing values from Table 4 Table 5 is taken from Dose Rate Calculation for Exhaust Main Drifts (Reference 2213 Table 3)
26
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 5 PWR Fuel Assembly Regions
Component Height Reference
Plenum 297688 cm (11720 in) Reference 2220 p 2A-34
Active Fuel 360172 cm (1418 in) Table 3
Bottom End-Fitting 1077 cm (424 in) Calculateda
Top End-Fitting 1998 cm (787 in) Calculatedb
Source Reference 2213 Table 3 aCalculated b ased on data Reference 2227 F igures 2-3 an d 2-7
(Region 9 Height [16723 cm] + Region 10 Height [508 cm] ndash Lo wer Fuel Plenum and End Cap [11033 cm])
bCalculated (Assembly Length ndash Active Fuel Length ndash P lenum Length ndash Bottom End-fitting Length)
625 Material Compositions
The TAD transportation cask com ponent m aterial specifications are defined in Table 1 The TAD canister is constructed of SS 316 (Assumpti on 321) The PWR fuel assembly materials used to homogenize the fuel regions are defined in Table 4 Table 6 c ontains the m aterial compositions defining the TAD canister WP and fuel assemblies
27
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 6 Chemical Compositions of Materials
Material Density (gcc)
Isotopic Weight Percent Reference
SS 302 NA
C 0150 Mn 2000 P 0045 S 0030 Si 0750 Cr 18000 Ni 9000 N 0100 Fe 69925
Attachment II PWR_fuel compxls worksheet ferrous Reference 222 SEC II A SA-240 Table 1 for SS 302 SS 304 and SS 304L Reference 222 SEC II A SA-351SA -351M Table 2 for SS CF3M
SS 304 NA
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 9250 N 0100 Fe 68745
SS 304L NA
C 003 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 10000 N 0100 Fe 6804 5
SS CF3M NA
C 0030 Mn 1500 P 0040 S 0040 Si 1500 Cr 19000 Ni 11000 Mo 2500 Fe 64390
Inconel 718 NA
C 0080 Mn 0350 Si 0350 Cr 19000 Ni 52500 Co 1000 Mo 3050 Fe 16809 Nb 5125 Ti 0900 Al 0500 Cu 0300 S 0015 P 0015 B 0006
Attachment II PWR_fuel compxls worksheet alloys aReference 223 p 666 Table 6 Reference 222 SEC II B SB-637 Table 1 for Inconel 718 Reference 224 Table 2 for Zircaloy 4
Zircaloy 4 656a Cr 0100 Fe 0210 O 0125 Sn 1450 Zr 98115
SS 316 798b
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 17000 Ni 12000 Mo 2500 N 0100 Fe 65495
Attachment II PWR_fuel compxls worksheet others Reference 222 SEC II A SA-240 Table 1 for SS 316 bReference 225 Table X1
626 Homogenization Assembly Materials
The atom density of an element or isotope in atomsbmiddotcm in a homogenized region is calculated according to the following equation (Reference 2223 Appendix B)
M i times N AvogadroNi = Equation 1 Ai timesV times K
where Ni = Atom density of elementisotope i (atomsbmiddotcm) Mi = Mass of elementisotope i (g) NAvogadro = Avogadrorsquos constant 06022 x 1024 (atomsmole)
28
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Ai = Atomic weight of elementisotope i (gmole) V = Homogenization volume (cm3) K = Unit transformation constant = 1024 (bmiddotcmcm3)
Equation 1 is used in A ttachment II spreadsheet PWR_fuel compxls worksheet BampWassy to calculate th e atom dens ities for v arious elem ents and iso topes The m ass of elementsisotop es and Avogadrorsquos constant are provided in Reference 2226
Table 7 lists the com position of the hom ogenized assem bly regions (active fuel plenum top end-fitting and bottom end-fitting) for the PWR assembly The active fuel region contains fresh unirradiated fuel (Assumption 324) Since the internal structure (ie basket) design of the TAD is currently not finalized the composition of either homogenized fuel does not include the basket materials and therefore does not tak e credit for any shielding that thes e materials may provide (Assumption 326)
Table 7 Isotopic Compositions of Homogenized PWR Assembly Regions
Element Isotope
Atom Densities for Homogenized Regions (atomsbsdotcm)
Active Fuel Bottom End-Fitting Plenum Top End-Fitting
10B 861E-09 764E-08 221E-08 570E-08 11B 347E-08 307E-07 890E-08 230E-07 C 519E-07 160E-05 138E-06 993E-06 N -- 570E-07 262E-08 117E-06 O 621E-03 -- 142E-05 -- Al 144E-06 128E-05 371E-06 957E-06 Si 971E-07 243E-04 259E-06 139E-04 P 377E-08 606E-06 102E-07 360E-06 S 365E-08 581E-06 971E-08 340E-06 Ti 147E-06 130E-05 376E-06 971E-06 Cr 320E-05 187E-03 779E-05 113E-03 Mn 497E-07 126E-04 141E-06 749E-05 Fe 303E-05 531E-03 717E-05 313E-03 Co 132E-06 117E-05 340E-06 876E-06 Ni 697E-05 144E-03 180E-04 940E-04 Cu 368E-07 327E-06 945E-07 244E-06 Zr 196E-03 -- 195E-03 -- Nb 430E-06 382E-05 110E-05 285E-05 Mo 248E-06 135E-04 636E-06 791E-05 Sn 223E-05 -- 222E-05 -- 234U 139E-06 -- -- -- 235U 157E-04 -- -- -- 236U 719E-07 -- -- -- 238U 294E-03 -- -- -- Total 114E-02 924E-03 235E-03 557E-03
Source Attachment II spreadsheet PWR_fuel compxls worksheet BampWassy
29
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
The isotopic composition of commercially available 235U enriched uranium is determined by the given initial 235U enrichment using the following equations (Reference 226 p 20)
wt235U =235Uenrichment _ of _ the _ associated _ fuel _ batch Equation 2
wt234U = 0007731times (wt235U )10837 Equation 3
wt236U = 00046times (wt235U ) Equation 4
wt238U =100 minus (wt234U + wt235U + wt236U ) Equation 5
The weight percentages of uran ium isotopes for PWR fuel are ca lculated in Attachm ent II spreadsheet PWR_fuel compxls worksheet BampWassy using Equations 2 through 5
627 PWR Source Terms
This calculation uses the following three PWR source terms bull Maximum source (50 wt initial 235U enrichment 80 GWdMTU burnup and 5-year
decay time) (Reference 229 Section 55) Table 8 lists th e gamma source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Design Basis source (4 0 wt initial 235U enrichment 60 GW dMTU burnup and 10-year decay tim e) (Reference 228 Section 552) Table 9 lists the gamm a source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Average source ( 40 wt initial 235U enrichment 48 GWdMTU burnup and 25-year decay time) (Reference 229 Section 55) Table 10 lists the gamma source terms for the fuel and non-fuel regions and the neutron source term for the fuel region
These sources (ie maximum design basis and av erage) are described in this section For dose rate calculations all the fuel assemblies in a transportation cask are of the sam e characteristics Also gamma radiation source term s for the PWR assem bly are prov ided for the f our assembly regions while neutron source term is only present in the active fuel region Gamma radiation sources in the non-active fuel region are distri buted unif ormly within each source region Gamma and neutron sources in the active fuel re gion are modeled as uni form distributions or with axial source profiles
The PWR gamma and neutron axial source profiles for the active fuel region presented in Table 11 are applied to the active fuel region of all three source terms (ie maximum design basis and average) when appropriate
30
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 8 Gamma and Neutron Sources for the Maximum PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting
Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 594E+11 233E+15 528E+11 379E+11 100E-01 000E+00 100E-01 116E+11 644E+14 609E+10 743E+10 400E-01 805E+07 200E-01 283E+10 522E+14 352E+10 179E+10 900E-01 411E+08 300E-01 141E+09 148E+14 196E+09 891E+08 140E+00 376E+08 400E-01 190E+09 985E+13 586E+09 117E+09 185E+00 276E+08 600E-01 191E+09 153E+15 110E+11 741E+07 300E+00 485E+08 800E-01 435E+09 470E+15 595E+10 237E+09 643E+00 443E+08 100E+00 137E+11 708E+14 803E+09 766E+10 200E+01 393E+07 133E+00 338E+13 455E+14 174E+13 217E+13 Total 211E+09 166E+00 953E+12 130E+14 491E+12 612E+12
--
200E+00 187E+03 144E+12 919E+02 113E+03 250E+00 226E+08 249E+12 116E+08 145E+08 300E+00 351E+05 110E+11 181E+05 225E+05 400E+00 766E-08 139E+10 100E-08 416E-08 500E+00 000E+00 709E+07 000E+00 000E+00 650E+00 000E+00 286E+07 000E+00 000E+00 800E+00 000E+00 558E+06 000E+00 000E+00 100E+01 000E+00 119E+06 000E+00 000E+00
Total 442E+13 113E+16 231E+13 284E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE2R2B14cut bWasteStreamE2R1B14cut cWasteStreamE2R3B14cut dWasteStreamE2R4B14cut
31
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 9 Gamma and Neutron Sources for the Design Basis PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary
(MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 273E+11 121E+15 188E+11 175E+11 100E-01 000E+00 100E-01 528E+10 329E+14 277E+10 339E+10 400E-01 316E+07 200E-01 128E+10 245E+14 117E+10 819E+09 900E-01 161E+08 300E-01 639E+08 713E+13 633E+08 407E+08 140E+00 148E+08 400E-01 850E+08 455E+13 164E+09 533E+08 185E+00 109E+08 600E-01 492E+08 226E+14 269E+10 337E+07 300E+00 191E+08 800E-01 291E+09 237E+15 160E+10 186E+09 643E+00 174E+08 100E+00 540E+09 122E+14 248E+09 341E+09 200E+01 154E+07 133E+00 154E+13 195E+14 797E+12 990E+12 Total 830E+08 166E+00 435E+12 450E+13 225E+12 280E+12
--
200E+00 235E+00 152E+11 149E+02 215E-02 250E+00 103E+08 517E+10 534E+07 664E+07 300E+00 160E+05 379E+09 829E+04 103E+05 400E+00 943E-10 497E+08 155E-10 519E-10 500E+00 000E+00 282E+07 000E+00 000E+00 650E+00 000E+00 113E+07 000E+00 000E+00 800E+00 000E+00 222E+06 000E+00 000E+00 100E+01 000E+00 471E+05 000E+00 000E+00
Total 201E+13 486E+15 105E+13 129E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B11cut bWasteStreamE5R1B11cut cWasteStreamE5R3B11cut dWasteStreamE5R4B11cut
32
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 10 Gamma and Neutron Sources for the Average PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 336E+10 670E+14 186E+10 217E+10 100E-01 00000E+00 100E-01 602E+09 199E+14 314E+09 387E+09 400E-01 748E+06 200E-01 146E+09 126E+14 853E+08 936E+08 900E-01 382E+07 300E-01 730E+07 389E+13 439E+07 469E+07 140E+00 352E+07 400E-01 947E+07 263E+13 716E+07 607E+07 185E+00 261E+07 600E-01 141E+07 205E+13 504E+08 383E+06 300E+00 469E+07 800E-01 208E+09 124E+15 192E+09 144E+09 643E+00 418E+07 100E+00 208E+09 110E+13 164E+09 144E+09 200E+01 365E+06 133E+00 175E+12 295E+13 909E+11 112E+12 Total 199E+08 166E+00 494E+11 513E+12 257E+11 318E+11
--
200E+00 973E-01 675E+10 614E+01 872E-03 250E+00 117E+07 353E+09 609E+06 754E+06 300E+00 182E+04 288E+08 944E+03 117E+04 400E+00 186E-11 198E+07 149E-11 127E-11 500E+00 000E+00 669E+06 000E+00 000E+00 650E+00 000E+00 269E+06 000E+00 000E+00 800E+00 000E+00 527E+05 000E+00 000E+00 100E+01 000E+00 112E+05 000E+00 000E+00
Total 229E+12 237E+15 119E+12 147E+12
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B9cut bWasteStreamE5R1B9cut cWasteStreamE5R3B9cut dWasteStreamE5R4B9cut
33
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 11 Gamma and Neutron Axial Source Profiles for a PWR Assembly
Axial boundaries (From midplane)
(cm)
TOP BOTTOM
Neutron Gamma Ne utron Gamma 000 1554 1117 1554 1117 1143 1537 1114 1571 1120 2286 1521 1111 1588 1123 3429 1504 1108 1605 1126 4572 1486 1104 1622 1129 5715 1464 1100 1636 1131 6858 1438 1095 1648 1133 8001 1401 1088 1657 1135 9144 1350 1078 1654 1134
10287 1277 1063 1625 1129 11430 1165 1039 1554 1117 12573 0998 09995 1414 1091 13716 0769 09365 1172 1041 14859 0492 08375 0816 0951 16002 0220 06850 0402 0797 17145 0046 04625 0092 0551 18288 00 00 00 00
Source Reference 2219 Table S445
34
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
63 MCNP SPECIFIC INPUT
631 Source Probability
A linear radial distribution is used for all gamma and neutron sources The linear radial distribution is sam pled usi ng the built-in power function p(x) = xc a with a = 1 for the radial direction This sampling method results in a uniform source distribution over the area bounded by the outer radius of the source
The source axial distributions are unifor m for all four source regions The a xial uni form xp(x) = c distribution is sampled using the built-in power function a with a = 0 for extent
The energy distribu tions of the gamma and neutron sour ce term s are treated as energ y probabilities and are applied in MCNP5 using SISP cards
632 Dose Rate and Flux Tallies
MCNP5 dose rate calculations feature separate runs for the following calculation types
bull a photon transport calculation for prim ary ga mma contribution to the dose rates fr om photon fluxes
bull a coupled neutronphoton transport calculat ion for neutrons a nd secondary gamma (photons generated by neutron be ing captured) contributions to dose rates from neutron and gamma fluxes
The tally type F2 is us ed in th is d esign ca lculation as f lux estim ators The type F2 tally evaluates the flux averaged over a surface in particlescm2s
To generate dose ra tes in te rms of remhr the FM (tally multiplier ) and DEDF (dose energydose conversion factors) cards are used to en ter the tally multiplier f actor (source intensity in particless) energy boundaries in MeV and corresponding dose conversion factors in (remhr)(particlescm2s) respectively These factors were used in the input files
In order for the F2 tally to accum ulate flux ov er a surface a specific s urface area is requ ired The SD cards are used to enter a surface area in cm2 over which the flux will be tallied for an F2 tally
633 Variance Reduction Techniques
Variance reduction technique is usually em ployed in order to increase the efficiency of a calculation and obtain statistically m eaningful results within re asonable com puter tim e In Monte Carlo calculations when variance reduction scheme is employed the weights of particles are adjusted in order to account for the biasing and to preserve a fair game
Geometry splitting and Russian roulette techniques described in Reference 2224 (pp 2-140 ndash 2-142) are useful in shielding calculations and therefore deployed in all the MCNP5 runs
35
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
As particles migrate in an important direction (toward the detector) they are increased in number to provide better sampling by means of geometry splitting across geometric boundaries Russian roulette (the reverse process) is played when particles travel in an unimportant direction to allow termination of unim portant histories The IMP card required for every cel l ca rd is us ed to implement this technique
The other variance reduction technique deployed in the MC NP5 runs is source intensity biasing for the gamma sources from the four source regions (active fuel bottom end-fitting plenum and top end-fitting) The natural total gamma source intensity of comm ercial SNF is dom inated by the gamma source in the active fuel region This active fuel gamma source usually accounts for over 95 o f the total g amma source intens ity In order to im prove the efficiency of the axial dose rate calculations a biased source probability distribution is employed for the prim ary gamma dose rate calculations The biased gamma source probability distribution is chosen to be 005 080 010 and 005 for the bottom end-fitting the active fuel the plenum and the top end-fitting regions respectively
64 DOSE CONVERSION FACTORS
Project Design Criteria Document (Reference 2211 Se ction 41015) requires the use of flux-to-dose rate conversion fact ors from ANSIANS-611-1977 (Reference 221) for dose rate evaluations Table 16 lists the neutron and ga mma dose conversion factors used in the MCNP5 calculations
Table 12 Gamma and Neutron Flux to Dose Conversion Factors
Gamma Neutron Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
001 396E-06 140 251E-06 250E-08 367E-06 003 582E-07 180 299E-06 100E-07 367E-06 005 290E-07 220 342E-06 100E-06 446E-06 007 258E-07 260 382E-06 100E-05 454E-06 010 283E-07 280 401E-06 100E-04 418E-06 015 379E-07 325 441E-06 100E-03 376E-06 020 501E-07 375 483E-06 100E-02 356E-06 025 631E-07 425 523E-06 100E-01 217E-05 030 759E-07 475 560E-06 500E-01 926E-05 035 878E-07 500 580E-06 100E+00 132E-04 040 985E-07 525 601E-06 250E+00 125E-04 045 108E-06 575 637E-06 500E+00 156E-04 050 117E-06 625 674E-06 700E+00 147E-04 055 127E-06 675 711E-06 100E+01 147E-04 060 136E-06 750 766E-06 140E+01 208E-04 065 144E-06 900 877E-06 200E+01 227E-04 070 152E-06 1100 103E-05 080 168E-06 1300 118E-05 100 198E-06 1500 133E-05
Source Reference 221 Tables 1 and 3
36
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION
By def inition (Ref erence 2224 Equation 219) the estimated st atistic relative error of the i component is
Ri = Si
2
Equation 6Ti
where i = tally component index Ri = relative error of the i component S2
i = variance of the i component Ti = tally i component
For a result (ie dose rate) computed as a sum of different tallies the statistical relative error of the computed value is o btained from the variance of the result - S2
total which is th e sum of the estimated variances of the individual tallies S2
i n
2 2STotal = sum Si Equation 7 i=1
where S2Total = total estimated variance
n = total number of components Therefore the total tally value (dose rate) and the associated relative error are derived according to Equations 8 and 9
n TTotal = sumTi Equation 8
i=1
n n
sum (Ri timesTi )2
2 sum Si 2
STotal = i=1 = i=1 Equation 9RTotal = TTotal TTotal TTotal
where RTotal = total estimated relative error TTotal = total estimated tally
Equations 8 and 9 are utilized in Attachm ent II to ev aluate to tal dos e ra tes and their r elative errors
37
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
7 RESULTS AND CONCLUSIONS
71 RESULTS
The following sections summarize the results of this calculation Section 711 presents results for Conceptual Cask A while Section 712 for Conceptual Cask B Section 713 provides comparisons of the dose-rate reduction factors du e to the two conceptual casks and the axial source distributions in the active fuel region Do se rates and relative errors can be found in Attachment II within the output files and Excel files
711 Dose Rates of Conceptual Cask A
This section presents dose-rate results of the calculation sets 1 and 2 as described in Section 61 for Cask A Set 1 has axial p rofile sources in the active fuel region a nd consist of six runs resulting from the three PWR SNF source term s (maximum design basis and average) and the two radiation sources (gammas and neutrons) Set 2 has uniform axial sources in the active fuel region and consists of six run s r esulting f rom the th ree P WR SNF source term s and th e tw o radiation sources
As described in Section 61 dose ra tes are calculated at the three exterior surfaces (radial top and bottom) and at distances 1 m and 2 m from the exterior surfaces The total dose rates for set 1 are presented in Tables 13 14 and 15 for the ra dial top and bottom dire ctions respectively However the com ponents (primary gamma neutr on and secondary gamma) contributing to the total dose rates as well as the re lative error calculations can be found in Attachment II Excel file MCNP-Results1xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 2 are shown in Tables 16 17 and 18 The dose-rate components and the relative errors can be found in A ttachment II Excel file MCNP-Results2xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 13 and 16 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 14 and 17 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 15 and 18 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carrying th e maximum PWR SNF Based on the results in Tables 13 through 18 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask A indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these 6 tables the d ose-rate red uction f actors between the m aximum and the design basis fuels the maxim um and the averag e fuels and th e design basis and the average fuels are a lso presented
38
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 320E-02 00237 116E-02 00222 262E-03 00219 275 1223 445
1 m 133E-02 00164 494E-03 00171 106E-03 00162 269 1261 468 2 m 749E-03 00198 285E-03 00225 584E-04 00162 263 1282 488
Ring Detectors 1 m 133E-02 00116 492E-03 00115 108E-03 00124 271 1229 454 2 m 756E-03 00118 279E-03 00110 605E-04 00128 271 1250 462
Source Attachment II MCNP-Results1xls worksheet Summary
Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 142E-02 00368 628E-03 00446 934E-04 00483 226 1520 672
1 m 570E-03 00289 263E-03 00426 375E-04 00381 217 1520 701 2 m 265E-03 00364 123E-03 00547 169E-04 00374 216 1575 730
Point Detectors 1 m 598E-03 00238 274E-03 00271 402E-04 00354 219 1489 681 2 m 273E-03 00218 123E-03 00245 180E-04 00336 221 1515 684
Source Attachment II MCNP-Results1xls worksheet Summary
Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 653E-03 00298 265E-03 00276 510E-04 00341 247 1278 518
1 m 276E-03 00238 112E-03 00208 207E-04 00249 248 1334 539 2 m 125E-03 00185 508E-04 00199 933E-05 00246 246 1336 544
Point Detectors 1 m 291E-03 00227 118E-03 00203 218E-04 00242 247 1335 540 2 m 130E-03 00209 524E-04 00187 955E-05 00233 247 1357 549
Source Attachment II MCNP-Results1xls worksheet Summary
Tables 13 14 and 15 are results of calculation set 1 for conceptual Cask A with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
39
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 265E-02 00247 990E-03 00222 215E-03 00278 268 1234 461
1 m 116E-02 00178 468E-03 00549 960E-04 00189 248 1208 488 2 m 713E-03 00273 265E-03 00161 602E-04 00360 269 1184 439
Ring Detectors 1 m 117E-02 00120 454E-03 00132 979E-04 00141 259 1199 463 2 m 722E-03 00130 276E-03 00141 589E-04 00153 261 1226 469
Source Attachment II MCNP-Results2xls worksheet Summary
Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 199E-02 00461 827E-03 00455 147E-03 00536 241 1359 564
1 m 849E-03 00564 323E-03 00314 563E-04 00418 263 1507 574 2 m 415E-03 00832 158E-03 00603 253E-04 00501 263 1641 623
Point Detectors 1 m 877E-03 00348 353E-03 00275 615E-04 00391 248 1426 574 2 m 393E-03 00341 160E-03 00278 270E-04 00378 246 1454 590
Source Attachment II MCNP-Results2xls worksheet Summary
Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 879E-03 00374 356E-03 00333 669E-04 00406 247 1315 533
1 m 365E-03 00223 147E-03 00209 269E-04 00253 248 1358 548 2 m 164E-03 00229 674E-04 00205 120E-04 00248 243 1364 560
Point Detectors 1 m 383E-03 00217 155E-03 00204 285E-04 00248 247 1347 546 2 m 172E-03 00197 689E-04 00186 124E-04 00225 249 1391 558
Source Attachment II MCNP-Results2xls worksheet Summary
Tables 16 17 and 18 ar e results of calculation set 2 for conceptual Cask A with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
40
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
229 BSC 2004 PWR Source Term Generation and Evaluation 000-00C-MGR0-00100-000-00B Las Vegas Nevada Bechtel SAIC Company ACC ENG200405240007
2210 BSC 2008 Basis of Design for the TAD Canister-Based Repository Design Concept 000-3DR-MGR0-00300-000-003 Las Vegas Nevada Bechtel SAIC Company ACC ENG200810060001
2211 BSC 2007 Project Design Criteria Document 000-3DR-MGR0-00100-000-007 Las Vegas Nevada Bechtel SAIC Company ACC ENG200710160005 ENG200711080001 ENG200712200003 ENG200801070001 ENG200801070002 ENG200801070016 ENG200801070017 ENG200801310006 ENG200803050002 ENG200803050011 ENG200803050012 ENG200803060009 ENG200803130004 ENG200807100001 ENG200811120006 ENG200811140004
2212 BSC 2004 PWR and BWR Source Term Sensitivity Study 000-00C-MGR0-00300-000-00A Las Vegas Nevada Bechtel SAIC Company ACC ENG200401140003 ENG200508150023
2213 BSC 2007 Dose Rate Calculation for Exhaust Main Drifts 800-00C-SS00-00700-000-00B Las Vegas Nevada Bechtel SAIC Company ACC ENG200711050017 ENG200803060001
2214 BSC 2006 Dual Purpose Canister Opening Study 050-30R-WHS0-00600-000-000 Las Vegas Nevada Bechtel SAIC Company ACC ENG200612200023
2215 BSC 2007 GROA Shielding Requirements Calculation 000-00C-MGR0-03300-000-00B Las Vegas Nevada Bechtel SAIC Company ACC ENG200705290037
2216 BSC 2002 Concrete Shielding Calculation for Dry Facility 1 110-00C-CS10-00100-000-00A Las Vegas Nevada Bechtel SAIC Company ACC MOL200301140075
2217 BSC 2003 Shielding Design Calculations for Dry Facility 1 110-00C-CS10-00200-000-00A Las Vegas Nevada Bechtel SAIC Company ACC ENG200306020003
2218 CRWMS MampO 1998 Calculation of the Effect of Source Geometry on the 21-PWR WP Dose Rates BBAC00000-01717-0210-00004 REV 00 Las Vegas Nevada CRWMS MampO ACC MOL199902220059 [DIRS 102134]
2219 CRWMS MampO 2000 Users Manual for SCALE-44A 10129-UM-44A-00 Las Vegas Nevada CRWMS MampO ACC MOL200011300136 MOL200108220084 MOL200108220085 MOL200108220086 MOL200108220087 [DIRS 153872]
2220 DOE (US Department of Energy) 1987 Appendix 2A Physical Descriptions of LWR Fuel Assemblies Volume 3 of Characteristics of Spent Fuel High-Level Waste and Other Radioactive Wastes Which May Require Long-Term Isolation DOERW-0184 Washington DC US Department of Energy Office of Civilian Radioactive Waste Management ACC HQX198804050024 [DIRS 132333]
11
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
2221 DOE 2007 Software Validation Report for MCNP5 v140 Document ID 11199-SVR-140-00-WINXP Las Vegas Nevada US Department of Energy Office of Repository Development ACC MOL200702280252 [DIRS 180516]
2222 DOE 2008 Transportation Aging and Disposal Canister System Performance Specification WMO-TADCS-000001 Rev 1 ICN 1 Washington DC US Department of Energy Office of Civilian Radioactive Waste Management ACC DOC200803310001 [DIRS 185304]
2223 Harmon CD II Busch RD Briesmeister JF and Forster RA 1994 Criticality Calculations with MCNPtrade A Primer LA-12827-M Los Alamos New Mexico Los Alamos National Laboratory TIC 234014 [DIRS 154532]
2224 LANL (Los Alamos National Laboratory) 2004 MCNP mdash A General Monte Carlo N-Particle Transport Code Version 5 (Appendix H is not included) LA-UR-03-1987 Volume I Los Alamos [New Mexico] Los Alamos National Laboratory ACC MOL200510240126 [DIRS 176521]
2225 MCNP5 V 140 2007 Windows XP STN 11199-140-00 [DIRS 180515]
2226 Parrington JR Knox HD Breneman SL Baum EM and Feiner F 1996 Nuclides and Isotopes Chart of the Nuclides 15th Edition San Jose California General Electric Company and KAPL Inc TIC 233705 LC Call Number QC7935 N8622 1996
2227 Punatar MK 2001 Summary Report of Commercial Reactor Criticality Data for Crystal River Unit 3 TDR-UDC-NU-000001 REV 02 Las Vegas Nevada Bechtel SAIC Company ACC MOL200107020087 [DIRS 155635]
2228 Sisley SE 2002 Transportation License Application for the FuelSolutionstrade System (TAC No L23311) Submittal of the FuelSolutiontrade Transportation SARs Revision 3 Letter from SE Sisley (BNFL) to the NRC April 11 2002 BFSNRC 02-011 with enclosures TIC 255245 [DIRS 171545]
NOTE Reference 2220 is a direct input but is not QA QA It is justified as acceptable for the intended use as it is directly from the DOE and is considered the best available data on the subject The referenced values cited in Tables 3 and 4 are valid for use since they are reliable and reasonable based on engineering judgment
23 DESIGN CONSTRAINTS
231 10 CFR 71 2008 Energy Packaging and Transportation of Radioactive Material Internet Accessible [DIRS 185678]
12
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
24 DESIGN OUTPUTS
The resu lts of this calculation will be us ed to substan tiate th e dose reduc tion f actor in the Repository ALARA Goal Compliance (Reference 227) which is cited as a reference in a PCSA calculation that supports the License Application
13
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
3 ASSUMPTIONS
31 ASSUMPTIONS REQUIRING VERIFICATION
None
32 ASSUMPTIONS NOT REQUIRING VERIFICATION
Assumptions 321 322 and 323 are m odeling assum ptions and do not require further verification The m aterials and dim ensions for the TAD canister and for the conceptu al transportation casks are only selected to charac terize two tr ansportation casks th at m eet 10 CFR7147 (Reference 231) dose rates when lo aded with the ldquom aximumrdquo and ldquoaveragerdquo pressurized water re actor (PW R) assem blies re spectively There is n o need to v erify those dimensions or m aterials at a later date The ca lculated results in Sect ion 711 verify that the conceptual casks would meet 10 CFR 7147 (Reference 231) dose rates
321 Material and Wall Thickness of TAD Canister
Assumption It is assumed that the TAD canister is made of stainless steel 316 (SS 316) and has a wall thickness of 025 in for the radial and bottom shells
Rationale Currently the design of the TAD canis ter d oes not ex ist Based on a survey of existing m ultipurpose a nd dual purpose caniste rs (DPC) (Ref erence 2214 p 56) a 025 in thickness is below the wall thick ness of any existing c anisters For the purp ose of this calculation this assumption leads to higher and conservative external dose rates Since SS 316 is the sam e material used for the waste pack age inner shell it is a l ogical cho ice f or the TAD canister
Although Reference 2214 is an engineering study with a QA N A status it is used here as an indirect input to support the assumption which is conservative for dose rate calculations
Usage This assumption is used in Sections 621 and 625
322 Material and Thickness of TAD Shield Plug
Assumption It is assu med that the TAD shield plug is made of SS 316 and has a thickness of 11 in
Rationale Currently the design of the TAD canister doe s not exist A thick shield plug of 11 in (Reference 2215 Table 12) is needed to keep the m aximum contact dose rate of the top surface below 1000 mrem hr (Reference 2222 Section 314) Since SS 316 is the sam e material used for the waste package inner shell it is a logical choice for the TAD shield plug
Usage This assumption is used in Section 621
14
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
323 Geometry and Materials of Conceptual TAD Transportation Casks
Assumption Two conceptual TAD transpo rtation casks designated as Cask A and Cask B are assumed to have a cylindrical geom etry and m aterials specified in Tab les 1 and 2 respectively The casks are basically construc ted of an inner layer of SS 316 for ga mma shielding a m iddle layer of 5-borated polyethylen e for neutron shielding and a th in outer layer of SS 316 whic h serves a structural function as well as shielding secondary gamma rays
Both Cask A and Cask B have a cavity height of 53785 cm (21175 in) and a cavity diameter of 16891 cm (6650 in) However Cask A has a total height of 610845 cm (24049 in) and an outside diameter of 26797 cm (10550 in) while the total height and outside diameter of Cask B are 58885 cm (23183 in) and 24765 cm (9750) respectively
Cask A will provide shielding to m eet the exterior radiat ion standards of 10 C FR 7147(b) (Reference 231) when loaded w ith a TAD canister carrying th e maximum PWR spent nuclear fuel (SNF) Cask B will satisf y the same radiation standards when loade d with a TAD caniste r carrying the average PWR SNF
Table 1 Geometry and Materials of Conceptual TAD Transportation Cask A
Component Dimension
Material (cm) (in)
Total Height 61085 2404 9 NA
Outside Diameter 26797 1055 0 NA
Cask Cavity Height 53785 2117 5 NA
Cask Cavity Diameter (Radius) 16891 (8446) 6650 (3325) NA
Radial Gamma Shield Thickness (Radius)a 3302 (11748)a 1300 (4625)a SS 316
Radial Neutron Shield Thickness (Radius)b 1524 (13272)b 600 (5225)b 5-borated polyethylene
Radial Outer Shell Thickness (Radius)c 127 (13399)c 050 (5275)c SS 316
Top Gamma Shield Thickness (Axial Position)d 600 (54385)d 236 (21411)d SS 316
Top Neutron Shield Thickness (Axial Position)d 1000 (55385)d 394 (21805)d 5-borated polyethylene
Top Outer Shell Thickness (Axial Position)d 200 (55585)d 079 (21884)d SS 316
Bottom Gamma Shield Thickness (Axial Position)d 35365 (-360)d 1392 (-1417)d SS 316
Bottom Neutron Shield Thickness (Axial Position)d 15 (-510)d 591 (-2008)d 5-borated polyethylene
Bottom Outer Shell Thickness (Axial Position)d 4 (-550)d 157 (-2165)d SS 316 a11748 = 3302 + 8446 and 4625 = 1300 + 3325 b13272 = 1524 + 11748 and 5225 = 600 + 4625 c13399 = 127 + 13272 and 5275 = 050 + 5225 dCoordinate relative to the bottom of the fuel assembly as modeled in MCNP5
15
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 2 Geometry and Materials of Conceptual TAD Transportation Cask B
Component Dimension
Material (cm) (in)
Total Height 58885 2318 3 NA
Outside Diameter 24765 9750 NA
Cask Cavity Height 53785 2117 5 NA
Cask Cavity Diameter (Radius) 16891 (8446) 6650 (3325) NA
Radial Gamma Shield Thickness (Radius)a 254 (10986)a 1000 (4325)a SS 316
Radial Neutron Shield Thickness (Radius)b 127 (12256)b 500 (4825)b 5-borated polyethylene
Radial Outer Shell Thickness (Radius)c 127 (12383)c 050 (4875)c SS 316
Top Gamma Shield Thickness (Axial Position)d 8 (54585)d 315 (21490)d SS 316
Top Neutron Shield Thickness (Axial Position)d None Non e NA
Top Outer Shell Thickness (Axial Position)d None Non e NA
Bottom Gamma Shield Thickness (Axial Position)d 3837 (-390)d 1510 (-1535)d SS 316
Bottom Neutron Shield Thickness (Axial Position)d 300 (-420)d 118 (-1654)d 5-borated polyethylene
Bottom Outer Shell Thickness (Axial Position)d 100 (-430)d 039 (-1693)d SS 316 a10986 = 254 + 8446 and 4325 = 1000 + 3325 b12256= 127 + 10986 and 4825 = 500+ 4325 c12383 = 127 + 12256 and 4875 = 050 + 4825 dCoordinate relative to the bottom of the fuel assembly as modeled in MCNP5
Rationale Currently a design for the TAD transporta tion cask does not exist The casks assumed for this calculation are so lely for estim ation of the dose reduction due to different source terms This is a conceptual repres entation only used in this calculation to estim ate the parameters of interest
Usage This assumption is used in Sections 61 and 622
324 Usage of Unirradiated Fuel for Commercial SNF
Assumption It is assumed that the active fuel region of the commercial SNF assembly contains the same isotopic concentrations as the fresh uni rradiated fuel and that the concentrations of fresh fuel with 5 initial enrichm ent corresp onding to m aximum SNF are used for all other SNFs
Rationale This assumption is a standard practice for shielding calculations throughout the industry accepted by the U S Nucle ar Regulatory Commission (NRC) (Reference 2228 Table 53-5) It sh ould be noted that this assumption applies to material composition only it does no t apply to source terms which are based on the characteristics of spent fuel
Usage This assumption is used in Sections 624 and 626
325 Homogenization of Radiation Source Regions
Assumption It is assu med that a commercial SNF assembly consis ts of four distinct reg ions (active fuel bottom end-fitting plenum and top end-fitting) The materials and radiation sources
16
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
of each assembly region are homogenized inside a volume defined by the TAD cavity radius and region height
Rationale The assembly representation is consistent with the industry practice for shielding calculations accepted by NRC (Reference 2228 Figure 53-6) The effec t of source homogenization is twofold (1) it d ecreases th e m ass de nsity of the source region and (2) it places source points slightly closer to detector locations thus reducing radiation attenuation The resu lts of Calculation of the Effect of Source Geometry on the 21-PWR WP Dose Rates (Reference 2218 pp 22-26) indicate that th e effect of assem bly homogenization gives nearly the same or conservative dose rates as the explicit fuel assembly model
Usage This assumption is used in Section 624
326 Ignoring Internal Fuel Basket Materials
Assumption It is assumed that the internal fuel basket materials are ignored
Rationale Inclusion of fuel basket m aterials in the smeared m aterial com position would increase the overall density and consequently increase the attenuati on of the radiation Therefore this assumption is conservative
Usage This assumption is used in Sections 621 624 and 626
17
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
4 METHODOLOGY
41 QUALITY ASSURANCE
This calculation was prepared in accordance with EG-PRO-3DP-G04B-00037 Calculations and Analyses (Reference 212) The results of th is calculation provides worker dose assessm ent adjustments and this will id entify radio logical hazards f or f acilities im portant to saf ety Therefore the approved version is designated as QA QA
42 USE OF COMPUTER SOFTWARE
421 Baseline Software
The Monte Carlo N-Particle com puter pr ogram (MCNP5) version 140 (Reference 2225) is used to calculate the dose rates (neutron pr imary gamm a and secondary gamm a) at various locations around a transportation cask and an aging overpack
The software specifications are as follows
bull Program Name MCNP5 bull VersionRevision Number Version 140 bull Operating Systems Windows XP bull Software Tracking Number 11199-140-00 bull Computer Type Dell OPTIPLEX GX620
MCNP5 which is Level 1 software is (a) appropriate for three-dim ensional neutron gamma and coupled neutrongamma shielding calculations (b) used within th e range of validation as documented in Software Validation Report for MCNP5 v140 (Reference 2221) and (c) obtained from Software C onfiguration Managem ent and qualified in accordance with procedure IT-PRO-0012 Qualification of Software (Reference 213) Therefore MCNP5 code is suitable for use in this design calculation All MCNP5 input and output files docum ented in this calculation are provided on a compact disc (CD) as Attachment II
All MCNP cases are executed on one of the following Q com puters QNW -004184 QNW -004187 QNW-004194 and QNW-004196 as shown in the output files
422 Commercial off the Shelf Software
The Excel sof tware is used to c alculate var ious inpu t values (i e atom densities weight percentages geometrical dimensions normalized source spectra and probabilities etc) Standard functions of Excel are also used in this desi gn calculation to display results (ie gamma and neutron dose rates) in tabular and graphic forms and to perform relative error calculations
The software specifications are as follows
bull Program Name Excel bull VersionRevision Number Microsoftreg Excel 2003
18
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
bull This software is installed on a persona l com puter running Microsoft W indows XP (central processing unit number 151834)
The user defined for mulas inputs results and gr aphical representations have been verified by hand calculations or visual inspection and are documented in sufficient detail to allow an independent repetition of the com putations Calculations were verifi ed by hand and graphical representations were found accurate by visual inspection
Per Software Management Microsoftreg Excel is not requir ed to be qualif ied due to its commercial availability status (Reference 211 Attachment 4 p 55 bullet 2)
43 CALCULATION APPROACH
This calculation em ploys the qualified so ftware MCNP5 version 140 (Reference 2225) a three-dimensional Monte Carlo code for pe rforming neutron and coupled neutron-gamm a calculations to estim ate dose rates at sele cted locations on and surrounding a conceptual transportation cask containing a loaded TAD canister
431 MCNP5 Program
MCNP5 a general Monte Carlo part icle transport code sim ulates particle transport through a three-dimensional representation of the nuclear system being analyzed During the random walk of particles through the system described by the geom etry the c ode collects inform ation about various events (su rface cross ing collis ions trac k leng th etc) and es timates fluxes in various geometric configurations specified as tallies by the user It also estimates the statistical precision of the results in the form of relative errors (Reference 2224 pp 1-2 to 1-8)
Per Project Design Criteria Document (Reference 2211 Section 41015) the flux estim ates are converted to dose rates using the Am erican Nuclear Society (ANS) flux-to-dose rate conversion factors for gammas and neutrons (R eference 221) The simple variance reduction techniques of Geometry SplittingRussian Roulette and source probability biasing (Sections 631 and 633) are used to enhance computational efficiency
19
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
5 LIST OF ATTACHMENTS
Number of Pages Attachment I List of Electronic Files on the CD 3 Attachment II Compact Disc NA
20
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
6 CALCULATIONS
This sectio n provides inform ation necess ary to perform the calcu lations in this docum ent Section 61 describes the configurations the type of CSNF to be analyzed the number of MCNP runs and the locations where dose rates are ca lculated Section 62 provides the calculation input that includes the details of the geom etry m odel radiation source term s and m aterial compositions Input specific to MCNP dose -rate conversion factors and relative error calculation are described in the later sections
61 DESCRIPTION OF CALCULATIONS
Dose rate calculations are perform ed with the MCNP5 version 140 com puter code (Reference 2225) Two conceptual transportation casks Cask A and Cask B (Assum ption 323) are employed Each cask contains a TAD canister that is loaded with 21 ident ical PW R SN F assemblies Three PWR source term s are analy zed they are the source term s corresponding to the maximum design basis and average PW R SN Fs The characteris tics of the P WR source terms are presented in S ection 627 Each PWR source term has neutron and ga mma radiation sources that require separate MCNP5 runs For each radiation source an axial profile source and a uniform source for the active fuel region are considered The uniform source for the active fuel region is included in this calculation because this approach was used in combination with source peaking factors in certain calculations (Reference 2216 Sections 37 and 39 and Reference 2217 Section 5242)
The total number of MCNP5 runs is 24 which re sults from a com bination of two conceptual casks three PWR source terms two radiation sources and two axia l source distributions for the active fuel region These 24 runs are categorized into four calcula tion sets Each calculation set consists of six runs that is a combination of three PWR source te rms and two radiation sources The characteristics of each calculation set are as follows
1 Cask A with axial profile sources in the active fuel region
2 Cask A with uniform axial sources in the active fuel region
3 Cask B with axial profile sources in the active fuel region
4 Cask B with uniform axial sources in the active fuel region
For each MCNP5 run dose rates are calculated at the exte rior surfaces and at distances 1 and 2 meters from the exterior surfaces Surface tallies and detector tallies (ring and point detectors) as indicated in Figure 1 are e mployed in all runs Figure 1 is used to illustrate the dep loyment of the surface and detector tallies re lative to the so urce regions and it should not be interpreted as an exact geometry of any particular run Surface tallies are deployed at all three distances while ring and point detectors are used only at 1 m and 2 m and not at the cask surfaces Using point detectors near a surface or in any scattering media is not recommended because very large scores can occur f rom collisions close ( less than a f ew centimeters) to the point detecto rs that can lead to resu lts with high r elative e rrors thus m aking the ca lculation d ifficult to o btain r eliable answers
21
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
For the radial direction surface tallies at the three distances (contact 1 m and 2 m) are computed for three su rface segments (cylindrical rings) between the planes at Z = 145 175 2 05 and 235 cm The geometric locations of the segments are shown in Figure 1 The axial locations of these segments correspond to the m iddle of the active fuel region of the PWR SNF assemblies The average dose rates for each of the segm ents are calculated for the outside surface and surfaces at 1 m and 2 m from the cask surface Two ring detectors (instead of point detectors) are deployed at 1 m and 2 m for the radial dire ction Ring detectors instead of point detectors are used in order to capitalize on the symm etry around the cask axis thus im proving the efficiency of the calculations
In the axial direction the average d ose rates within three concentric radial surfaces defined by radii of 40 80 and 120 cm (shown in Figure 1) are calculated for the top and bottom surfaces and at distances 1 m and 2 m from these surfaces Finally point detectors at 1 m and 2 m from the top and bottom axial surfaces are employed
22
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Point Detector at 2 m x
Ring Ring Detector Detector at 2 m at 1 m
x x
Z = 00 cm
Z = 145 cm
Z = 175 cm
Z = 205 cm
Z = 235 cm
R = 80 cm
R = 120 cm
R = 40 cm
Active Fuel
Shield Plug
Top End-Fitting Plenum
Bottom End-Fitting
Ring Detector at 1 m
x
Point Detector at 1 m x
Ring Detector
at 2 m x
D = 26797 cm
H =
610
845
cm
Point Detector at 1 m x
Point Detector at 2 m x
Figure 1 Geometry and Tally Scheme for the TAD Transportation Cask
23
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
62 CALCULATION INPUT
Technical product input and sources of the input used in the deve lopment of this calculation are documented in this section Tables in this docum ent and in th e associated Microsoftreg Excel spreadsheets referenced m ay present num erical values with m any significant figures these values are not to be considered as high precision values since the significant figures are results of calculated values andor unit conversions
621 TAD Canister
The TAD canis ter will contain either 21 P WR or 44 BW R (boiling water reactor) SNF assemblies (Reference 2222 Section 321) While the canister design is iden tical for both PWR and BWR SNF assemblies the internal basket structure is different depending on the SNF assemblies However the internal basket stru cture m aterial is no t in cluded in the calcu lation model (Assumption 326)
The TAD canister is a right-circu lar cylinder with a diam eter of 665 in and a height between 186 and 212 in (Reference 2222 Section 321) The average and maximum total dose rates on the top surf ace of a loaded TAD ca nister must not exceed 800 and 1000 m remhr respectively (Reference 2222 Section 314) The TAD canister used in this calculation is m ade of SS 316 with a radial wall and bottom thickness of 025 in (Assumption 321) The top of the canister has a shield plug that is 11 in thick SS 316 (Ass umption 322) A thick shield plug is needed to keep the maxim um contact dose rate of th e top surface below 1000 m remhr The overall dimensions of the TAD canister are provided in Table 3
Table 3 Dimensions of TAD Canister
Component Dimension
(in) (cm)
Maximum heighta 212 53848
Outer diametera 665 16891
Thickness of bottom lidb 025 0635
Shell thicknessb 025 0635
Lifting Featurec 6 1524
Height without Lifting Feature 206 52324
Thickness of shield plugd 110 2794
aReference 2222 Section 311 bAssumption 321 cReference 2222 p Attachment C-1 dAssumption 322
622 Conceptual TAD Transportation Casks
Two conceptual TAD transportation casks designa ted as Cask A and Cask B are em ployed in this calculation (Assumption 323) They both have a cylindrical geometry with dimensions and materials specified in Tables 1 and 2 of Section 323 Cask A will provide shielding to meet the exterior radiation standards of 10 CFR 7147(b) (Reference 231) when loaded with a TAD
24
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
canister car rying the m aximum PWR SNF Cask B will s atisfy th e sa me radiatio n standa rds when loaded with a TAD canister c arrying the average PWR SNF The reason to analyze both Casks A and B is to cover a broad range of characteristics of the CSNF
The cavity dimensions of the conceptual cask s are 53785 cm (21175 in) in height and 16891 cm (665 in) in diam eter (Tab les 1 and 2) This cav ity will accommoda te the TAD canister described in Table 3 without the lifting feature This is the geometry model used in the MCNP5 calculations
623 Fuel Assembly Selection
PWR and BWR Source Term Sensitivity Study (Reference 2211 Tables 71 through 84) shows that the source terms generated for the Bamp W 15x15 Mark B fuel assembly with 475 kg uranium loading bound the source terms of other PWR assembly types ther efore this assembly type is selected as the representative PWR fuel assembly The gamma and neutron source terms for the BampW 15x15 Mark B assembly are generated in PWR Source Term Generation and Evaluation (Reference 229) and are used in this calculation
624 BampW 15x15 Mark B PWR Fuel Assembly
BampW 15x15 Mark B fuel assembly consists of four regions top end-fitting plenum active fuel and bottom end-fitting The m aterials and ra diation sources of each assem bly region are homogenized inside a volume defined by the region height and the interior diam eter of the TAD canister (Assumption 325) The active fuel region is homogenized with fresh unirradiated fuel (Assumption 324) Since the internal structure (i e basket) design of t he TAD is currently not finalized the com position of the hom ogenized fuel does not include the basket m aterials (Assumption 326) and therefore does not take cred it for any shielding that these m aterials may provide
Table 4 provides the design param eters for the BampW 15x15 Mark B fuel assembly Data provided here are used in Attachment II PWR_fuel compxls worksheet BampWassy
25
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 4 BampW 15x15 Mark B Fuel Assembly Description
Component Material Characteristic Value Specific Reference Array Size 15 x 15
Reference 2227 Table 2-2 Fuel Pins Assembly 208 Guide Tubes Assembly 16 Instrument Tubes Assembly 1
Assembly NA Pin Pellet Diameter 0936244 cm (03686 in) Reference 2220 p 2A-34 Pin Pitch 144272 cm (0568 in)
Reference 2227 Table 2-2 Active Fuel Height 360172 cm (1418 in) Assembly Width 2168144 cm (8536 in)
Reference 2220 p 2A-31 Assembly Height 4206875 cm (165625 in) Mass U assembly 46363 kg
Guide tube Zircaloy-4 Outer Diameter 13462 cm (053 in)
Reference 2227 Table 2-2
Inner Diameter 126492 cm (0498 in)
Instrument tube Zircaloy-4 Outer Diameter 138193 cm (05441 in) Inner Diameter 112014 cm (0441 in)
Cladding` Zircaloy-4 Inner Diameter 095758 cm (0377 in) Outer Diameter 10922 cm (043 in)
Plenum region NA Length 297688 cm (11720 in) Reference 2220 p 2A-34 Top nozzle SS CF3M MassAssembly (Top) 748 kg
Reference 2220 p 2A-32
Bottom nozzle SS CF3M MassAssembly (Bottom) 816 kg Guide tubes Zircaloy-4 MassAssembly (in Core) 80 kg Instrument tube Zircaloy-4 MassAssembly (in Core) 064 kg Spacer-plenum Inconel-718 MassAssembly (Plenum) 104 kg Spacer-bottom Inconel-718 MassAssembly (Bottom) 13 kg Spacer-in core Inconel-718 MassAssembly (in Core) 49 kg Spring retainer SS CF3M MassAssembly (Top) 091 kg Holddown spring Inconel-718 MassAssembly (Top) 18 kg Upper end plug SS 304 MassAssembly (Top) 006 kg Upper nut SS 304L MassAssembly (Top) 051 kg Lower nut SS 304 MassAssembly (Bottom) 015 kg Grid supports Zircaloy-4 MassAssembly (in Core) 064 kg Plenum spring SS 302 MassAssembly (Plenum) 0042 lb (001905 kg) Reference 2220 p 2A-34
Note Som e d ata i n this tab le ar e given i n British u nits in th e r eferences thes e d ata ar e converted into metric units as the inputs to MCNP5 are in metric units
The assem bly region heights as m odeled in MC NP are presented in Table 5 utilizing values from Table 4 Table 5 is taken from Dose Rate Calculation for Exhaust Main Drifts (Reference 2213 Table 3)
26
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 5 PWR Fuel Assembly Regions
Component Height Reference
Plenum 297688 cm (11720 in) Reference 2220 p 2A-34
Active Fuel 360172 cm (1418 in) Table 3
Bottom End-Fitting 1077 cm (424 in) Calculateda
Top End-Fitting 1998 cm (787 in) Calculatedb
Source Reference 2213 Table 3 aCalculated b ased on data Reference 2227 F igures 2-3 an d 2-7
(Region 9 Height [16723 cm] + Region 10 Height [508 cm] ndash Lo wer Fuel Plenum and End Cap [11033 cm])
bCalculated (Assembly Length ndash Active Fuel Length ndash P lenum Length ndash Bottom End-fitting Length)
625 Material Compositions
The TAD transportation cask com ponent m aterial specifications are defined in Table 1 The TAD canister is constructed of SS 316 (Assumpti on 321) The PWR fuel assembly materials used to homogenize the fuel regions are defined in Table 4 Table 6 c ontains the m aterial compositions defining the TAD canister WP and fuel assemblies
27
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 6 Chemical Compositions of Materials
Material Density (gcc)
Isotopic Weight Percent Reference
SS 302 NA
C 0150 Mn 2000 P 0045 S 0030 Si 0750 Cr 18000 Ni 9000 N 0100 Fe 69925
Attachment II PWR_fuel compxls worksheet ferrous Reference 222 SEC II A SA-240 Table 1 for SS 302 SS 304 and SS 304L Reference 222 SEC II A SA-351SA -351M Table 2 for SS CF3M
SS 304 NA
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 9250 N 0100 Fe 68745
SS 304L NA
C 003 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 10000 N 0100 Fe 6804 5
SS CF3M NA
C 0030 Mn 1500 P 0040 S 0040 Si 1500 Cr 19000 Ni 11000 Mo 2500 Fe 64390
Inconel 718 NA
C 0080 Mn 0350 Si 0350 Cr 19000 Ni 52500 Co 1000 Mo 3050 Fe 16809 Nb 5125 Ti 0900 Al 0500 Cu 0300 S 0015 P 0015 B 0006
Attachment II PWR_fuel compxls worksheet alloys aReference 223 p 666 Table 6 Reference 222 SEC II B SB-637 Table 1 for Inconel 718 Reference 224 Table 2 for Zircaloy 4
Zircaloy 4 656a Cr 0100 Fe 0210 O 0125 Sn 1450 Zr 98115
SS 316 798b
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 17000 Ni 12000 Mo 2500 N 0100 Fe 65495
Attachment II PWR_fuel compxls worksheet others Reference 222 SEC II A SA-240 Table 1 for SS 316 bReference 225 Table X1
626 Homogenization Assembly Materials
The atom density of an element or isotope in atomsbmiddotcm in a homogenized region is calculated according to the following equation (Reference 2223 Appendix B)
M i times N AvogadroNi = Equation 1 Ai timesV times K
where Ni = Atom density of elementisotope i (atomsbmiddotcm) Mi = Mass of elementisotope i (g) NAvogadro = Avogadrorsquos constant 06022 x 1024 (atomsmole)
28
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Ai = Atomic weight of elementisotope i (gmole) V = Homogenization volume (cm3) K = Unit transformation constant = 1024 (bmiddotcmcm3)
Equation 1 is used in A ttachment II spreadsheet PWR_fuel compxls worksheet BampWassy to calculate th e atom dens ities for v arious elem ents and iso topes The m ass of elementsisotop es and Avogadrorsquos constant are provided in Reference 2226
Table 7 lists the com position of the hom ogenized assem bly regions (active fuel plenum top end-fitting and bottom end-fitting) for the PWR assembly The active fuel region contains fresh unirradiated fuel (Assumption 324) Since the internal structure (ie basket) design of the TAD is currently not finalized the composition of either homogenized fuel does not include the basket materials and therefore does not tak e credit for any shielding that thes e materials may provide (Assumption 326)
Table 7 Isotopic Compositions of Homogenized PWR Assembly Regions
Element Isotope
Atom Densities for Homogenized Regions (atomsbsdotcm)
Active Fuel Bottom End-Fitting Plenum Top End-Fitting
10B 861E-09 764E-08 221E-08 570E-08 11B 347E-08 307E-07 890E-08 230E-07 C 519E-07 160E-05 138E-06 993E-06 N -- 570E-07 262E-08 117E-06 O 621E-03 -- 142E-05 -- Al 144E-06 128E-05 371E-06 957E-06 Si 971E-07 243E-04 259E-06 139E-04 P 377E-08 606E-06 102E-07 360E-06 S 365E-08 581E-06 971E-08 340E-06 Ti 147E-06 130E-05 376E-06 971E-06 Cr 320E-05 187E-03 779E-05 113E-03 Mn 497E-07 126E-04 141E-06 749E-05 Fe 303E-05 531E-03 717E-05 313E-03 Co 132E-06 117E-05 340E-06 876E-06 Ni 697E-05 144E-03 180E-04 940E-04 Cu 368E-07 327E-06 945E-07 244E-06 Zr 196E-03 -- 195E-03 -- Nb 430E-06 382E-05 110E-05 285E-05 Mo 248E-06 135E-04 636E-06 791E-05 Sn 223E-05 -- 222E-05 -- 234U 139E-06 -- -- -- 235U 157E-04 -- -- -- 236U 719E-07 -- -- -- 238U 294E-03 -- -- -- Total 114E-02 924E-03 235E-03 557E-03
Source Attachment II spreadsheet PWR_fuel compxls worksheet BampWassy
29
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
The isotopic composition of commercially available 235U enriched uranium is determined by the given initial 235U enrichment using the following equations (Reference 226 p 20)
wt235U =235Uenrichment _ of _ the _ associated _ fuel _ batch Equation 2
wt234U = 0007731times (wt235U )10837 Equation 3
wt236U = 00046times (wt235U ) Equation 4
wt238U =100 minus (wt234U + wt235U + wt236U ) Equation 5
The weight percentages of uran ium isotopes for PWR fuel are ca lculated in Attachm ent II spreadsheet PWR_fuel compxls worksheet BampWassy using Equations 2 through 5
627 PWR Source Terms
This calculation uses the following three PWR source terms bull Maximum source (50 wt initial 235U enrichment 80 GWdMTU burnup and 5-year
decay time) (Reference 229 Section 55) Table 8 lists th e gamma source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Design Basis source (4 0 wt initial 235U enrichment 60 GW dMTU burnup and 10-year decay tim e) (Reference 228 Section 552) Table 9 lists the gamm a source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Average source ( 40 wt initial 235U enrichment 48 GWdMTU burnup and 25-year decay time) (Reference 229 Section 55) Table 10 lists the gamma source terms for the fuel and non-fuel regions and the neutron source term for the fuel region
These sources (ie maximum design basis and av erage) are described in this section For dose rate calculations all the fuel assemblies in a transportation cask are of the sam e characteristics Also gamma radiation source term s for the PWR assem bly are prov ided for the f our assembly regions while neutron source term is only present in the active fuel region Gamma radiation sources in the non-active fuel region are distri buted unif ormly within each source region Gamma and neutron sources in the active fuel re gion are modeled as uni form distributions or with axial source profiles
The PWR gamma and neutron axial source profiles for the active fuel region presented in Table 11 are applied to the active fuel region of all three source terms (ie maximum design basis and average) when appropriate
30
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 8 Gamma and Neutron Sources for the Maximum PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting
Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 594E+11 233E+15 528E+11 379E+11 100E-01 000E+00 100E-01 116E+11 644E+14 609E+10 743E+10 400E-01 805E+07 200E-01 283E+10 522E+14 352E+10 179E+10 900E-01 411E+08 300E-01 141E+09 148E+14 196E+09 891E+08 140E+00 376E+08 400E-01 190E+09 985E+13 586E+09 117E+09 185E+00 276E+08 600E-01 191E+09 153E+15 110E+11 741E+07 300E+00 485E+08 800E-01 435E+09 470E+15 595E+10 237E+09 643E+00 443E+08 100E+00 137E+11 708E+14 803E+09 766E+10 200E+01 393E+07 133E+00 338E+13 455E+14 174E+13 217E+13 Total 211E+09 166E+00 953E+12 130E+14 491E+12 612E+12
--
200E+00 187E+03 144E+12 919E+02 113E+03 250E+00 226E+08 249E+12 116E+08 145E+08 300E+00 351E+05 110E+11 181E+05 225E+05 400E+00 766E-08 139E+10 100E-08 416E-08 500E+00 000E+00 709E+07 000E+00 000E+00 650E+00 000E+00 286E+07 000E+00 000E+00 800E+00 000E+00 558E+06 000E+00 000E+00 100E+01 000E+00 119E+06 000E+00 000E+00
Total 442E+13 113E+16 231E+13 284E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE2R2B14cut bWasteStreamE2R1B14cut cWasteStreamE2R3B14cut dWasteStreamE2R4B14cut
31
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 9 Gamma and Neutron Sources for the Design Basis PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary
(MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 273E+11 121E+15 188E+11 175E+11 100E-01 000E+00 100E-01 528E+10 329E+14 277E+10 339E+10 400E-01 316E+07 200E-01 128E+10 245E+14 117E+10 819E+09 900E-01 161E+08 300E-01 639E+08 713E+13 633E+08 407E+08 140E+00 148E+08 400E-01 850E+08 455E+13 164E+09 533E+08 185E+00 109E+08 600E-01 492E+08 226E+14 269E+10 337E+07 300E+00 191E+08 800E-01 291E+09 237E+15 160E+10 186E+09 643E+00 174E+08 100E+00 540E+09 122E+14 248E+09 341E+09 200E+01 154E+07 133E+00 154E+13 195E+14 797E+12 990E+12 Total 830E+08 166E+00 435E+12 450E+13 225E+12 280E+12
--
200E+00 235E+00 152E+11 149E+02 215E-02 250E+00 103E+08 517E+10 534E+07 664E+07 300E+00 160E+05 379E+09 829E+04 103E+05 400E+00 943E-10 497E+08 155E-10 519E-10 500E+00 000E+00 282E+07 000E+00 000E+00 650E+00 000E+00 113E+07 000E+00 000E+00 800E+00 000E+00 222E+06 000E+00 000E+00 100E+01 000E+00 471E+05 000E+00 000E+00
Total 201E+13 486E+15 105E+13 129E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B11cut bWasteStreamE5R1B11cut cWasteStreamE5R3B11cut dWasteStreamE5R4B11cut
32
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 10 Gamma and Neutron Sources for the Average PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 336E+10 670E+14 186E+10 217E+10 100E-01 00000E+00 100E-01 602E+09 199E+14 314E+09 387E+09 400E-01 748E+06 200E-01 146E+09 126E+14 853E+08 936E+08 900E-01 382E+07 300E-01 730E+07 389E+13 439E+07 469E+07 140E+00 352E+07 400E-01 947E+07 263E+13 716E+07 607E+07 185E+00 261E+07 600E-01 141E+07 205E+13 504E+08 383E+06 300E+00 469E+07 800E-01 208E+09 124E+15 192E+09 144E+09 643E+00 418E+07 100E+00 208E+09 110E+13 164E+09 144E+09 200E+01 365E+06 133E+00 175E+12 295E+13 909E+11 112E+12 Total 199E+08 166E+00 494E+11 513E+12 257E+11 318E+11
--
200E+00 973E-01 675E+10 614E+01 872E-03 250E+00 117E+07 353E+09 609E+06 754E+06 300E+00 182E+04 288E+08 944E+03 117E+04 400E+00 186E-11 198E+07 149E-11 127E-11 500E+00 000E+00 669E+06 000E+00 000E+00 650E+00 000E+00 269E+06 000E+00 000E+00 800E+00 000E+00 527E+05 000E+00 000E+00 100E+01 000E+00 112E+05 000E+00 000E+00
Total 229E+12 237E+15 119E+12 147E+12
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B9cut bWasteStreamE5R1B9cut cWasteStreamE5R3B9cut dWasteStreamE5R4B9cut
33
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 11 Gamma and Neutron Axial Source Profiles for a PWR Assembly
Axial boundaries (From midplane)
(cm)
TOP BOTTOM
Neutron Gamma Ne utron Gamma 000 1554 1117 1554 1117 1143 1537 1114 1571 1120 2286 1521 1111 1588 1123 3429 1504 1108 1605 1126 4572 1486 1104 1622 1129 5715 1464 1100 1636 1131 6858 1438 1095 1648 1133 8001 1401 1088 1657 1135 9144 1350 1078 1654 1134
10287 1277 1063 1625 1129 11430 1165 1039 1554 1117 12573 0998 09995 1414 1091 13716 0769 09365 1172 1041 14859 0492 08375 0816 0951 16002 0220 06850 0402 0797 17145 0046 04625 0092 0551 18288 00 00 00 00
Source Reference 2219 Table S445
34
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
63 MCNP SPECIFIC INPUT
631 Source Probability
A linear radial distribution is used for all gamma and neutron sources The linear radial distribution is sam pled usi ng the built-in power function p(x) = xc a with a = 1 for the radial direction This sampling method results in a uniform source distribution over the area bounded by the outer radius of the source
The source axial distributions are unifor m for all four source regions The a xial uni form xp(x) = c distribution is sampled using the built-in power function a with a = 0 for extent
The energy distribu tions of the gamma and neutron sour ce term s are treated as energ y probabilities and are applied in MCNP5 using SISP cards
632 Dose Rate and Flux Tallies
MCNP5 dose rate calculations feature separate runs for the following calculation types
bull a photon transport calculation for prim ary ga mma contribution to the dose rates fr om photon fluxes
bull a coupled neutronphoton transport calculat ion for neutrons a nd secondary gamma (photons generated by neutron be ing captured) contributions to dose rates from neutron and gamma fluxes
The tally type F2 is us ed in th is d esign ca lculation as f lux estim ators The type F2 tally evaluates the flux averaged over a surface in particlescm2s
To generate dose ra tes in te rms of remhr the FM (tally multiplier ) and DEDF (dose energydose conversion factors) cards are used to en ter the tally multiplier f actor (source intensity in particless) energy boundaries in MeV and corresponding dose conversion factors in (remhr)(particlescm2s) respectively These factors were used in the input files
In order for the F2 tally to accum ulate flux ov er a surface a specific s urface area is requ ired The SD cards are used to enter a surface area in cm2 over which the flux will be tallied for an F2 tally
633 Variance Reduction Techniques
Variance reduction technique is usually em ployed in order to increase the efficiency of a calculation and obtain statistically m eaningful results within re asonable com puter tim e In Monte Carlo calculations when variance reduction scheme is employed the weights of particles are adjusted in order to account for the biasing and to preserve a fair game
Geometry splitting and Russian roulette techniques described in Reference 2224 (pp 2-140 ndash 2-142) are useful in shielding calculations and therefore deployed in all the MCNP5 runs
35
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
As particles migrate in an important direction (toward the detector) they are increased in number to provide better sampling by means of geometry splitting across geometric boundaries Russian roulette (the reverse process) is played when particles travel in an unimportant direction to allow termination of unim portant histories The IMP card required for every cel l ca rd is us ed to implement this technique
The other variance reduction technique deployed in the MC NP5 runs is source intensity biasing for the gamma sources from the four source regions (active fuel bottom end-fitting plenum and top end-fitting) The natural total gamma source intensity of comm ercial SNF is dom inated by the gamma source in the active fuel region This active fuel gamma source usually accounts for over 95 o f the total g amma source intens ity In order to im prove the efficiency of the axial dose rate calculations a biased source probability distribution is employed for the prim ary gamma dose rate calculations The biased gamma source probability distribution is chosen to be 005 080 010 and 005 for the bottom end-fitting the active fuel the plenum and the top end-fitting regions respectively
64 DOSE CONVERSION FACTORS
Project Design Criteria Document (Reference 2211 Se ction 41015) requires the use of flux-to-dose rate conversion fact ors from ANSIANS-611-1977 (Reference 221) for dose rate evaluations Table 16 lists the neutron and ga mma dose conversion factors used in the MCNP5 calculations
Table 12 Gamma and Neutron Flux to Dose Conversion Factors
Gamma Neutron Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
001 396E-06 140 251E-06 250E-08 367E-06 003 582E-07 180 299E-06 100E-07 367E-06 005 290E-07 220 342E-06 100E-06 446E-06 007 258E-07 260 382E-06 100E-05 454E-06 010 283E-07 280 401E-06 100E-04 418E-06 015 379E-07 325 441E-06 100E-03 376E-06 020 501E-07 375 483E-06 100E-02 356E-06 025 631E-07 425 523E-06 100E-01 217E-05 030 759E-07 475 560E-06 500E-01 926E-05 035 878E-07 500 580E-06 100E+00 132E-04 040 985E-07 525 601E-06 250E+00 125E-04 045 108E-06 575 637E-06 500E+00 156E-04 050 117E-06 625 674E-06 700E+00 147E-04 055 127E-06 675 711E-06 100E+01 147E-04 060 136E-06 750 766E-06 140E+01 208E-04 065 144E-06 900 877E-06 200E+01 227E-04 070 152E-06 1100 103E-05 080 168E-06 1300 118E-05 100 198E-06 1500 133E-05
Source Reference 221 Tables 1 and 3
36
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION
By def inition (Ref erence 2224 Equation 219) the estimated st atistic relative error of the i component is
Ri = Si
2
Equation 6Ti
where i = tally component index Ri = relative error of the i component S2
i = variance of the i component Ti = tally i component
For a result (ie dose rate) computed as a sum of different tallies the statistical relative error of the computed value is o btained from the variance of the result - S2
total which is th e sum of the estimated variances of the individual tallies S2
i n
2 2STotal = sum Si Equation 7 i=1
where S2Total = total estimated variance
n = total number of components Therefore the total tally value (dose rate) and the associated relative error are derived according to Equations 8 and 9
n TTotal = sumTi Equation 8
i=1
n n
sum (Ri timesTi )2
2 sum Si 2
STotal = i=1 = i=1 Equation 9RTotal = TTotal TTotal TTotal
where RTotal = total estimated relative error TTotal = total estimated tally
Equations 8 and 9 are utilized in Attachm ent II to ev aluate to tal dos e ra tes and their r elative errors
37
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
7 RESULTS AND CONCLUSIONS
71 RESULTS
The following sections summarize the results of this calculation Section 711 presents results for Conceptual Cask A while Section 712 for Conceptual Cask B Section 713 provides comparisons of the dose-rate reduction factors du e to the two conceptual casks and the axial source distributions in the active fuel region Do se rates and relative errors can be found in Attachment II within the output files and Excel files
711 Dose Rates of Conceptual Cask A
This section presents dose-rate results of the calculation sets 1 and 2 as described in Section 61 for Cask A Set 1 has axial p rofile sources in the active fuel region a nd consist of six runs resulting from the three PWR SNF source term s (maximum design basis and average) and the two radiation sources (gammas and neutrons) Set 2 has uniform axial sources in the active fuel region and consists of six run s r esulting f rom the th ree P WR SNF source term s and th e tw o radiation sources
As described in Section 61 dose ra tes are calculated at the three exterior surfaces (radial top and bottom) and at distances 1 m and 2 m from the exterior surfaces The total dose rates for set 1 are presented in Tables 13 14 and 15 for the ra dial top and bottom dire ctions respectively However the com ponents (primary gamma neutr on and secondary gamma) contributing to the total dose rates as well as the re lative error calculations can be found in Attachment II Excel file MCNP-Results1xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 2 are shown in Tables 16 17 and 18 The dose-rate components and the relative errors can be found in A ttachment II Excel file MCNP-Results2xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 13 and 16 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 14 and 17 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 15 and 18 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carrying th e maximum PWR SNF Based on the results in Tables 13 through 18 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask A indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these 6 tables the d ose-rate red uction f actors between the m aximum and the design basis fuels the maxim um and the averag e fuels and th e design basis and the average fuels are a lso presented
38
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 320E-02 00237 116E-02 00222 262E-03 00219 275 1223 445
1 m 133E-02 00164 494E-03 00171 106E-03 00162 269 1261 468 2 m 749E-03 00198 285E-03 00225 584E-04 00162 263 1282 488
Ring Detectors 1 m 133E-02 00116 492E-03 00115 108E-03 00124 271 1229 454 2 m 756E-03 00118 279E-03 00110 605E-04 00128 271 1250 462
Source Attachment II MCNP-Results1xls worksheet Summary
Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 142E-02 00368 628E-03 00446 934E-04 00483 226 1520 672
1 m 570E-03 00289 263E-03 00426 375E-04 00381 217 1520 701 2 m 265E-03 00364 123E-03 00547 169E-04 00374 216 1575 730
Point Detectors 1 m 598E-03 00238 274E-03 00271 402E-04 00354 219 1489 681 2 m 273E-03 00218 123E-03 00245 180E-04 00336 221 1515 684
Source Attachment II MCNP-Results1xls worksheet Summary
Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 653E-03 00298 265E-03 00276 510E-04 00341 247 1278 518
1 m 276E-03 00238 112E-03 00208 207E-04 00249 248 1334 539 2 m 125E-03 00185 508E-04 00199 933E-05 00246 246 1336 544
Point Detectors 1 m 291E-03 00227 118E-03 00203 218E-04 00242 247 1335 540 2 m 130E-03 00209 524E-04 00187 955E-05 00233 247 1357 549
Source Attachment II MCNP-Results1xls worksheet Summary
Tables 13 14 and 15 are results of calculation set 1 for conceptual Cask A with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
39
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 265E-02 00247 990E-03 00222 215E-03 00278 268 1234 461
1 m 116E-02 00178 468E-03 00549 960E-04 00189 248 1208 488 2 m 713E-03 00273 265E-03 00161 602E-04 00360 269 1184 439
Ring Detectors 1 m 117E-02 00120 454E-03 00132 979E-04 00141 259 1199 463 2 m 722E-03 00130 276E-03 00141 589E-04 00153 261 1226 469
Source Attachment II MCNP-Results2xls worksheet Summary
Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 199E-02 00461 827E-03 00455 147E-03 00536 241 1359 564
1 m 849E-03 00564 323E-03 00314 563E-04 00418 263 1507 574 2 m 415E-03 00832 158E-03 00603 253E-04 00501 263 1641 623
Point Detectors 1 m 877E-03 00348 353E-03 00275 615E-04 00391 248 1426 574 2 m 393E-03 00341 160E-03 00278 270E-04 00378 246 1454 590
Source Attachment II MCNP-Results2xls worksheet Summary
Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 879E-03 00374 356E-03 00333 669E-04 00406 247 1315 533
1 m 365E-03 00223 147E-03 00209 269E-04 00253 248 1358 548 2 m 164E-03 00229 674E-04 00205 120E-04 00248 243 1364 560
Point Detectors 1 m 383E-03 00217 155E-03 00204 285E-04 00248 247 1347 546 2 m 172E-03 00197 689E-04 00186 124E-04 00225 249 1391 558
Source Attachment II MCNP-Results2xls worksheet Summary
Tables 16 17 and 18 ar e results of calculation set 2 for conceptual Cask A with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
40
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
2221 DOE 2007 Software Validation Report for MCNP5 v140 Document ID 11199-SVR-140-00-WINXP Las Vegas Nevada US Department of Energy Office of Repository Development ACC MOL200702280252 [DIRS 180516]
2222 DOE 2008 Transportation Aging and Disposal Canister System Performance Specification WMO-TADCS-000001 Rev 1 ICN 1 Washington DC US Department of Energy Office of Civilian Radioactive Waste Management ACC DOC200803310001 [DIRS 185304]
2223 Harmon CD II Busch RD Briesmeister JF and Forster RA 1994 Criticality Calculations with MCNPtrade A Primer LA-12827-M Los Alamos New Mexico Los Alamos National Laboratory TIC 234014 [DIRS 154532]
2224 LANL (Los Alamos National Laboratory) 2004 MCNP mdash A General Monte Carlo N-Particle Transport Code Version 5 (Appendix H is not included) LA-UR-03-1987 Volume I Los Alamos [New Mexico] Los Alamos National Laboratory ACC MOL200510240126 [DIRS 176521]
2225 MCNP5 V 140 2007 Windows XP STN 11199-140-00 [DIRS 180515]
2226 Parrington JR Knox HD Breneman SL Baum EM and Feiner F 1996 Nuclides and Isotopes Chart of the Nuclides 15th Edition San Jose California General Electric Company and KAPL Inc TIC 233705 LC Call Number QC7935 N8622 1996
2227 Punatar MK 2001 Summary Report of Commercial Reactor Criticality Data for Crystal River Unit 3 TDR-UDC-NU-000001 REV 02 Las Vegas Nevada Bechtel SAIC Company ACC MOL200107020087 [DIRS 155635]
2228 Sisley SE 2002 Transportation License Application for the FuelSolutionstrade System (TAC No L23311) Submittal of the FuelSolutiontrade Transportation SARs Revision 3 Letter from SE Sisley (BNFL) to the NRC April 11 2002 BFSNRC 02-011 with enclosures TIC 255245 [DIRS 171545]
NOTE Reference 2220 is a direct input but is not QA QA It is justified as acceptable for the intended use as it is directly from the DOE and is considered the best available data on the subject The referenced values cited in Tables 3 and 4 are valid for use since they are reliable and reasonable based on engineering judgment
23 DESIGN CONSTRAINTS
231 10 CFR 71 2008 Energy Packaging and Transportation of Radioactive Material Internet Accessible [DIRS 185678]
12
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
24 DESIGN OUTPUTS
The resu lts of this calculation will be us ed to substan tiate th e dose reduc tion f actor in the Repository ALARA Goal Compliance (Reference 227) which is cited as a reference in a PCSA calculation that supports the License Application
13
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
3 ASSUMPTIONS
31 ASSUMPTIONS REQUIRING VERIFICATION
None
32 ASSUMPTIONS NOT REQUIRING VERIFICATION
Assumptions 321 322 and 323 are m odeling assum ptions and do not require further verification The m aterials and dim ensions for the TAD canister and for the conceptu al transportation casks are only selected to charac terize two tr ansportation casks th at m eet 10 CFR7147 (Reference 231) dose rates when lo aded with the ldquom aximumrdquo and ldquoaveragerdquo pressurized water re actor (PW R) assem blies re spectively There is n o need to v erify those dimensions or m aterials at a later date The ca lculated results in Sect ion 711 verify that the conceptual casks would meet 10 CFR 7147 (Reference 231) dose rates
321 Material and Wall Thickness of TAD Canister
Assumption It is assumed that the TAD canister is made of stainless steel 316 (SS 316) and has a wall thickness of 025 in for the radial and bottom shells
Rationale Currently the design of the TAD canis ter d oes not ex ist Based on a survey of existing m ultipurpose a nd dual purpose caniste rs (DPC) (Ref erence 2214 p 56) a 025 in thickness is below the wall thick ness of any existing c anisters For the purp ose of this calculation this assumption leads to higher and conservative external dose rates Since SS 316 is the sam e material used for the waste pack age inner shell it is a l ogical cho ice f or the TAD canister
Although Reference 2214 is an engineering study with a QA N A status it is used here as an indirect input to support the assumption which is conservative for dose rate calculations
Usage This assumption is used in Sections 621 and 625
322 Material and Thickness of TAD Shield Plug
Assumption It is assu med that the TAD shield plug is made of SS 316 and has a thickness of 11 in
Rationale Currently the design of the TAD canister doe s not exist A thick shield plug of 11 in (Reference 2215 Table 12) is needed to keep the m aximum contact dose rate of the top surface below 1000 mrem hr (Reference 2222 Section 314) Since SS 316 is the sam e material used for the waste package inner shell it is a logical choice for the TAD shield plug
Usage This assumption is used in Section 621
14
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
323 Geometry and Materials of Conceptual TAD Transportation Casks
Assumption Two conceptual TAD transpo rtation casks designated as Cask A and Cask B are assumed to have a cylindrical geom etry and m aterials specified in Tab les 1 and 2 respectively The casks are basically construc ted of an inner layer of SS 316 for ga mma shielding a m iddle layer of 5-borated polyethylen e for neutron shielding and a th in outer layer of SS 316 whic h serves a structural function as well as shielding secondary gamma rays
Both Cask A and Cask B have a cavity height of 53785 cm (21175 in) and a cavity diameter of 16891 cm (6650 in) However Cask A has a total height of 610845 cm (24049 in) and an outside diameter of 26797 cm (10550 in) while the total height and outside diameter of Cask B are 58885 cm (23183 in) and 24765 cm (9750) respectively
Cask A will provide shielding to m eet the exterior radiat ion standards of 10 C FR 7147(b) (Reference 231) when loaded w ith a TAD canister carrying th e maximum PWR spent nuclear fuel (SNF) Cask B will satisf y the same radiation standards when loade d with a TAD caniste r carrying the average PWR SNF
Table 1 Geometry and Materials of Conceptual TAD Transportation Cask A
Component Dimension
Material (cm) (in)
Total Height 61085 2404 9 NA
Outside Diameter 26797 1055 0 NA
Cask Cavity Height 53785 2117 5 NA
Cask Cavity Diameter (Radius) 16891 (8446) 6650 (3325) NA
Radial Gamma Shield Thickness (Radius)a 3302 (11748)a 1300 (4625)a SS 316
Radial Neutron Shield Thickness (Radius)b 1524 (13272)b 600 (5225)b 5-borated polyethylene
Radial Outer Shell Thickness (Radius)c 127 (13399)c 050 (5275)c SS 316
Top Gamma Shield Thickness (Axial Position)d 600 (54385)d 236 (21411)d SS 316
Top Neutron Shield Thickness (Axial Position)d 1000 (55385)d 394 (21805)d 5-borated polyethylene
Top Outer Shell Thickness (Axial Position)d 200 (55585)d 079 (21884)d SS 316
Bottom Gamma Shield Thickness (Axial Position)d 35365 (-360)d 1392 (-1417)d SS 316
Bottom Neutron Shield Thickness (Axial Position)d 15 (-510)d 591 (-2008)d 5-borated polyethylene
Bottom Outer Shell Thickness (Axial Position)d 4 (-550)d 157 (-2165)d SS 316 a11748 = 3302 + 8446 and 4625 = 1300 + 3325 b13272 = 1524 + 11748 and 5225 = 600 + 4625 c13399 = 127 + 13272 and 5275 = 050 + 5225 dCoordinate relative to the bottom of the fuel assembly as modeled in MCNP5
15
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 2 Geometry and Materials of Conceptual TAD Transportation Cask B
Component Dimension
Material (cm) (in)
Total Height 58885 2318 3 NA
Outside Diameter 24765 9750 NA
Cask Cavity Height 53785 2117 5 NA
Cask Cavity Diameter (Radius) 16891 (8446) 6650 (3325) NA
Radial Gamma Shield Thickness (Radius)a 254 (10986)a 1000 (4325)a SS 316
Radial Neutron Shield Thickness (Radius)b 127 (12256)b 500 (4825)b 5-borated polyethylene
Radial Outer Shell Thickness (Radius)c 127 (12383)c 050 (4875)c SS 316
Top Gamma Shield Thickness (Axial Position)d 8 (54585)d 315 (21490)d SS 316
Top Neutron Shield Thickness (Axial Position)d None Non e NA
Top Outer Shell Thickness (Axial Position)d None Non e NA
Bottom Gamma Shield Thickness (Axial Position)d 3837 (-390)d 1510 (-1535)d SS 316
Bottom Neutron Shield Thickness (Axial Position)d 300 (-420)d 118 (-1654)d 5-borated polyethylene
Bottom Outer Shell Thickness (Axial Position)d 100 (-430)d 039 (-1693)d SS 316 a10986 = 254 + 8446 and 4325 = 1000 + 3325 b12256= 127 + 10986 and 4825 = 500+ 4325 c12383 = 127 + 12256 and 4875 = 050 + 4825 dCoordinate relative to the bottom of the fuel assembly as modeled in MCNP5
Rationale Currently a design for the TAD transporta tion cask does not exist The casks assumed for this calculation are so lely for estim ation of the dose reduction due to different source terms This is a conceptual repres entation only used in this calculation to estim ate the parameters of interest
Usage This assumption is used in Sections 61 and 622
324 Usage of Unirradiated Fuel for Commercial SNF
Assumption It is assumed that the active fuel region of the commercial SNF assembly contains the same isotopic concentrations as the fresh uni rradiated fuel and that the concentrations of fresh fuel with 5 initial enrichm ent corresp onding to m aximum SNF are used for all other SNFs
Rationale This assumption is a standard practice for shielding calculations throughout the industry accepted by the U S Nucle ar Regulatory Commission (NRC) (Reference 2228 Table 53-5) It sh ould be noted that this assumption applies to material composition only it does no t apply to source terms which are based on the characteristics of spent fuel
Usage This assumption is used in Sections 624 and 626
325 Homogenization of Radiation Source Regions
Assumption It is assu med that a commercial SNF assembly consis ts of four distinct reg ions (active fuel bottom end-fitting plenum and top end-fitting) The materials and radiation sources
16
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
of each assembly region are homogenized inside a volume defined by the TAD cavity radius and region height
Rationale The assembly representation is consistent with the industry practice for shielding calculations accepted by NRC (Reference 2228 Figure 53-6) The effec t of source homogenization is twofold (1) it d ecreases th e m ass de nsity of the source region and (2) it places source points slightly closer to detector locations thus reducing radiation attenuation The resu lts of Calculation of the Effect of Source Geometry on the 21-PWR WP Dose Rates (Reference 2218 pp 22-26) indicate that th e effect of assem bly homogenization gives nearly the same or conservative dose rates as the explicit fuel assembly model
Usage This assumption is used in Section 624
326 Ignoring Internal Fuel Basket Materials
Assumption It is assumed that the internal fuel basket materials are ignored
Rationale Inclusion of fuel basket m aterials in the smeared m aterial com position would increase the overall density and consequently increase the attenuati on of the radiation Therefore this assumption is conservative
Usage This assumption is used in Sections 621 624 and 626
17
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
4 METHODOLOGY
41 QUALITY ASSURANCE
This calculation was prepared in accordance with EG-PRO-3DP-G04B-00037 Calculations and Analyses (Reference 212) The results of th is calculation provides worker dose assessm ent adjustments and this will id entify radio logical hazards f or f acilities im portant to saf ety Therefore the approved version is designated as QA QA
42 USE OF COMPUTER SOFTWARE
421 Baseline Software
The Monte Carlo N-Particle com puter pr ogram (MCNP5) version 140 (Reference 2225) is used to calculate the dose rates (neutron pr imary gamm a and secondary gamm a) at various locations around a transportation cask and an aging overpack
The software specifications are as follows
bull Program Name MCNP5 bull VersionRevision Number Version 140 bull Operating Systems Windows XP bull Software Tracking Number 11199-140-00 bull Computer Type Dell OPTIPLEX GX620
MCNP5 which is Level 1 software is (a) appropriate for three-dim ensional neutron gamma and coupled neutrongamma shielding calculations (b) used within th e range of validation as documented in Software Validation Report for MCNP5 v140 (Reference 2221) and (c) obtained from Software C onfiguration Managem ent and qualified in accordance with procedure IT-PRO-0012 Qualification of Software (Reference 213) Therefore MCNP5 code is suitable for use in this design calculation All MCNP5 input and output files docum ented in this calculation are provided on a compact disc (CD) as Attachment II
All MCNP cases are executed on one of the following Q com puters QNW -004184 QNW -004187 QNW-004194 and QNW-004196 as shown in the output files
422 Commercial off the Shelf Software
The Excel sof tware is used to c alculate var ious inpu t values (i e atom densities weight percentages geometrical dimensions normalized source spectra and probabilities etc) Standard functions of Excel are also used in this desi gn calculation to display results (ie gamma and neutron dose rates) in tabular and graphic forms and to perform relative error calculations
The software specifications are as follows
bull Program Name Excel bull VersionRevision Number Microsoftreg Excel 2003
18
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
bull This software is installed on a persona l com puter running Microsoft W indows XP (central processing unit number 151834)
The user defined for mulas inputs results and gr aphical representations have been verified by hand calculations or visual inspection and are documented in sufficient detail to allow an independent repetition of the com putations Calculations were verifi ed by hand and graphical representations were found accurate by visual inspection
Per Software Management Microsoftreg Excel is not requir ed to be qualif ied due to its commercial availability status (Reference 211 Attachment 4 p 55 bullet 2)
43 CALCULATION APPROACH
This calculation em ploys the qualified so ftware MCNP5 version 140 (Reference 2225) a three-dimensional Monte Carlo code for pe rforming neutron and coupled neutron-gamm a calculations to estim ate dose rates at sele cted locations on and surrounding a conceptual transportation cask containing a loaded TAD canister
431 MCNP5 Program
MCNP5 a general Monte Carlo part icle transport code sim ulates particle transport through a three-dimensional representation of the nuclear system being analyzed During the random walk of particles through the system described by the geom etry the c ode collects inform ation about various events (su rface cross ing collis ions trac k leng th etc) and es timates fluxes in various geometric configurations specified as tallies by the user It also estimates the statistical precision of the results in the form of relative errors (Reference 2224 pp 1-2 to 1-8)
Per Project Design Criteria Document (Reference 2211 Section 41015) the flux estim ates are converted to dose rates using the Am erican Nuclear Society (ANS) flux-to-dose rate conversion factors for gammas and neutrons (R eference 221) The simple variance reduction techniques of Geometry SplittingRussian Roulette and source probability biasing (Sections 631 and 633) are used to enhance computational efficiency
19
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
5 LIST OF ATTACHMENTS
Number of Pages Attachment I List of Electronic Files on the CD 3 Attachment II Compact Disc NA
20
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
6 CALCULATIONS
This sectio n provides inform ation necess ary to perform the calcu lations in this docum ent Section 61 describes the configurations the type of CSNF to be analyzed the number of MCNP runs and the locations where dose rates are ca lculated Section 62 provides the calculation input that includes the details of the geom etry m odel radiation source term s and m aterial compositions Input specific to MCNP dose -rate conversion factors and relative error calculation are described in the later sections
61 DESCRIPTION OF CALCULATIONS
Dose rate calculations are perform ed with the MCNP5 version 140 com puter code (Reference 2225) Two conceptual transportation casks Cask A and Cask B (Assum ption 323) are employed Each cask contains a TAD canister that is loaded with 21 ident ical PW R SN F assemblies Three PWR source term s are analy zed they are the source term s corresponding to the maximum design basis and average PW R SN Fs The characteris tics of the P WR source terms are presented in S ection 627 Each PWR source term has neutron and ga mma radiation sources that require separate MCNP5 runs For each radiation source an axial profile source and a uniform source for the active fuel region are considered The uniform source for the active fuel region is included in this calculation because this approach was used in combination with source peaking factors in certain calculations (Reference 2216 Sections 37 and 39 and Reference 2217 Section 5242)
The total number of MCNP5 runs is 24 which re sults from a com bination of two conceptual casks three PWR source terms two radiation sources and two axia l source distributions for the active fuel region These 24 runs are categorized into four calcula tion sets Each calculation set consists of six runs that is a combination of three PWR source te rms and two radiation sources The characteristics of each calculation set are as follows
1 Cask A with axial profile sources in the active fuel region
2 Cask A with uniform axial sources in the active fuel region
3 Cask B with axial profile sources in the active fuel region
4 Cask B with uniform axial sources in the active fuel region
For each MCNP5 run dose rates are calculated at the exte rior surfaces and at distances 1 and 2 meters from the exterior surfaces Surface tallies and detector tallies (ring and point detectors) as indicated in Figure 1 are e mployed in all runs Figure 1 is used to illustrate the dep loyment of the surface and detector tallies re lative to the so urce regions and it should not be interpreted as an exact geometry of any particular run Surface tallies are deployed at all three distances while ring and point detectors are used only at 1 m and 2 m and not at the cask surfaces Using point detectors near a surface or in any scattering media is not recommended because very large scores can occur f rom collisions close ( less than a f ew centimeters) to the point detecto rs that can lead to resu lts with high r elative e rrors thus m aking the ca lculation d ifficult to o btain r eliable answers
21
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
For the radial direction surface tallies at the three distances (contact 1 m and 2 m) are computed for three su rface segments (cylindrical rings) between the planes at Z = 145 175 2 05 and 235 cm The geometric locations of the segments are shown in Figure 1 The axial locations of these segments correspond to the m iddle of the active fuel region of the PWR SNF assemblies The average dose rates for each of the segm ents are calculated for the outside surface and surfaces at 1 m and 2 m from the cask surface Two ring detectors (instead of point detectors) are deployed at 1 m and 2 m for the radial dire ction Ring detectors instead of point detectors are used in order to capitalize on the symm etry around the cask axis thus im proving the efficiency of the calculations
In the axial direction the average d ose rates within three concentric radial surfaces defined by radii of 40 80 and 120 cm (shown in Figure 1) are calculated for the top and bottom surfaces and at distances 1 m and 2 m from these surfaces Finally point detectors at 1 m and 2 m from the top and bottom axial surfaces are employed
22
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Point Detector at 2 m x
Ring Ring Detector Detector at 2 m at 1 m
x x
Z = 00 cm
Z = 145 cm
Z = 175 cm
Z = 205 cm
Z = 235 cm
R = 80 cm
R = 120 cm
R = 40 cm
Active Fuel
Shield Plug
Top End-Fitting Plenum
Bottom End-Fitting
Ring Detector at 1 m
x
Point Detector at 1 m x
Ring Detector
at 2 m x
D = 26797 cm
H =
610
845
cm
Point Detector at 1 m x
Point Detector at 2 m x
Figure 1 Geometry and Tally Scheme for the TAD Transportation Cask
23
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
62 CALCULATION INPUT
Technical product input and sources of the input used in the deve lopment of this calculation are documented in this section Tables in this docum ent and in th e associated Microsoftreg Excel spreadsheets referenced m ay present num erical values with m any significant figures these values are not to be considered as high precision values since the significant figures are results of calculated values andor unit conversions
621 TAD Canister
The TAD canis ter will contain either 21 P WR or 44 BW R (boiling water reactor) SNF assemblies (Reference 2222 Section 321) While the canister design is iden tical for both PWR and BWR SNF assemblies the internal basket structure is different depending on the SNF assemblies However the internal basket stru cture m aterial is no t in cluded in the calcu lation model (Assumption 326)
The TAD canister is a right-circu lar cylinder with a diam eter of 665 in and a height between 186 and 212 in (Reference 2222 Section 321) The average and maximum total dose rates on the top surf ace of a loaded TAD ca nister must not exceed 800 and 1000 m remhr respectively (Reference 2222 Section 314) The TAD canister used in this calculation is m ade of SS 316 with a radial wall and bottom thickness of 025 in (Assumption 321) The top of the canister has a shield plug that is 11 in thick SS 316 (Ass umption 322) A thick shield plug is needed to keep the maxim um contact dose rate of th e top surface below 1000 m remhr The overall dimensions of the TAD canister are provided in Table 3
Table 3 Dimensions of TAD Canister
Component Dimension
(in) (cm)
Maximum heighta 212 53848
Outer diametera 665 16891
Thickness of bottom lidb 025 0635
Shell thicknessb 025 0635
Lifting Featurec 6 1524
Height without Lifting Feature 206 52324
Thickness of shield plugd 110 2794
aReference 2222 Section 311 bAssumption 321 cReference 2222 p Attachment C-1 dAssumption 322
622 Conceptual TAD Transportation Casks
Two conceptual TAD transportation casks designa ted as Cask A and Cask B are em ployed in this calculation (Assumption 323) They both have a cylindrical geometry with dimensions and materials specified in Tables 1 and 2 of Section 323 Cask A will provide shielding to meet the exterior radiation standards of 10 CFR 7147(b) (Reference 231) when loaded with a TAD
24
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
canister car rying the m aximum PWR SNF Cask B will s atisfy th e sa me radiatio n standa rds when loaded with a TAD canister c arrying the average PWR SNF The reason to analyze both Casks A and B is to cover a broad range of characteristics of the CSNF
The cavity dimensions of the conceptual cask s are 53785 cm (21175 in) in height and 16891 cm (665 in) in diam eter (Tab les 1 and 2) This cav ity will accommoda te the TAD canister described in Table 3 without the lifting feature This is the geometry model used in the MCNP5 calculations
623 Fuel Assembly Selection
PWR and BWR Source Term Sensitivity Study (Reference 2211 Tables 71 through 84) shows that the source terms generated for the Bamp W 15x15 Mark B fuel assembly with 475 kg uranium loading bound the source terms of other PWR assembly types ther efore this assembly type is selected as the representative PWR fuel assembly The gamma and neutron source terms for the BampW 15x15 Mark B assembly are generated in PWR Source Term Generation and Evaluation (Reference 229) and are used in this calculation
624 BampW 15x15 Mark B PWR Fuel Assembly
BampW 15x15 Mark B fuel assembly consists of four regions top end-fitting plenum active fuel and bottom end-fitting The m aterials and ra diation sources of each assem bly region are homogenized inside a volume defined by the region height and the interior diam eter of the TAD canister (Assumption 325) The active fuel region is homogenized with fresh unirradiated fuel (Assumption 324) Since the internal structure (i e basket) design of t he TAD is currently not finalized the com position of the hom ogenized fuel does not include the basket m aterials (Assumption 326) and therefore does not take cred it for any shielding that these m aterials may provide
Table 4 provides the design param eters for the BampW 15x15 Mark B fuel assembly Data provided here are used in Attachment II PWR_fuel compxls worksheet BampWassy
25
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 4 BampW 15x15 Mark B Fuel Assembly Description
Component Material Characteristic Value Specific Reference Array Size 15 x 15
Reference 2227 Table 2-2 Fuel Pins Assembly 208 Guide Tubes Assembly 16 Instrument Tubes Assembly 1
Assembly NA Pin Pellet Diameter 0936244 cm (03686 in) Reference 2220 p 2A-34 Pin Pitch 144272 cm (0568 in)
Reference 2227 Table 2-2 Active Fuel Height 360172 cm (1418 in) Assembly Width 2168144 cm (8536 in)
Reference 2220 p 2A-31 Assembly Height 4206875 cm (165625 in) Mass U assembly 46363 kg
Guide tube Zircaloy-4 Outer Diameter 13462 cm (053 in)
Reference 2227 Table 2-2
Inner Diameter 126492 cm (0498 in)
Instrument tube Zircaloy-4 Outer Diameter 138193 cm (05441 in) Inner Diameter 112014 cm (0441 in)
Cladding` Zircaloy-4 Inner Diameter 095758 cm (0377 in) Outer Diameter 10922 cm (043 in)
Plenum region NA Length 297688 cm (11720 in) Reference 2220 p 2A-34 Top nozzle SS CF3M MassAssembly (Top) 748 kg
Reference 2220 p 2A-32
Bottom nozzle SS CF3M MassAssembly (Bottom) 816 kg Guide tubes Zircaloy-4 MassAssembly (in Core) 80 kg Instrument tube Zircaloy-4 MassAssembly (in Core) 064 kg Spacer-plenum Inconel-718 MassAssembly (Plenum) 104 kg Spacer-bottom Inconel-718 MassAssembly (Bottom) 13 kg Spacer-in core Inconel-718 MassAssembly (in Core) 49 kg Spring retainer SS CF3M MassAssembly (Top) 091 kg Holddown spring Inconel-718 MassAssembly (Top) 18 kg Upper end plug SS 304 MassAssembly (Top) 006 kg Upper nut SS 304L MassAssembly (Top) 051 kg Lower nut SS 304 MassAssembly (Bottom) 015 kg Grid supports Zircaloy-4 MassAssembly (in Core) 064 kg Plenum spring SS 302 MassAssembly (Plenum) 0042 lb (001905 kg) Reference 2220 p 2A-34
Note Som e d ata i n this tab le ar e given i n British u nits in th e r eferences thes e d ata ar e converted into metric units as the inputs to MCNP5 are in metric units
The assem bly region heights as m odeled in MC NP are presented in Table 5 utilizing values from Table 4 Table 5 is taken from Dose Rate Calculation for Exhaust Main Drifts (Reference 2213 Table 3)
26
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 5 PWR Fuel Assembly Regions
Component Height Reference
Plenum 297688 cm (11720 in) Reference 2220 p 2A-34
Active Fuel 360172 cm (1418 in) Table 3
Bottom End-Fitting 1077 cm (424 in) Calculateda
Top End-Fitting 1998 cm (787 in) Calculatedb
Source Reference 2213 Table 3 aCalculated b ased on data Reference 2227 F igures 2-3 an d 2-7
(Region 9 Height [16723 cm] + Region 10 Height [508 cm] ndash Lo wer Fuel Plenum and End Cap [11033 cm])
bCalculated (Assembly Length ndash Active Fuel Length ndash P lenum Length ndash Bottom End-fitting Length)
625 Material Compositions
The TAD transportation cask com ponent m aterial specifications are defined in Table 1 The TAD canister is constructed of SS 316 (Assumpti on 321) The PWR fuel assembly materials used to homogenize the fuel regions are defined in Table 4 Table 6 c ontains the m aterial compositions defining the TAD canister WP and fuel assemblies
27
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 6 Chemical Compositions of Materials
Material Density (gcc)
Isotopic Weight Percent Reference
SS 302 NA
C 0150 Mn 2000 P 0045 S 0030 Si 0750 Cr 18000 Ni 9000 N 0100 Fe 69925
Attachment II PWR_fuel compxls worksheet ferrous Reference 222 SEC II A SA-240 Table 1 for SS 302 SS 304 and SS 304L Reference 222 SEC II A SA-351SA -351M Table 2 for SS CF3M
SS 304 NA
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 9250 N 0100 Fe 68745
SS 304L NA
C 003 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 10000 N 0100 Fe 6804 5
SS CF3M NA
C 0030 Mn 1500 P 0040 S 0040 Si 1500 Cr 19000 Ni 11000 Mo 2500 Fe 64390
Inconel 718 NA
C 0080 Mn 0350 Si 0350 Cr 19000 Ni 52500 Co 1000 Mo 3050 Fe 16809 Nb 5125 Ti 0900 Al 0500 Cu 0300 S 0015 P 0015 B 0006
Attachment II PWR_fuel compxls worksheet alloys aReference 223 p 666 Table 6 Reference 222 SEC II B SB-637 Table 1 for Inconel 718 Reference 224 Table 2 for Zircaloy 4
Zircaloy 4 656a Cr 0100 Fe 0210 O 0125 Sn 1450 Zr 98115
SS 316 798b
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 17000 Ni 12000 Mo 2500 N 0100 Fe 65495
Attachment II PWR_fuel compxls worksheet others Reference 222 SEC II A SA-240 Table 1 for SS 316 bReference 225 Table X1
626 Homogenization Assembly Materials
The atom density of an element or isotope in atomsbmiddotcm in a homogenized region is calculated according to the following equation (Reference 2223 Appendix B)
M i times N AvogadroNi = Equation 1 Ai timesV times K
where Ni = Atom density of elementisotope i (atomsbmiddotcm) Mi = Mass of elementisotope i (g) NAvogadro = Avogadrorsquos constant 06022 x 1024 (atomsmole)
28
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Ai = Atomic weight of elementisotope i (gmole) V = Homogenization volume (cm3) K = Unit transformation constant = 1024 (bmiddotcmcm3)
Equation 1 is used in A ttachment II spreadsheet PWR_fuel compxls worksheet BampWassy to calculate th e atom dens ities for v arious elem ents and iso topes The m ass of elementsisotop es and Avogadrorsquos constant are provided in Reference 2226
Table 7 lists the com position of the hom ogenized assem bly regions (active fuel plenum top end-fitting and bottom end-fitting) for the PWR assembly The active fuel region contains fresh unirradiated fuel (Assumption 324) Since the internal structure (ie basket) design of the TAD is currently not finalized the composition of either homogenized fuel does not include the basket materials and therefore does not tak e credit for any shielding that thes e materials may provide (Assumption 326)
Table 7 Isotopic Compositions of Homogenized PWR Assembly Regions
Element Isotope
Atom Densities for Homogenized Regions (atomsbsdotcm)
Active Fuel Bottom End-Fitting Plenum Top End-Fitting
10B 861E-09 764E-08 221E-08 570E-08 11B 347E-08 307E-07 890E-08 230E-07 C 519E-07 160E-05 138E-06 993E-06 N -- 570E-07 262E-08 117E-06 O 621E-03 -- 142E-05 -- Al 144E-06 128E-05 371E-06 957E-06 Si 971E-07 243E-04 259E-06 139E-04 P 377E-08 606E-06 102E-07 360E-06 S 365E-08 581E-06 971E-08 340E-06 Ti 147E-06 130E-05 376E-06 971E-06 Cr 320E-05 187E-03 779E-05 113E-03 Mn 497E-07 126E-04 141E-06 749E-05 Fe 303E-05 531E-03 717E-05 313E-03 Co 132E-06 117E-05 340E-06 876E-06 Ni 697E-05 144E-03 180E-04 940E-04 Cu 368E-07 327E-06 945E-07 244E-06 Zr 196E-03 -- 195E-03 -- Nb 430E-06 382E-05 110E-05 285E-05 Mo 248E-06 135E-04 636E-06 791E-05 Sn 223E-05 -- 222E-05 -- 234U 139E-06 -- -- -- 235U 157E-04 -- -- -- 236U 719E-07 -- -- -- 238U 294E-03 -- -- -- Total 114E-02 924E-03 235E-03 557E-03
Source Attachment II spreadsheet PWR_fuel compxls worksheet BampWassy
29
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
The isotopic composition of commercially available 235U enriched uranium is determined by the given initial 235U enrichment using the following equations (Reference 226 p 20)
wt235U =235Uenrichment _ of _ the _ associated _ fuel _ batch Equation 2
wt234U = 0007731times (wt235U )10837 Equation 3
wt236U = 00046times (wt235U ) Equation 4
wt238U =100 minus (wt234U + wt235U + wt236U ) Equation 5
The weight percentages of uran ium isotopes for PWR fuel are ca lculated in Attachm ent II spreadsheet PWR_fuel compxls worksheet BampWassy using Equations 2 through 5
627 PWR Source Terms
This calculation uses the following three PWR source terms bull Maximum source (50 wt initial 235U enrichment 80 GWdMTU burnup and 5-year
decay time) (Reference 229 Section 55) Table 8 lists th e gamma source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Design Basis source (4 0 wt initial 235U enrichment 60 GW dMTU burnup and 10-year decay tim e) (Reference 228 Section 552) Table 9 lists the gamm a source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Average source ( 40 wt initial 235U enrichment 48 GWdMTU burnup and 25-year decay time) (Reference 229 Section 55) Table 10 lists the gamma source terms for the fuel and non-fuel regions and the neutron source term for the fuel region
These sources (ie maximum design basis and av erage) are described in this section For dose rate calculations all the fuel assemblies in a transportation cask are of the sam e characteristics Also gamma radiation source term s for the PWR assem bly are prov ided for the f our assembly regions while neutron source term is only present in the active fuel region Gamma radiation sources in the non-active fuel region are distri buted unif ormly within each source region Gamma and neutron sources in the active fuel re gion are modeled as uni form distributions or with axial source profiles
The PWR gamma and neutron axial source profiles for the active fuel region presented in Table 11 are applied to the active fuel region of all three source terms (ie maximum design basis and average) when appropriate
30
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 8 Gamma and Neutron Sources for the Maximum PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting
Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 594E+11 233E+15 528E+11 379E+11 100E-01 000E+00 100E-01 116E+11 644E+14 609E+10 743E+10 400E-01 805E+07 200E-01 283E+10 522E+14 352E+10 179E+10 900E-01 411E+08 300E-01 141E+09 148E+14 196E+09 891E+08 140E+00 376E+08 400E-01 190E+09 985E+13 586E+09 117E+09 185E+00 276E+08 600E-01 191E+09 153E+15 110E+11 741E+07 300E+00 485E+08 800E-01 435E+09 470E+15 595E+10 237E+09 643E+00 443E+08 100E+00 137E+11 708E+14 803E+09 766E+10 200E+01 393E+07 133E+00 338E+13 455E+14 174E+13 217E+13 Total 211E+09 166E+00 953E+12 130E+14 491E+12 612E+12
--
200E+00 187E+03 144E+12 919E+02 113E+03 250E+00 226E+08 249E+12 116E+08 145E+08 300E+00 351E+05 110E+11 181E+05 225E+05 400E+00 766E-08 139E+10 100E-08 416E-08 500E+00 000E+00 709E+07 000E+00 000E+00 650E+00 000E+00 286E+07 000E+00 000E+00 800E+00 000E+00 558E+06 000E+00 000E+00 100E+01 000E+00 119E+06 000E+00 000E+00
Total 442E+13 113E+16 231E+13 284E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE2R2B14cut bWasteStreamE2R1B14cut cWasteStreamE2R3B14cut dWasteStreamE2R4B14cut
31
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 9 Gamma and Neutron Sources for the Design Basis PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary
(MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 273E+11 121E+15 188E+11 175E+11 100E-01 000E+00 100E-01 528E+10 329E+14 277E+10 339E+10 400E-01 316E+07 200E-01 128E+10 245E+14 117E+10 819E+09 900E-01 161E+08 300E-01 639E+08 713E+13 633E+08 407E+08 140E+00 148E+08 400E-01 850E+08 455E+13 164E+09 533E+08 185E+00 109E+08 600E-01 492E+08 226E+14 269E+10 337E+07 300E+00 191E+08 800E-01 291E+09 237E+15 160E+10 186E+09 643E+00 174E+08 100E+00 540E+09 122E+14 248E+09 341E+09 200E+01 154E+07 133E+00 154E+13 195E+14 797E+12 990E+12 Total 830E+08 166E+00 435E+12 450E+13 225E+12 280E+12
--
200E+00 235E+00 152E+11 149E+02 215E-02 250E+00 103E+08 517E+10 534E+07 664E+07 300E+00 160E+05 379E+09 829E+04 103E+05 400E+00 943E-10 497E+08 155E-10 519E-10 500E+00 000E+00 282E+07 000E+00 000E+00 650E+00 000E+00 113E+07 000E+00 000E+00 800E+00 000E+00 222E+06 000E+00 000E+00 100E+01 000E+00 471E+05 000E+00 000E+00
Total 201E+13 486E+15 105E+13 129E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B11cut bWasteStreamE5R1B11cut cWasteStreamE5R3B11cut dWasteStreamE5R4B11cut
32
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 10 Gamma and Neutron Sources for the Average PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 336E+10 670E+14 186E+10 217E+10 100E-01 00000E+00 100E-01 602E+09 199E+14 314E+09 387E+09 400E-01 748E+06 200E-01 146E+09 126E+14 853E+08 936E+08 900E-01 382E+07 300E-01 730E+07 389E+13 439E+07 469E+07 140E+00 352E+07 400E-01 947E+07 263E+13 716E+07 607E+07 185E+00 261E+07 600E-01 141E+07 205E+13 504E+08 383E+06 300E+00 469E+07 800E-01 208E+09 124E+15 192E+09 144E+09 643E+00 418E+07 100E+00 208E+09 110E+13 164E+09 144E+09 200E+01 365E+06 133E+00 175E+12 295E+13 909E+11 112E+12 Total 199E+08 166E+00 494E+11 513E+12 257E+11 318E+11
--
200E+00 973E-01 675E+10 614E+01 872E-03 250E+00 117E+07 353E+09 609E+06 754E+06 300E+00 182E+04 288E+08 944E+03 117E+04 400E+00 186E-11 198E+07 149E-11 127E-11 500E+00 000E+00 669E+06 000E+00 000E+00 650E+00 000E+00 269E+06 000E+00 000E+00 800E+00 000E+00 527E+05 000E+00 000E+00 100E+01 000E+00 112E+05 000E+00 000E+00
Total 229E+12 237E+15 119E+12 147E+12
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B9cut bWasteStreamE5R1B9cut cWasteStreamE5R3B9cut dWasteStreamE5R4B9cut
33
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 11 Gamma and Neutron Axial Source Profiles for a PWR Assembly
Axial boundaries (From midplane)
(cm)
TOP BOTTOM
Neutron Gamma Ne utron Gamma 000 1554 1117 1554 1117 1143 1537 1114 1571 1120 2286 1521 1111 1588 1123 3429 1504 1108 1605 1126 4572 1486 1104 1622 1129 5715 1464 1100 1636 1131 6858 1438 1095 1648 1133 8001 1401 1088 1657 1135 9144 1350 1078 1654 1134
10287 1277 1063 1625 1129 11430 1165 1039 1554 1117 12573 0998 09995 1414 1091 13716 0769 09365 1172 1041 14859 0492 08375 0816 0951 16002 0220 06850 0402 0797 17145 0046 04625 0092 0551 18288 00 00 00 00
Source Reference 2219 Table S445
34
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
63 MCNP SPECIFIC INPUT
631 Source Probability
A linear radial distribution is used for all gamma and neutron sources The linear radial distribution is sam pled usi ng the built-in power function p(x) = xc a with a = 1 for the radial direction This sampling method results in a uniform source distribution over the area bounded by the outer radius of the source
The source axial distributions are unifor m for all four source regions The a xial uni form xp(x) = c distribution is sampled using the built-in power function a with a = 0 for extent
The energy distribu tions of the gamma and neutron sour ce term s are treated as energ y probabilities and are applied in MCNP5 using SISP cards
632 Dose Rate and Flux Tallies
MCNP5 dose rate calculations feature separate runs for the following calculation types
bull a photon transport calculation for prim ary ga mma contribution to the dose rates fr om photon fluxes
bull a coupled neutronphoton transport calculat ion for neutrons a nd secondary gamma (photons generated by neutron be ing captured) contributions to dose rates from neutron and gamma fluxes
The tally type F2 is us ed in th is d esign ca lculation as f lux estim ators The type F2 tally evaluates the flux averaged over a surface in particlescm2s
To generate dose ra tes in te rms of remhr the FM (tally multiplier ) and DEDF (dose energydose conversion factors) cards are used to en ter the tally multiplier f actor (source intensity in particless) energy boundaries in MeV and corresponding dose conversion factors in (remhr)(particlescm2s) respectively These factors were used in the input files
In order for the F2 tally to accum ulate flux ov er a surface a specific s urface area is requ ired The SD cards are used to enter a surface area in cm2 over which the flux will be tallied for an F2 tally
633 Variance Reduction Techniques
Variance reduction technique is usually em ployed in order to increase the efficiency of a calculation and obtain statistically m eaningful results within re asonable com puter tim e In Monte Carlo calculations when variance reduction scheme is employed the weights of particles are adjusted in order to account for the biasing and to preserve a fair game
Geometry splitting and Russian roulette techniques described in Reference 2224 (pp 2-140 ndash 2-142) are useful in shielding calculations and therefore deployed in all the MCNP5 runs
35
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
As particles migrate in an important direction (toward the detector) they are increased in number to provide better sampling by means of geometry splitting across geometric boundaries Russian roulette (the reverse process) is played when particles travel in an unimportant direction to allow termination of unim portant histories The IMP card required for every cel l ca rd is us ed to implement this technique
The other variance reduction technique deployed in the MC NP5 runs is source intensity biasing for the gamma sources from the four source regions (active fuel bottom end-fitting plenum and top end-fitting) The natural total gamma source intensity of comm ercial SNF is dom inated by the gamma source in the active fuel region This active fuel gamma source usually accounts for over 95 o f the total g amma source intens ity In order to im prove the efficiency of the axial dose rate calculations a biased source probability distribution is employed for the prim ary gamma dose rate calculations The biased gamma source probability distribution is chosen to be 005 080 010 and 005 for the bottom end-fitting the active fuel the plenum and the top end-fitting regions respectively
64 DOSE CONVERSION FACTORS
Project Design Criteria Document (Reference 2211 Se ction 41015) requires the use of flux-to-dose rate conversion fact ors from ANSIANS-611-1977 (Reference 221) for dose rate evaluations Table 16 lists the neutron and ga mma dose conversion factors used in the MCNP5 calculations
Table 12 Gamma and Neutron Flux to Dose Conversion Factors
Gamma Neutron Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
001 396E-06 140 251E-06 250E-08 367E-06 003 582E-07 180 299E-06 100E-07 367E-06 005 290E-07 220 342E-06 100E-06 446E-06 007 258E-07 260 382E-06 100E-05 454E-06 010 283E-07 280 401E-06 100E-04 418E-06 015 379E-07 325 441E-06 100E-03 376E-06 020 501E-07 375 483E-06 100E-02 356E-06 025 631E-07 425 523E-06 100E-01 217E-05 030 759E-07 475 560E-06 500E-01 926E-05 035 878E-07 500 580E-06 100E+00 132E-04 040 985E-07 525 601E-06 250E+00 125E-04 045 108E-06 575 637E-06 500E+00 156E-04 050 117E-06 625 674E-06 700E+00 147E-04 055 127E-06 675 711E-06 100E+01 147E-04 060 136E-06 750 766E-06 140E+01 208E-04 065 144E-06 900 877E-06 200E+01 227E-04 070 152E-06 1100 103E-05 080 168E-06 1300 118E-05 100 198E-06 1500 133E-05
Source Reference 221 Tables 1 and 3
36
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION
By def inition (Ref erence 2224 Equation 219) the estimated st atistic relative error of the i component is
Ri = Si
2
Equation 6Ti
where i = tally component index Ri = relative error of the i component S2
i = variance of the i component Ti = tally i component
For a result (ie dose rate) computed as a sum of different tallies the statistical relative error of the computed value is o btained from the variance of the result - S2
total which is th e sum of the estimated variances of the individual tallies S2
i n
2 2STotal = sum Si Equation 7 i=1
where S2Total = total estimated variance
n = total number of components Therefore the total tally value (dose rate) and the associated relative error are derived according to Equations 8 and 9
n TTotal = sumTi Equation 8
i=1
n n
sum (Ri timesTi )2
2 sum Si 2
STotal = i=1 = i=1 Equation 9RTotal = TTotal TTotal TTotal
where RTotal = total estimated relative error TTotal = total estimated tally
Equations 8 and 9 are utilized in Attachm ent II to ev aluate to tal dos e ra tes and their r elative errors
37
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
7 RESULTS AND CONCLUSIONS
71 RESULTS
The following sections summarize the results of this calculation Section 711 presents results for Conceptual Cask A while Section 712 for Conceptual Cask B Section 713 provides comparisons of the dose-rate reduction factors du e to the two conceptual casks and the axial source distributions in the active fuel region Do se rates and relative errors can be found in Attachment II within the output files and Excel files
711 Dose Rates of Conceptual Cask A
This section presents dose-rate results of the calculation sets 1 and 2 as described in Section 61 for Cask A Set 1 has axial p rofile sources in the active fuel region a nd consist of six runs resulting from the three PWR SNF source term s (maximum design basis and average) and the two radiation sources (gammas and neutrons) Set 2 has uniform axial sources in the active fuel region and consists of six run s r esulting f rom the th ree P WR SNF source term s and th e tw o radiation sources
As described in Section 61 dose ra tes are calculated at the three exterior surfaces (radial top and bottom) and at distances 1 m and 2 m from the exterior surfaces The total dose rates for set 1 are presented in Tables 13 14 and 15 for the ra dial top and bottom dire ctions respectively However the com ponents (primary gamma neutr on and secondary gamma) contributing to the total dose rates as well as the re lative error calculations can be found in Attachment II Excel file MCNP-Results1xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 2 are shown in Tables 16 17 and 18 The dose-rate components and the relative errors can be found in A ttachment II Excel file MCNP-Results2xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 13 and 16 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 14 and 17 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 15 and 18 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carrying th e maximum PWR SNF Based on the results in Tables 13 through 18 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask A indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these 6 tables the d ose-rate red uction f actors between the m aximum and the design basis fuels the maxim um and the averag e fuels and th e design basis and the average fuels are a lso presented
38
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 320E-02 00237 116E-02 00222 262E-03 00219 275 1223 445
1 m 133E-02 00164 494E-03 00171 106E-03 00162 269 1261 468 2 m 749E-03 00198 285E-03 00225 584E-04 00162 263 1282 488
Ring Detectors 1 m 133E-02 00116 492E-03 00115 108E-03 00124 271 1229 454 2 m 756E-03 00118 279E-03 00110 605E-04 00128 271 1250 462
Source Attachment II MCNP-Results1xls worksheet Summary
Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 142E-02 00368 628E-03 00446 934E-04 00483 226 1520 672
1 m 570E-03 00289 263E-03 00426 375E-04 00381 217 1520 701 2 m 265E-03 00364 123E-03 00547 169E-04 00374 216 1575 730
Point Detectors 1 m 598E-03 00238 274E-03 00271 402E-04 00354 219 1489 681 2 m 273E-03 00218 123E-03 00245 180E-04 00336 221 1515 684
Source Attachment II MCNP-Results1xls worksheet Summary
Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 653E-03 00298 265E-03 00276 510E-04 00341 247 1278 518
1 m 276E-03 00238 112E-03 00208 207E-04 00249 248 1334 539 2 m 125E-03 00185 508E-04 00199 933E-05 00246 246 1336 544
Point Detectors 1 m 291E-03 00227 118E-03 00203 218E-04 00242 247 1335 540 2 m 130E-03 00209 524E-04 00187 955E-05 00233 247 1357 549
Source Attachment II MCNP-Results1xls worksheet Summary
Tables 13 14 and 15 are results of calculation set 1 for conceptual Cask A with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
39
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 265E-02 00247 990E-03 00222 215E-03 00278 268 1234 461
1 m 116E-02 00178 468E-03 00549 960E-04 00189 248 1208 488 2 m 713E-03 00273 265E-03 00161 602E-04 00360 269 1184 439
Ring Detectors 1 m 117E-02 00120 454E-03 00132 979E-04 00141 259 1199 463 2 m 722E-03 00130 276E-03 00141 589E-04 00153 261 1226 469
Source Attachment II MCNP-Results2xls worksheet Summary
Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 199E-02 00461 827E-03 00455 147E-03 00536 241 1359 564
1 m 849E-03 00564 323E-03 00314 563E-04 00418 263 1507 574 2 m 415E-03 00832 158E-03 00603 253E-04 00501 263 1641 623
Point Detectors 1 m 877E-03 00348 353E-03 00275 615E-04 00391 248 1426 574 2 m 393E-03 00341 160E-03 00278 270E-04 00378 246 1454 590
Source Attachment II MCNP-Results2xls worksheet Summary
Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 879E-03 00374 356E-03 00333 669E-04 00406 247 1315 533
1 m 365E-03 00223 147E-03 00209 269E-04 00253 248 1358 548 2 m 164E-03 00229 674E-04 00205 120E-04 00248 243 1364 560
Point Detectors 1 m 383E-03 00217 155E-03 00204 285E-04 00248 247 1347 546 2 m 172E-03 00197 689E-04 00186 124E-04 00225 249 1391 558
Source Attachment II MCNP-Results2xls worksheet Summary
Tables 16 17 and 18 ar e results of calculation set 2 for conceptual Cask A with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
40
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
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Directory of DCDave
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I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
24 DESIGN OUTPUTS
The resu lts of this calculation will be us ed to substan tiate th e dose reduc tion f actor in the Repository ALARA Goal Compliance (Reference 227) which is cited as a reference in a PCSA calculation that supports the License Application
13
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
3 ASSUMPTIONS
31 ASSUMPTIONS REQUIRING VERIFICATION
None
32 ASSUMPTIONS NOT REQUIRING VERIFICATION
Assumptions 321 322 and 323 are m odeling assum ptions and do not require further verification The m aterials and dim ensions for the TAD canister and for the conceptu al transportation casks are only selected to charac terize two tr ansportation casks th at m eet 10 CFR7147 (Reference 231) dose rates when lo aded with the ldquom aximumrdquo and ldquoaveragerdquo pressurized water re actor (PW R) assem blies re spectively There is n o need to v erify those dimensions or m aterials at a later date The ca lculated results in Sect ion 711 verify that the conceptual casks would meet 10 CFR 7147 (Reference 231) dose rates
321 Material and Wall Thickness of TAD Canister
Assumption It is assumed that the TAD canister is made of stainless steel 316 (SS 316) and has a wall thickness of 025 in for the radial and bottom shells
Rationale Currently the design of the TAD canis ter d oes not ex ist Based on a survey of existing m ultipurpose a nd dual purpose caniste rs (DPC) (Ref erence 2214 p 56) a 025 in thickness is below the wall thick ness of any existing c anisters For the purp ose of this calculation this assumption leads to higher and conservative external dose rates Since SS 316 is the sam e material used for the waste pack age inner shell it is a l ogical cho ice f or the TAD canister
Although Reference 2214 is an engineering study with a QA N A status it is used here as an indirect input to support the assumption which is conservative for dose rate calculations
Usage This assumption is used in Sections 621 and 625
322 Material and Thickness of TAD Shield Plug
Assumption It is assu med that the TAD shield plug is made of SS 316 and has a thickness of 11 in
Rationale Currently the design of the TAD canister doe s not exist A thick shield plug of 11 in (Reference 2215 Table 12) is needed to keep the m aximum contact dose rate of the top surface below 1000 mrem hr (Reference 2222 Section 314) Since SS 316 is the sam e material used for the waste package inner shell it is a logical choice for the TAD shield plug
Usage This assumption is used in Section 621
14
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
323 Geometry and Materials of Conceptual TAD Transportation Casks
Assumption Two conceptual TAD transpo rtation casks designated as Cask A and Cask B are assumed to have a cylindrical geom etry and m aterials specified in Tab les 1 and 2 respectively The casks are basically construc ted of an inner layer of SS 316 for ga mma shielding a m iddle layer of 5-borated polyethylen e for neutron shielding and a th in outer layer of SS 316 whic h serves a structural function as well as shielding secondary gamma rays
Both Cask A and Cask B have a cavity height of 53785 cm (21175 in) and a cavity diameter of 16891 cm (6650 in) However Cask A has a total height of 610845 cm (24049 in) and an outside diameter of 26797 cm (10550 in) while the total height and outside diameter of Cask B are 58885 cm (23183 in) and 24765 cm (9750) respectively
Cask A will provide shielding to m eet the exterior radiat ion standards of 10 C FR 7147(b) (Reference 231) when loaded w ith a TAD canister carrying th e maximum PWR spent nuclear fuel (SNF) Cask B will satisf y the same radiation standards when loade d with a TAD caniste r carrying the average PWR SNF
Table 1 Geometry and Materials of Conceptual TAD Transportation Cask A
Component Dimension
Material (cm) (in)
Total Height 61085 2404 9 NA
Outside Diameter 26797 1055 0 NA
Cask Cavity Height 53785 2117 5 NA
Cask Cavity Diameter (Radius) 16891 (8446) 6650 (3325) NA
Radial Gamma Shield Thickness (Radius)a 3302 (11748)a 1300 (4625)a SS 316
Radial Neutron Shield Thickness (Radius)b 1524 (13272)b 600 (5225)b 5-borated polyethylene
Radial Outer Shell Thickness (Radius)c 127 (13399)c 050 (5275)c SS 316
Top Gamma Shield Thickness (Axial Position)d 600 (54385)d 236 (21411)d SS 316
Top Neutron Shield Thickness (Axial Position)d 1000 (55385)d 394 (21805)d 5-borated polyethylene
Top Outer Shell Thickness (Axial Position)d 200 (55585)d 079 (21884)d SS 316
Bottom Gamma Shield Thickness (Axial Position)d 35365 (-360)d 1392 (-1417)d SS 316
Bottom Neutron Shield Thickness (Axial Position)d 15 (-510)d 591 (-2008)d 5-borated polyethylene
Bottom Outer Shell Thickness (Axial Position)d 4 (-550)d 157 (-2165)d SS 316 a11748 = 3302 + 8446 and 4625 = 1300 + 3325 b13272 = 1524 + 11748 and 5225 = 600 + 4625 c13399 = 127 + 13272 and 5275 = 050 + 5225 dCoordinate relative to the bottom of the fuel assembly as modeled in MCNP5
15
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 2 Geometry and Materials of Conceptual TAD Transportation Cask B
Component Dimension
Material (cm) (in)
Total Height 58885 2318 3 NA
Outside Diameter 24765 9750 NA
Cask Cavity Height 53785 2117 5 NA
Cask Cavity Diameter (Radius) 16891 (8446) 6650 (3325) NA
Radial Gamma Shield Thickness (Radius)a 254 (10986)a 1000 (4325)a SS 316
Radial Neutron Shield Thickness (Radius)b 127 (12256)b 500 (4825)b 5-borated polyethylene
Radial Outer Shell Thickness (Radius)c 127 (12383)c 050 (4875)c SS 316
Top Gamma Shield Thickness (Axial Position)d 8 (54585)d 315 (21490)d SS 316
Top Neutron Shield Thickness (Axial Position)d None Non e NA
Top Outer Shell Thickness (Axial Position)d None Non e NA
Bottom Gamma Shield Thickness (Axial Position)d 3837 (-390)d 1510 (-1535)d SS 316
Bottom Neutron Shield Thickness (Axial Position)d 300 (-420)d 118 (-1654)d 5-borated polyethylene
Bottom Outer Shell Thickness (Axial Position)d 100 (-430)d 039 (-1693)d SS 316 a10986 = 254 + 8446 and 4325 = 1000 + 3325 b12256= 127 + 10986 and 4825 = 500+ 4325 c12383 = 127 + 12256 and 4875 = 050 + 4825 dCoordinate relative to the bottom of the fuel assembly as modeled in MCNP5
Rationale Currently a design for the TAD transporta tion cask does not exist The casks assumed for this calculation are so lely for estim ation of the dose reduction due to different source terms This is a conceptual repres entation only used in this calculation to estim ate the parameters of interest
Usage This assumption is used in Sections 61 and 622
324 Usage of Unirradiated Fuel for Commercial SNF
Assumption It is assumed that the active fuel region of the commercial SNF assembly contains the same isotopic concentrations as the fresh uni rradiated fuel and that the concentrations of fresh fuel with 5 initial enrichm ent corresp onding to m aximum SNF are used for all other SNFs
Rationale This assumption is a standard practice for shielding calculations throughout the industry accepted by the U S Nucle ar Regulatory Commission (NRC) (Reference 2228 Table 53-5) It sh ould be noted that this assumption applies to material composition only it does no t apply to source terms which are based on the characteristics of spent fuel
Usage This assumption is used in Sections 624 and 626
325 Homogenization of Radiation Source Regions
Assumption It is assu med that a commercial SNF assembly consis ts of four distinct reg ions (active fuel bottom end-fitting plenum and top end-fitting) The materials and radiation sources
16
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
of each assembly region are homogenized inside a volume defined by the TAD cavity radius and region height
Rationale The assembly representation is consistent with the industry practice for shielding calculations accepted by NRC (Reference 2228 Figure 53-6) The effec t of source homogenization is twofold (1) it d ecreases th e m ass de nsity of the source region and (2) it places source points slightly closer to detector locations thus reducing radiation attenuation The resu lts of Calculation of the Effect of Source Geometry on the 21-PWR WP Dose Rates (Reference 2218 pp 22-26) indicate that th e effect of assem bly homogenization gives nearly the same or conservative dose rates as the explicit fuel assembly model
Usage This assumption is used in Section 624
326 Ignoring Internal Fuel Basket Materials
Assumption It is assumed that the internal fuel basket materials are ignored
Rationale Inclusion of fuel basket m aterials in the smeared m aterial com position would increase the overall density and consequently increase the attenuati on of the radiation Therefore this assumption is conservative
Usage This assumption is used in Sections 621 624 and 626
17
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
4 METHODOLOGY
41 QUALITY ASSURANCE
This calculation was prepared in accordance with EG-PRO-3DP-G04B-00037 Calculations and Analyses (Reference 212) The results of th is calculation provides worker dose assessm ent adjustments and this will id entify radio logical hazards f or f acilities im portant to saf ety Therefore the approved version is designated as QA QA
42 USE OF COMPUTER SOFTWARE
421 Baseline Software
The Monte Carlo N-Particle com puter pr ogram (MCNP5) version 140 (Reference 2225) is used to calculate the dose rates (neutron pr imary gamm a and secondary gamm a) at various locations around a transportation cask and an aging overpack
The software specifications are as follows
bull Program Name MCNP5 bull VersionRevision Number Version 140 bull Operating Systems Windows XP bull Software Tracking Number 11199-140-00 bull Computer Type Dell OPTIPLEX GX620
MCNP5 which is Level 1 software is (a) appropriate for three-dim ensional neutron gamma and coupled neutrongamma shielding calculations (b) used within th e range of validation as documented in Software Validation Report for MCNP5 v140 (Reference 2221) and (c) obtained from Software C onfiguration Managem ent and qualified in accordance with procedure IT-PRO-0012 Qualification of Software (Reference 213) Therefore MCNP5 code is suitable for use in this design calculation All MCNP5 input and output files docum ented in this calculation are provided on a compact disc (CD) as Attachment II
All MCNP cases are executed on one of the following Q com puters QNW -004184 QNW -004187 QNW-004194 and QNW-004196 as shown in the output files
422 Commercial off the Shelf Software
The Excel sof tware is used to c alculate var ious inpu t values (i e atom densities weight percentages geometrical dimensions normalized source spectra and probabilities etc) Standard functions of Excel are also used in this desi gn calculation to display results (ie gamma and neutron dose rates) in tabular and graphic forms and to perform relative error calculations
The software specifications are as follows
bull Program Name Excel bull VersionRevision Number Microsoftreg Excel 2003
18
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
bull This software is installed on a persona l com puter running Microsoft W indows XP (central processing unit number 151834)
The user defined for mulas inputs results and gr aphical representations have been verified by hand calculations or visual inspection and are documented in sufficient detail to allow an independent repetition of the com putations Calculations were verifi ed by hand and graphical representations were found accurate by visual inspection
Per Software Management Microsoftreg Excel is not requir ed to be qualif ied due to its commercial availability status (Reference 211 Attachment 4 p 55 bullet 2)
43 CALCULATION APPROACH
This calculation em ploys the qualified so ftware MCNP5 version 140 (Reference 2225) a three-dimensional Monte Carlo code for pe rforming neutron and coupled neutron-gamm a calculations to estim ate dose rates at sele cted locations on and surrounding a conceptual transportation cask containing a loaded TAD canister
431 MCNP5 Program
MCNP5 a general Monte Carlo part icle transport code sim ulates particle transport through a three-dimensional representation of the nuclear system being analyzed During the random walk of particles through the system described by the geom etry the c ode collects inform ation about various events (su rface cross ing collis ions trac k leng th etc) and es timates fluxes in various geometric configurations specified as tallies by the user It also estimates the statistical precision of the results in the form of relative errors (Reference 2224 pp 1-2 to 1-8)
Per Project Design Criteria Document (Reference 2211 Section 41015) the flux estim ates are converted to dose rates using the Am erican Nuclear Society (ANS) flux-to-dose rate conversion factors for gammas and neutrons (R eference 221) The simple variance reduction techniques of Geometry SplittingRussian Roulette and source probability biasing (Sections 631 and 633) are used to enhance computational efficiency
19
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
5 LIST OF ATTACHMENTS
Number of Pages Attachment I List of Electronic Files on the CD 3 Attachment II Compact Disc NA
20
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
6 CALCULATIONS
This sectio n provides inform ation necess ary to perform the calcu lations in this docum ent Section 61 describes the configurations the type of CSNF to be analyzed the number of MCNP runs and the locations where dose rates are ca lculated Section 62 provides the calculation input that includes the details of the geom etry m odel radiation source term s and m aterial compositions Input specific to MCNP dose -rate conversion factors and relative error calculation are described in the later sections
61 DESCRIPTION OF CALCULATIONS
Dose rate calculations are perform ed with the MCNP5 version 140 com puter code (Reference 2225) Two conceptual transportation casks Cask A and Cask B (Assum ption 323) are employed Each cask contains a TAD canister that is loaded with 21 ident ical PW R SN F assemblies Three PWR source term s are analy zed they are the source term s corresponding to the maximum design basis and average PW R SN Fs The characteris tics of the P WR source terms are presented in S ection 627 Each PWR source term has neutron and ga mma radiation sources that require separate MCNP5 runs For each radiation source an axial profile source and a uniform source for the active fuel region are considered The uniform source for the active fuel region is included in this calculation because this approach was used in combination with source peaking factors in certain calculations (Reference 2216 Sections 37 and 39 and Reference 2217 Section 5242)
The total number of MCNP5 runs is 24 which re sults from a com bination of two conceptual casks three PWR source terms two radiation sources and two axia l source distributions for the active fuel region These 24 runs are categorized into four calcula tion sets Each calculation set consists of six runs that is a combination of three PWR source te rms and two radiation sources The characteristics of each calculation set are as follows
1 Cask A with axial profile sources in the active fuel region
2 Cask A with uniform axial sources in the active fuel region
3 Cask B with axial profile sources in the active fuel region
4 Cask B with uniform axial sources in the active fuel region
For each MCNP5 run dose rates are calculated at the exte rior surfaces and at distances 1 and 2 meters from the exterior surfaces Surface tallies and detector tallies (ring and point detectors) as indicated in Figure 1 are e mployed in all runs Figure 1 is used to illustrate the dep loyment of the surface and detector tallies re lative to the so urce regions and it should not be interpreted as an exact geometry of any particular run Surface tallies are deployed at all three distances while ring and point detectors are used only at 1 m and 2 m and not at the cask surfaces Using point detectors near a surface or in any scattering media is not recommended because very large scores can occur f rom collisions close ( less than a f ew centimeters) to the point detecto rs that can lead to resu lts with high r elative e rrors thus m aking the ca lculation d ifficult to o btain r eliable answers
21
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
For the radial direction surface tallies at the three distances (contact 1 m and 2 m) are computed for three su rface segments (cylindrical rings) between the planes at Z = 145 175 2 05 and 235 cm The geometric locations of the segments are shown in Figure 1 The axial locations of these segments correspond to the m iddle of the active fuel region of the PWR SNF assemblies The average dose rates for each of the segm ents are calculated for the outside surface and surfaces at 1 m and 2 m from the cask surface Two ring detectors (instead of point detectors) are deployed at 1 m and 2 m for the radial dire ction Ring detectors instead of point detectors are used in order to capitalize on the symm etry around the cask axis thus im proving the efficiency of the calculations
In the axial direction the average d ose rates within three concentric radial surfaces defined by radii of 40 80 and 120 cm (shown in Figure 1) are calculated for the top and bottom surfaces and at distances 1 m and 2 m from these surfaces Finally point detectors at 1 m and 2 m from the top and bottom axial surfaces are employed
22
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Point Detector at 2 m x
Ring Ring Detector Detector at 2 m at 1 m
x x
Z = 00 cm
Z = 145 cm
Z = 175 cm
Z = 205 cm
Z = 235 cm
R = 80 cm
R = 120 cm
R = 40 cm
Active Fuel
Shield Plug
Top End-Fitting Plenum
Bottom End-Fitting
Ring Detector at 1 m
x
Point Detector at 1 m x
Ring Detector
at 2 m x
D = 26797 cm
H =
610
845
cm
Point Detector at 1 m x
Point Detector at 2 m x
Figure 1 Geometry and Tally Scheme for the TAD Transportation Cask
23
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
62 CALCULATION INPUT
Technical product input and sources of the input used in the deve lopment of this calculation are documented in this section Tables in this docum ent and in th e associated Microsoftreg Excel spreadsheets referenced m ay present num erical values with m any significant figures these values are not to be considered as high precision values since the significant figures are results of calculated values andor unit conversions
621 TAD Canister
The TAD canis ter will contain either 21 P WR or 44 BW R (boiling water reactor) SNF assemblies (Reference 2222 Section 321) While the canister design is iden tical for both PWR and BWR SNF assemblies the internal basket structure is different depending on the SNF assemblies However the internal basket stru cture m aterial is no t in cluded in the calcu lation model (Assumption 326)
The TAD canister is a right-circu lar cylinder with a diam eter of 665 in and a height between 186 and 212 in (Reference 2222 Section 321) The average and maximum total dose rates on the top surf ace of a loaded TAD ca nister must not exceed 800 and 1000 m remhr respectively (Reference 2222 Section 314) The TAD canister used in this calculation is m ade of SS 316 with a radial wall and bottom thickness of 025 in (Assumption 321) The top of the canister has a shield plug that is 11 in thick SS 316 (Ass umption 322) A thick shield plug is needed to keep the maxim um contact dose rate of th e top surface below 1000 m remhr The overall dimensions of the TAD canister are provided in Table 3
Table 3 Dimensions of TAD Canister
Component Dimension
(in) (cm)
Maximum heighta 212 53848
Outer diametera 665 16891
Thickness of bottom lidb 025 0635
Shell thicknessb 025 0635
Lifting Featurec 6 1524
Height without Lifting Feature 206 52324
Thickness of shield plugd 110 2794
aReference 2222 Section 311 bAssumption 321 cReference 2222 p Attachment C-1 dAssumption 322
622 Conceptual TAD Transportation Casks
Two conceptual TAD transportation casks designa ted as Cask A and Cask B are em ployed in this calculation (Assumption 323) They both have a cylindrical geometry with dimensions and materials specified in Tables 1 and 2 of Section 323 Cask A will provide shielding to meet the exterior radiation standards of 10 CFR 7147(b) (Reference 231) when loaded with a TAD
24
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
canister car rying the m aximum PWR SNF Cask B will s atisfy th e sa me radiatio n standa rds when loaded with a TAD canister c arrying the average PWR SNF The reason to analyze both Casks A and B is to cover a broad range of characteristics of the CSNF
The cavity dimensions of the conceptual cask s are 53785 cm (21175 in) in height and 16891 cm (665 in) in diam eter (Tab les 1 and 2) This cav ity will accommoda te the TAD canister described in Table 3 without the lifting feature This is the geometry model used in the MCNP5 calculations
623 Fuel Assembly Selection
PWR and BWR Source Term Sensitivity Study (Reference 2211 Tables 71 through 84) shows that the source terms generated for the Bamp W 15x15 Mark B fuel assembly with 475 kg uranium loading bound the source terms of other PWR assembly types ther efore this assembly type is selected as the representative PWR fuel assembly The gamma and neutron source terms for the BampW 15x15 Mark B assembly are generated in PWR Source Term Generation and Evaluation (Reference 229) and are used in this calculation
624 BampW 15x15 Mark B PWR Fuel Assembly
BampW 15x15 Mark B fuel assembly consists of four regions top end-fitting plenum active fuel and bottom end-fitting The m aterials and ra diation sources of each assem bly region are homogenized inside a volume defined by the region height and the interior diam eter of the TAD canister (Assumption 325) The active fuel region is homogenized with fresh unirradiated fuel (Assumption 324) Since the internal structure (i e basket) design of t he TAD is currently not finalized the com position of the hom ogenized fuel does not include the basket m aterials (Assumption 326) and therefore does not take cred it for any shielding that these m aterials may provide
Table 4 provides the design param eters for the BampW 15x15 Mark B fuel assembly Data provided here are used in Attachment II PWR_fuel compxls worksheet BampWassy
25
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 4 BampW 15x15 Mark B Fuel Assembly Description
Component Material Characteristic Value Specific Reference Array Size 15 x 15
Reference 2227 Table 2-2 Fuel Pins Assembly 208 Guide Tubes Assembly 16 Instrument Tubes Assembly 1
Assembly NA Pin Pellet Diameter 0936244 cm (03686 in) Reference 2220 p 2A-34 Pin Pitch 144272 cm (0568 in)
Reference 2227 Table 2-2 Active Fuel Height 360172 cm (1418 in) Assembly Width 2168144 cm (8536 in)
Reference 2220 p 2A-31 Assembly Height 4206875 cm (165625 in) Mass U assembly 46363 kg
Guide tube Zircaloy-4 Outer Diameter 13462 cm (053 in)
Reference 2227 Table 2-2
Inner Diameter 126492 cm (0498 in)
Instrument tube Zircaloy-4 Outer Diameter 138193 cm (05441 in) Inner Diameter 112014 cm (0441 in)
Cladding` Zircaloy-4 Inner Diameter 095758 cm (0377 in) Outer Diameter 10922 cm (043 in)
Plenum region NA Length 297688 cm (11720 in) Reference 2220 p 2A-34 Top nozzle SS CF3M MassAssembly (Top) 748 kg
Reference 2220 p 2A-32
Bottom nozzle SS CF3M MassAssembly (Bottom) 816 kg Guide tubes Zircaloy-4 MassAssembly (in Core) 80 kg Instrument tube Zircaloy-4 MassAssembly (in Core) 064 kg Spacer-plenum Inconel-718 MassAssembly (Plenum) 104 kg Spacer-bottom Inconel-718 MassAssembly (Bottom) 13 kg Spacer-in core Inconel-718 MassAssembly (in Core) 49 kg Spring retainer SS CF3M MassAssembly (Top) 091 kg Holddown spring Inconel-718 MassAssembly (Top) 18 kg Upper end plug SS 304 MassAssembly (Top) 006 kg Upper nut SS 304L MassAssembly (Top) 051 kg Lower nut SS 304 MassAssembly (Bottom) 015 kg Grid supports Zircaloy-4 MassAssembly (in Core) 064 kg Plenum spring SS 302 MassAssembly (Plenum) 0042 lb (001905 kg) Reference 2220 p 2A-34
Note Som e d ata i n this tab le ar e given i n British u nits in th e r eferences thes e d ata ar e converted into metric units as the inputs to MCNP5 are in metric units
The assem bly region heights as m odeled in MC NP are presented in Table 5 utilizing values from Table 4 Table 5 is taken from Dose Rate Calculation for Exhaust Main Drifts (Reference 2213 Table 3)
26
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 5 PWR Fuel Assembly Regions
Component Height Reference
Plenum 297688 cm (11720 in) Reference 2220 p 2A-34
Active Fuel 360172 cm (1418 in) Table 3
Bottom End-Fitting 1077 cm (424 in) Calculateda
Top End-Fitting 1998 cm (787 in) Calculatedb
Source Reference 2213 Table 3 aCalculated b ased on data Reference 2227 F igures 2-3 an d 2-7
(Region 9 Height [16723 cm] + Region 10 Height [508 cm] ndash Lo wer Fuel Plenum and End Cap [11033 cm])
bCalculated (Assembly Length ndash Active Fuel Length ndash P lenum Length ndash Bottom End-fitting Length)
625 Material Compositions
The TAD transportation cask com ponent m aterial specifications are defined in Table 1 The TAD canister is constructed of SS 316 (Assumpti on 321) The PWR fuel assembly materials used to homogenize the fuel regions are defined in Table 4 Table 6 c ontains the m aterial compositions defining the TAD canister WP and fuel assemblies
27
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 6 Chemical Compositions of Materials
Material Density (gcc)
Isotopic Weight Percent Reference
SS 302 NA
C 0150 Mn 2000 P 0045 S 0030 Si 0750 Cr 18000 Ni 9000 N 0100 Fe 69925
Attachment II PWR_fuel compxls worksheet ferrous Reference 222 SEC II A SA-240 Table 1 for SS 302 SS 304 and SS 304L Reference 222 SEC II A SA-351SA -351M Table 2 for SS CF3M
SS 304 NA
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 9250 N 0100 Fe 68745
SS 304L NA
C 003 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 10000 N 0100 Fe 6804 5
SS CF3M NA
C 0030 Mn 1500 P 0040 S 0040 Si 1500 Cr 19000 Ni 11000 Mo 2500 Fe 64390
Inconel 718 NA
C 0080 Mn 0350 Si 0350 Cr 19000 Ni 52500 Co 1000 Mo 3050 Fe 16809 Nb 5125 Ti 0900 Al 0500 Cu 0300 S 0015 P 0015 B 0006
Attachment II PWR_fuel compxls worksheet alloys aReference 223 p 666 Table 6 Reference 222 SEC II B SB-637 Table 1 for Inconel 718 Reference 224 Table 2 for Zircaloy 4
Zircaloy 4 656a Cr 0100 Fe 0210 O 0125 Sn 1450 Zr 98115
SS 316 798b
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 17000 Ni 12000 Mo 2500 N 0100 Fe 65495
Attachment II PWR_fuel compxls worksheet others Reference 222 SEC II A SA-240 Table 1 for SS 316 bReference 225 Table X1
626 Homogenization Assembly Materials
The atom density of an element or isotope in atomsbmiddotcm in a homogenized region is calculated according to the following equation (Reference 2223 Appendix B)
M i times N AvogadroNi = Equation 1 Ai timesV times K
where Ni = Atom density of elementisotope i (atomsbmiddotcm) Mi = Mass of elementisotope i (g) NAvogadro = Avogadrorsquos constant 06022 x 1024 (atomsmole)
28
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Ai = Atomic weight of elementisotope i (gmole) V = Homogenization volume (cm3) K = Unit transformation constant = 1024 (bmiddotcmcm3)
Equation 1 is used in A ttachment II spreadsheet PWR_fuel compxls worksheet BampWassy to calculate th e atom dens ities for v arious elem ents and iso topes The m ass of elementsisotop es and Avogadrorsquos constant are provided in Reference 2226
Table 7 lists the com position of the hom ogenized assem bly regions (active fuel plenum top end-fitting and bottom end-fitting) for the PWR assembly The active fuel region contains fresh unirradiated fuel (Assumption 324) Since the internal structure (ie basket) design of the TAD is currently not finalized the composition of either homogenized fuel does not include the basket materials and therefore does not tak e credit for any shielding that thes e materials may provide (Assumption 326)
Table 7 Isotopic Compositions of Homogenized PWR Assembly Regions
Element Isotope
Atom Densities for Homogenized Regions (atomsbsdotcm)
Active Fuel Bottom End-Fitting Plenum Top End-Fitting
10B 861E-09 764E-08 221E-08 570E-08 11B 347E-08 307E-07 890E-08 230E-07 C 519E-07 160E-05 138E-06 993E-06 N -- 570E-07 262E-08 117E-06 O 621E-03 -- 142E-05 -- Al 144E-06 128E-05 371E-06 957E-06 Si 971E-07 243E-04 259E-06 139E-04 P 377E-08 606E-06 102E-07 360E-06 S 365E-08 581E-06 971E-08 340E-06 Ti 147E-06 130E-05 376E-06 971E-06 Cr 320E-05 187E-03 779E-05 113E-03 Mn 497E-07 126E-04 141E-06 749E-05 Fe 303E-05 531E-03 717E-05 313E-03 Co 132E-06 117E-05 340E-06 876E-06 Ni 697E-05 144E-03 180E-04 940E-04 Cu 368E-07 327E-06 945E-07 244E-06 Zr 196E-03 -- 195E-03 -- Nb 430E-06 382E-05 110E-05 285E-05 Mo 248E-06 135E-04 636E-06 791E-05 Sn 223E-05 -- 222E-05 -- 234U 139E-06 -- -- -- 235U 157E-04 -- -- -- 236U 719E-07 -- -- -- 238U 294E-03 -- -- -- Total 114E-02 924E-03 235E-03 557E-03
Source Attachment II spreadsheet PWR_fuel compxls worksheet BampWassy
29
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
The isotopic composition of commercially available 235U enriched uranium is determined by the given initial 235U enrichment using the following equations (Reference 226 p 20)
wt235U =235Uenrichment _ of _ the _ associated _ fuel _ batch Equation 2
wt234U = 0007731times (wt235U )10837 Equation 3
wt236U = 00046times (wt235U ) Equation 4
wt238U =100 minus (wt234U + wt235U + wt236U ) Equation 5
The weight percentages of uran ium isotopes for PWR fuel are ca lculated in Attachm ent II spreadsheet PWR_fuel compxls worksheet BampWassy using Equations 2 through 5
627 PWR Source Terms
This calculation uses the following three PWR source terms bull Maximum source (50 wt initial 235U enrichment 80 GWdMTU burnup and 5-year
decay time) (Reference 229 Section 55) Table 8 lists th e gamma source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Design Basis source (4 0 wt initial 235U enrichment 60 GW dMTU burnup and 10-year decay tim e) (Reference 228 Section 552) Table 9 lists the gamm a source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Average source ( 40 wt initial 235U enrichment 48 GWdMTU burnup and 25-year decay time) (Reference 229 Section 55) Table 10 lists the gamma source terms for the fuel and non-fuel regions and the neutron source term for the fuel region
These sources (ie maximum design basis and av erage) are described in this section For dose rate calculations all the fuel assemblies in a transportation cask are of the sam e characteristics Also gamma radiation source term s for the PWR assem bly are prov ided for the f our assembly regions while neutron source term is only present in the active fuel region Gamma radiation sources in the non-active fuel region are distri buted unif ormly within each source region Gamma and neutron sources in the active fuel re gion are modeled as uni form distributions or with axial source profiles
The PWR gamma and neutron axial source profiles for the active fuel region presented in Table 11 are applied to the active fuel region of all three source terms (ie maximum design basis and average) when appropriate
30
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 8 Gamma and Neutron Sources for the Maximum PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting
Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 594E+11 233E+15 528E+11 379E+11 100E-01 000E+00 100E-01 116E+11 644E+14 609E+10 743E+10 400E-01 805E+07 200E-01 283E+10 522E+14 352E+10 179E+10 900E-01 411E+08 300E-01 141E+09 148E+14 196E+09 891E+08 140E+00 376E+08 400E-01 190E+09 985E+13 586E+09 117E+09 185E+00 276E+08 600E-01 191E+09 153E+15 110E+11 741E+07 300E+00 485E+08 800E-01 435E+09 470E+15 595E+10 237E+09 643E+00 443E+08 100E+00 137E+11 708E+14 803E+09 766E+10 200E+01 393E+07 133E+00 338E+13 455E+14 174E+13 217E+13 Total 211E+09 166E+00 953E+12 130E+14 491E+12 612E+12
--
200E+00 187E+03 144E+12 919E+02 113E+03 250E+00 226E+08 249E+12 116E+08 145E+08 300E+00 351E+05 110E+11 181E+05 225E+05 400E+00 766E-08 139E+10 100E-08 416E-08 500E+00 000E+00 709E+07 000E+00 000E+00 650E+00 000E+00 286E+07 000E+00 000E+00 800E+00 000E+00 558E+06 000E+00 000E+00 100E+01 000E+00 119E+06 000E+00 000E+00
Total 442E+13 113E+16 231E+13 284E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE2R2B14cut bWasteStreamE2R1B14cut cWasteStreamE2R3B14cut dWasteStreamE2R4B14cut
31
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 9 Gamma and Neutron Sources for the Design Basis PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary
(MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 273E+11 121E+15 188E+11 175E+11 100E-01 000E+00 100E-01 528E+10 329E+14 277E+10 339E+10 400E-01 316E+07 200E-01 128E+10 245E+14 117E+10 819E+09 900E-01 161E+08 300E-01 639E+08 713E+13 633E+08 407E+08 140E+00 148E+08 400E-01 850E+08 455E+13 164E+09 533E+08 185E+00 109E+08 600E-01 492E+08 226E+14 269E+10 337E+07 300E+00 191E+08 800E-01 291E+09 237E+15 160E+10 186E+09 643E+00 174E+08 100E+00 540E+09 122E+14 248E+09 341E+09 200E+01 154E+07 133E+00 154E+13 195E+14 797E+12 990E+12 Total 830E+08 166E+00 435E+12 450E+13 225E+12 280E+12
--
200E+00 235E+00 152E+11 149E+02 215E-02 250E+00 103E+08 517E+10 534E+07 664E+07 300E+00 160E+05 379E+09 829E+04 103E+05 400E+00 943E-10 497E+08 155E-10 519E-10 500E+00 000E+00 282E+07 000E+00 000E+00 650E+00 000E+00 113E+07 000E+00 000E+00 800E+00 000E+00 222E+06 000E+00 000E+00 100E+01 000E+00 471E+05 000E+00 000E+00
Total 201E+13 486E+15 105E+13 129E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B11cut bWasteStreamE5R1B11cut cWasteStreamE5R3B11cut dWasteStreamE5R4B11cut
32
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 10 Gamma and Neutron Sources for the Average PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 336E+10 670E+14 186E+10 217E+10 100E-01 00000E+00 100E-01 602E+09 199E+14 314E+09 387E+09 400E-01 748E+06 200E-01 146E+09 126E+14 853E+08 936E+08 900E-01 382E+07 300E-01 730E+07 389E+13 439E+07 469E+07 140E+00 352E+07 400E-01 947E+07 263E+13 716E+07 607E+07 185E+00 261E+07 600E-01 141E+07 205E+13 504E+08 383E+06 300E+00 469E+07 800E-01 208E+09 124E+15 192E+09 144E+09 643E+00 418E+07 100E+00 208E+09 110E+13 164E+09 144E+09 200E+01 365E+06 133E+00 175E+12 295E+13 909E+11 112E+12 Total 199E+08 166E+00 494E+11 513E+12 257E+11 318E+11
--
200E+00 973E-01 675E+10 614E+01 872E-03 250E+00 117E+07 353E+09 609E+06 754E+06 300E+00 182E+04 288E+08 944E+03 117E+04 400E+00 186E-11 198E+07 149E-11 127E-11 500E+00 000E+00 669E+06 000E+00 000E+00 650E+00 000E+00 269E+06 000E+00 000E+00 800E+00 000E+00 527E+05 000E+00 000E+00 100E+01 000E+00 112E+05 000E+00 000E+00
Total 229E+12 237E+15 119E+12 147E+12
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B9cut bWasteStreamE5R1B9cut cWasteStreamE5R3B9cut dWasteStreamE5R4B9cut
33
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 11 Gamma and Neutron Axial Source Profiles for a PWR Assembly
Axial boundaries (From midplane)
(cm)
TOP BOTTOM
Neutron Gamma Ne utron Gamma 000 1554 1117 1554 1117 1143 1537 1114 1571 1120 2286 1521 1111 1588 1123 3429 1504 1108 1605 1126 4572 1486 1104 1622 1129 5715 1464 1100 1636 1131 6858 1438 1095 1648 1133 8001 1401 1088 1657 1135 9144 1350 1078 1654 1134
10287 1277 1063 1625 1129 11430 1165 1039 1554 1117 12573 0998 09995 1414 1091 13716 0769 09365 1172 1041 14859 0492 08375 0816 0951 16002 0220 06850 0402 0797 17145 0046 04625 0092 0551 18288 00 00 00 00
Source Reference 2219 Table S445
34
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
63 MCNP SPECIFIC INPUT
631 Source Probability
A linear radial distribution is used for all gamma and neutron sources The linear radial distribution is sam pled usi ng the built-in power function p(x) = xc a with a = 1 for the radial direction This sampling method results in a uniform source distribution over the area bounded by the outer radius of the source
The source axial distributions are unifor m for all four source regions The a xial uni form xp(x) = c distribution is sampled using the built-in power function a with a = 0 for extent
The energy distribu tions of the gamma and neutron sour ce term s are treated as energ y probabilities and are applied in MCNP5 using SISP cards
632 Dose Rate and Flux Tallies
MCNP5 dose rate calculations feature separate runs for the following calculation types
bull a photon transport calculation for prim ary ga mma contribution to the dose rates fr om photon fluxes
bull a coupled neutronphoton transport calculat ion for neutrons a nd secondary gamma (photons generated by neutron be ing captured) contributions to dose rates from neutron and gamma fluxes
The tally type F2 is us ed in th is d esign ca lculation as f lux estim ators The type F2 tally evaluates the flux averaged over a surface in particlescm2s
To generate dose ra tes in te rms of remhr the FM (tally multiplier ) and DEDF (dose energydose conversion factors) cards are used to en ter the tally multiplier f actor (source intensity in particless) energy boundaries in MeV and corresponding dose conversion factors in (remhr)(particlescm2s) respectively These factors were used in the input files
In order for the F2 tally to accum ulate flux ov er a surface a specific s urface area is requ ired The SD cards are used to enter a surface area in cm2 over which the flux will be tallied for an F2 tally
633 Variance Reduction Techniques
Variance reduction technique is usually em ployed in order to increase the efficiency of a calculation and obtain statistically m eaningful results within re asonable com puter tim e In Monte Carlo calculations when variance reduction scheme is employed the weights of particles are adjusted in order to account for the biasing and to preserve a fair game
Geometry splitting and Russian roulette techniques described in Reference 2224 (pp 2-140 ndash 2-142) are useful in shielding calculations and therefore deployed in all the MCNP5 runs
35
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
As particles migrate in an important direction (toward the detector) they are increased in number to provide better sampling by means of geometry splitting across geometric boundaries Russian roulette (the reverse process) is played when particles travel in an unimportant direction to allow termination of unim portant histories The IMP card required for every cel l ca rd is us ed to implement this technique
The other variance reduction technique deployed in the MC NP5 runs is source intensity biasing for the gamma sources from the four source regions (active fuel bottom end-fitting plenum and top end-fitting) The natural total gamma source intensity of comm ercial SNF is dom inated by the gamma source in the active fuel region This active fuel gamma source usually accounts for over 95 o f the total g amma source intens ity In order to im prove the efficiency of the axial dose rate calculations a biased source probability distribution is employed for the prim ary gamma dose rate calculations The biased gamma source probability distribution is chosen to be 005 080 010 and 005 for the bottom end-fitting the active fuel the plenum and the top end-fitting regions respectively
64 DOSE CONVERSION FACTORS
Project Design Criteria Document (Reference 2211 Se ction 41015) requires the use of flux-to-dose rate conversion fact ors from ANSIANS-611-1977 (Reference 221) for dose rate evaluations Table 16 lists the neutron and ga mma dose conversion factors used in the MCNP5 calculations
Table 12 Gamma and Neutron Flux to Dose Conversion Factors
Gamma Neutron Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
001 396E-06 140 251E-06 250E-08 367E-06 003 582E-07 180 299E-06 100E-07 367E-06 005 290E-07 220 342E-06 100E-06 446E-06 007 258E-07 260 382E-06 100E-05 454E-06 010 283E-07 280 401E-06 100E-04 418E-06 015 379E-07 325 441E-06 100E-03 376E-06 020 501E-07 375 483E-06 100E-02 356E-06 025 631E-07 425 523E-06 100E-01 217E-05 030 759E-07 475 560E-06 500E-01 926E-05 035 878E-07 500 580E-06 100E+00 132E-04 040 985E-07 525 601E-06 250E+00 125E-04 045 108E-06 575 637E-06 500E+00 156E-04 050 117E-06 625 674E-06 700E+00 147E-04 055 127E-06 675 711E-06 100E+01 147E-04 060 136E-06 750 766E-06 140E+01 208E-04 065 144E-06 900 877E-06 200E+01 227E-04 070 152E-06 1100 103E-05 080 168E-06 1300 118E-05 100 198E-06 1500 133E-05
Source Reference 221 Tables 1 and 3
36
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION
By def inition (Ref erence 2224 Equation 219) the estimated st atistic relative error of the i component is
Ri = Si
2
Equation 6Ti
where i = tally component index Ri = relative error of the i component S2
i = variance of the i component Ti = tally i component
For a result (ie dose rate) computed as a sum of different tallies the statistical relative error of the computed value is o btained from the variance of the result - S2
total which is th e sum of the estimated variances of the individual tallies S2
i n
2 2STotal = sum Si Equation 7 i=1
where S2Total = total estimated variance
n = total number of components Therefore the total tally value (dose rate) and the associated relative error are derived according to Equations 8 and 9
n TTotal = sumTi Equation 8
i=1
n n
sum (Ri timesTi )2
2 sum Si 2
STotal = i=1 = i=1 Equation 9RTotal = TTotal TTotal TTotal
where RTotal = total estimated relative error TTotal = total estimated tally
Equations 8 and 9 are utilized in Attachm ent II to ev aluate to tal dos e ra tes and their r elative errors
37
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
7 RESULTS AND CONCLUSIONS
71 RESULTS
The following sections summarize the results of this calculation Section 711 presents results for Conceptual Cask A while Section 712 for Conceptual Cask B Section 713 provides comparisons of the dose-rate reduction factors du e to the two conceptual casks and the axial source distributions in the active fuel region Do se rates and relative errors can be found in Attachment II within the output files and Excel files
711 Dose Rates of Conceptual Cask A
This section presents dose-rate results of the calculation sets 1 and 2 as described in Section 61 for Cask A Set 1 has axial p rofile sources in the active fuel region a nd consist of six runs resulting from the three PWR SNF source term s (maximum design basis and average) and the two radiation sources (gammas and neutrons) Set 2 has uniform axial sources in the active fuel region and consists of six run s r esulting f rom the th ree P WR SNF source term s and th e tw o radiation sources
As described in Section 61 dose ra tes are calculated at the three exterior surfaces (radial top and bottom) and at distances 1 m and 2 m from the exterior surfaces The total dose rates for set 1 are presented in Tables 13 14 and 15 for the ra dial top and bottom dire ctions respectively However the com ponents (primary gamma neutr on and secondary gamma) contributing to the total dose rates as well as the re lative error calculations can be found in Attachment II Excel file MCNP-Results1xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 2 are shown in Tables 16 17 and 18 The dose-rate components and the relative errors can be found in A ttachment II Excel file MCNP-Results2xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 13 and 16 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 14 and 17 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 15 and 18 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carrying th e maximum PWR SNF Based on the results in Tables 13 through 18 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask A indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these 6 tables the d ose-rate red uction f actors between the m aximum and the design basis fuels the maxim um and the averag e fuels and th e design basis and the average fuels are a lso presented
38
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 320E-02 00237 116E-02 00222 262E-03 00219 275 1223 445
1 m 133E-02 00164 494E-03 00171 106E-03 00162 269 1261 468 2 m 749E-03 00198 285E-03 00225 584E-04 00162 263 1282 488
Ring Detectors 1 m 133E-02 00116 492E-03 00115 108E-03 00124 271 1229 454 2 m 756E-03 00118 279E-03 00110 605E-04 00128 271 1250 462
Source Attachment II MCNP-Results1xls worksheet Summary
Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 142E-02 00368 628E-03 00446 934E-04 00483 226 1520 672
1 m 570E-03 00289 263E-03 00426 375E-04 00381 217 1520 701 2 m 265E-03 00364 123E-03 00547 169E-04 00374 216 1575 730
Point Detectors 1 m 598E-03 00238 274E-03 00271 402E-04 00354 219 1489 681 2 m 273E-03 00218 123E-03 00245 180E-04 00336 221 1515 684
Source Attachment II MCNP-Results1xls worksheet Summary
Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 653E-03 00298 265E-03 00276 510E-04 00341 247 1278 518
1 m 276E-03 00238 112E-03 00208 207E-04 00249 248 1334 539 2 m 125E-03 00185 508E-04 00199 933E-05 00246 246 1336 544
Point Detectors 1 m 291E-03 00227 118E-03 00203 218E-04 00242 247 1335 540 2 m 130E-03 00209 524E-04 00187 955E-05 00233 247 1357 549
Source Attachment II MCNP-Results1xls worksheet Summary
Tables 13 14 and 15 are results of calculation set 1 for conceptual Cask A with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
39
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 265E-02 00247 990E-03 00222 215E-03 00278 268 1234 461
1 m 116E-02 00178 468E-03 00549 960E-04 00189 248 1208 488 2 m 713E-03 00273 265E-03 00161 602E-04 00360 269 1184 439
Ring Detectors 1 m 117E-02 00120 454E-03 00132 979E-04 00141 259 1199 463 2 m 722E-03 00130 276E-03 00141 589E-04 00153 261 1226 469
Source Attachment II MCNP-Results2xls worksheet Summary
Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 199E-02 00461 827E-03 00455 147E-03 00536 241 1359 564
1 m 849E-03 00564 323E-03 00314 563E-04 00418 263 1507 574 2 m 415E-03 00832 158E-03 00603 253E-04 00501 263 1641 623
Point Detectors 1 m 877E-03 00348 353E-03 00275 615E-04 00391 248 1426 574 2 m 393E-03 00341 160E-03 00278 270E-04 00378 246 1454 590
Source Attachment II MCNP-Results2xls worksheet Summary
Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 879E-03 00374 356E-03 00333 669E-04 00406 247 1315 533
1 m 365E-03 00223 147E-03 00209 269E-04 00253 248 1358 548 2 m 164E-03 00229 674E-04 00205 120E-04 00248 243 1364 560
Point Detectors 1 m 383E-03 00217 155E-03 00204 285E-04 00248 247 1347 546 2 m 172E-03 00197 689E-04 00186 124E-04 00225 249 1391 558
Source Attachment II MCNP-Results2xls worksheet Summary
Tables 16 17 and 18 ar e results of calculation set 2 for conceptual Cask A with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
40
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
3 ASSUMPTIONS
31 ASSUMPTIONS REQUIRING VERIFICATION
None
32 ASSUMPTIONS NOT REQUIRING VERIFICATION
Assumptions 321 322 and 323 are m odeling assum ptions and do not require further verification The m aterials and dim ensions for the TAD canister and for the conceptu al transportation casks are only selected to charac terize two tr ansportation casks th at m eet 10 CFR7147 (Reference 231) dose rates when lo aded with the ldquom aximumrdquo and ldquoaveragerdquo pressurized water re actor (PW R) assem blies re spectively There is n o need to v erify those dimensions or m aterials at a later date The ca lculated results in Sect ion 711 verify that the conceptual casks would meet 10 CFR 7147 (Reference 231) dose rates
321 Material and Wall Thickness of TAD Canister
Assumption It is assumed that the TAD canister is made of stainless steel 316 (SS 316) and has a wall thickness of 025 in for the radial and bottom shells
Rationale Currently the design of the TAD canis ter d oes not ex ist Based on a survey of existing m ultipurpose a nd dual purpose caniste rs (DPC) (Ref erence 2214 p 56) a 025 in thickness is below the wall thick ness of any existing c anisters For the purp ose of this calculation this assumption leads to higher and conservative external dose rates Since SS 316 is the sam e material used for the waste pack age inner shell it is a l ogical cho ice f or the TAD canister
Although Reference 2214 is an engineering study with a QA N A status it is used here as an indirect input to support the assumption which is conservative for dose rate calculations
Usage This assumption is used in Sections 621 and 625
322 Material and Thickness of TAD Shield Plug
Assumption It is assu med that the TAD shield plug is made of SS 316 and has a thickness of 11 in
Rationale Currently the design of the TAD canister doe s not exist A thick shield plug of 11 in (Reference 2215 Table 12) is needed to keep the m aximum contact dose rate of the top surface below 1000 mrem hr (Reference 2222 Section 314) Since SS 316 is the sam e material used for the waste package inner shell it is a logical choice for the TAD shield plug
Usage This assumption is used in Section 621
14
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
323 Geometry and Materials of Conceptual TAD Transportation Casks
Assumption Two conceptual TAD transpo rtation casks designated as Cask A and Cask B are assumed to have a cylindrical geom etry and m aterials specified in Tab les 1 and 2 respectively The casks are basically construc ted of an inner layer of SS 316 for ga mma shielding a m iddle layer of 5-borated polyethylen e for neutron shielding and a th in outer layer of SS 316 whic h serves a structural function as well as shielding secondary gamma rays
Both Cask A and Cask B have a cavity height of 53785 cm (21175 in) and a cavity diameter of 16891 cm (6650 in) However Cask A has a total height of 610845 cm (24049 in) and an outside diameter of 26797 cm (10550 in) while the total height and outside diameter of Cask B are 58885 cm (23183 in) and 24765 cm (9750) respectively
Cask A will provide shielding to m eet the exterior radiat ion standards of 10 C FR 7147(b) (Reference 231) when loaded w ith a TAD canister carrying th e maximum PWR spent nuclear fuel (SNF) Cask B will satisf y the same radiation standards when loade d with a TAD caniste r carrying the average PWR SNF
Table 1 Geometry and Materials of Conceptual TAD Transportation Cask A
Component Dimension
Material (cm) (in)
Total Height 61085 2404 9 NA
Outside Diameter 26797 1055 0 NA
Cask Cavity Height 53785 2117 5 NA
Cask Cavity Diameter (Radius) 16891 (8446) 6650 (3325) NA
Radial Gamma Shield Thickness (Radius)a 3302 (11748)a 1300 (4625)a SS 316
Radial Neutron Shield Thickness (Radius)b 1524 (13272)b 600 (5225)b 5-borated polyethylene
Radial Outer Shell Thickness (Radius)c 127 (13399)c 050 (5275)c SS 316
Top Gamma Shield Thickness (Axial Position)d 600 (54385)d 236 (21411)d SS 316
Top Neutron Shield Thickness (Axial Position)d 1000 (55385)d 394 (21805)d 5-borated polyethylene
Top Outer Shell Thickness (Axial Position)d 200 (55585)d 079 (21884)d SS 316
Bottom Gamma Shield Thickness (Axial Position)d 35365 (-360)d 1392 (-1417)d SS 316
Bottom Neutron Shield Thickness (Axial Position)d 15 (-510)d 591 (-2008)d 5-borated polyethylene
Bottom Outer Shell Thickness (Axial Position)d 4 (-550)d 157 (-2165)d SS 316 a11748 = 3302 + 8446 and 4625 = 1300 + 3325 b13272 = 1524 + 11748 and 5225 = 600 + 4625 c13399 = 127 + 13272 and 5275 = 050 + 5225 dCoordinate relative to the bottom of the fuel assembly as modeled in MCNP5
15
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 2 Geometry and Materials of Conceptual TAD Transportation Cask B
Component Dimension
Material (cm) (in)
Total Height 58885 2318 3 NA
Outside Diameter 24765 9750 NA
Cask Cavity Height 53785 2117 5 NA
Cask Cavity Diameter (Radius) 16891 (8446) 6650 (3325) NA
Radial Gamma Shield Thickness (Radius)a 254 (10986)a 1000 (4325)a SS 316
Radial Neutron Shield Thickness (Radius)b 127 (12256)b 500 (4825)b 5-borated polyethylene
Radial Outer Shell Thickness (Radius)c 127 (12383)c 050 (4875)c SS 316
Top Gamma Shield Thickness (Axial Position)d 8 (54585)d 315 (21490)d SS 316
Top Neutron Shield Thickness (Axial Position)d None Non e NA
Top Outer Shell Thickness (Axial Position)d None Non e NA
Bottom Gamma Shield Thickness (Axial Position)d 3837 (-390)d 1510 (-1535)d SS 316
Bottom Neutron Shield Thickness (Axial Position)d 300 (-420)d 118 (-1654)d 5-borated polyethylene
Bottom Outer Shell Thickness (Axial Position)d 100 (-430)d 039 (-1693)d SS 316 a10986 = 254 + 8446 and 4325 = 1000 + 3325 b12256= 127 + 10986 and 4825 = 500+ 4325 c12383 = 127 + 12256 and 4875 = 050 + 4825 dCoordinate relative to the bottom of the fuel assembly as modeled in MCNP5
Rationale Currently a design for the TAD transporta tion cask does not exist The casks assumed for this calculation are so lely for estim ation of the dose reduction due to different source terms This is a conceptual repres entation only used in this calculation to estim ate the parameters of interest
Usage This assumption is used in Sections 61 and 622
324 Usage of Unirradiated Fuel for Commercial SNF
Assumption It is assumed that the active fuel region of the commercial SNF assembly contains the same isotopic concentrations as the fresh uni rradiated fuel and that the concentrations of fresh fuel with 5 initial enrichm ent corresp onding to m aximum SNF are used for all other SNFs
Rationale This assumption is a standard practice for shielding calculations throughout the industry accepted by the U S Nucle ar Regulatory Commission (NRC) (Reference 2228 Table 53-5) It sh ould be noted that this assumption applies to material composition only it does no t apply to source terms which are based on the characteristics of spent fuel
Usage This assumption is used in Sections 624 and 626
325 Homogenization of Radiation Source Regions
Assumption It is assu med that a commercial SNF assembly consis ts of four distinct reg ions (active fuel bottom end-fitting plenum and top end-fitting) The materials and radiation sources
16
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
of each assembly region are homogenized inside a volume defined by the TAD cavity radius and region height
Rationale The assembly representation is consistent with the industry practice for shielding calculations accepted by NRC (Reference 2228 Figure 53-6) The effec t of source homogenization is twofold (1) it d ecreases th e m ass de nsity of the source region and (2) it places source points slightly closer to detector locations thus reducing radiation attenuation The resu lts of Calculation of the Effect of Source Geometry on the 21-PWR WP Dose Rates (Reference 2218 pp 22-26) indicate that th e effect of assem bly homogenization gives nearly the same or conservative dose rates as the explicit fuel assembly model
Usage This assumption is used in Section 624
326 Ignoring Internal Fuel Basket Materials
Assumption It is assumed that the internal fuel basket materials are ignored
Rationale Inclusion of fuel basket m aterials in the smeared m aterial com position would increase the overall density and consequently increase the attenuati on of the radiation Therefore this assumption is conservative
Usage This assumption is used in Sections 621 624 and 626
17
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
4 METHODOLOGY
41 QUALITY ASSURANCE
This calculation was prepared in accordance with EG-PRO-3DP-G04B-00037 Calculations and Analyses (Reference 212) The results of th is calculation provides worker dose assessm ent adjustments and this will id entify radio logical hazards f or f acilities im portant to saf ety Therefore the approved version is designated as QA QA
42 USE OF COMPUTER SOFTWARE
421 Baseline Software
The Monte Carlo N-Particle com puter pr ogram (MCNP5) version 140 (Reference 2225) is used to calculate the dose rates (neutron pr imary gamm a and secondary gamm a) at various locations around a transportation cask and an aging overpack
The software specifications are as follows
bull Program Name MCNP5 bull VersionRevision Number Version 140 bull Operating Systems Windows XP bull Software Tracking Number 11199-140-00 bull Computer Type Dell OPTIPLEX GX620
MCNP5 which is Level 1 software is (a) appropriate for three-dim ensional neutron gamma and coupled neutrongamma shielding calculations (b) used within th e range of validation as documented in Software Validation Report for MCNP5 v140 (Reference 2221) and (c) obtained from Software C onfiguration Managem ent and qualified in accordance with procedure IT-PRO-0012 Qualification of Software (Reference 213) Therefore MCNP5 code is suitable for use in this design calculation All MCNP5 input and output files docum ented in this calculation are provided on a compact disc (CD) as Attachment II
All MCNP cases are executed on one of the following Q com puters QNW -004184 QNW -004187 QNW-004194 and QNW-004196 as shown in the output files
422 Commercial off the Shelf Software
The Excel sof tware is used to c alculate var ious inpu t values (i e atom densities weight percentages geometrical dimensions normalized source spectra and probabilities etc) Standard functions of Excel are also used in this desi gn calculation to display results (ie gamma and neutron dose rates) in tabular and graphic forms and to perform relative error calculations
The software specifications are as follows
bull Program Name Excel bull VersionRevision Number Microsoftreg Excel 2003
18
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
bull This software is installed on a persona l com puter running Microsoft W indows XP (central processing unit number 151834)
The user defined for mulas inputs results and gr aphical representations have been verified by hand calculations or visual inspection and are documented in sufficient detail to allow an independent repetition of the com putations Calculations were verifi ed by hand and graphical representations were found accurate by visual inspection
Per Software Management Microsoftreg Excel is not requir ed to be qualif ied due to its commercial availability status (Reference 211 Attachment 4 p 55 bullet 2)
43 CALCULATION APPROACH
This calculation em ploys the qualified so ftware MCNP5 version 140 (Reference 2225) a three-dimensional Monte Carlo code for pe rforming neutron and coupled neutron-gamm a calculations to estim ate dose rates at sele cted locations on and surrounding a conceptual transportation cask containing a loaded TAD canister
431 MCNP5 Program
MCNP5 a general Monte Carlo part icle transport code sim ulates particle transport through a three-dimensional representation of the nuclear system being analyzed During the random walk of particles through the system described by the geom etry the c ode collects inform ation about various events (su rface cross ing collis ions trac k leng th etc) and es timates fluxes in various geometric configurations specified as tallies by the user It also estimates the statistical precision of the results in the form of relative errors (Reference 2224 pp 1-2 to 1-8)
Per Project Design Criteria Document (Reference 2211 Section 41015) the flux estim ates are converted to dose rates using the Am erican Nuclear Society (ANS) flux-to-dose rate conversion factors for gammas and neutrons (R eference 221) The simple variance reduction techniques of Geometry SplittingRussian Roulette and source probability biasing (Sections 631 and 633) are used to enhance computational efficiency
19
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
5 LIST OF ATTACHMENTS
Number of Pages Attachment I List of Electronic Files on the CD 3 Attachment II Compact Disc NA
20
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
6 CALCULATIONS
This sectio n provides inform ation necess ary to perform the calcu lations in this docum ent Section 61 describes the configurations the type of CSNF to be analyzed the number of MCNP runs and the locations where dose rates are ca lculated Section 62 provides the calculation input that includes the details of the geom etry m odel radiation source term s and m aterial compositions Input specific to MCNP dose -rate conversion factors and relative error calculation are described in the later sections
61 DESCRIPTION OF CALCULATIONS
Dose rate calculations are perform ed with the MCNP5 version 140 com puter code (Reference 2225) Two conceptual transportation casks Cask A and Cask B (Assum ption 323) are employed Each cask contains a TAD canister that is loaded with 21 ident ical PW R SN F assemblies Three PWR source term s are analy zed they are the source term s corresponding to the maximum design basis and average PW R SN Fs The characteris tics of the P WR source terms are presented in S ection 627 Each PWR source term has neutron and ga mma radiation sources that require separate MCNP5 runs For each radiation source an axial profile source and a uniform source for the active fuel region are considered The uniform source for the active fuel region is included in this calculation because this approach was used in combination with source peaking factors in certain calculations (Reference 2216 Sections 37 and 39 and Reference 2217 Section 5242)
The total number of MCNP5 runs is 24 which re sults from a com bination of two conceptual casks three PWR source terms two radiation sources and two axia l source distributions for the active fuel region These 24 runs are categorized into four calcula tion sets Each calculation set consists of six runs that is a combination of three PWR source te rms and two radiation sources The characteristics of each calculation set are as follows
1 Cask A with axial profile sources in the active fuel region
2 Cask A with uniform axial sources in the active fuel region
3 Cask B with axial profile sources in the active fuel region
4 Cask B with uniform axial sources in the active fuel region
For each MCNP5 run dose rates are calculated at the exte rior surfaces and at distances 1 and 2 meters from the exterior surfaces Surface tallies and detector tallies (ring and point detectors) as indicated in Figure 1 are e mployed in all runs Figure 1 is used to illustrate the dep loyment of the surface and detector tallies re lative to the so urce regions and it should not be interpreted as an exact geometry of any particular run Surface tallies are deployed at all three distances while ring and point detectors are used only at 1 m and 2 m and not at the cask surfaces Using point detectors near a surface or in any scattering media is not recommended because very large scores can occur f rom collisions close ( less than a f ew centimeters) to the point detecto rs that can lead to resu lts with high r elative e rrors thus m aking the ca lculation d ifficult to o btain r eliable answers
21
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
For the radial direction surface tallies at the three distances (contact 1 m and 2 m) are computed for three su rface segments (cylindrical rings) between the planes at Z = 145 175 2 05 and 235 cm The geometric locations of the segments are shown in Figure 1 The axial locations of these segments correspond to the m iddle of the active fuel region of the PWR SNF assemblies The average dose rates for each of the segm ents are calculated for the outside surface and surfaces at 1 m and 2 m from the cask surface Two ring detectors (instead of point detectors) are deployed at 1 m and 2 m for the radial dire ction Ring detectors instead of point detectors are used in order to capitalize on the symm etry around the cask axis thus im proving the efficiency of the calculations
In the axial direction the average d ose rates within three concentric radial surfaces defined by radii of 40 80 and 120 cm (shown in Figure 1) are calculated for the top and bottom surfaces and at distances 1 m and 2 m from these surfaces Finally point detectors at 1 m and 2 m from the top and bottom axial surfaces are employed
22
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Point Detector at 2 m x
Ring Ring Detector Detector at 2 m at 1 m
x x
Z = 00 cm
Z = 145 cm
Z = 175 cm
Z = 205 cm
Z = 235 cm
R = 80 cm
R = 120 cm
R = 40 cm
Active Fuel
Shield Plug
Top End-Fitting Plenum
Bottom End-Fitting
Ring Detector at 1 m
x
Point Detector at 1 m x
Ring Detector
at 2 m x
D = 26797 cm
H =
610
845
cm
Point Detector at 1 m x
Point Detector at 2 m x
Figure 1 Geometry and Tally Scheme for the TAD Transportation Cask
23
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
62 CALCULATION INPUT
Technical product input and sources of the input used in the deve lopment of this calculation are documented in this section Tables in this docum ent and in th e associated Microsoftreg Excel spreadsheets referenced m ay present num erical values with m any significant figures these values are not to be considered as high precision values since the significant figures are results of calculated values andor unit conversions
621 TAD Canister
The TAD canis ter will contain either 21 P WR or 44 BW R (boiling water reactor) SNF assemblies (Reference 2222 Section 321) While the canister design is iden tical for both PWR and BWR SNF assemblies the internal basket structure is different depending on the SNF assemblies However the internal basket stru cture m aterial is no t in cluded in the calcu lation model (Assumption 326)
The TAD canister is a right-circu lar cylinder with a diam eter of 665 in and a height between 186 and 212 in (Reference 2222 Section 321) The average and maximum total dose rates on the top surf ace of a loaded TAD ca nister must not exceed 800 and 1000 m remhr respectively (Reference 2222 Section 314) The TAD canister used in this calculation is m ade of SS 316 with a radial wall and bottom thickness of 025 in (Assumption 321) The top of the canister has a shield plug that is 11 in thick SS 316 (Ass umption 322) A thick shield plug is needed to keep the maxim um contact dose rate of th e top surface below 1000 m remhr The overall dimensions of the TAD canister are provided in Table 3
Table 3 Dimensions of TAD Canister
Component Dimension
(in) (cm)
Maximum heighta 212 53848
Outer diametera 665 16891
Thickness of bottom lidb 025 0635
Shell thicknessb 025 0635
Lifting Featurec 6 1524
Height without Lifting Feature 206 52324
Thickness of shield plugd 110 2794
aReference 2222 Section 311 bAssumption 321 cReference 2222 p Attachment C-1 dAssumption 322
622 Conceptual TAD Transportation Casks
Two conceptual TAD transportation casks designa ted as Cask A and Cask B are em ployed in this calculation (Assumption 323) They both have a cylindrical geometry with dimensions and materials specified in Tables 1 and 2 of Section 323 Cask A will provide shielding to meet the exterior radiation standards of 10 CFR 7147(b) (Reference 231) when loaded with a TAD
24
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
canister car rying the m aximum PWR SNF Cask B will s atisfy th e sa me radiatio n standa rds when loaded with a TAD canister c arrying the average PWR SNF The reason to analyze both Casks A and B is to cover a broad range of characteristics of the CSNF
The cavity dimensions of the conceptual cask s are 53785 cm (21175 in) in height and 16891 cm (665 in) in diam eter (Tab les 1 and 2) This cav ity will accommoda te the TAD canister described in Table 3 without the lifting feature This is the geometry model used in the MCNP5 calculations
623 Fuel Assembly Selection
PWR and BWR Source Term Sensitivity Study (Reference 2211 Tables 71 through 84) shows that the source terms generated for the Bamp W 15x15 Mark B fuel assembly with 475 kg uranium loading bound the source terms of other PWR assembly types ther efore this assembly type is selected as the representative PWR fuel assembly The gamma and neutron source terms for the BampW 15x15 Mark B assembly are generated in PWR Source Term Generation and Evaluation (Reference 229) and are used in this calculation
624 BampW 15x15 Mark B PWR Fuel Assembly
BampW 15x15 Mark B fuel assembly consists of four regions top end-fitting plenum active fuel and bottom end-fitting The m aterials and ra diation sources of each assem bly region are homogenized inside a volume defined by the region height and the interior diam eter of the TAD canister (Assumption 325) The active fuel region is homogenized with fresh unirradiated fuel (Assumption 324) Since the internal structure (i e basket) design of t he TAD is currently not finalized the com position of the hom ogenized fuel does not include the basket m aterials (Assumption 326) and therefore does not take cred it for any shielding that these m aterials may provide
Table 4 provides the design param eters for the BampW 15x15 Mark B fuel assembly Data provided here are used in Attachment II PWR_fuel compxls worksheet BampWassy
25
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 4 BampW 15x15 Mark B Fuel Assembly Description
Component Material Characteristic Value Specific Reference Array Size 15 x 15
Reference 2227 Table 2-2 Fuel Pins Assembly 208 Guide Tubes Assembly 16 Instrument Tubes Assembly 1
Assembly NA Pin Pellet Diameter 0936244 cm (03686 in) Reference 2220 p 2A-34 Pin Pitch 144272 cm (0568 in)
Reference 2227 Table 2-2 Active Fuel Height 360172 cm (1418 in) Assembly Width 2168144 cm (8536 in)
Reference 2220 p 2A-31 Assembly Height 4206875 cm (165625 in) Mass U assembly 46363 kg
Guide tube Zircaloy-4 Outer Diameter 13462 cm (053 in)
Reference 2227 Table 2-2
Inner Diameter 126492 cm (0498 in)
Instrument tube Zircaloy-4 Outer Diameter 138193 cm (05441 in) Inner Diameter 112014 cm (0441 in)
Cladding` Zircaloy-4 Inner Diameter 095758 cm (0377 in) Outer Diameter 10922 cm (043 in)
Plenum region NA Length 297688 cm (11720 in) Reference 2220 p 2A-34 Top nozzle SS CF3M MassAssembly (Top) 748 kg
Reference 2220 p 2A-32
Bottom nozzle SS CF3M MassAssembly (Bottom) 816 kg Guide tubes Zircaloy-4 MassAssembly (in Core) 80 kg Instrument tube Zircaloy-4 MassAssembly (in Core) 064 kg Spacer-plenum Inconel-718 MassAssembly (Plenum) 104 kg Spacer-bottom Inconel-718 MassAssembly (Bottom) 13 kg Spacer-in core Inconel-718 MassAssembly (in Core) 49 kg Spring retainer SS CF3M MassAssembly (Top) 091 kg Holddown spring Inconel-718 MassAssembly (Top) 18 kg Upper end plug SS 304 MassAssembly (Top) 006 kg Upper nut SS 304L MassAssembly (Top) 051 kg Lower nut SS 304 MassAssembly (Bottom) 015 kg Grid supports Zircaloy-4 MassAssembly (in Core) 064 kg Plenum spring SS 302 MassAssembly (Plenum) 0042 lb (001905 kg) Reference 2220 p 2A-34
Note Som e d ata i n this tab le ar e given i n British u nits in th e r eferences thes e d ata ar e converted into metric units as the inputs to MCNP5 are in metric units
The assem bly region heights as m odeled in MC NP are presented in Table 5 utilizing values from Table 4 Table 5 is taken from Dose Rate Calculation for Exhaust Main Drifts (Reference 2213 Table 3)
26
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 5 PWR Fuel Assembly Regions
Component Height Reference
Plenum 297688 cm (11720 in) Reference 2220 p 2A-34
Active Fuel 360172 cm (1418 in) Table 3
Bottom End-Fitting 1077 cm (424 in) Calculateda
Top End-Fitting 1998 cm (787 in) Calculatedb
Source Reference 2213 Table 3 aCalculated b ased on data Reference 2227 F igures 2-3 an d 2-7
(Region 9 Height [16723 cm] + Region 10 Height [508 cm] ndash Lo wer Fuel Plenum and End Cap [11033 cm])
bCalculated (Assembly Length ndash Active Fuel Length ndash P lenum Length ndash Bottom End-fitting Length)
625 Material Compositions
The TAD transportation cask com ponent m aterial specifications are defined in Table 1 The TAD canister is constructed of SS 316 (Assumpti on 321) The PWR fuel assembly materials used to homogenize the fuel regions are defined in Table 4 Table 6 c ontains the m aterial compositions defining the TAD canister WP and fuel assemblies
27
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 6 Chemical Compositions of Materials
Material Density (gcc)
Isotopic Weight Percent Reference
SS 302 NA
C 0150 Mn 2000 P 0045 S 0030 Si 0750 Cr 18000 Ni 9000 N 0100 Fe 69925
Attachment II PWR_fuel compxls worksheet ferrous Reference 222 SEC II A SA-240 Table 1 for SS 302 SS 304 and SS 304L Reference 222 SEC II A SA-351SA -351M Table 2 for SS CF3M
SS 304 NA
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 9250 N 0100 Fe 68745
SS 304L NA
C 003 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 10000 N 0100 Fe 6804 5
SS CF3M NA
C 0030 Mn 1500 P 0040 S 0040 Si 1500 Cr 19000 Ni 11000 Mo 2500 Fe 64390
Inconel 718 NA
C 0080 Mn 0350 Si 0350 Cr 19000 Ni 52500 Co 1000 Mo 3050 Fe 16809 Nb 5125 Ti 0900 Al 0500 Cu 0300 S 0015 P 0015 B 0006
Attachment II PWR_fuel compxls worksheet alloys aReference 223 p 666 Table 6 Reference 222 SEC II B SB-637 Table 1 for Inconel 718 Reference 224 Table 2 for Zircaloy 4
Zircaloy 4 656a Cr 0100 Fe 0210 O 0125 Sn 1450 Zr 98115
SS 316 798b
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 17000 Ni 12000 Mo 2500 N 0100 Fe 65495
Attachment II PWR_fuel compxls worksheet others Reference 222 SEC II A SA-240 Table 1 for SS 316 bReference 225 Table X1
626 Homogenization Assembly Materials
The atom density of an element or isotope in atomsbmiddotcm in a homogenized region is calculated according to the following equation (Reference 2223 Appendix B)
M i times N AvogadroNi = Equation 1 Ai timesV times K
where Ni = Atom density of elementisotope i (atomsbmiddotcm) Mi = Mass of elementisotope i (g) NAvogadro = Avogadrorsquos constant 06022 x 1024 (atomsmole)
28
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Ai = Atomic weight of elementisotope i (gmole) V = Homogenization volume (cm3) K = Unit transformation constant = 1024 (bmiddotcmcm3)
Equation 1 is used in A ttachment II spreadsheet PWR_fuel compxls worksheet BampWassy to calculate th e atom dens ities for v arious elem ents and iso topes The m ass of elementsisotop es and Avogadrorsquos constant are provided in Reference 2226
Table 7 lists the com position of the hom ogenized assem bly regions (active fuel plenum top end-fitting and bottom end-fitting) for the PWR assembly The active fuel region contains fresh unirradiated fuel (Assumption 324) Since the internal structure (ie basket) design of the TAD is currently not finalized the composition of either homogenized fuel does not include the basket materials and therefore does not tak e credit for any shielding that thes e materials may provide (Assumption 326)
Table 7 Isotopic Compositions of Homogenized PWR Assembly Regions
Element Isotope
Atom Densities for Homogenized Regions (atomsbsdotcm)
Active Fuel Bottom End-Fitting Plenum Top End-Fitting
10B 861E-09 764E-08 221E-08 570E-08 11B 347E-08 307E-07 890E-08 230E-07 C 519E-07 160E-05 138E-06 993E-06 N -- 570E-07 262E-08 117E-06 O 621E-03 -- 142E-05 -- Al 144E-06 128E-05 371E-06 957E-06 Si 971E-07 243E-04 259E-06 139E-04 P 377E-08 606E-06 102E-07 360E-06 S 365E-08 581E-06 971E-08 340E-06 Ti 147E-06 130E-05 376E-06 971E-06 Cr 320E-05 187E-03 779E-05 113E-03 Mn 497E-07 126E-04 141E-06 749E-05 Fe 303E-05 531E-03 717E-05 313E-03 Co 132E-06 117E-05 340E-06 876E-06 Ni 697E-05 144E-03 180E-04 940E-04 Cu 368E-07 327E-06 945E-07 244E-06 Zr 196E-03 -- 195E-03 -- Nb 430E-06 382E-05 110E-05 285E-05 Mo 248E-06 135E-04 636E-06 791E-05 Sn 223E-05 -- 222E-05 -- 234U 139E-06 -- -- -- 235U 157E-04 -- -- -- 236U 719E-07 -- -- -- 238U 294E-03 -- -- -- Total 114E-02 924E-03 235E-03 557E-03
Source Attachment II spreadsheet PWR_fuel compxls worksheet BampWassy
29
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
The isotopic composition of commercially available 235U enriched uranium is determined by the given initial 235U enrichment using the following equations (Reference 226 p 20)
wt235U =235Uenrichment _ of _ the _ associated _ fuel _ batch Equation 2
wt234U = 0007731times (wt235U )10837 Equation 3
wt236U = 00046times (wt235U ) Equation 4
wt238U =100 minus (wt234U + wt235U + wt236U ) Equation 5
The weight percentages of uran ium isotopes for PWR fuel are ca lculated in Attachm ent II spreadsheet PWR_fuel compxls worksheet BampWassy using Equations 2 through 5
627 PWR Source Terms
This calculation uses the following three PWR source terms bull Maximum source (50 wt initial 235U enrichment 80 GWdMTU burnup and 5-year
decay time) (Reference 229 Section 55) Table 8 lists th e gamma source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Design Basis source (4 0 wt initial 235U enrichment 60 GW dMTU burnup and 10-year decay tim e) (Reference 228 Section 552) Table 9 lists the gamm a source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Average source ( 40 wt initial 235U enrichment 48 GWdMTU burnup and 25-year decay time) (Reference 229 Section 55) Table 10 lists the gamma source terms for the fuel and non-fuel regions and the neutron source term for the fuel region
These sources (ie maximum design basis and av erage) are described in this section For dose rate calculations all the fuel assemblies in a transportation cask are of the sam e characteristics Also gamma radiation source term s for the PWR assem bly are prov ided for the f our assembly regions while neutron source term is only present in the active fuel region Gamma radiation sources in the non-active fuel region are distri buted unif ormly within each source region Gamma and neutron sources in the active fuel re gion are modeled as uni form distributions or with axial source profiles
The PWR gamma and neutron axial source profiles for the active fuel region presented in Table 11 are applied to the active fuel region of all three source terms (ie maximum design basis and average) when appropriate
30
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 8 Gamma and Neutron Sources for the Maximum PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting
Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 594E+11 233E+15 528E+11 379E+11 100E-01 000E+00 100E-01 116E+11 644E+14 609E+10 743E+10 400E-01 805E+07 200E-01 283E+10 522E+14 352E+10 179E+10 900E-01 411E+08 300E-01 141E+09 148E+14 196E+09 891E+08 140E+00 376E+08 400E-01 190E+09 985E+13 586E+09 117E+09 185E+00 276E+08 600E-01 191E+09 153E+15 110E+11 741E+07 300E+00 485E+08 800E-01 435E+09 470E+15 595E+10 237E+09 643E+00 443E+08 100E+00 137E+11 708E+14 803E+09 766E+10 200E+01 393E+07 133E+00 338E+13 455E+14 174E+13 217E+13 Total 211E+09 166E+00 953E+12 130E+14 491E+12 612E+12
--
200E+00 187E+03 144E+12 919E+02 113E+03 250E+00 226E+08 249E+12 116E+08 145E+08 300E+00 351E+05 110E+11 181E+05 225E+05 400E+00 766E-08 139E+10 100E-08 416E-08 500E+00 000E+00 709E+07 000E+00 000E+00 650E+00 000E+00 286E+07 000E+00 000E+00 800E+00 000E+00 558E+06 000E+00 000E+00 100E+01 000E+00 119E+06 000E+00 000E+00
Total 442E+13 113E+16 231E+13 284E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE2R2B14cut bWasteStreamE2R1B14cut cWasteStreamE2R3B14cut dWasteStreamE2R4B14cut
31
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 9 Gamma and Neutron Sources for the Design Basis PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary
(MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 273E+11 121E+15 188E+11 175E+11 100E-01 000E+00 100E-01 528E+10 329E+14 277E+10 339E+10 400E-01 316E+07 200E-01 128E+10 245E+14 117E+10 819E+09 900E-01 161E+08 300E-01 639E+08 713E+13 633E+08 407E+08 140E+00 148E+08 400E-01 850E+08 455E+13 164E+09 533E+08 185E+00 109E+08 600E-01 492E+08 226E+14 269E+10 337E+07 300E+00 191E+08 800E-01 291E+09 237E+15 160E+10 186E+09 643E+00 174E+08 100E+00 540E+09 122E+14 248E+09 341E+09 200E+01 154E+07 133E+00 154E+13 195E+14 797E+12 990E+12 Total 830E+08 166E+00 435E+12 450E+13 225E+12 280E+12
--
200E+00 235E+00 152E+11 149E+02 215E-02 250E+00 103E+08 517E+10 534E+07 664E+07 300E+00 160E+05 379E+09 829E+04 103E+05 400E+00 943E-10 497E+08 155E-10 519E-10 500E+00 000E+00 282E+07 000E+00 000E+00 650E+00 000E+00 113E+07 000E+00 000E+00 800E+00 000E+00 222E+06 000E+00 000E+00 100E+01 000E+00 471E+05 000E+00 000E+00
Total 201E+13 486E+15 105E+13 129E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B11cut bWasteStreamE5R1B11cut cWasteStreamE5R3B11cut dWasteStreamE5R4B11cut
32
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 10 Gamma and Neutron Sources for the Average PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 336E+10 670E+14 186E+10 217E+10 100E-01 00000E+00 100E-01 602E+09 199E+14 314E+09 387E+09 400E-01 748E+06 200E-01 146E+09 126E+14 853E+08 936E+08 900E-01 382E+07 300E-01 730E+07 389E+13 439E+07 469E+07 140E+00 352E+07 400E-01 947E+07 263E+13 716E+07 607E+07 185E+00 261E+07 600E-01 141E+07 205E+13 504E+08 383E+06 300E+00 469E+07 800E-01 208E+09 124E+15 192E+09 144E+09 643E+00 418E+07 100E+00 208E+09 110E+13 164E+09 144E+09 200E+01 365E+06 133E+00 175E+12 295E+13 909E+11 112E+12 Total 199E+08 166E+00 494E+11 513E+12 257E+11 318E+11
--
200E+00 973E-01 675E+10 614E+01 872E-03 250E+00 117E+07 353E+09 609E+06 754E+06 300E+00 182E+04 288E+08 944E+03 117E+04 400E+00 186E-11 198E+07 149E-11 127E-11 500E+00 000E+00 669E+06 000E+00 000E+00 650E+00 000E+00 269E+06 000E+00 000E+00 800E+00 000E+00 527E+05 000E+00 000E+00 100E+01 000E+00 112E+05 000E+00 000E+00
Total 229E+12 237E+15 119E+12 147E+12
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B9cut bWasteStreamE5R1B9cut cWasteStreamE5R3B9cut dWasteStreamE5R4B9cut
33
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 11 Gamma and Neutron Axial Source Profiles for a PWR Assembly
Axial boundaries (From midplane)
(cm)
TOP BOTTOM
Neutron Gamma Ne utron Gamma 000 1554 1117 1554 1117 1143 1537 1114 1571 1120 2286 1521 1111 1588 1123 3429 1504 1108 1605 1126 4572 1486 1104 1622 1129 5715 1464 1100 1636 1131 6858 1438 1095 1648 1133 8001 1401 1088 1657 1135 9144 1350 1078 1654 1134
10287 1277 1063 1625 1129 11430 1165 1039 1554 1117 12573 0998 09995 1414 1091 13716 0769 09365 1172 1041 14859 0492 08375 0816 0951 16002 0220 06850 0402 0797 17145 0046 04625 0092 0551 18288 00 00 00 00
Source Reference 2219 Table S445
34
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
63 MCNP SPECIFIC INPUT
631 Source Probability
A linear radial distribution is used for all gamma and neutron sources The linear radial distribution is sam pled usi ng the built-in power function p(x) = xc a with a = 1 for the radial direction This sampling method results in a uniform source distribution over the area bounded by the outer radius of the source
The source axial distributions are unifor m for all four source regions The a xial uni form xp(x) = c distribution is sampled using the built-in power function a with a = 0 for extent
The energy distribu tions of the gamma and neutron sour ce term s are treated as energ y probabilities and are applied in MCNP5 using SISP cards
632 Dose Rate and Flux Tallies
MCNP5 dose rate calculations feature separate runs for the following calculation types
bull a photon transport calculation for prim ary ga mma contribution to the dose rates fr om photon fluxes
bull a coupled neutronphoton transport calculat ion for neutrons a nd secondary gamma (photons generated by neutron be ing captured) contributions to dose rates from neutron and gamma fluxes
The tally type F2 is us ed in th is d esign ca lculation as f lux estim ators The type F2 tally evaluates the flux averaged over a surface in particlescm2s
To generate dose ra tes in te rms of remhr the FM (tally multiplier ) and DEDF (dose energydose conversion factors) cards are used to en ter the tally multiplier f actor (source intensity in particless) energy boundaries in MeV and corresponding dose conversion factors in (remhr)(particlescm2s) respectively These factors were used in the input files
In order for the F2 tally to accum ulate flux ov er a surface a specific s urface area is requ ired The SD cards are used to enter a surface area in cm2 over which the flux will be tallied for an F2 tally
633 Variance Reduction Techniques
Variance reduction technique is usually em ployed in order to increase the efficiency of a calculation and obtain statistically m eaningful results within re asonable com puter tim e In Monte Carlo calculations when variance reduction scheme is employed the weights of particles are adjusted in order to account for the biasing and to preserve a fair game
Geometry splitting and Russian roulette techniques described in Reference 2224 (pp 2-140 ndash 2-142) are useful in shielding calculations and therefore deployed in all the MCNP5 runs
35
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
As particles migrate in an important direction (toward the detector) they are increased in number to provide better sampling by means of geometry splitting across geometric boundaries Russian roulette (the reverse process) is played when particles travel in an unimportant direction to allow termination of unim portant histories The IMP card required for every cel l ca rd is us ed to implement this technique
The other variance reduction technique deployed in the MC NP5 runs is source intensity biasing for the gamma sources from the four source regions (active fuel bottom end-fitting plenum and top end-fitting) The natural total gamma source intensity of comm ercial SNF is dom inated by the gamma source in the active fuel region This active fuel gamma source usually accounts for over 95 o f the total g amma source intens ity In order to im prove the efficiency of the axial dose rate calculations a biased source probability distribution is employed for the prim ary gamma dose rate calculations The biased gamma source probability distribution is chosen to be 005 080 010 and 005 for the bottom end-fitting the active fuel the plenum and the top end-fitting regions respectively
64 DOSE CONVERSION FACTORS
Project Design Criteria Document (Reference 2211 Se ction 41015) requires the use of flux-to-dose rate conversion fact ors from ANSIANS-611-1977 (Reference 221) for dose rate evaluations Table 16 lists the neutron and ga mma dose conversion factors used in the MCNP5 calculations
Table 12 Gamma and Neutron Flux to Dose Conversion Factors
Gamma Neutron Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
001 396E-06 140 251E-06 250E-08 367E-06 003 582E-07 180 299E-06 100E-07 367E-06 005 290E-07 220 342E-06 100E-06 446E-06 007 258E-07 260 382E-06 100E-05 454E-06 010 283E-07 280 401E-06 100E-04 418E-06 015 379E-07 325 441E-06 100E-03 376E-06 020 501E-07 375 483E-06 100E-02 356E-06 025 631E-07 425 523E-06 100E-01 217E-05 030 759E-07 475 560E-06 500E-01 926E-05 035 878E-07 500 580E-06 100E+00 132E-04 040 985E-07 525 601E-06 250E+00 125E-04 045 108E-06 575 637E-06 500E+00 156E-04 050 117E-06 625 674E-06 700E+00 147E-04 055 127E-06 675 711E-06 100E+01 147E-04 060 136E-06 750 766E-06 140E+01 208E-04 065 144E-06 900 877E-06 200E+01 227E-04 070 152E-06 1100 103E-05 080 168E-06 1300 118E-05 100 198E-06 1500 133E-05
Source Reference 221 Tables 1 and 3
36
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION
By def inition (Ref erence 2224 Equation 219) the estimated st atistic relative error of the i component is
Ri = Si
2
Equation 6Ti
where i = tally component index Ri = relative error of the i component S2
i = variance of the i component Ti = tally i component
For a result (ie dose rate) computed as a sum of different tallies the statistical relative error of the computed value is o btained from the variance of the result - S2
total which is th e sum of the estimated variances of the individual tallies S2
i n
2 2STotal = sum Si Equation 7 i=1
where S2Total = total estimated variance
n = total number of components Therefore the total tally value (dose rate) and the associated relative error are derived according to Equations 8 and 9
n TTotal = sumTi Equation 8
i=1
n n
sum (Ri timesTi )2
2 sum Si 2
STotal = i=1 = i=1 Equation 9RTotal = TTotal TTotal TTotal
where RTotal = total estimated relative error TTotal = total estimated tally
Equations 8 and 9 are utilized in Attachm ent II to ev aluate to tal dos e ra tes and their r elative errors
37
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
7 RESULTS AND CONCLUSIONS
71 RESULTS
The following sections summarize the results of this calculation Section 711 presents results for Conceptual Cask A while Section 712 for Conceptual Cask B Section 713 provides comparisons of the dose-rate reduction factors du e to the two conceptual casks and the axial source distributions in the active fuel region Do se rates and relative errors can be found in Attachment II within the output files and Excel files
711 Dose Rates of Conceptual Cask A
This section presents dose-rate results of the calculation sets 1 and 2 as described in Section 61 for Cask A Set 1 has axial p rofile sources in the active fuel region a nd consist of six runs resulting from the three PWR SNF source term s (maximum design basis and average) and the two radiation sources (gammas and neutrons) Set 2 has uniform axial sources in the active fuel region and consists of six run s r esulting f rom the th ree P WR SNF source term s and th e tw o radiation sources
As described in Section 61 dose ra tes are calculated at the three exterior surfaces (radial top and bottom) and at distances 1 m and 2 m from the exterior surfaces The total dose rates for set 1 are presented in Tables 13 14 and 15 for the ra dial top and bottom dire ctions respectively However the com ponents (primary gamma neutr on and secondary gamma) contributing to the total dose rates as well as the re lative error calculations can be found in Attachment II Excel file MCNP-Results1xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 2 are shown in Tables 16 17 and 18 The dose-rate components and the relative errors can be found in A ttachment II Excel file MCNP-Results2xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 13 and 16 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 14 and 17 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 15 and 18 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carrying th e maximum PWR SNF Based on the results in Tables 13 through 18 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask A indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these 6 tables the d ose-rate red uction f actors between the m aximum and the design basis fuels the maxim um and the averag e fuels and th e design basis and the average fuels are a lso presented
38
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 320E-02 00237 116E-02 00222 262E-03 00219 275 1223 445
1 m 133E-02 00164 494E-03 00171 106E-03 00162 269 1261 468 2 m 749E-03 00198 285E-03 00225 584E-04 00162 263 1282 488
Ring Detectors 1 m 133E-02 00116 492E-03 00115 108E-03 00124 271 1229 454 2 m 756E-03 00118 279E-03 00110 605E-04 00128 271 1250 462
Source Attachment II MCNP-Results1xls worksheet Summary
Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 142E-02 00368 628E-03 00446 934E-04 00483 226 1520 672
1 m 570E-03 00289 263E-03 00426 375E-04 00381 217 1520 701 2 m 265E-03 00364 123E-03 00547 169E-04 00374 216 1575 730
Point Detectors 1 m 598E-03 00238 274E-03 00271 402E-04 00354 219 1489 681 2 m 273E-03 00218 123E-03 00245 180E-04 00336 221 1515 684
Source Attachment II MCNP-Results1xls worksheet Summary
Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 653E-03 00298 265E-03 00276 510E-04 00341 247 1278 518
1 m 276E-03 00238 112E-03 00208 207E-04 00249 248 1334 539 2 m 125E-03 00185 508E-04 00199 933E-05 00246 246 1336 544
Point Detectors 1 m 291E-03 00227 118E-03 00203 218E-04 00242 247 1335 540 2 m 130E-03 00209 524E-04 00187 955E-05 00233 247 1357 549
Source Attachment II MCNP-Results1xls worksheet Summary
Tables 13 14 and 15 are results of calculation set 1 for conceptual Cask A with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
39
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 265E-02 00247 990E-03 00222 215E-03 00278 268 1234 461
1 m 116E-02 00178 468E-03 00549 960E-04 00189 248 1208 488 2 m 713E-03 00273 265E-03 00161 602E-04 00360 269 1184 439
Ring Detectors 1 m 117E-02 00120 454E-03 00132 979E-04 00141 259 1199 463 2 m 722E-03 00130 276E-03 00141 589E-04 00153 261 1226 469
Source Attachment II MCNP-Results2xls worksheet Summary
Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 199E-02 00461 827E-03 00455 147E-03 00536 241 1359 564
1 m 849E-03 00564 323E-03 00314 563E-04 00418 263 1507 574 2 m 415E-03 00832 158E-03 00603 253E-04 00501 263 1641 623
Point Detectors 1 m 877E-03 00348 353E-03 00275 615E-04 00391 248 1426 574 2 m 393E-03 00341 160E-03 00278 270E-04 00378 246 1454 590
Source Attachment II MCNP-Results2xls worksheet Summary
Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 879E-03 00374 356E-03 00333 669E-04 00406 247 1315 533
1 m 365E-03 00223 147E-03 00209 269E-04 00253 248 1358 548 2 m 164E-03 00229 674E-04 00205 120E-04 00248 243 1364 560
Point Detectors 1 m 383E-03 00217 155E-03 00204 285E-04 00248 247 1347 546 2 m 172E-03 00197 689E-04 00186 124E-04 00225 249 1391 558
Source Attachment II MCNP-Results2xls worksheet Summary
Tables 16 17 and 18 ar e results of calculation set 2 for conceptual Cask A with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
40
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
323 Geometry and Materials of Conceptual TAD Transportation Casks
Assumption Two conceptual TAD transpo rtation casks designated as Cask A and Cask B are assumed to have a cylindrical geom etry and m aterials specified in Tab les 1 and 2 respectively The casks are basically construc ted of an inner layer of SS 316 for ga mma shielding a m iddle layer of 5-borated polyethylen e for neutron shielding and a th in outer layer of SS 316 whic h serves a structural function as well as shielding secondary gamma rays
Both Cask A and Cask B have a cavity height of 53785 cm (21175 in) and a cavity diameter of 16891 cm (6650 in) However Cask A has a total height of 610845 cm (24049 in) and an outside diameter of 26797 cm (10550 in) while the total height and outside diameter of Cask B are 58885 cm (23183 in) and 24765 cm (9750) respectively
Cask A will provide shielding to m eet the exterior radiat ion standards of 10 C FR 7147(b) (Reference 231) when loaded w ith a TAD canister carrying th e maximum PWR spent nuclear fuel (SNF) Cask B will satisf y the same radiation standards when loade d with a TAD caniste r carrying the average PWR SNF
Table 1 Geometry and Materials of Conceptual TAD Transportation Cask A
Component Dimension
Material (cm) (in)
Total Height 61085 2404 9 NA
Outside Diameter 26797 1055 0 NA
Cask Cavity Height 53785 2117 5 NA
Cask Cavity Diameter (Radius) 16891 (8446) 6650 (3325) NA
Radial Gamma Shield Thickness (Radius)a 3302 (11748)a 1300 (4625)a SS 316
Radial Neutron Shield Thickness (Radius)b 1524 (13272)b 600 (5225)b 5-borated polyethylene
Radial Outer Shell Thickness (Radius)c 127 (13399)c 050 (5275)c SS 316
Top Gamma Shield Thickness (Axial Position)d 600 (54385)d 236 (21411)d SS 316
Top Neutron Shield Thickness (Axial Position)d 1000 (55385)d 394 (21805)d 5-borated polyethylene
Top Outer Shell Thickness (Axial Position)d 200 (55585)d 079 (21884)d SS 316
Bottom Gamma Shield Thickness (Axial Position)d 35365 (-360)d 1392 (-1417)d SS 316
Bottom Neutron Shield Thickness (Axial Position)d 15 (-510)d 591 (-2008)d 5-borated polyethylene
Bottom Outer Shell Thickness (Axial Position)d 4 (-550)d 157 (-2165)d SS 316 a11748 = 3302 + 8446 and 4625 = 1300 + 3325 b13272 = 1524 + 11748 and 5225 = 600 + 4625 c13399 = 127 + 13272 and 5275 = 050 + 5225 dCoordinate relative to the bottom of the fuel assembly as modeled in MCNP5
15
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 2 Geometry and Materials of Conceptual TAD Transportation Cask B
Component Dimension
Material (cm) (in)
Total Height 58885 2318 3 NA
Outside Diameter 24765 9750 NA
Cask Cavity Height 53785 2117 5 NA
Cask Cavity Diameter (Radius) 16891 (8446) 6650 (3325) NA
Radial Gamma Shield Thickness (Radius)a 254 (10986)a 1000 (4325)a SS 316
Radial Neutron Shield Thickness (Radius)b 127 (12256)b 500 (4825)b 5-borated polyethylene
Radial Outer Shell Thickness (Radius)c 127 (12383)c 050 (4875)c SS 316
Top Gamma Shield Thickness (Axial Position)d 8 (54585)d 315 (21490)d SS 316
Top Neutron Shield Thickness (Axial Position)d None Non e NA
Top Outer Shell Thickness (Axial Position)d None Non e NA
Bottom Gamma Shield Thickness (Axial Position)d 3837 (-390)d 1510 (-1535)d SS 316
Bottom Neutron Shield Thickness (Axial Position)d 300 (-420)d 118 (-1654)d 5-borated polyethylene
Bottom Outer Shell Thickness (Axial Position)d 100 (-430)d 039 (-1693)d SS 316 a10986 = 254 + 8446 and 4325 = 1000 + 3325 b12256= 127 + 10986 and 4825 = 500+ 4325 c12383 = 127 + 12256 and 4875 = 050 + 4825 dCoordinate relative to the bottom of the fuel assembly as modeled in MCNP5
Rationale Currently a design for the TAD transporta tion cask does not exist The casks assumed for this calculation are so lely for estim ation of the dose reduction due to different source terms This is a conceptual repres entation only used in this calculation to estim ate the parameters of interest
Usage This assumption is used in Sections 61 and 622
324 Usage of Unirradiated Fuel for Commercial SNF
Assumption It is assumed that the active fuel region of the commercial SNF assembly contains the same isotopic concentrations as the fresh uni rradiated fuel and that the concentrations of fresh fuel with 5 initial enrichm ent corresp onding to m aximum SNF are used for all other SNFs
Rationale This assumption is a standard practice for shielding calculations throughout the industry accepted by the U S Nucle ar Regulatory Commission (NRC) (Reference 2228 Table 53-5) It sh ould be noted that this assumption applies to material composition only it does no t apply to source terms which are based on the characteristics of spent fuel
Usage This assumption is used in Sections 624 and 626
325 Homogenization of Radiation Source Regions
Assumption It is assu med that a commercial SNF assembly consis ts of four distinct reg ions (active fuel bottom end-fitting plenum and top end-fitting) The materials and radiation sources
16
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
of each assembly region are homogenized inside a volume defined by the TAD cavity radius and region height
Rationale The assembly representation is consistent with the industry practice for shielding calculations accepted by NRC (Reference 2228 Figure 53-6) The effec t of source homogenization is twofold (1) it d ecreases th e m ass de nsity of the source region and (2) it places source points slightly closer to detector locations thus reducing radiation attenuation The resu lts of Calculation of the Effect of Source Geometry on the 21-PWR WP Dose Rates (Reference 2218 pp 22-26) indicate that th e effect of assem bly homogenization gives nearly the same or conservative dose rates as the explicit fuel assembly model
Usage This assumption is used in Section 624
326 Ignoring Internal Fuel Basket Materials
Assumption It is assumed that the internal fuel basket materials are ignored
Rationale Inclusion of fuel basket m aterials in the smeared m aterial com position would increase the overall density and consequently increase the attenuati on of the radiation Therefore this assumption is conservative
Usage This assumption is used in Sections 621 624 and 626
17
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
4 METHODOLOGY
41 QUALITY ASSURANCE
This calculation was prepared in accordance with EG-PRO-3DP-G04B-00037 Calculations and Analyses (Reference 212) The results of th is calculation provides worker dose assessm ent adjustments and this will id entify radio logical hazards f or f acilities im portant to saf ety Therefore the approved version is designated as QA QA
42 USE OF COMPUTER SOFTWARE
421 Baseline Software
The Monte Carlo N-Particle com puter pr ogram (MCNP5) version 140 (Reference 2225) is used to calculate the dose rates (neutron pr imary gamm a and secondary gamm a) at various locations around a transportation cask and an aging overpack
The software specifications are as follows
bull Program Name MCNP5 bull VersionRevision Number Version 140 bull Operating Systems Windows XP bull Software Tracking Number 11199-140-00 bull Computer Type Dell OPTIPLEX GX620
MCNP5 which is Level 1 software is (a) appropriate for three-dim ensional neutron gamma and coupled neutrongamma shielding calculations (b) used within th e range of validation as documented in Software Validation Report for MCNP5 v140 (Reference 2221) and (c) obtained from Software C onfiguration Managem ent and qualified in accordance with procedure IT-PRO-0012 Qualification of Software (Reference 213) Therefore MCNP5 code is suitable for use in this design calculation All MCNP5 input and output files docum ented in this calculation are provided on a compact disc (CD) as Attachment II
All MCNP cases are executed on one of the following Q com puters QNW -004184 QNW -004187 QNW-004194 and QNW-004196 as shown in the output files
422 Commercial off the Shelf Software
The Excel sof tware is used to c alculate var ious inpu t values (i e atom densities weight percentages geometrical dimensions normalized source spectra and probabilities etc) Standard functions of Excel are also used in this desi gn calculation to display results (ie gamma and neutron dose rates) in tabular and graphic forms and to perform relative error calculations
The software specifications are as follows
bull Program Name Excel bull VersionRevision Number Microsoftreg Excel 2003
18
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
bull This software is installed on a persona l com puter running Microsoft W indows XP (central processing unit number 151834)
The user defined for mulas inputs results and gr aphical representations have been verified by hand calculations or visual inspection and are documented in sufficient detail to allow an independent repetition of the com putations Calculations were verifi ed by hand and graphical representations were found accurate by visual inspection
Per Software Management Microsoftreg Excel is not requir ed to be qualif ied due to its commercial availability status (Reference 211 Attachment 4 p 55 bullet 2)
43 CALCULATION APPROACH
This calculation em ploys the qualified so ftware MCNP5 version 140 (Reference 2225) a three-dimensional Monte Carlo code for pe rforming neutron and coupled neutron-gamm a calculations to estim ate dose rates at sele cted locations on and surrounding a conceptual transportation cask containing a loaded TAD canister
431 MCNP5 Program
MCNP5 a general Monte Carlo part icle transport code sim ulates particle transport through a three-dimensional representation of the nuclear system being analyzed During the random walk of particles through the system described by the geom etry the c ode collects inform ation about various events (su rface cross ing collis ions trac k leng th etc) and es timates fluxes in various geometric configurations specified as tallies by the user It also estimates the statistical precision of the results in the form of relative errors (Reference 2224 pp 1-2 to 1-8)
Per Project Design Criteria Document (Reference 2211 Section 41015) the flux estim ates are converted to dose rates using the Am erican Nuclear Society (ANS) flux-to-dose rate conversion factors for gammas and neutrons (R eference 221) The simple variance reduction techniques of Geometry SplittingRussian Roulette and source probability biasing (Sections 631 and 633) are used to enhance computational efficiency
19
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
5 LIST OF ATTACHMENTS
Number of Pages Attachment I List of Electronic Files on the CD 3 Attachment II Compact Disc NA
20
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
6 CALCULATIONS
This sectio n provides inform ation necess ary to perform the calcu lations in this docum ent Section 61 describes the configurations the type of CSNF to be analyzed the number of MCNP runs and the locations where dose rates are ca lculated Section 62 provides the calculation input that includes the details of the geom etry m odel radiation source term s and m aterial compositions Input specific to MCNP dose -rate conversion factors and relative error calculation are described in the later sections
61 DESCRIPTION OF CALCULATIONS
Dose rate calculations are perform ed with the MCNP5 version 140 com puter code (Reference 2225) Two conceptual transportation casks Cask A and Cask B (Assum ption 323) are employed Each cask contains a TAD canister that is loaded with 21 ident ical PW R SN F assemblies Three PWR source term s are analy zed they are the source term s corresponding to the maximum design basis and average PW R SN Fs The characteris tics of the P WR source terms are presented in S ection 627 Each PWR source term has neutron and ga mma radiation sources that require separate MCNP5 runs For each radiation source an axial profile source and a uniform source for the active fuel region are considered The uniform source for the active fuel region is included in this calculation because this approach was used in combination with source peaking factors in certain calculations (Reference 2216 Sections 37 and 39 and Reference 2217 Section 5242)
The total number of MCNP5 runs is 24 which re sults from a com bination of two conceptual casks three PWR source terms two radiation sources and two axia l source distributions for the active fuel region These 24 runs are categorized into four calcula tion sets Each calculation set consists of six runs that is a combination of three PWR source te rms and two radiation sources The characteristics of each calculation set are as follows
1 Cask A with axial profile sources in the active fuel region
2 Cask A with uniform axial sources in the active fuel region
3 Cask B with axial profile sources in the active fuel region
4 Cask B with uniform axial sources in the active fuel region
For each MCNP5 run dose rates are calculated at the exte rior surfaces and at distances 1 and 2 meters from the exterior surfaces Surface tallies and detector tallies (ring and point detectors) as indicated in Figure 1 are e mployed in all runs Figure 1 is used to illustrate the dep loyment of the surface and detector tallies re lative to the so urce regions and it should not be interpreted as an exact geometry of any particular run Surface tallies are deployed at all three distances while ring and point detectors are used only at 1 m and 2 m and not at the cask surfaces Using point detectors near a surface or in any scattering media is not recommended because very large scores can occur f rom collisions close ( less than a f ew centimeters) to the point detecto rs that can lead to resu lts with high r elative e rrors thus m aking the ca lculation d ifficult to o btain r eliable answers
21
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
For the radial direction surface tallies at the three distances (contact 1 m and 2 m) are computed for three su rface segments (cylindrical rings) between the planes at Z = 145 175 2 05 and 235 cm The geometric locations of the segments are shown in Figure 1 The axial locations of these segments correspond to the m iddle of the active fuel region of the PWR SNF assemblies The average dose rates for each of the segm ents are calculated for the outside surface and surfaces at 1 m and 2 m from the cask surface Two ring detectors (instead of point detectors) are deployed at 1 m and 2 m for the radial dire ction Ring detectors instead of point detectors are used in order to capitalize on the symm etry around the cask axis thus im proving the efficiency of the calculations
In the axial direction the average d ose rates within three concentric radial surfaces defined by radii of 40 80 and 120 cm (shown in Figure 1) are calculated for the top and bottom surfaces and at distances 1 m and 2 m from these surfaces Finally point detectors at 1 m and 2 m from the top and bottom axial surfaces are employed
22
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Point Detector at 2 m x
Ring Ring Detector Detector at 2 m at 1 m
x x
Z = 00 cm
Z = 145 cm
Z = 175 cm
Z = 205 cm
Z = 235 cm
R = 80 cm
R = 120 cm
R = 40 cm
Active Fuel
Shield Plug
Top End-Fitting Plenum
Bottom End-Fitting
Ring Detector at 1 m
x
Point Detector at 1 m x
Ring Detector
at 2 m x
D = 26797 cm
H =
610
845
cm
Point Detector at 1 m x
Point Detector at 2 m x
Figure 1 Geometry and Tally Scheme for the TAD Transportation Cask
23
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
62 CALCULATION INPUT
Technical product input and sources of the input used in the deve lopment of this calculation are documented in this section Tables in this docum ent and in th e associated Microsoftreg Excel spreadsheets referenced m ay present num erical values with m any significant figures these values are not to be considered as high precision values since the significant figures are results of calculated values andor unit conversions
621 TAD Canister
The TAD canis ter will contain either 21 P WR or 44 BW R (boiling water reactor) SNF assemblies (Reference 2222 Section 321) While the canister design is iden tical for both PWR and BWR SNF assemblies the internal basket structure is different depending on the SNF assemblies However the internal basket stru cture m aterial is no t in cluded in the calcu lation model (Assumption 326)
The TAD canister is a right-circu lar cylinder with a diam eter of 665 in and a height between 186 and 212 in (Reference 2222 Section 321) The average and maximum total dose rates on the top surf ace of a loaded TAD ca nister must not exceed 800 and 1000 m remhr respectively (Reference 2222 Section 314) The TAD canister used in this calculation is m ade of SS 316 with a radial wall and bottom thickness of 025 in (Assumption 321) The top of the canister has a shield plug that is 11 in thick SS 316 (Ass umption 322) A thick shield plug is needed to keep the maxim um contact dose rate of th e top surface below 1000 m remhr The overall dimensions of the TAD canister are provided in Table 3
Table 3 Dimensions of TAD Canister
Component Dimension
(in) (cm)
Maximum heighta 212 53848
Outer diametera 665 16891
Thickness of bottom lidb 025 0635
Shell thicknessb 025 0635
Lifting Featurec 6 1524
Height without Lifting Feature 206 52324
Thickness of shield plugd 110 2794
aReference 2222 Section 311 bAssumption 321 cReference 2222 p Attachment C-1 dAssumption 322
622 Conceptual TAD Transportation Casks
Two conceptual TAD transportation casks designa ted as Cask A and Cask B are em ployed in this calculation (Assumption 323) They both have a cylindrical geometry with dimensions and materials specified in Tables 1 and 2 of Section 323 Cask A will provide shielding to meet the exterior radiation standards of 10 CFR 7147(b) (Reference 231) when loaded with a TAD
24
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
canister car rying the m aximum PWR SNF Cask B will s atisfy th e sa me radiatio n standa rds when loaded with a TAD canister c arrying the average PWR SNF The reason to analyze both Casks A and B is to cover a broad range of characteristics of the CSNF
The cavity dimensions of the conceptual cask s are 53785 cm (21175 in) in height and 16891 cm (665 in) in diam eter (Tab les 1 and 2) This cav ity will accommoda te the TAD canister described in Table 3 without the lifting feature This is the geometry model used in the MCNP5 calculations
623 Fuel Assembly Selection
PWR and BWR Source Term Sensitivity Study (Reference 2211 Tables 71 through 84) shows that the source terms generated for the Bamp W 15x15 Mark B fuel assembly with 475 kg uranium loading bound the source terms of other PWR assembly types ther efore this assembly type is selected as the representative PWR fuel assembly The gamma and neutron source terms for the BampW 15x15 Mark B assembly are generated in PWR Source Term Generation and Evaluation (Reference 229) and are used in this calculation
624 BampW 15x15 Mark B PWR Fuel Assembly
BampW 15x15 Mark B fuel assembly consists of four regions top end-fitting plenum active fuel and bottom end-fitting The m aterials and ra diation sources of each assem bly region are homogenized inside a volume defined by the region height and the interior diam eter of the TAD canister (Assumption 325) The active fuel region is homogenized with fresh unirradiated fuel (Assumption 324) Since the internal structure (i e basket) design of t he TAD is currently not finalized the com position of the hom ogenized fuel does not include the basket m aterials (Assumption 326) and therefore does not take cred it for any shielding that these m aterials may provide
Table 4 provides the design param eters for the BampW 15x15 Mark B fuel assembly Data provided here are used in Attachment II PWR_fuel compxls worksheet BampWassy
25
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 4 BampW 15x15 Mark B Fuel Assembly Description
Component Material Characteristic Value Specific Reference Array Size 15 x 15
Reference 2227 Table 2-2 Fuel Pins Assembly 208 Guide Tubes Assembly 16 Instrument Tubes Assembly 1
Assembly NA Pin Pellet Diameter 0936244 cm (03686 in) Reference 2220 p 2A-34 Pin Pitch 144272 cm (0568 in)
Reference 2227 Table 2-2 Active Fuel Height 360172 cm (1418 in) Assembly Width 2168144 cm (8536 in)
Reference 2220 p 2A-31 Assembly Height 4206875 cm (165625 in) Mass U assembly 46363 kg
Guide tube Zircaloy-4 Outer Diameter 13462 cm (053 in)
Reference 2227 Table 2-2
Inner Diameter 126492 cm (0498 in)
Instrument tube Zircaloy-4 Outer Diameter 138193 cm (05441 in) Inner Diameter 112014 cm (0441 in)
Cladding` Zircaloy-4 Inner Diameter 095758 cm (0377 in) Outer Diameter 10922 cm (043 in)
Plenum region NA Length 297688 cm (11720 in) Reference 2220 p 2A-34 Top nozzle SS CF3M MassAssembly (Top) 748 kg
Reference 2220 p 2A-32
Bottom nozzle SS CF3M MassAssembly (Bottom) 816 kg Guide tubes Zircaloy-4 MassAssembly (in Core) 80 kg Instrument tube Zircaloy-4 MassAssembly (in Core) 064 kg Spacer-plenum Inconel-718 MassAssembly (Plenum) 104 kg Spacer-bottom Inconel-718 MassAssembly (Bottom) 13 kg Spacer-in core Inconel-718 MassAssembly (in Core) 49 kg Spring retainer SS CF3M MassAssembly (Top) 091 kg Holddown spring Inconel-718 MassAssembly (Top) 18 kg Upper end plug SS 304 MassAssembly (Top) 006 kg Upper nut SS 304L MassAssembly (Top) 051 kg Lower nut SS 304 MassAssembly (Bottom) 015 kg Grid supports Zircaloy-4 MassAssembly (in Core) 064 kg Plenum spring SS 302 MassAssembly (Plenum) 0042 lb (001905 kg) Reference 2220 p 2A-34
Note Som e d ata i n this tab le ar e given i n British u nits in th e r eferences thes e d ata ar e converted into metric units as the inputs to MCNP5 are in metric units
The assem bly region heights as m odeled in MC NP are presented in Table 5 utilizing values from Table 4 Table 5 is taken from Dose Rate Calculation for Exhaust Main Drifts (Reference 2213 Table 3)
26
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 5 PWR Fuel Assembly Regions
Component Height Reference
Plenum 297688 cm (11720 in) Reference 2220 p 2A-34
Active Fuel 360172 cm (1418 in) Table 3
Bottom End-Fitting 1077 cm (424 in) Calculateda
Top End-Fitting 1998 cm (787 in) Calculatedb
Source Reference 2213 Table 3 aCalculated b ased on data Reference 2227 F igures 2-3 an d 2-7
(Region 9 Height [16723 cm] + Region 10 Height [508 cm] ndash Lo wer Fuel Plenum and End Cap [11033 cm])
bCalculated (Assembly Length ndash Active Fuel Length ndash P lenum Length ndash Bottom End-fitting Length)
625 Material Compositions
The TAD transportation cask com ponent m aterial specifications are defined in Table 1 The TAD canister is constructed of SS 316 (Assumpti on 321) The PWR fuel assembly materials used to homogenize the fuel regions are defined in Table 4 Table 6 c ontains the m aterial compositions defining the TAD canister WP and fuel assemblies
27
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 6 Chemical Compositions of Materials
Material Density (gcc)
Isotopic Weight Percent Reference
SS 302 NA
C 0150 Mn 2000 P 0045 S 0030 Si 0750 Cr 18000 Ni 9000 N 0100 Fe 69925
Attachment II PWR_fuel compxls worksheet ferrous Reference 222 SEC II A SA-240 Table 1 for SS 302 SS 304 and SS 304L Reference 222 SEC II A SA-351SA -351M Table 2 for SS CF3M
SS 304 NA
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 9250 N 0100 Fe 68745
SS 304L NA
C 003 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 10000 N 0100 Fe 6804 5
SS CF3M NA
C 0030 Mn 1500 P 0040 S 0040 Si 1500 Cr 19000 Ni 11000 Mo 2500 Fe 64390
Inconel 718 NA
C 0080 Mn 0350 Si 0350 Cr 19000 Ni 52500 Co 1000 Mo 3050 Fe 16809 Nb 5125 Ti 0900 Al 0500 Cu 0300 S 0015 P 0015 B 0006
Attachment II PWR_fuel compxls worksheet alloys aReference 223 p 666 Table 6 Reference 222 SEC II B SB-637 Table 1 for Inconel 718 Reference 224 Table 2 for Zircaloy 4
Zircaloy 4 656a Cr 0100 Fe 0210 O 0125 Sn 1450 Zr 98115
SS 316 798b
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 17000 Ni 12000 Mo 2500 N 0100 Fe 65495
Attachment II PWR_fuel compxls worksheet others Reference 222 SEC II A SA-240 Table 1 for SS 316 bReference 225 Table X1
626 Homogenization Assembly Materials
The atom density of an element or isotope in atomsbmiddotcm in a homogenized region is calculated according to the following equation (Reference 2223 Appendix B)
M i times N AvogadroNi = Equation 1 Ai timesV times K
where Ni = Atom density of elementisotope i (atomsbmiddotcm) Mi = Mass of elementisotope i (g) NAvogadro = Avogadrorsquos constant 06022 x 1024 (atomsmole)
28
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Ai = Atomic weight of elementisotope i (gmole) V = Homogenization volume (cm3) K = Unit transformation constant = 1024 (bmiddotcmcm3)
Equation 1 is used in A ttachment II spreadsheet PWR_fuel compxls worksheet BampWassy to calculate th e atom dens ities for v arious elem ents and iso topes The m ass of elementsisotop es and Avogadrorsquos constant are provided in Reference 2226
Table 7 lists the com position of the hom ogenized assem bly regions (active fuel plenum top end-fitting and bottom end-fitting) for the PWR assembly The active fuel region contains fresh unirradiated fuel (Assumption 324) Since the internal structure (ie basket) design of the TAD is currently not finalized the composition of either homogenized fuel does not include the basket materials and therefore does not tak e credit for any shielding that thes e materials may provide (Assumption 326)
Table 7 Isotopic Compositions of Homogenized PWR Assembly Regions
Element Isotope
Atom Densities for Homogenized Regions (atomsbsdotcm)
Active Fuel Bottom End-Fitting Plenum Top End-Fitting
10B 861E-09 764E-08 221E-08 570E-08 11B 347E-08 307E-07 890E-08 230E-07 C 519E-07 160E-05 138E-06 993E-06 N -- 570E-07 262E-08 117E-06 O 621E-03 -- 142E-05 -- Al 144E-06 128E-05 371E-06 957E-06 Si 971E-07 243E-04 259E-06 139E-04 P 377E-08 606E-06 102E-07 360E-06 S 365E-08 581E-06 971E-08 340E-06 Ti 147E-06 130E-05 376E-06 971E-06 Cr 320E-05 187E-03 779E-05 113E-03 Mn 497E-07 126E-04 141E-06 749E-05 Fe 303E-05 531E-03 717E-05 313E-03 Co 132E-06 117E-05 340E-06 876E-06 Ni 697E-05 144E-03 180E-04 940E-04 Cu 368E-07 327E-06 945E-07 244E-06 Zr 196E-03 -- 195E-03 -- Nb 430E-06 382E-05 110E-05 285E-05 Mo 248E-06 135E-04 636E-06 791E-05 Sn 223E-05 -- 222E-05 -- 234U 139E-06 -- -- -- 235U 157E-04 -- -- -- 236U 719E-07 -- -- -- 238U 294E-03 -- -- -- Total 114E-02 924E-03 235E-03 557E-03
Source Attachment II spreadsheet PWR_fuel compxls worksheet BampWassy
29
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
The isotopic composition of commercially available 235U enriched uranium is determined by the given initial 235U enrichment using the following equations (Reference 226 p 20)
wt235U =235Uenrichment _ of _ the _ associated _ fuel _ batch Equation 2
wt234U = 0007731times (wt235U )10837 Equation 3
wt236U = 00046times (wt235U ) Equation 4
wt238U =100 minus (wt234U + wt235U + wt236U ) Equation 5
The weight percentages of uran ium isotopes for PWR fuel are ca lculated in Attachm ent II spreadsheet PWR_fuel compxls worksheet BampWassy using Equations 2 through 5
627 PWR Source Terms
This calculation uses the following three PWR source terms bull Maximum source (50 wt initial 235U enrichment 80 GWdMTU burnup and 5-year
decay time) (Reference 229 Section 55) Table 8 lists th e gamma source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Design Basis source (4 0 wt initial 235U enrichment 60 GW dMTU burnup and 10-year decay tim e) (Reference 228 Section 552) Table 9 lists the gamm a source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Average source ( 40 wt initial 235U enrichment 48 GWdMTU burnup and 25-year decay time) (Reference 229 Section 55) Table 10 lists the gamma source terms for the fuel and non-fuel regions and the neutron source term for the fuel region
These sources (ie maximum design basis and av erage) are described in this section For dose rate calculations all the fuel assemblies in a transportation cask are of the sam e characteristics Also gamma radiation source term s for the PWR assem bly are prov ided for the f our assembly regions while neutron source term is only present in the active fuel region Gamma radiation sources in the non-active fuel region are distri buted unif ormly within each source region Gamma and neutron sources in the active fuel re gion are modeled as uni form distributions or with axial source profiles
The PWR gamma and neutron axial source profiles for the active fuel region presented in Table 11 are applied to the active fuel region of all three source terms (ie maximum design basis and average) when appropriate
30
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 8 Gamma and Neutron Sources for the Maximum PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting
Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 594E+11 233E+15 528E+11 379E+11 100E-01 000E+00 100E-01 116E+11 644E+14 609E+10 743E+10 400E-01 805E+07 200E-01 283E+10 522E+14 352E+10 179E+10 900E-01 411E+08 300E-01 141E+09 148E+14 196E+09 891E+08 140E+00 376E+08 400E-01 190E+09 985E+13 586E+09 117E+09 185E+00 276E+08 600E-01 191E+09 153E+15 110E+11 741E+07 300E+00 485E+08 800E-01 435E+09 470E+15 595E+10 237E+09 643E+00 443E+08 100E+00 137E+11 708E+14 803E+09 766E+10 200E+01 393E+07 133E+00 338E+13 455E+14 174E+13 217E+13 Total 211E+09 166E+00 953E+12 130E+14 491E+12 612E+12
--
200E+00 187E+03 144E+12 919E+02 113E+03 250E+00 226E+08 249E+12 116E+08 145E+08 300E+00 351E+05 110E+11 181E+05 225E+05 400E+00 766E-08 139E+10 100E-08 416E-08 500E+00 000E+00 709E+07 000E+00 000E+00 650E+00 000E+00 286E+07 000E+00 000E+00 800E+00 000E+00 558E+06 000E+00 000E+00 100E+01 000E+00 119E+06 000E+00 000E+00
Total 442E+13 113E+16 231E+13 284E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE2R2B14cut bWasteStreamE2R1B14cut cWasteStreamE2R3B14cut dWasteStreamE2R4B14cut
31
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 9 Gamma and Neutron Sources for the Design Basis PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary
(MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 273E+11 121E+15 188E+11 175E+11 100E-01 000E+00 100E-01 528E+10 329E+14 277E+10 339E+10 400E-01 316E+07 200E-01 128E+10 245E+14 117E+10 819E+09 900E-01 161E+08 300E-01 639E+08 713E+13 633E+08 407E+08 140E+00 148E+08 400E-01 850E+08 455E+13 164E+09 533E+08 185E+00 109E+08 600E-01 492E+08 226E+14 269E+10 337E+07 300E+00 191E+08 800E-01 291E+09 237E+15 160E+10 186E+09 643E+00 174E+08 100E+00 540E+09 122E+14 248E+09 341E+09 200E+01 154E+07 133E+00 154E+13 195E+14 797E+12 990E+12 Total 830E+08 166E+00 435E+12 450E+13 225E+12 280E+12
--
200E+00 235E+00 152E+11 149E+02 215E-02 250E+00 103E+08 517E+10 534E+07 664E+07 300E+00 160E+05 379E+09 829E+04 103E+05 400E+00 943E-10 497E+08 155E-10 519E-10 500E+00 000E+00 282E+07 000E+00 000E+00 650E+00 000E+00 113E+07 000E+00 000E+00 800E+00 000E+00 222E+06 000E+00 000E+00 100E+01 000E+00 471E+05 000E+00 000E+00
Total 201E+13 486E+15 105E+13 129E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B11cut bWasteStreamE5R1B11cut cWasteStreamE5R3B11cut dWasteStreamE5R4B11cut
32
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 10 Gamma and Neutron Sources for the Average PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 336E+10 670E+14 186E+10 217E+10 100E-01 00000E+00 100E-01 602E+09 199E+14 314E+09 387E+09 400E-01 748E+06 200E-01 146E+09 126E+14 853E+08 936E+08 900E-01 382E+07 300E-01 730E+07 389E+13 439E+07 469E+07 140E+00 352E+07 400E-01 947E+07 263E+13 716E+07 607E+07 185E+00 261E+07 600E-01 141E+07 205E+13 504E+08 383E+06 300E+00 469E+07 800E-01 208E+09 124E+15 192E+09 144E+09 643E+00 418E+07 100E+00 208E+09 110E+13 164E+09 144E+09 200E+01 365E+06 133E+00 175E+12 295E+13 909E+11 112E+12 Total 199E+08 166E+00 494E+11 513E+12 257E+11 318E+11
--
200E+00 973E-01 675E+10 614E+01 872E-03 250E+00 117E+07 353E+09 609E+06 754E+06 300E+00 182E+04 288E+08 944E+03 117E+04 400E+00 186E-11 198E+07 149E-11 127E-11 500E+00 000E+00 669E+06 000E+00 000E+00 650E+00 000E+00 269E+06 000E+00 000E+00 800E+00 000E+00 527E+05 000E+00 000E+00 100E+01 000E+00 112E+05 000E+00 000E+00
Total 229E+12 237E+15 119E+12 147E+12
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B9cut bWasteStreamE5R1B9cut cWasteStreamE5R3B9cut dWasteStreamE5R4B9cut
33
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 11 Gamma and Neutron Axial Source Profiles for a PWR Assembly
Axial boundaries (From midplane)
(cm)
TOP BOTTOM
Neutron Gamma Ne utron Gamma 000 1554 1117 1554 1117 1143 1537 1114 1571 1120 2286 1521 1111 1588 1123 3429 1504 1108 1605 1126 4572 1486 1104 1622 1129 5715 1464 1100 1636 1131 6858 1438 1095 1648 1133 8001 1401 1088 1657 1135 9144 1350 1078 1654 1134
10287 1277 1063 1625 1129 11430 1165 1039 1554 1117 12573 0998 09995 1414 1091 13716 0769 09365 1172 1041 14859 0492 08375 0816 0951 16002 0220 06850 0402 0797 17145 0046 04625 0092 0551 18288 00 00 00 00
Source Reference 2219 Table S445
34
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
63 MCNP SPECIFIC INPUT
631 Source Probability
A linear radial distribution is used for all gamma and neutron sources The linear radial distribution is sam pled usi ng the built-in power function p(x) = xc a with a = 1 for the radial direction This sampling method results in a uniform source distribution over the area bounded by the outer radius of the source
The source axial distributions are unifor m for all four source regions The a xial uni form xp(x) = c distribution is sampled using the built-in power function a with a = 0 for extent
The energy distribu tions of the gamma and neutron sour ce term s are treated as energ y probabilities and are applied in MCNP5 using SISP cards
632 Dose Rate and Flux Tallies
MCNP5 dose rate calculations feature separate runs for the following calculation types
bull a photon transport calculation for prim ary ga mma contribution to the dose rates fr om photon fluxes
bull a coupled neutronphoton transport calculat ion for neutrons a nd secondary gamma (photons generated by neutron be ing captured) contributions to dose rates from neutron and gamma fluxes
The tally type F2 is us ed in th is d esign ca lculation as f lux estim ators The type F2 tally evaluates the flux averaged over a surface in particlescm2s
To generate dose ra tes in te rms of remhr the FM (tally multiplier ) and DEDF (dose energydose conversion factors) cards are used to en ter the tally multiplier f actor (source intensity in particless) energy boundaries in MeV and corresponding dose conversion factors in (remhr)(particlescm2s) respectively These factors were used in the input files
In order for the F2 tally to accum ulate flux ov er a surface a specific s urface area is requ ired The SD cards are used to enter a surface area in cm2 over which the flux will be tallied for an F2 tally
633 Variance Reduction Techniques
Variance reduction technique is usually em ployed in order to increase the efficiency of a calculation and obtain statistically m eaningful results within re asonable com puter tim e In Monte Carlo calculations when variance reduction scheme is employed the weights of particles are adjusted in order to account for the biasing and to preserve a fair game
Geometry splitting and Russian roulette techniques described in Reference 2224 (pp 2-140 ndash 2-142) are useful in shielding calculations and therefore deployed in all the MCNP5 runs
35
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
As particles migrate in an important direction (toward the detector) they are increased in number to provide better sampling by means of geometry splitting across geometric boundaries Russian roulette (the reverse process) is played when particles travel in an unimportant direction to allow termination of unim portant histories The IMP card required for every cel l ca rd is us ed to implement this technique
The other variance reduction technique deployed in the MC NP5 runs is source intensity biasing for the gamma sources from the four source regions (active fuel bottom end-fitting plenum and top end-fitting) The natural total gamma source intensity of comm ercial SNF is dom inated by the gamma source in the active fuel region This active fuel gamma source usually accounts for over 95 o f the total g amma source intens ity In order to im prove the efficiency of the axial dose rate calculations a biased source probability distribution is employed for the prim ary gamma dose rate calculations The biased gamma source probability distribution is chosen to be 005 080 010 and 005 for the bottom end-fitting the active fuel the plenum and the top end-fitting regions respectively
64 DOSE CONVERSION FACTORS
Project Design Criteria Document (Reference 2211 Se ction 41015) requires the use of flux-to-dose rate conversion fact ors from ANSIANS-611-1977 (Reference 221) for dose rate evaluations Table 16 lists the neutron and ga mma dose conversion factors used in the MCNP5 calculations
Table 12 Gamma and Neutron Flux to Dose Conversion Factors
Gamma Neutron Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
001 396E-06 140 251E-06 250E-08 367E-06 003 582E-07 180 299E-06 100E-07 367E-06 005 290E-07 220 342E-06 100E-06 446E-06 007 258E-07 260 382E-06 100E-05 454E-06 010 283E-07 280 401E-06 100E-04 418E-06 015 379E-07 325 441E-06 100E-03 376E-06 020 501E-07 375 483E-06 100E-02 356E-06 025 631E-07 425 523E-06 100E-01 217E-05 030 759E-07 475 560E-06 500E-01 926E-05 035 878E-07 500 580E-06 100E+00 132E-04 040 985E-07 525 601E-06 250E+00 125E-04 045 108E-06 575 637E-06 500E+00 156E-04 050 117E-06 625 674E-06 700E+00 147E-04 055 127E-06 675 711E-06 100E+01 147E-04 060 136E-06 750 766E-06 140E+01 208E-04 065 144E-06 900 877E-06 200E+01 227E-04 070 152E-06 1100 103E-05 080 168E-06 1300 118E-05 100 198E-06 1500 133E-05
Source Reference 221 Tables 1 and 3
36
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION
By def inition (Ref erence 2224 Equation 219) the estimated st atistic relative error of the i component is
Ri = Si
2
Equation 6Ti
where i = tally component index Ri = relative error of the i component S2
i = variance of the i component Ti = tally i component
For a result (ie dose rate) computed as a sum of different tallies the statistical relative error of the computed value is o btained from the variance of the result - S2
total which is th e sum of the estimated variances of the individual tallies S2
i n
2 2STotal = sum Si Equation 7 i=1
where S2Total = total estimated variance
n = total number of components Therefore the total tally value (dose rate) and the associated relative error are derived according to Equations 8 and 9
n TTotal = sumTi Equation 8
i=1
n n
sum (Ri timesTi )2
2 sum Si 2
STotal = i=1 = i=1 Equation 9RTotal = TTotal TTotal TTotal
where RTotal = total estimated relative error TTotal = total estimated tally
Equations 8 and 9 are utilized in Attachm ent II to ev aluate to tal dos e ra tes and their r elative errors
37
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
7 RESULTS AND CONCLUSIONS
71 RESULTS
The following sections summarize the results of this calculation Section 711 presents results for Conceptual Cask A while Section 712 for Conceptual Cask B Section 713 provides comparisons of the dose-rate reduction factors du e to the two conceptual casks and the axial source distributions in the active fuel region Do se rates and relative errors can be found in Attachment II within the output files and Excel files
711 Dose Rates of Conceptual Cask A
This section presents dose-rate results of the calculation sets 1 and 2 as described in Section 61 for Cask A Set 1 has axial p rofile sources in the active fuel region a nd consist of six runs resulting from the three PWR SNF source term s (maximum design basis and average) and the two radiation sources (gammas and neutrons) Set 2 has uniform axial sources in the active fuel region and consists of six run s r esulting f rom the th ree P WR SNF source term s and th e tw o radiation sources
As described in Section 61 dose ra tes are calculated at the three exterior surfaces (radial top and bottom) and at distances 1 m and 2 m from the exterior surfaces The total dose rates for set 1 are presented in Tables 13 14 and 15 for the ra dial top and bottom dire ctions respectively However the com ponents (primary gamma neutr on and secondary gamma) contributing to the total dose rates as well as the re lative error calculations can be found in Attachment II Excel file MCNP-Results1xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 2 are shown in Tables 16 17 and 18 The dose-rate components and the relative errors can be found in A ttachment II Excel file MCNP-Results2xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 13 and 16 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 14 and 17 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 15 and 18 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carrying th e maximum PWR SNF Based on the results in Tables 13 through 18 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask A indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these 6 tables the d ose-rate red uction f actors between the m aximum and the design basis fuels the maxim um and the averag e fuels and th e design basis and the average fuels are a lso presented
38
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 320E-02 00237 116E-02 00222 262E-03 00219 275 1223 445
1 m 133E-02 00164 494E-03 00171 106E-03 00162 269 1261 468 2 m 749E-03 00198 285E-03 00225 584E-04 00162 263 1282 488
Ring Detectors 1 m 133E-02 00116 492E-03 00115 108E-03 00124 271 1229 454 2 m 756E-03 00118 279E-03 00110 605E-04 00128 271 1250 462
Source Attachment II MCNP-Results1xls worksheet Summary
Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 142E-02 00368 628E-03 00446 934E-04 00483 226 1520 672
1 m 570E-03 00289 263E-03 00426 375E-04 00381 217 1520 701 2 m 265E-03 00364 123E-03 00547 169E-04 00374 216 1575 730
Point Detectors 1 m 598E-03 00238 274E-03 00271 402E-04 00354 219 1489 681 2 m 273E-03 00218 123E-03 00245 180E-04 00336 221 1515 684
Source Attachment II MCNP-Results1xls worksheet Summary
Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 653E-03 00298 265E-03 00276 510E-04 00341 247 1278 518
1 m 276E-03 00238 112E-03 00208 207E-04 00249 248 1334 539 2 m 125E-03 00185 508E-04 00199 933E-05 00246 246 1336 544
Point Detectors 1 m 291E-03 00227 118E-03 00203 218E-04 00242 247 1335 540 2 m 130E-03 00209 524E-04 00187 955E-05 00233 247 1357 549
Source Attachment II MCNP-Results1xls worksheet Summary
Tables 13 14 and 15 are results of calculation set 1 for conceptual Cask A with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
39
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 265E-02 00247 990E-03 00222 215E-03 00278 268 1234 461
1 m 116E-02 00178 468E-03 00549 960E-04 00189 248 1208 488 2 m 713E-03 00273 265E-03 00161 602E-04 00360 269 1184 439
Ring Detectors 1 m 117E-02 00120 454E-03 00132 979E-04 00141 259 1199 463 2 m 722E-03 00130 276E-03 00141 589E-04 00153 261 1226 469
Source Attachment II MCNP-Results2xls worksheet Summary
Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 199E-02 00461 827E-03 00455 147E-03 00536 241 1359 564
1 m 849E-03 00564 323E-03 00314 563E-04 00418 263 1507 574 2 m 415E-03 00832 158E-03 00603 253E-04 00501 263 1641 623
Point Detectors 1 m 877E-03 00348 353E-03 00275 615E-04 00391 248 1426 574 2 m 393E-03 00341 160E-03 00278 270E-04 00378 246 1454 590
Source Attachment II MCNP-Results2xls worksheet Summary
Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 879E-03 00374 356E-03 00333 669E-04 00406 247 1315 533
1 m 365E-03 00223 147E-03 00209 269E-04 00253 248 1358 548 2 m 164E-03 00229 674E-04 00205 120E-04 00248 243 1364 560
Point Detectors 1 m 383E-03 00217 155E-03 00204 285E-04 00248 247 1347 546 2 m 172E-03 00197 689E-04 00186 124E-04 00225 249 1391 558
Source Attachment II MCNP-Results2xls worksheet Summary
Tables 16 17 and 18 ar e results of calculation set 2 for conceptual Cask A with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
40
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 2 Geometry and Materials of Conceptual TAD Transportation Cask B
Component Dimension
Material (cm) (in)
Total Height 58885 2318 3 NA
Outside Diameter 24765 9750 NA
Cask Cavity Height 53785 2117 5 NA
Cask Cavity Diameter (Radius) 16891 (8446) 6650 (3325) NA
Radial Gamma Shield Thickness (Radius)a 254 (10986)a 1000 (4325)a SS 316
Radial Neutron Shield Thickness (Radius)b 127 (12256)b 500 (4825)b 5-borated polyethylene
Radial Outer Shell Thickness (Radius)c 127 (12383)c 050 (4875)c SS 316
Top Gamma Shield Thickness (Axial Position)d 8 (54585)d 315 (21490)d SS 316
Top Neutron Shield Thickness (Axial Position)d None Non e NA
Top Outer Shell Thickness (Axial Position)d None Non e NA
Bottom Gamma Shield Thickness (Axial Position)d 3837 (-390)d 1510 (-1535)d SS 316
Bottom Neutron Shield Thickness (Axial Position)d 300 (-420)d 118 (-1654)d 5-borated polyethylene
Bottom Outer Shell Thickness (Axial Position)d 100 (-430)d 039 (-1693)d SS 316 a10986 = 254 + 8446 and 4325 = 1000 + 3325 b12256= 127 + 10986 and 4825 = 500+ 4325 c12383 = 127 + 12256 and 4875 = 050 + 4825 dCoordinate relative to the bottom of the fuel assembly as modeled in MCNP5
Rationale Currently a design for the TAD transporta tion cask does not exist The casks assumed for this calculation are so lely for estim ation of the dose reduction due to different source terms This is a conceptual repres entation only used in this calculation to estim ate the parameters of interest
Usage This assumption is used in Sections 61 and 622
324 Usage of Unirradiated Fuel for Commercial SNF
Assumption It is assumed that the active fuel region of the commercial SNF assembly contains the same isotopic concentrations as the fresh uni rradiated fuel and that the concentrations of fresh fuel with 5 initial enrichm ent corresp onding to m aximum SNF are used for all other SNFs
Rationale This assumption is a standard practice for shielding calculations throughout the industry accepted by the U S Nucle ar Regulatory Commission (NRC) (Reference 2228 Table 53-5) It sh ould be noted that this assumption applies to material composition only it does no t apply to source terms which are based on the characteristics of spent fuel
Usage This assumption is used in Sections 624 and 626
325 Homogenization of Radiation Source Regions
Assumption It is assu med that a commercial SNF assembly consis ts of four distinct reg ions (active fuel bottom end-fitting plenum and top end-fitting) The materials and radiation sources
16
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
of each assembly region are homogenized inside a volume defined by the TAD cavity radius and region height
Rationale The assembly representation is consistent with the industry practice for shielding calculations accepted by NRC (Reference 2228 Figure 53-6) The effec t of source homogenization is twofold (1) it d ecreases th e m ass de nsity of the source region and (2) it places source points slightly closer to detector locations thus reducing radiation attenuation The resu lts of Calculation of the Effect of Source Geometry on the 21-PWR WP Dose Rates (Reference 2218 pp 22-26) indicate that th e effect of assem bly homogenization gives nearly the same or conservative dose rates as the explicit fuel assembly model
Usage This assumption is used in Section 624
326 Ignoring Internal Fuel Basket Materials
Assumption It is assumed that the internal fuel basket materials are ignored
Rationale Inclusion of fuel basket m aterials in the smeared m aterial com position would increase the overall density and consequently increase the attenuati on of the radiation Therefore this assumption is conservative
Usage This assumption is used in Sections 621 624 and 626
17
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
4 METHODOLOGY
41 QUALITY ASSURANCE
This calculation was prepared in accordance with EG-PRO-3DP-G04B-00037 Calculations and Analyses (Reference 212) The results of th is calculation provides worker dose assessm ent adjustments and this will id entify radio logical hazards f or f acilities im portant to saf ety Therefore the approved version is designated as QA QA
42 USE OF COMPUTER SOFTWARE
421 Baseline Software
The Monte Carlo N-Particle com puter pr ogram (MCNP5) version 140 (Reference 2225) is used to calculate the dose rates (neutron pr imary gamm a and secondary gamm a) at various locations around a transportation cask and an aging overpack
The software specifications are as follows
bull Program Name MCNP5 bull VersionRevision Number Version 140 bull Operating Systems Windows XP bull Software Tracking Number 11199-140-00 bull Computer Type Dell OPTIPLEX GX620
MCNP5 which is Level 1 software is (a) appropriate for three-dim ensional neutron gamma and coupled neutrongamma shielding calculations (b) used within th e range of validation as documented in Software Validation Report for MCNP5 v140 (Reference 2221) and (c) obtained from Software C onfiguration Managem ent and qualified in accordance with procedure IT-PRO-0012 Qualification of Software (Reference 213) Therefore MCNP5 code is suitable for use in this design calculation All MCNP5 input and output files docum ented in this calculation are provided on a compact disc (CD) as Attachment II
All MCNP cases are executed on one of the following Q com puters QNW -004184 QNW -004187 QNW-004194 and QNW-004196 as shown in the output files
422 Commercial off the Shelf Software
The Excel sof tware is used to c alculate var ious inpu t values (i e atom densities weight percentages geometrical dimensions normalized source spectra and probabilities etc) Standard functions of Excel are also used in this desi gn calculation to display results (ie gamma and neutron dose rates) in tabular and graphic forms and to perform relative error calculations
The software specifications are as follows
bull Program Name Excel bull VersionRevision Number Microsoftreg Excel 2003
18
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
bull This software is installed on a persona l com puter running Microsoft W indows XP (central processing unit number 151834)
The user defined for mulas inputs results and gr aphical representations have been verified by hand calculations or visual inspection and are documented in sufficient detail to allow an independent repetition of the com putations Calculations were verifi ed by hand and graphical representations were found accurate by visual inspection
Per Software Management Microsoftreg Excel is not requir ed to be qualif ied due to its commercial availability status (Reference 211 Attachment 4 p 55 bullet 2)
43 CALCULATION APPROACH
This calculation em ploys the qualified so ftware MCNP5 version 140 (Reference 2225) a three-dimensional Monte Carlo code for pe rforming neutron and coupled neutron-gamm a calculations to estim ate dose rates at sele cted locations on and surrounding a conceptual transportation cask containing a loaded TAD canister
431 MCNP5 Program
MCNP5 a general Monte Carlo part icle transport code sim ulates particle transport through a three-dimensional representation of the nuclear system being analyzed During the random walk of particles through the system described by the geom etry the c ode collects inform ation about various events (su rface cross ing collis ions trac k leng th etc) and es timates fluxes in various geometric configurations specified as tallies by the user It also estimates the statistical precision of the results in the form of relative errors (Reference 2224 pp 1-2 to 1-8)
Per Project Design Criteria Document (Reference 2211 Section 41015) the flux estim ates are converted to dose rates using the Am erican Nuclear Society (ANS) flux-to-dose rate conversion factors for gammas and neutrons (R eference 221) The simple variance reduction techniques of Geometry SplittingRussian Roulette and source probability biasing (Sections 631 and 633) are used to enhance computational efficiency
19
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
5 LIST OF ATTACHMENTS
Number of Pages Attachment I List of Electronic Files on the CD 3 Attachment II Compact Disc NA
20
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
6 CALCULATIONS
This sectio n provides inform ation necess ary to perform the calcu lations in this docum ent Section 61 describes the configurations the type of CSNF to be analyzed the number of MCNP runs and the locations where dose rates are ca lculated Section 62 provides the calculation input that includes the details of the geom etry m odel radiation source term s and m aterial compositions Input specific to MCNP dose -rate conversion factors and relative error calculation are described in the later sections
61 DESCRIPTION OF CALCULATIONS
Dose rate calculations are perform ed with the MCNP5 version 140 com puter code (Reference 2225) Two conceptual transportation casks Cask A and Cask B (Assum ption 323) are employed Each cask contains a TAD canister that is loaded with 21 ident ical PW R SN F assemblies Three PWR source term s are analy zed they are the source term s corresponding to the maximum design basis and average PW R SN Fs The characteris tics of the P WR source terms are presented in S ection 627 Each PWR source term has neutron and ga mma radiation sources that require separate MCNP5 runs For each radiation source an axial profile source and a uniform source for the active fuel region are considered The uniform source for the active fuel region is included in this calculation because this approach was used in combination with source peaking factors in certain calculations (Reference 2216 Sections 37 and 39 and Reference 2217 Section 5242)
The total number of MCNP5 runs is 24 which re sults from a com bination of two conceptual casks three PWR source terms two radiation sources and two axia l source distributions for the active fuel region These 24 runs are categorized into four calcula tion sets Each calculation set consists of six runs that is a combination of three PWR source te rms and two radiation sources The characteristics of each calculation set are as follows
1 Cask A with axial profile sources in the active fuel region
2 Cask A with uniform axial sources in the active fuel region
3 Cask B with axial profile sources in the active fuel region
4 Cask B with uniform axial sources in the active fuel region
For each MCNP5 run dose rates are calculated at the exte rior surfaces and at distances 1 and 2 meters from the exterior surfaces Surface tallies and detector tallies (ring and point detectors) as indicated in Figure 1 are e mployed in all runs Figure 1 is used to illustrate the dep loyment of the surface and detector tallies re lative to the so urce regions and it should not be interpreted as an exact geometry of any particular run Surface tallies are deployed at all three distances while ring and point detectors are used only at 1 m and 2 m and not at the cask surfaces Using point detectors near a surface or in any scattering media is not recommended because very large scores can occur f rom collisions close ( less than a f ew centimeters) to the point detecto rs that can lead to resu lts with high r elative e rrors thus m aking the ca lculation d ifficult to o btain r eliable answers
21
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
For the radial direction surface tallies at the three distances (contact 1 m and 2 m) are computed for three su rface segments (cylindrical rings) between the planes at Z = 145 175 2 05 and 235 cm The geometric locations of the segments are shown in Figure 1 The axial locations of these segments correspond to the m iddle of the active fuel region of the PWR SNF assemblies The average dose rates for each of the segm ents are calculated for the outside surface and surfaces at 1 m and 2 m from the cask surface Two ring detectors (instead of point detectors) are deployed at 1 m and 2 m for the radial dire ction Ring detectors instead of point detectors are used in order to capitalize on the symm etry around the cask axis thus im proving the efficiency of the calculations
In the axial direction the average d ose rates within three concentric radial surfaces defined by radii of 40 80 and 120 cm (shown in Figure 1) are calculated for the top and bottom surfaces and at distances 1 m and 2 m from these surfaces Finally point detectors at 1 m and 2 m from the top and bottom axial surfaces are employed
22
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Point Detector at 2 m x
Ring Ring Detector Detector at 2 m at 1 m
x x
Z = 00 cm
Z = 145 cm
Z = 175 cm
Z = 205 cm
Z = 235 cm
R = 80 cm
R = 120 cm
R = 40 cm
Active Fuel
Shield Plug
Top End-Fitting Plenum
Bottom End-Fitting
Ring Detector at 1 m
x
Point Detector at 1 m x
Ring Detector
at 2 m x
D = 26797 cm
H =
610
845
cm
Point Detector at 1 m x
Point Detector at 2 m x
Figure 1 Geometry and Tally Scheme for the TAD Transportation Cask
23
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
62 CALCULATION INPUT
Technical product input and sources of the input used in the deve lopment of this calculation are documented in this section Tables in this docum ent and in th e associated Microsoftreg Excel spreadsheets referenced m ay present num erical values with m any significant figures these values are not to be considered as high precision values since the significant figures are results of calculated values andor unit conversions
621 TAD Canister
The TAD canis ter will contain either 21 P WR or 44 BW R (boiling water reactor) SNF assemblies (Reference 2222 Section 321) While the canister design is iden tical for both PWR and BWR SNF assemblies the internal basket structure is different depending on the SNF assemblies However the internal basket stru cture m aterial is no t in cluded in the calcu lation model (Assumption 326)
The TAD canister is a right-circu lar cylinder with a diam eter of 665 in and a height between 186 and 212 in (Reference 2222 Section 321) The average and maximum total dose rates on the top surf ace of a loaded TAD ca nister must not exceed 800 and 1000 m remhr respectively (Reference 2222 Section 314) The TAD canister used in this calculation is m ade of SS 316 with a radial wall and bottom thickness of 025 in (Assumption 321) The top of the canister has a shield plug that is 11 in thick SS 316 (Ass umption 322) A thick shield plug is needed to keep the maxim um contact dose rate of th e top surface below 1000 m remhr The overall dimensions of the TAD canister are provided in Table 3
Table 3 Dimensions of TAD Canister
Component Dimension
(in) (cm)
Maximum heighta 212 53848
Outer diametera 665 16891
Thickness of bottom lidb 025 0635
Shell thicknessb 025 0635
Lifting Featurec 6 1524
Height without Lifting Feature 206 52324
Thickness of shield plugd 110 2794
aReference 2222 Section 311 bAssumption 321 cReference 2222 p Attachment C-1 dAssumption 322
622 Conceptual TAD Transportation Casks
Two conceptual TAD transportation casks designa ted as Cask A and Cask B are em ployed in this calculation (Assumption 323) They both have a cylindrical geometry with dimensions and materials specified in Tables 1 and 2 of Section 323 Cask A will provide shielding to meet the exterior radiation standards of 10 CFR 7147(b) (Reference 231) when loaded with a TAD
24
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
canister car rying the m aximum PWR SNF Cask B will s atisfy th e sa me radiatio n standa rds when loaded with a TAD canister c arrying the average PWR SNF The reason to analyze both Casks A and B is to cover a broad range of characteristics of the CSNF
The cavity dimensions of the conceptual cask s are 53785 cm (21175 in) in height and 16891 cm (665 in) in diam eter (Tab les 1 and 2) This cav ity will accommoda te the TAD canister described in Table 3 without the lifting feature This is the geometry model used in the MCNP5 calculations
623 Fuel Assembly Selection
PWR and BWR Source Term Sensitivity Study (Reference 2211 Tables 71 through 84) shows that the source terms generated for the Bamp W 15x15 Mark B fuel assembly with 475 kg uranium loading bound the source terms of other PWR assembly types ther efore this assembly type is selected as the representative PWR fuel assembly The gamma and neutron source terms for the BampW 15x15 Mark B assembly are generated in PWR Source Term Generation and Evaluation (Reference 229) and are used in this calculation
624 BampW 15x15 Mark B PWR Fuel Assembly
BampW 15x15 Mark B fuel assembly consists of four regions top end-fitting plenum active fuel and bottom end-fitting The m aterials and ra diation sources of each assem bly region are homogenized inside a volume defined by the region height and the interior diam eter of the TAD canister (Assumption 325) The active fuel region is homogenized with fresh unirradiated fuel (Assumption 324) Since the internal structure (i e basket) design of t he TAD is currently not finalized the com position of the hom ogenized fuel does not include the basket m aterials (Assumption 326) and therefore does not take cred it for any shielding that these m aterials may provide
Table 4 provides the design param eters for the BampW 15x15 Mark B fuel assembly Data provided here are used in Attachment II PWR_fuel compxls worksheet BampWassy
25
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 4 BampW 15x15 Mark B Fuel Assembly Description
Component Material Characteristic Value Specific Reference Array Size 15 x 15
Reference 2227 Table 2-2 Fuel Pins Assembly 208 Guide Tubes Assembly 16 Instrument Tubes Assembly 1
Assembly NA Pin Pellet Diameter 0936244 cm (03686 in) Reference 2220 p 2A-34 Pin Pitch 144272 cm (0568 in)
Reference 2227 Table 2-2 Active Fuel Height 360172 cm (1418 in) Assembly Width 2168144 cm (8536 in)
Reference 2220 p 2A-31 Assembly Height 4206875 cm (165625 in) Mass U assembly 46363 kg
Guide tube Zircaloy-4 Outer Diameter 13462 cm (053 in)
Reference 2227 Table 2-2
Inner Diameter 126492 cm (0498 in)
Instrument tube Zircaloy-4 Outer Diameter 138193 cm (05441 in) Inner Diameter 112014 cm (0441 in)
Cladding` Zircaloy-4 Inner Diameter 095758 cm (0377 in) Outer Diameter 10922 cm (043 in)
Plenum region NA Length 297688 cm (11720 in) Reference 2220 p 2A-34 Top nozzle SS CF3M MassAssembly (Top) 748 kg
Reference 2220 p 2A-32
Bottom nozzle SS CF3M MassAssembly (Bottom) 816 kg Guide tubes Zircaloy-4 MassAssembly (in Core) 80 kg Instrument tube Zircaloy-4 MassAssembly (in Core) 064 kg Spacer-plenum Inconel-718 MassAssembly (Plenum) 104 kg Spacer-bottom Inconel-718 MassAssembly (Bottom) 13 kg Spacer-in core Inconel-718 MassAssembly (in Core) 49 kg Spring retainer SS CF3M MassAssembly (Top) 091 kg Holddown spring Inconel-718 MassAssembly (Top) 18 kg Upper end plug SS 304 MassAssembly (Top) 006 kg Upper nut SS 304L MassAssembly (Top) 051 kg Lower nut SS 304 MassAssembly (Bottom) 015 kg Grid supports Zircaloy-4 MassAssembly (in Core) 064 kg Plenum spring SS 302 MassAssembly (Plenum) 0042 lb (001905 kg) Reference 2220 p 2A-34
Note Som e d ata i n this tab le ar e given i n British u nits in th e r eferences thes e d ata ar e converted into metric units as the inputs to MCNP5 are in metric units
The assem bly region heights as m odeled in MC NP are presented in Table 5 utilizing values from Table 4 Table 5 is taken from Dose Rate Calculation for Exhaust Main Drifts (Reference 2213 Table 3)
26
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 5 PWR Fuel Assembly Regions
Component Height Reference
Plenum 297688 cm (11720 in) Reference 2220 p 2A-34
Active Fuel 360172 cm (1418 in) Table 3
Bottom End-Fitting 1077 cm (424 in) Calculateda
Top End-Fitting 1998 cm (787 in) Calculatedb
Source Reference 2213 Table 3 aCalculated b ased on data Reference 2227 F igures 2-3 an d 2-7
(Region 9 Height [16723 cm] + Region 10 Height [508 cm] ndash Lo wer Fuel Plenum and End Cap [11033 cm])
bCalculated (Assembly Length ndash Active Fuel Length ndash P lenum Length ndash Bottom End-fitting Length)
625 Material Compositions
The TAD transportation cask com ponent m aterial specifications are defined in Table 1 The TAD canister is constructed of SS 316 (Assumpti on 321) The PWR fuel assembly materials used to homogenize the fuel regions are defined in Table 4 Table 6 c ontains the m aterial compositions defining the TAD canister WP and fuel assemblies
27
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 6 Chemical Compositions of Materials
Material Density (gcc)
Isotopic Weight Percent Reference
SS 302 NA
C 0150 Mn 2000 P 0045 S 0030 Si 0750 Cr 18000 Ni 9000 N 0100 Fe 69925
Attachment II PWR_fuel compxls worksheet ferrous Reference 222 SEC II A SA-240 Table 1 for SS 302 SS 304 and SS 304L Reference 222 SEC II A SA-351SA -351M Table 2 for SS CF3M
SS 304 NA
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 9250 N 0100 Fe 68745
SS 304L NA
C 003 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 10000 N 0100 Fe 6804 5
SS CF3M NA
C 0030 Mn 1500 P 0040 S 0040 Si 1500 Cr 19000 Ni 11000 Mo 2500 Fe 64390
Inconel 718 NA
C 0080 Mn 0350 Si 0350 Cr 19000 Ni 52500 Co 1000 Mo 3050 Fe 16809 Nb 5125 Ti 0900 Al 0500 Cu 0300 S 0015 P 0015 B 0006
Attachment II PWR_fuel compxls worksheet alloys aReference 223 p 666 Table 6 Reference 222 SEC II B SB-637 Table 1 for Inconel 718 Reference 224 Table 2 for Zircaloy 4
Zircaloy 4 656a Cr 0100 Fe 0210 O 0125 Sn 1450 Zr 98115
SS 316 798b
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 17000 Ni 12000 Mo 2500 N 0100 Fe 65495
Attachment II PWR_fuel compxls worksheet others Reference 222 SEC II A SA-240 Table 1 for SS 316 bReference 225 Table X1
626 Homogenization Assembly Materials
The atom density of an element or isotope in atomsbmiddotcm in a homogenized region is calculated according to the following equation (Reference 2223 Appendix B)
M i times N AvogadroNi = Equation 1 Ai timesV times K
where Ni = Atom density of elementisotope i (atomsbmiddotcm) Mi = Mass of elementisotope i (g) NAvogadro = Avogadrorsquos constant 06022 x 1024 (atomsmole)
28
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Ai = Atomic weight of elementisotope i (gmole) V = Homogenization volume (cm3) K = Unit transformation constant = 1024 (bmiddotcmcm3)
Equation 1 is used in A ttachment II spreadsheet PWR_fuel compxls worksheet BampWassy to calculate th e atom dens ities for v arious elem ents and iso topes The m ass of elementsisotop es and Avogadrorsquos constant are provided in Reference 2226
Table 7 lists the com position of the hom ogenized assem bly regions (active fuel plenum top end-fitting and bottom end-fitting) for the PWR assembly The active fuel region contains fresh unirradiated fuel (Assumption 324) Since the internal structure (ie basket) design of the TAD is currently not finalized the composition of either homogenized fuel does not include the basket materials and therefore does not tak e credit for any shielding that thes e materials may provide (Assumption 326)
Table 7 Isotopic Compositions of Homogenized PWR Assembly Regions
Element Isotope
Atom Densities for Homogenized Regions (atomsbsdotcm)
Active Fuel Bottom End-Fitting Plenum Top End-Fitting
10B 861E-09 764E-08 221E-08 570E-08 11B 347E-08 307E-07 890E-08 230E-07 C 519E-07 160E-05 138E-06 993E-06 N -- 570E-07 262E-08 117E-06 O 621E-03 -- 142E-05 -- Al 144E-06 128E-05 371E-06 957E-06 Si 971E-07 243E-04 259E-06 139E-04 P 377E-08 606E-06 102E-07 360E-06 S 365E-08 581E-06 971E-08 340E-06 Ti 147E-06 130E-05 376E-06 971E-06 Cr 320E-05 187E-03 779E-05 113E-03 Mn 497E-07 126E-04 141E-06 749E-05 Fe 303E-05 531E-03 717E-05 313E-03 Co 132E-06 117E-05 340E-06 876E-06 Ni 697E-05 144E-03 180E-04 940E-04 Cu 368E-07 327E-06 945E-07 244E-06 Zr 196E-03 -- 195E-03 -- Nb 430E-06 382E-05 110E-05 285E-05 Mo 248E-06 135E-04 636E-06 791E-05 Sn 223E-05 -- 222E-05 -- 234U 139E-06 -- -- -- 235U 157E-04 -- -- -- 236U 719E-07 -- -- -- 238U 294E-03 -- -- -- Total 114E-02 924E-03 235E-03 557E-03
Source Attachment II spreadsheet PWR_fuel compxls worksheet BampWassy
29
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
The isotopic composition of commercially available 235U enriched uranium is determined by the given initial 235U enrichment using the following equations (Reference 226 p 20)
wt235U =235Uenrichment _ of _ the _ associated _ fuel _ batch Equation 2
wt234U = 0007731times (wt235U )10837 Equation 3
wt236U = 00046times (wt235U ) Equation 4
wt238U =100 minus (wt234U + wt235U + wt236U ) Equation 5
The weight percentages of uran ium isotopes for PWR fuel are ca lculated in Attachm ent II spreadsheet PWR_fuel compxls worksheet BampWassy using Equations 2 through 5
627 PWR Source Terms
This calculation uses the following three PWR source terms bull Maximum source (50 wt initial 235U enrichment 80 GWdMTU burnup and 5-year
decay time) (Reference 229 Section 55) Table 8 lists th e gamma source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Design Basis source (4 0 wt initial 235U enrichment 60 GW dMTU burnup and 10-year decay tim e) (Reference 228 Section 552) Table 9 lists the gamm a source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Average source ( 40 wt initial 235U enrichment 48 GWdMTU burnup and 25-year decay time) (Reference 229 Section 55) Table 10 lists the gamma source terms for the fuel and non-fuel regions and the neutron source term for the fuel region
These sources (ie maximum design basis and av erage) are described in this section For dose rate calculations all the fuel assemblies in a transportation cask are of the sam e characteristics Also gamma radiation source term s for the PWR assem bly are prov ided for the f our assembly regions while neutron source term is only present in the active fuel region Gamma radiation sources in the non-active fuel region are distri buted unif ormly within each source region Gamma and neutron sources in the active fuel re gion are modeled as uni form distributions or with axial source profiles
The PWR gamma and neutron axial source profiles for the active fuel region presented in Table 11 are applied to the active fuel region of all three source terms (ie maximum design basis and average) when appropriate
30
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 8 Gamma and Neutron Sources for the Maximum PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting
Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 594E+11 233E+15 528E+11 379E+11 100E-01 000E+00 100E-01 116E+11 644E+14 609E+10 743E+10 400E-01 805E+07 200E-01 283E+10 522E+14 352E+10 179E+10 900E-01 411E+08 300E-01 141E+09 148E+14 196E+09 891E+08 140E+00 376E+08 400E-01 190E+09 985E+13 586E+09 117E+09 185E+00 276E+08 600E-01 191E+09 153E+15 110E+11 741E+07 300E+00 485E+08 800E-01 435E+09 470E+15 595E+10 237E+09 643E+00 443E+08 100E+00 137E+11 708E+14 803E+09 766E+10 200E+01 393E+07 133E+00 338E+13 455E+14 174E+13 217E+13 Total 211E+09 166E+00 953E+12 130E+14 491E+12 612E+12
--
200E+00 187E+03 144E+12 919E+02 113E+03 250E+00 226E+08 249E+12 116E+08 145E+08 300E+00 351E+05 110E+11 181E+05 225E+05 400E+00 766E-08 139E+10 100E-08 416E-08 500E+00 000E+00 709E+07 000E+00 000E+00 650E+00 000E+00 286E+07 000E+00 000E+00 800E+00 000E+00 558E+06 000E+00 000E+00 100E+01 000E+00 119E+06 000E+00 000E+00
Total 442E+13 113E+16 231E+13 284E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE2R2B14cut bWasteStreamE2R1B14cut cWasteStreamE2R3B14cut dWasteStreamE2R4B14cut
31
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 9 Gamma and Neutron Sources for the Design Basis PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary
(MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 273E+11 121E+15 188E+11 175E+11 100E-01 000E+00 100E-01 528E+10 329E+14 277E+10 339E+10 400E-01 316E+07 200E-01 128E+10 245E+14 117E+10 819E+09 900E-01 161E+08 300E-01 639E+08 713E+13 633E+08 407E+08 140E+00 148E+08 400E-01 850E+08 455E+13 164E+09 533E+08 185E+00 109E+08 600E-01 492E+08 226E+14 269E+10 337E+07 300E+00 191E+08 800E-01 291E+09 237E+15 160E+10 186E+09 643E+00 174E+08 100E+00 540E+09 122E+14 248E+09 341E+09 200E+01 154E+07 133E+00 154E+13 195E+14 797E+12 990E+12 Total 830E+08 166E+00 435E+12 450E+13 225E+12 280E+12
--
200E+00 235E+00 152E+11 149E+02 215E-02 250E+00 103E+08 517E+10 534E+07 664E+07 300E+00 160E+05 379E+09 829E+04 103E+05 400E+00 943E-10 497E+08 155E-10 519E-10 500E+00 000E+00 282E+07 000E+00 000E+00 650E+00 000E+00 113E+07 000E+00 000E+00 800E+00 000E+00 222E+06 000E+00 000E+00 100E+01 000E+00 471E+05 000E+00 000E+00
Total 201E+13 486E+15 105E+13 129E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B11cut bWasteStreamE5R1B11cut cWasteStreamE5R3B11cut dWasteStreamE5R4B11cut
32
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 10 Gamma and Neutron Sources for the Average PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 336E+10 670E+14 186E+10 217E+10 100E-01 00000E+00 100E-01 602E+09 199E+14 314E+09 387E+09 400E-01 748E+06 200E-01 146E+09 126E+14 853E+08 936E+08 900E-01 382E+07 300E-01 730E+07 389E+13 439E+07 469E+07 140E+00 352E+07 400E-01 947E+07 263E+13 716E+07 607E+07 185E+00 261E+07 600E-01 141E+07 205E+13 504E+08 383E+06 300E+00 469E+07 800E-01 208E+09 124E+15 192E+09 144E+09 643E+00 418E+07 100E+00 208E+09 110E+13 164E+09 144E+09 200E+01 365E+06 133E+00 175E+12 295E+13 909E+11 112E+12 Total 199E+08 166E+00 494E+11 513E+12 257E+11 318E+11
--
200E+00 973E-01 675E+10 614E+01 872E-03 250E+00 117E+07 353E+09 609E+06 754E+06 300E+00 182E+04 288E+08 944E+03 117E+04 400E+00 186E-11 198E+07 149E-11 127E-11 500E+00 000E+00 669E+06 000E+00 000E+00 650E+00 000E+00 269E+06 000E+00 000E+00 800E+00 000E+00 527E+05 000E+00 000E+00 100E+01 000E+00 112E+05 000E+00 000E+00
Total 229E+12 237E+15 119E+12 147E+12
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B9cut bWasteStreamE5R1B9cut cWasteStreamE5R3B9cut dWasteStreamE5R4B9cut
33
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 11 Gamma and Neutron Axial Source Profiles for a PWR Assembly
Axial boundaries (From midplane)
(cm)
TOP BOTTOM
Neutron Gamma Ne utron Gamma 000 1554 1117 1554 1117 1143 1537 1114 1571 1120 2286 1521 1111 1588 1123 3429 1504 1108 1605 1126 4572 1486 1104 1622 1129 5715 1464 1100 1636 1131 6858 1438 1095 1648 1133 8001 1401 1088 1657 1135 9144 1350 1078 1654 1134
10287 1277 1063 1625 1129 11430 1165 1039 1554 1117 12573 0998 09995 1414 1091 13716 0769 09365 1172 1041 14859 0492 08375 0816 0951 16002 0220 06850 0402 0797 17145 0046 04625 0092 0551 18288 00 00 00 00
Source Reference 2219 Table S445
34
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
63 MCNP SPECIFIC INPUT
631 Source Probability
A linear radial distribution is used for all gamma and neutron sources The linear radial distribution is sam pled usi ng the built-in power function p(x) = xc a with a = 1 for the radial direction This sampling method results in a uniform source distribution over the area bounded by the outer radius of the source
The source axial distributions are unifor m for all four source regions The a xial uni form xp(x) = c distribution is sampled using the built-in power function a with a = 0 for extent
The energy distribu tions of the gamma and neutron sour ce term s are treated as energ y probabilities and are applied in MCNP5 using SISP cards
632 Dose Rate and Flux Tallies
MCNP5 dose rate calculations feature separate runs for the following calculation types
bull a photon transport calculation for prim ary ga mma contribution to the dose rates fr om photon fluxes
bull a coupled neutronphoton transport calculat ion for neutrons a nd secondary gamma (photons generated by neutron be ing captured) contributions to dose rates from neutron and gamma fluxes
The tally type F2 is us ed in th is d esign ca lculation as f lux estim ators The type F2 tally evaluates the flux averaged over a surface in particlescm2s
To generate dose ra tes in te rms of remhr the FM (tally multiplier ) and DEDF (dose energydose conversion factors) cards are used to en ter the tally multiplier f actor (source intensity in particless) energy boundaries in MeV and corresponding dose conversion factors in (remhr)(particlescm2s) respectively These factors were used in the input files
In order for the F2 tally to accum ulate flux ov er a surface a specific s urface area is requ ired The SD cards are used to enter a surface area in cm2 over which the flux will be tallied for an F2 tally
633 Variance Reduction Techniques
Variance reduction technique is usually em ployed in order to increase the efficiency of a calculation and obtain statistically m eaningful results within re asonable com puter tim e In Monte Carlo calculations when variance reduction scheme is employed the weights of particles are adjusted in order to account for the biasing and to preserve a fair game
Geometry splitting and Russian roulette techniques described in Reference 2224 (pp 2-140 ndash 2-142) are useful in shielding calculations and therefore deployed in all the MCNP5 runs
35
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
As particles migrate in an important direction (toward the detector) they are increased in number to provide better sampling by means of geometry splitting across geometric boundaries Russian roulette (the reverse process) is played when particles travel in an unimportant direction to allow termination of unim portant histories The IMP card required for every cel l ca rd is us ed to implement this technique
The other variance reduction technique deployed in the MC NP5 runs is source intensity biasing for the gamma sources from the four source regions (active fuel bottom end-fitting plenum and top end-fitting) The natural total gamma source intensity of comm ercial SNF is dom inated by the gamma source in the active fuel region This active fuel gamma source usually accounts for over 95 o f the total g amma source intens ity In order to im prove the efficiency of the axial dose rate calculations a biased source probability distribution is employed for the prim ary gamma dose rate calculations The biased gamma source probability distribution is chosen to be 005 080 010 and 005 for the bottom end-fitting the active fuel the plenum and the top end-fitting regions respectively
64 DOSE CONVERSION FACTORS
Project Design Criteria Document (Reference 2211 Se ction 41015) requires the use of flux-to-dose rate conversion fact ors from ANSIANS-611-1977 (Reference 221) for dose rate evaluations Table 16 lists the neutron and ga mma dose conversion factors used in the MCNP5 calculations
Table 12 Gamma and Neutron Flux to Dose Conversion Factors
Gamma Neutron Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
001 396E-06 140 251E-06 250E-08 367E-06 003 582E-07 180 299E-06 100E-07 367E-06 005 290E-07 220 342E-06 100E-06 446E-06 007 258E-07 260 382E-06 100E-05 454E-06 010 283E-07 280 401E-06 100E-04 418E-06 015 379E-07 325 441E-06 100E-03 376E-06 020 501E-07 375 483E-06 100E-02 356E-06 025 631E-07 425 523E-06 100E-01 217E-05 030 759E-07 475 560E-06 500E-01 926E-05 035 878E-07 500 580E-06 100E+00 132E-04 040 985E-07 525 601E-06 250E+00 125E-04 045 108E-06 575 637E-06 500E+00 156E-04 050 117E-06 625 674E-06 700E+00 147E-04 055 127E-06 675 711E-06 100E+01 147E-04 060 136E-06 750 766E-06 140E+01 208E-04 065 144E-06 900 877E-06 200E+01 227E-04 070 152E-06 1100 103E-05 080 168E-06 1300 118E-05 100 198E-06 1500 133E-05
Source Reference 221 Tables 1 and 3
36
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION
By def inition (Ref erence 2224 Equation 219) the estimated st atistic relative error of the i component is
Ri = Si
2
Equation 6Ti
where i = tally component index Ri = relative error of the i component S2
i = variance of the i component Ti = tally i component
For a result (ie dose rate) computed as a sum of different tallies the statistical relative error of the computed value is o btained from the variance of the result - S2
total which is th e sum of the estimated variances of the individual tallies S2
i n
2 2STotal = sum Si Equation 7 i=1
where S2Total = total estimated variance
n = total number of components Therefore the total tally value (dose rate) and the associated relative error are derived according to Equations 8 and 9
n TTotal = sumTi Equation 8
i=1
n n
sum (Ri timesTi )2
2 sum Si 2
STotal = i=1 = i=1 Equation 9RTotal = TTotal TTotal TTotal
where RTotal = total estimated relative error TTotal = total estimated tally
Equations 8 and 9 are utilized in Attachm ent II to ev aluate to tal dos e ra tes and their r elative errors
37
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
7 RESULTS AND CONCLUSIONS
71 RESULTS
The following sections summarize the results of this calculation Section 711 presents results for Conceptual Cask A while Section 712 for Conceptual Cask B Section 713 provides comparisons of the dose-rate reduction factors du e to the two conceptual casks and the axial source distributions in the active fuel region Do se rates and relative errors can be found in Attachment II within the output files and Excel files
711 Dose Rates of Conceptual Cask A
This section presents dose-rate results of the calculation sets 1 and 2 as described in Section 61 for Cask A Set 1 has axial p rofile sources in the active fuel region a nd consist of six runs resulting from the three PWR SNF source term s (maximum design basis and average) and the two radiation sources (gammas and neutrons) Set 2 has uniform axial sources in the active fuel region and consists of six run s r esulting f rom the th ree P WR SNF source term s and th e tw o radiation sources
As described in Section 61 dose ra tes are calculated at the three exterior surfaces (radial top and bottom) and at distances 1 m and 2 m from the exterior surfaces The total dose rates for set 1 are presented in Tables 13 14 and 15 for the ra dial top and bottom dire ctions respectively However the com ponents (primary gamma neutr on and secondary gamma) contributing to the total dose rates as well as the re lative error calculations can be found in Attachment II Excel file MCNP-Results1xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 2 are shown in Tables 16 17 and 18 The dose-rate components and the relative errors can be found in A ttachment II Excel file MCNP-Results2xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 13 and 16 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 14 and 17 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 15 and 18 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carrying th e maximum PWR SNF Based on the results in Tables 13 through 18 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask A indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these 6 tables the d ose-rate red uction f actors between the m aximum and the design basis fuels the maxim um and the averag e fuels and th e design basis and the average fuels are a lso presented
38
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 320E-02 00237 116E-02 00222 262E-03 00219 275 1223 445
1 m 133E-02 00164 494E-03 00171 106E-03 00162 269 1261 468 2 m 749E-03 00198 285E-03 00225 584E-04 00162 263 1282 488
Ring Detectors 1 m 133E-02 00116 492E-03 00115 108E-03 00124 271 1229 454 2 m 756E-03 00118 279E-03 00110 605E-04 00128 271 1250 462
Source Attachment II MCNP-Results1xls worksheet Summary
Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 142E-02 00368 628E-03 00446 934E-04 00483 226 1520 672
1 m 570E-03 00289 263E-03 00426 375E-04 00381 217 1520 701 2 m 265E-03 00364 123E-03 00547 169E-04 00374 216 1575 730
Point Detectors 1 m 598E-03 00238 274E-03 00271 402E-04 00354 219 1489 681 2 m 273E-03 00218 123E-03 00245 180E-04 00336 221 1515 684
Source Attachment II MCNP-Results1xls worksheet Summary
Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 653E-03 00298 265E-03 00276 510E-04 00341 247 1278 518
1 m 276E-03 00238 112E-03 00208 207E-04 00249 248 1334 539 2 m 125E-03 00185 508E-04 00199 933E-05 00246 246 1336 544
Point Detectors 1 m 291E-03 00227 118E-03 00203 218E-04 00242 247 1335 540 2 m 130E-03 00209 524E-04 00187 955E-05 00233 247 1357 549
Source Attachment II MCNP-Results1xls worksheet Summary
Tables 13 14 and 15 are results of calculation set 1 for conceptual Cask A with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
39
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 265E-02 00247 990E-03 00222 215E-03 00278 268 1234 461
1 m 116E-02 00178 468E-03 00549 960E-04 00189 248 1208 488 2 m 713E-03 00273 265E-03 00161 602E-04 00360 269 1184 439
Ring Detectors 1 m 117E-02 00120 454E-03 00132 979E-04 00141 259 1199 463 2 m 722E-03 00130 276E-03 00141 589E-04 00153 261 1226 469
Source Attachment II MCNP-Results2xls worksheet Summary
Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 199E-02 00461 827E-03 00455 147E-03 00536 241 1359 564
1 m 849E-03 00564 323E-03 00314 563E-04 00418 263 1507 574 2 m 415E-03 00832 158E-03 00603 253E-04 00501 263 1641 623
Point Detectors 1 m 877E-03 00348 353E-03 00275 615E-04 00391 248 1426 574 2 m 393E-03 00341 160E-03 00278 270E-04 00378 246 1454 590
Source Attachment II MCNP-Results2xls worksheet Summary
Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 879E-03 00374 356E-03 00333 669E-04 00406 247 1315 533
1 m 365E-03 00223 147E-03 00209 269E-04 00253 248 1358 548 2 m 164E-03 00229 674E-04 00205 120E-04 00248 243 1364 560
Point Detectors 1 m 383E-03 00217 155E-03 00204 285E-04 00248 247 1347 546 2 m 172E-03 00197 689E-04 00186 124E-04 00225 249 1391 558
Source Attachment II MCNP-Results2xls worksheet Summary
Tables 16 17 and 18 ar e results of calculation set 2 for conceptual Cask A with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
40
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
of each assembly region are homogenized inside a volume defined by the TAD cavity radius and region height
Rationale The assembly representation is consistent with the industry practice for shielding calculations accepted by NRC (Reference 2228 Figure 53-6) The effec t of source homogenization is twofold (1) it d ecreases th e m ass de nsity of the source region and (2) it places source points slightly closer to detector locations thus reducing radiation attenuation The resu lts of Calculation of the Effect of Source Geometry on the 21-PWR WP Dose Rates (Reference 2218 pp 22-26) indicate that th e effect of assem bly homogenization gives nearly the same or conservative dose rates as the explicit fuel assembly model
Usage This assumption is used in Section 624
326 Ignoring Internal Fuel Basket Materials
Assumption It is assumed that the internal fuel basket materials are ignored
Rationale Inclusion of fuel basket m aterials in the smeared m aterial com position would increase the overall density and consequently increase the attenuati on of the radiation Therefore this assumption is conservative
Usage This assumption is used in Sections 621 624 and 626
17
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
4 METHODOLOGY
41 QUALITY ASSURANCE
This calculation was prepared in accordance with EG-PRO-3DP-G04B-00037 Calculations and Analyses (Reference 212) The results of th is calculation provides worker dose assessm ent adjustments and this will id entify radio logical hazards f or f acilities im portant to saf ety Therefore the approved version is designated as QA QA
42 USE OF COMPUTER SOFTWARE
421 Baseline Software
The Monte Carlo N-Particle com puter pr ogram (MCNP5) version 140 (Reference 2225) is used to calculate the dose rates (neutron pr imary gamm a and secondary gamm a) at various locations around a transportation cask and an aging overpack
The software specifications are as follows
bull Program Name MCNP5 bull VersionRevision Number Version 140 bull Operating Systems Windows XP bull Software Tracking Number 11199-140-00 bull Computer Type Dell OPTIPLEX GX620
MCNP5 which is Level 1 software is (a) appropriate for three-dim ensional neutron gamma and coupled neutrongamma shielding calculations (b) used within th e range of validation as documented in Software Validation Report for MCNP5 v140 (Reference 2221) and (c) obtained from Software C onfiguration Managem ent and qualified in accordance with procedure IT-PRO-0012 Qualification of Software (Reference 213) Therefore MCNP5 code is suitable for use in this design calculation All MCNP5 input and output files docum ented in this calculation are provided on a compact disc (CD) as Attachment II
All MCNP cases are executed on one of the following Q com puters QNW -004184 QNW -004187 QNW-004194 and QNW-004196 as shown in the output files
422 Commercial off the Shelf Software
The Excel sof tware is used to c alculate var ious inpu t values (i e atom densities weight percentages geometrical dimensions normalized source spectra and probabilities etc) Standard functions of Excel are also used in this desi gn calculation to display results (ie gamma and neutron dose rates) in tabular and graphic forms and to perform relative error calculations
The software specifications are as follows
bull Program Name Excel bull VersionRevision Number Microsoftreg Excel 2003
18
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
bull This software is installed on a persona l com puter running Microsoft W indows XP (central processing unit number 151834)
The user defined for mulas inputs results and gr aphical representations have been verified by hand calculations or visual inspection and are documented in sufficient detail to allow an independent repetition of the com putations Calculations were verifi ed by hand and graphical representations were found accurate by visual inspection
Per Software Management Microsoftreg Excel is not requir ed to be qualif ied due to its commercial availability status (Reference 211 Attachment 4 p 55 bullet 2)
43 CALCULATION APPROACH
This calculation em ploys the qualified so ftware MCNP5 version 140 (Reference 2225) a three-dimensional Monte Carlo code for pe rforming neutron and coupled neutron-gamm a calculations to estim ate dose rates at sele cted locations on and surrounding a conceptual transportation cask containing a loaded TAD canister
431 MCNP5 Program
MCNP5 a general Monte Carlo part icle transport code sim ulates particle transport through a three-dimensional representation of the nuclear system being analyzed During the random walk of particles through the system described by the geom etry the c ode collects inform ation about various events (su rface cross ing collis ions trac k leng th etc) and es timates fluxes in various geometric configurations specified as tallies by the user It also estimates the statistical precision of the results in the form of relative errors (Reference 2224 pp 1-2 to 1-8)
Per Project Design Criteria Document (Reference 2211 Section 41015) the flux estim ates are converted to dose rates using the Am erican Nuclear Society (ANS) flux-to-dose rate conversion factors for gammas and neutrons (R eference 221) The simple variance reduction techniques of Geometry SplittingRussian Roulette and source probability biasing (Sections 631 and 633) are used to enhance computational efficiency
19
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
5 LIST OF ATTACHMENTS
Number of Pages Attachment I List of Electronic Files on the CD 3 Attachment II Compact Disc NA
20
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
6 CALCULATIONS
This sectio n provides inform ation necess ary to perform the calcu lations in this docum ent Section 61 describes the configurations the type of CSNF to be analyzed the number of MCNP runs and the locations where dose rates are ca lculated Section 62 provides the calculation input that includes the details of the geom etry m odel radiation source term s and m aterial compositions Input specific to MCNP dose -rate conversion factors and relative error calculation are described in the later sections
61 DESCRIPTION OF CALCULATIONS
Dose rate calculations are perform ed with the MCNP5 version 140 com puter code (Reference 2225) Two conceptual transportation casks Cask A and Cask B (Assum ption 323) are employed Each cask contains a TAD canister that is loaded with 21 ident ical PW R SN F assemblies Three PWR source term s are analy zed they are the source term s corresponding to the maximum design basis and average PW R SN Fs The characteris tics of the P WR source terms are presented in S ection 627 Each PWR source term has neutron and ga mma radiation sources that require separate MCNP5 runs For each radiation source an axial profile source and a uniform source for the active fuel region are considered The uniform source for the active fuel region is included in this calculation because this approach was used in combination with source peaking factors in certain calculations (Reference 2216 Sections 37 and 39 and Reference 2217 Section 5242)
The total number of MCNP5 runs is 24 which re sults from a com bination of two conceptual casks three PWR source terms two radiation sources and two axia l source distributions for the active fuel region These 24 runs are categorized into four calcula tion sets Each calculation set consists of six runs that is a combination of three PWR source te rms and two radiation sources The characteristics of each calculation set are as follows
1 Cask A with axial profile sources in the active fuel region
2 Cask A with uniform axial sources in the active fuel region
3 Cask B with axial profile sources in the active fuel region
4 Cask B with uniform axial sources in the active fuel region
For each MCNP5 run dose rates are calculated at the exte rior surfaces and at distances 1 and 2 meters from the exterior surfaces Surface tallies and detector tallies (ring and point detectors) as indicated in Figure 1 are e mployed in all runs Figure 1 is used to illustrate the dep loyment of the surface and detector tallies re lative to the so urce regions and it should not be interpreted as an exact geometry of any particular run Surface tallies are deployed at all three distances while ring and point detectors are used only at 1 m and 2 m and not at the cask surfaces Using point detectors near a surface or in any scattering media is not recommended because very large scores can occur f rom collisions close ( less than a f ew centimeters) to the point detecto rs that can lead to resu lts with high r elative e rrors thus m aking the ca lculation d ifficult to o btain r eliable answers
21
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
For the radial direction surface tallies at the three distances (contact 1 m and 2 m) are computed for three su rface segments (cylindrical rings) between the planes at Z = 145 175 2 05 and 235 cm The geometric locations of the segments are shown in Figure 1 The axial locations of these segments correspond to the m iddle of the active fuel region of the PWR SNF assemblies The average dose rates for each of the segm ents are calculated for the outside surface and surfaces at 1 m and 2 m from the cask surface Two ring detectors (instead of point detectors) are deployed at 1 m and 2 m for the radial dire ction Ring detectors instead of point detectors are used in order to capitalize on the symm etry around the cask axis thus im proving the efficiency of the calculations
In the axial direction the average d ose rates within three concentric radial surfaces defined by radii of 40 80 and 120 cm (shown in Figure 1) are calculated for the top and bottom surfaces and at distances 1 m and 2 m from these surfaces Finally point detectors at 1 m and 2 m from the top and bottom axial surfaces are employed
22
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Point Detector at 2 m x
Ring Ring Detector Detector at 2 m at 1 m
x x
Z = 00 cm
Z = 145 cm
Z = 175 cm
Z = 205 cm
Z = 235 cm
R = 80 cm
R = 120 cm
R = 40 cm
Active Fuel
Shield Plug
Top End-Fitting Plenum
Bottom End-Fitting
Ring Detector at 1 m
x
Point Detector at 1 m x
Ring Detector
at 2 m x
D = 26797 cm
H =
610
845
cm
Point Detector at 1 m x
Point Detector at 2 m x
Figure 1 Geometry and Tally Scheme for the TAD Transportation Cask
23
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
62 CALCULATION INPUT
Technical product input and sources of the input used in the deve lopment of this calculation are documented in this section Tables in this docum ent and in th e associated Microsoftreg Excel spreadsheets referenced m ay present num erical values with m any significant figures these values are not to be considered as high precision values since the significant figures are results of calculated values andor unit conversions
621 TAD Canister
The TAD canis ter will contain either 21 P WR or 44 BW R (boiling water reactor) SNF assemblies (Reference 2222 Section 321) While the canister design is iden tical for both PWR and BWR SNF assemblies the internal basket structure is different depending on the SNF assemblies However the internal basket stru cture m aterial is no t in cluded in the calcu lation model (Assumption 326)
The TAD canister is a right-circu lar cylinder with a diam eter of 665 in and a height between 186 and 212 in (Reference 2222 Section 321) The average and maximum total dose rates on the top surf ace of a loaded TAD ca nister must not exceed 800 and 1000 m remhr respectively (Reference 2222 Section 314) The TAD canister used in this calculation is m ade of SS 316 with a radial wall and bottom thickness of 025 in (Assumption 321) The top of the canister has a shield plug that is 11 in thick SS 316 (Ass umption 322) A thick shield plug is needed to keep the maxim um contact dose rate of th e top surface below 1000 m remhr The overall dimensions of the TAD canister are provided in Table 3
Table 3 Dimensions of TAD Canister
Component Dimension
(in) (cm)
Maximum heighta 212 53848
Outer diametera 665 16891
Thickness of bottom lidb 025 0635
Shell thicknessb 025 0635
Lifting Featurec 6 1524
Height without Lifting Feature 206 52324
Thickness of shield plugd 110 2794
aReference 2222 Section 311 bAssumption 321 cReference 2222 p Attachment C-1 dAssumption 322
622 Conceptual TAD Transportation Casks
Two conceptual TAD transportation casks designa ted as Cask A and Cask B are em ployed in this calculation (Assumption 323) They both have a cylindrical geometry with dimensions and materials specified in Tables 1 and 2 of Section 323 Cask A will provide shielding to meet the exterior radiation standards of 10 CFR 7147(b) (Reference 231) when loaded with a TAD
24
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
canister car rying the m aximum PWR SNF Cask B will s atisfy th e sa me radiatio n standa rds when loaded with a TAD canister c arrying the average PWR SNF The reason to analyze both Casks A and B is to cover a broad range of characteristics of the CSNF
The cavity dimensions of the conceptual cask s are 53785 cm (21175 in) in height and 16891 cm (665 in) in diam eter (Tab les 1 and 2) This cav ity will accommoda te the TAD canister described in Table 3 without the lifting feature This is the geometry model used in the MCNP5 calculations
623 Fuel Assembly Selection
PWR and BWR Source Term Sensitivity Study (Reference 2211 Tables 71 through 84) shows that the source terms generated for the Bamp W 15x15 Mark B fuel assembly with 475 kg uranium loading bound the source terms of other PWR assembly types ther efore this assembly type is selected as the representative PWR fuel assembly The gamma and neutron source terms for the BampW 15x15 Mark B assembly are generated in PWR Source Term Generation and Evaluation (Reference 229) and are used in this calculation
624 BampW 15x15 Mark B PWR Fuel Assembly
BampW 15x15 Mark B fuel assembly consists of four regions top end-fitting plenum active fuel and bottom end-fitting The m aterials and ra diation sources of each assem bly region are homogenized inside a volume defined by the region height and the interior diam eter of the TAD canister (Assumption 325) The active fuel region is homogenized with fresh unirradiated fuel (Assumption 324) Since the internal structure (i e basket) design of t he TAD is currently not finalized the com position of the hom ogenized fuel does not include the basket m aterials (Assumption 326) and therefore does not take cred it for any shielding that these m aterials may provide
Table 4 provides the design param eters for the BampW 15x15 Mark B fuel assembly Data provided here are used in Attachment II PWR_fuel compxls worksheet BampWassy
25
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 4 BampW 15x15 Mark B Fuel Assembly Description
Component Material Characteristic Value Specific Reference Array Size 15 x 15
Reference 2227 Table 2-2 Fuel Pins Assembly 208 Guide Tubes Assembly 16 Instrument Tubes Assembly 1
Assembly NA Pin Pellet Diameter 0936244 cm (03686 in) Reference 2220 p 2A-34 Pin Pitch 144272 cm (0568 in)
Reference 2227 Table 2-2 Active Fuel Height 360172 cm (1418 in) Assembly Width 2168144 cm (8536 in)
Reference 2220 p 2A-31 Assembly Height 4206875 cm (165625 in) Mass U assembly 46363 kg
Guide tube Zircaloy-4 Outer Diameter 13462 cm (053 in)
Reference 2227 Table 2-2
Inner Diameter 126492 cm (0498 in)
Instrument tube Zircaloy-4 Outer Diameter 138193 cm (05441 in) Inner Diameter 112014 cm (0441 in)
Cladding` Zircaloy-4 Inner Diameter 095758 cm (0377 in) Outer Diameter 10922 cm (043 in)
Plenum region NA Length 297688 cm (11720 in) Reference 2220 p 2A-34 Top nozzle SS CF3M MassAssembly (Top) 748 kg
Reference 2220 p 2A-32
Bottom nozzle SS CF3M MassAssembly (Bottom) 816 kg Guide tubes Zircaloy-4 MassAssembly (in Core) 80 kg Instrument tube Zircaloy-4 MassAssembly (in Core) 064 kg Spacer-plenum Inconel-718 MassAssembly (Plenum) 104 kg Spacer-bottom Inconel-718 MassAssembly (Bottom) 13 kg Spacer-in core Inconel-718 MassAssembly (in Core) 49 kg Spring retainer SS CF3M MassAssembly (Top) 091 kg Holddown spring Inconel-718 MassAssembly (Top) 18 kg Upper end plug SS 304 MassAssembly (Top) 006 kg Upper nut SS 304L MassAssembly (Top) 051 kg Lower nut SS 304 MassAssembly (Bottom) 015 kg Grid supports Zircaloy-4 MassAssembly (in Core) 064 kg Plenum spring SS 302 MassAssembly (Plenum) 0042 lb (001905 kg) Reference 2220 p 2A-34
Note Som e d ata i n this tab le ar e given i n British u nits in th e r eferences thes e d ata ar e converted into metric units as the inputs to MCNP5 are in metric units
The assem bly region heights as m odeled in MC NP are presented in Table 5 utilizing values from Table 4 Table 5 is taken from Dose Rate Calculation for Exhaust Main Drifts (Reference 2213 Table 3)
26
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 5 PWR Fuel Assembly Regions
Component Height Reference
Plenum 297688 cm (11720 in) Reference 2220 p 2A-34
Active Fuel 360172 cm (1418 in) Table 3
Bottom End-Fitting 1077 cm (424 in) Calculateda
Top End-Fitting 1998 cm (787 in) Calculatedb
Source Reference 2213 Table 3 aCalculated b ased on data Reference 2227 F igures 2-3 an d 2-7
(Region 9 Height [16723 cm] + Region 10 Height [508 cm] ndash Lo wer Fuel Plenum and End Cap [11033 cm])
bCalculated (Assembly Length ndash Active Fuel Length ndash P lenum Length ndash Bottom End-fitting Length)
625 Material Compositions
The TAD transportation cask com ponent m aterial specifications are defined in Table 1 The TAD canister is constructed of SS 316 (Assumpti on 321) The PWR fuel assembly materials used to homogenize the fuel regions are defined in Table 4 Table 6 c ontains the m aterial compositions defining the TAD canister WP and fuel assemblies
27
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 6 Chemical Compositions of Materials
Material Density (gcc)
Isotopic Weight Percent Reference
SS 302 NA
C 0150 Mn 2000 P 0045 S 0030 Si 0750 Cr 18000 Ni 9000 N 0100 Fe 69925
Attachment II PWR_fuel compxls worksheet ferrous Reference 222 SEC II A SA-240 Table 1 for SS 302 SS 304 and SS 304L Reference 222 SEC II A SA-351SA -351M Table 2 for SS CF3M
SS 304 NA
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 9250 N 0100 Fe 68745
SS 304L NA
C 003 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 10000 N 0100 Fe 6804 5
SS CF3M NA
C 0030 Mn 1500 P 0040 S 0040 Si 1500 Cr 19000 Ni 11000 Mo 2500 Fe 64390
Inconel 718 NA
C 0080 Mn 0350 Si 0350 Cr 19000 Ni 52500 Co 1000 Mo 3050 Fe 16809 Nb 5125 Ti 0900 Al 0500 Cu 0300 S 0015 P 0015 B 0006
Attachment II PWR_fuel compxls worksheet alloys aReference 223 p 666 Table 6 Reference 222 SEC II B SB-637 Table 1 for Inconel 718 Reference 224 Table 2 for Zircaloy 4
Zircaloy 4 656a Cr 0100 Fe 0210 O 0125 Sn 1450 Zr 98115
SS 316 798b
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 17000 Ni 12000 Mo 2500 N 0100 Fe 65495
Attachment II PWR_fuel compxls worksheet others Reference 222 SEC II A SA-240 Table 1 for SS 316 bReference 225 Table X1
626 Homogenization Assembly Materials
The atom density of an element or isotope in atomsbmiddotcm in a homogenized region is calculated according to the following equation (Reference 2223 Appendix B)
M i times N AvogadroNi = Equation 1 Ai timesV times K
where Ni = Atom density of elementisotope i (atomsbmiddotcm) Mi = Mass of elementisotope i (g) NAvogadro = Avogadrorsquos constant 06022 x 1024 (atomsmole)
28
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Ai = Atomic weight of elementisotope i (gmole) V = Homogenization volume (cm3) K = Unit transformation constant = 1024 (bmiddotcmcm3)
Equation 1 is used in A ttachment II spreadsheet PWR_fuel compxls worksheet BampWassy to calculate th e atom dens ities for v arious elem ents and iso topes The m ass of elementsisotop es and Avogadrorsquos constant are provided in Reference 2226
Table 7 lists the com position of the hom ogenized assem bly regions (active fuel plenum top end-fitting and bottom end-fitting) for the PWR assembly The active fuel region contains fresh unirradiated fuel (Assumption 324) Since the internal structure (ie basket) design of the TAD is currently not finalized the composition of either homogenized fuel does not include the basket materials and therefore does not tak e credit for any shielding that thes e materials may provide (Assumption 326)
Table 7 Isotopic Compositions of Homogenized PWR Assembly Regions
Element Isotope
Atom Densities for Homogenized Regions (atomsbsdotcm)
Active Fuel Bottom End-Fitting Plenum Top End-Fitting
10B 861E-09 764E-08 221E-08 570E-08 11B 347E-08 307E-07 890E-08 230E-07 C 519E-07 160E-05 138E-06 993E-06 N -- 570E-07 262E-08 117E-06 O 621E-03 -- 142E-05 -- Al 144E-06 128E-05 371E-06 957E-06 Si 971E-07 243E-04 259E-06 139E-04 P 377E-08 606E-06 102E-07 360E-06 S 365E-08 581E-06 971E-08 340E-06 Ti 147E-06 130E-05 376E-06 971E-06 Cr 320E-05 187E-03 779E-05 113E-03 Mn 497E-07 126E-04 141E-06 749E-05 Fe 303E-05 531E-03 717E-05 313E-03 Co 132E-06 117E-05 340E-06 876E-06 Ni 697E-05 144E-03 180E-04 940E-04 Cu 368E-07 327E-06 945E-07 244E-06 Zr 196E-03 -- 195E-03 -- Nb 430E-06 382E-05 110E-05 285E-05 Mo 248E-06 135E-04 636E-06 791E-05 Sn 223E-05 -- 222E-05 -- 234U 139E-06 -- -- -- 235U 157E-04 -- -- -- 236U 719E-07 -- -- -- 238U 294E-03 -- -- -- Total 114E-02 924E-03 235E-03 557E-03
Source Attachment II spreadsheet PWR_fuel compxls worksheet BampWassy
29
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
The isotopic composition of commercially available 235U enriched uranium is determined by the given initial 235U enrichment using the following equations (Reference 226 p 20)
wt235U =235Uenrichment _ of _ the _ associated _ fuel _ batch Equation 2
wt234U = 0007731times (wt235U )10837 Equation 3
wt236U = 00046times (wt235U ) Equation 4
wt238U =100 minus (wt234U + wt235U + wt236U ) Equation 5
The weight percentages of uran ium isotopes for PWR fuel are ca lculated in Attachm ent II spreadsheet PWR_fuel compxls worksheet BampWassy using Equations 2 through 5
627 PWR Source Terms
This calculation uses the following three PWR source terms bull Maximum source (50 wt initial 235U enrichment 80 GWdMTU burnup and 5-year
decay time) (Reference 229 Section 55) Table 8 lists th e gamma source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Design Basis source (4 0 wt initial 235U enrichment 60 GW dMTU burnup and 10-year decay tim e) (Reference 228 Section 552) Table 9 lists the gamm a source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Average source ( 40 wt initial 235U enrichment 48 GWdMTU burnup and 25-year decay time) (Reference 229 Section 55) Table 10 lists the gamma source terms for the fuel and non-fuel regions and the neutron source term for the fuel region
These sources (ie maximum design basis and av erage) are described in this section For dose rate calculations all the fuel assemblies in a transportation cask are of the sam e characteristics Also gamma radiation source term s for the PWR assem bly are prov ided for the f our assembly regions while neutron source term is only present in the active fuel region Gamma radiation sources in the non-active fuel region are distri buted unif ormly within each source region Gamma and neutron sources in the active fuel re gion are modeled as uni form distributions or with axial source profiles
The PWR gamma and neutron axial source profiles for the active fuel region presented in Table 11 are applied to the active fuel region of all three source terms (ie maximum design basis and average) when appropriate
30
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 8 Gamma and Neutron Sources for the Maximum PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting
Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 594E+11 233E+15 528E+11 379E+11 100E-01 000E+00 100E-01 116E+11 644E+14 609E+10 743E+10 400E-01 805E+07 200E-01 283E+10 522E+14 352E+10 179E+10 900E-01 411E+08 300E-01 141E+09 148E+14 196E+09 891E+08 140E+00 376E+08 400E-01 190E+09 985E+13 586E+09 117E+09 185E+00 276E+08 600E-01 191E+09 153E+15 110E+11 741E+07 300E+00 485E+08 800E-01 435E+09 470E+15 595E+10 237E+09 643E+00 443E+08 100E+00 137E+11 708E+14 803E+09 766E+10 200E+01 393E+07 133E+00 338E+13 455E+14 174E+13 217E+13 Total 211E+09 166E+00 953E+12 130E+14 491E+12 612E+12
--
200E+00 187E+03 144E+12 919E+02 113E+03 250E+00 226E+08 249E+12 116E+08 145E+08 300E+00 351E+05 110E+11 181E+05 225E+05 400E+00 766E-08 139E+10 100E-08 416E-08 500E+00 000E+00 709E+07 000E+00 000E+00 650E+00 000E+00 286E+07 000E+00 000E+00 800E+00 000E+00 558E+06 000E+00 000E+00 100E+01 000E+00 119E+06 000E+00 000E+00
Total 442E+13 113E+16 231E+13 284E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE2R2B14cut bWasteStreamE2R1B14cut cWasteStreamE2R3B14cut dWasteStreamE2R4B14cut
31
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 9 Gamma and Neutron Sources for the Design Basis PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary
(MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 273E+11 121E+15 188E+11 175E+11 100E-01 000E+00 100E-01 528E+10 329E+14 277E+10 339E+10 400E-01 316E+07 200E-01 128E+10 245E+14 117E+10 819E+09 900E-01 161E+08 300E-01 639E+08 713E+13 633E+08 407E+08 140E+00 148E+08 400E-01 850E+08 455E+13 164E+09 533E+08 185E+00 109E+08 600E-01 492E+08 226E+14 269E+10 337E+07 300E+00 191E+08 800E-01 291E+09 237E+15 160E+10 186E+09 643E+00 174E+08 100E+00 540E+09 122E+14 248E+09 341E+09 200E+01 154E+07 133E+00 154E+13 195E+14 797E+12 990E+12 Total 830E+08 166E+00 435E+12 450E+13 225E+12 280E+12
--
200E+00 235E+00 152E+11 149E+02 215E-02 250E+00 103E+08 517E+10 534E+07 664E+07 300E+00 160E+05 379E+09 829E+04 103E+05 400E+00 943E-10 497E+08 155E-10 519E-10 500E+00 000E+00 282E+07 000E+00 000E+00 650E+00 000E+00 113E+07 000E+00 000E+00 800E+00 000E+00 222E+06 000E+00 000E+00 100E+01 000E+00 471E+05 000E+00 000E+00
Total 201E+13 486E+15 105E+13 129E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B11cut bWasteStreamE5R1B11cut cWasteStreamE5R3B11cut dWasteStreamE5R4B11cut
32
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 10 Gamma and Neutron Sources for the Average PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 336E+10 670E+14 186E+10 217E+10 100E-01 00000E+00 100E-01 602E+09 199E+14 314E+09 387E+09 400E-01 748E+06 200E-01 146E+09 126E+14 853E+08 936E+08 900E-01 382E+07 300E-01 730E+07 389E+13 439E+07 469E+07 140E+00 352E+07 400E-01 947E+07 263E+13 716E+07 607E+07 185E+00 261E+07 600E-01 141E+07 205E+13 504E+08 383E+06 300E+00 469E+07 800E-01 208E+09 124E+15 192E+09 144E+09 643E+00 418E+07 100E+00 208E+09 110E+13 164E+09 144E+09 200E+01 365E+06 133E+00 175E+12 295E+13 909E+11 112E+12 Total 199E+08 166E+00 494E+11 513E+12 257E+11 318E+11
--
200E+00 973E-01 675E+10 614E+01 872E-03 250E+00 117E+07 353E+09 609E+06 754E+06 300E+00 182E+04 288E+08 944E+03 117E+04 400E+00 186E-11 198E+07 149E-11 127E-11 500E+00 000E+00 669E+06 000E+00 000E+00 650E+00 000E+00 269E+06 000E+00 000E+00 800E+00 000E+00 527E+05 000E+00 000E+00 100E+01 000E+00 112E+05 000E+00 000E+00
Total 229E+12 237E+15 119E+12 147E+12
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B9cut bWasteStreamE5R1B9cut cWasteStreamE5R3B9cut dWasteStreamE5R4B9cut
33
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 11 Gamma and Neutron Axial Source Profiles for a PWR Assembly
Axial boundaries (From midplane)
(cm)
TOP BOTTOM
Neutron Gamma Ne utron Gamma 000 1554 1117 1554 1117 1143 1537 1114 1571 1120 2286 1521 1111 1588 1123 3429 1504 1108 1605 1126 4572 1486 1104 1622 1129 5715 1464 1100 1636 1131 6858 1438 1095 1648 1133 8001 1401 1088 1657 1135 9144 1350 1078 1654 1134
10287 1277 1063 1625 1129 11430 1165 1039 1554 1117 12573 0998 09995 1414 1091 13716 0769 09365 1172 1041 14859 0492 08375 0816 0951 16002 0220 06850 0402 0797 17145 0046 04625 0092 0551 18288 00 00 00 00
Source Reference 2219 Table S445
34
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
63 MCNP SPECIFIC INPUT
631 Source Probability
A linear radial distribution is used for all gamma and neutron sources The linear radial distribution is sam pled usi ng the built-in power function p(x) = xc a with a = 1 for the radial direction This sampling method results in a uniform source distribution over the area bounded by the outer radius of the source
The source axial distributions are unifor m for all four source regions The a xial uni form xp(x) = c distribution is sampled using the built-in power function a with a = 0 for extent
The energy distribu tions of the gamma and neutron sour ce term s are treated as energ y probabilities and are applied in MCNP5 using SISP cards
632 Dose Rate and Flux Tallies
MCNP5 dose rate calculations feature separate runs for the following calculation types
bull a photon transport calculation for prim ary ga mma contribution to the dose rates fr om photon fluxes
bull a coupled neutronphoton transport calculat ion for neutrons a nd secondary gamma (photons generated by neutron be ing captured) contributions to dose rates from neutron and gamma fluxes
The tally type F2 is us ed in th is d esign ca lculation as f lux estim ators The type F2 tally evaluates the flux averaged over a surface in particlescm2s
To generate dose ra tes in te rms of remhr the FM (tally multiplier ) and DEDF (dose energydose conversion factors) cards are used to en ter the tally multiplier f actor (source intensity in particless) energy boundaries in MeV and corresponding dose conversion factors in (remhr)(particlescm2s) respectively These factors were used in the input files
In order for the F2 tally to accum ulate flux ov er a surface a specific s urface area is requ ired The SD cards are used to enter a surface area in cm2 over which the flux will be tallied for an F2 tally
633 Variance Reduction Techniques
Variance reduction technique is usually em ployed in order to increase the efficiency of a calculation and obtain statistically m eaningful results within re asonable com puter tim e In Monte Carlo calculations when variance reduction scheme is employed the weights of particles are adjusted in order to account for the biasing and to preserve a fair game
Geometry splitting and Russian roulette techniques described in Reference 2224 (pp 2-140 ndash 2-142) are useful in shielding calculations and therefore deployed in all the MCNP5 runs
35
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
As particles migrate in an important direction (toward the detector) they are increased in number to provide better sampling by means of geometry splitting across geometric boundaries Russian roulette (the reverse process) is played when particles travel in an unimportant direction to allow termination of unim portant histories The IMP card required for every cel l ca rd is us ed to implement this technique
The other variance reduction technique deployed in the MC NP5 runs is source intensity biasing for the gamma sources from the four source regions (active fuel bottom end-fitting plenum and top end-fitting) The natural total gamma source intensity of comm ercial SNF is dom inated by the gamma source in the active fuel region This active fuel gamma source usually accounts for over 95 o f the total g amma source intens ity In order to im prove the efficiency of the axial dose rate calculations a biased source probability distribution is employed for the prim ary gamma dose rate calculations The biased gamma source probability distribution is chosen to be 005 080 010 and 005 for the bottom end-fitting the active fuel the plenum and the top end-fitting regions respectively
64 DOSE CONVERSION FACTORS
Project Design Criteria Document (Reference 2211 Se ction 41015) requires the use of flux-to-dose rate conversion fact ors from ANSIANS-611-1977 (Reference 221) for dose rate evaluations Table 16 lists the neutron and ga mma dose conversion factors used in the MCNP5 calculations
Table 12 Gamma and Neutron Flux to Dose Conversion Factors
Gamma Neutron Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
001 396E-06 140 251E-06 250E-08 367E-06 003 582E-07 180 299E-06 100E-07 367E-06 005 290E-07 220 342E-06 100E-06 446E-06 007 258E-07 260 382E-06 100E-05 454E-06 010 283E-07 280 401E-06 100E-04 418E-06 015 379E-07 325 441E-06 100E-03 376E-06 020 501E-07 375 483E-06 100E-02 356E-06 025 631E-07 425 523E-06 100E-01 217E-05 030 759E-07 475 560E-06 500E-01 926E-05 035 878E-07 500 580E-06 100E+00 132E-04 040 985E-07 525 601E-06 250E+00 125E-04 045 108E-06 575 637E-06 500E+00 156E-04 050 117E-06 625 674E-06 700E+00 147E-04 055 127E-06 675 711E-06 100E+01 147E-04 060 136E-06 750 766E-06 140E+01 208E-04 065 144E-06 900 877E-06 200E+01 227E-04 070 152E-06 1100 103E-05 080 168E-06 1300 118E-05 100 198E-06 1500 133E-05
Source Reference 221 Tables 1 and 3
36
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION
By def inition (Ref erence 2224 Equation 219) the estimated st atistic relative error of the i component is
Ri = Si
2
Equation 6Ti
where i = tally component index Ri = relative error of the i component S2
i = variance of the i component Ti = tally i component
For a result (ie dose rate) computed as a sum of different tallies the statistical relative error of the computed value is o btained from the variance of the result - S2
total which is th e sum of the estimated variances of the individual tallies S2
i n
2 2STotal = sum Si Equation 7 i=1
where S2Total = total estimated variance
n = total number of components Therefore the total tally value (dose rate) and the associated relative error are derived according to Equations 8 and 9
n TTotal = sumTi Equation 8
i=1
n n
sum (Ri timesTi )2
2 sum Si 2
STotal = i=1 = i=1 Equation 9RTotal = TTotal TTotal TTotal
where RTotal = total estimated relative error TTotal = total estimated tally
Equations 8 and 9 are utilized in Attachm ent II to ev aluate to tal dos e ra tes and their r elative errors
37
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
7 RESULTS AND CONCLUSIONS
71 RESULTS
The following sections summarize the results of this calculation Section 711 presents results for Conceptual Cask A while Section 712 for Conceptual Cask B Section 713 provides comparisons of the dose-rate reduction factors du e to the two conceptual casks and the axial source distributions in the active fuel region Do se rates and relative errors can be found in Attachment II within the output files and Excel files
711 Dose Rates of Conceptual Cask A
This section presents dose-rate results of the calculation sets 1 and 2 as described in Section 61 for Cask A Set 1 has axial p rofile sources in the active fuel region a nd consist of six runs resulting from the three PWR SNF source term s (maximum design basis and average) and the two radiation sources (gammas and neutrons) Set 2 has uniform axial sources in the active fuel region and consists of six run s r esulting f rom the th ree P WR SNF source term s and th e tw o radiation sources
As described in Section 61 dose ra tes are calculated at the three exterior surfaces (radial top and bottom) and at distances 1 m and 2 m from the exterior surfaces The total dose rates for set 1 are presented in Tables 13 14 and 15 for the ra dial top and bottom dire ctions respectively However the com ponents (primary gamma neutr on and secondary gamma) contributing to the total dose rates as well as the re lative error calculations can be found in Attachment II Excel file MCNP-Results1xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 2 are shown in Tables 16 17 and 18 The dose-rate components and the relative errors can be found in A ttachment II Excel file MCNP-Results2xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 13 and 16 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 14 and 17 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 15 and 18 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carrying th e maximum PWR SNF Based on the results in Tables 13 through 18 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask A indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these 6 tables the d ose-rate red uction f actors between the m aximum and the design basis fuels the maxim um and the averag e fuels and th e design basis and the average fuels are a lso presented
38
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 320E-02 00237 116E-02 00222 262E-03 00219 275 1223 445
1 m 133E-02 00164 494E-03 00171 106E-03 00162 269 1261 468 2 m 749E-03 00198 285E-03 00225 584E-04 00162 263 1282 488
Ring Detectors 1 m 133E-02 00116 492E-03 00115 108E-03 00124 271 1229 454 2 m 756E-03 00118 279E-03 00110 605E-04 00128 271 1250 462
Source Attachment II MCNP-Results1xls worksheet Summary
Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 142E-02 00368 628E-03 00446 934E-04 00483 226 1520 672
1 m 570E-03 00289 263E-03 00426 375E-04 00381 217 1520 701 2 m 265E-03 00364 123E-03 00547 169E-04 00374 216 1575 730
Point Detectors 1 m 598E-03 00238 274E-03 00271 402E-04 00354 219 1489 681 2 m 273E-03 00218 123E-03 00245 180E-04 00336 221 1515 684
Source Attachment II MCNP-Results1xls worksheet Summary
Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 653E-03 00298 265E-03 00276 510E-04 00341 247 1278 518
1 m 276E-03 00238 112E-03 00208 207E-04 00249 248 1334 539 2 m 125E-03 00185 508E-04 00199 933E-05 00246 246 1336 544
Point Detectors 1 m 291E-03 00227 118E-03 00203 218E-04 00242 247 1335 540 2 m 130E-03 00209 524E-04 00187 955E-05 00233 247 1357 549
Source Attachment II MCNP-Results1xls worksheet Summary
Tables 13 14 and 15 are results of calculation set 1 for conceptual Cask A with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
39
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 265E-02 00247 990E-03 00222 215E-03 00278 268 1234 461
1 m 116E-02 00178 468E-03 00549 960E-04 00189 248 1208 488 2 m 713E-03 00273 265E-03 00161 602E-04 00360 269 1184 439
Ring Detectors 1 m 117E-02 00120 454E-03 00132 979E-04 00141 259 1199 463 2 m 722E-03 00130 276E-03 00141 589E-04 00153 261 1226 469
Source Attachment II MCNP-Results2xls worksheet Summary
Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 199E-02 00461 827E-03 00455 147E-03 00536 241 1359 564
1 m 849E-03 00564 323E-03 00314 563E-04 00418 263 1507 574 2 m 415E-03 00832 158E-03 00603 253E-04 00501 263 1641 623
Point Detectors 1 m 877E-03 00348 353E-03 00275 615E-04 00391 248 1426 574 2 m 393E-03 00341 160E-03 00278 270E-04 00378 246 1454 590
Source Attachment II MCNP-Results2xls worksheet Summary
Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 879E-03 00374 356E-03 00333 669E-04 00406 247 1315 533
1 m 365E-03 00223 147E-03 00209 269E-04 00253 248 1358 548 2 m 164E-03 00229 674E-04 00205 120E-04 00248 243 1364 560
Point Detectors 1 m 383E-03 00217 155E-03 00204 285E-04 00248 247 1347 546 2 m 172E-03 00197 689E-04 00186 124E-04 00225 249 1391 558
Source Attachment II MCNP-Results2xls worksheet Summary
Tables 16 17 and 18 ar e results of calculation set 2 for conceptual Cask A with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
40
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
4 METHODOLOGY
41 QUALITY ASSURANCE
This calculation was prepared in accordance with EG-PRO-3DP-G04B-00037 Calculations and Analyses (Reference 212) The results of th is calculation provides worker dose assessm ent adjustments and this will id entify radio logical hazards f or f acilities im portant to saf ety Therefore the approved version is designated as QA QA
42 USE OF COMPUTER SOFTWARE
421 Baseline Software
The Monte Carlo N-Particle com puter pr ogram (MCNP5) version 140 (Reference 2225) is used to calculate the dose rates (neutron pr imary gamm a and secondary gamm a) at various locations around a transportation cask and an aging overpack
The software specifications are as follows
bull Program Name MCNP5 bull VersionRevision Number Version 140 bull Operating Systems Windows XP bull Software Tracking Number 11199-140-00 bull Computer Type Dell OPTIPLEX GX620
MCNP5 which is Level 1 software is (a) appropriate for three-dim ensional neutron gamma and coupled neutrongamma shielding calculations (b) used within th e range of validation as documented in Software Validation Report for MCNP5 v140 (Reference 2221) and (c) obtained from Software C onfiguration Managem ent and qualified in accordance with procedure IT-PRO-0012 Qualification of Software (Reference 213) Therefore MCNP5 code is suitable for use in this design calculation All MCNP5 input and output files docum ented in this calculation are provided on a compact disc (CD) as Attachment II
All MCNP cases are executed on one of the following Q com puters QNW -004184 QNW -004187 QNW-004194 and QNW-004196 as shown in the output files
422 Commercial off the Shelf Software
The Excel sof tware is used to c alculate var ious inpu t values (i e atom densities weight percentages geometrical dimensions normalized source spectra and probabilities etc) Standard functions of Excel are also used in this desi gn calculation to display results (ie gamma and neutron dose rates) in tabular and graphic forms and to perform relative error calculations
The software specifications are as follows
bull Program Name Excel bull VersionRevision Number Microsoftreg Excel 2003
18
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
bull This software is installed on a persona l com puter running Microsoft W indows XP (central processing unit number 151834)
The user defined for mulas inputs results and gr aphical representations have been verified by hand calculations or visual inspection and are documented in sufficient detail to allow an independent repetition of the com putations Calculations were verifi ed by hand and graphical representations were found accurate by visual inspection
Per Software Management Microsoftreg Excel is not requir ed to be qualif ied due to its commercial availability status (Reference 211 Attachment 4 p 55 bullet 2)
43 CALCULATION APPROACH
This calculation em ploys the qualified so ftware MCNP5 version 140 (Reference 2225) a three-dimensional Monte Carlo code for pe rforming neutron and coupled neutron-gamm a calculations to estim ate dose rates at sele cted locations on and surrounding a conceptual transportation cask containing a loaded TAD canister
431 MCNP5 Program
MCNP5 a general Monte Carlo part icle transport code sim ulates particle transport through a three-dimensional representation of the nuclear system being analyzed During the random walk of particles through the system described by the geom etry the c ode collects inform ation about various events (su rface cross ing collis ions trac k leng th etc) and es timates fluxes in various geometric configurations specified as tallies by the user It also estimates the statistical precision of the results in the form of relative errors (Reference 2224 pp 1-2 to 1-8)
Per Project Design Criteria Document (Reference 2211 Section 41015) the flux estim ates are converted to dose rates using the Am erican Nuclear Society (ANS) flux-to-dose rate conversion factors for gammas and neutrons (R eference 221) The simple variance reduction techniques of Geometry SplittingRussian Roulette and source probability biasing (Sections 631 and 633) are used to enhance computational efficiency
19
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
5 LIST OF ATTACHMENTS
Number of Pages Attachment I List of Electronic Files on the CD 3 Attachment II Compact Disc NA
20
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
6 CALCULATIONS
This sectio n provides inform ation necess ary to perform the calcu lations in this docum ent Section 61 describes the configurations the type of CSNF to be analyzed the number of MCNP runs and the locations where dose rates are ca lculated Section 62 provides the calculation input that includes the details of the geom etry m odel radiation source term s and m aterial compositions Input specific to MCNP dose -rate conversion factors and relative error calculation are described in the later sections
61 DESCRIPTION OF CALCULATIONS
Dose rate calculations are perform ed with the MCNP5 version 140 com puter code (Reference 2225) Two conceptual transportation casks Cask A and Cask B (Assum ption 323) are employed Each cask contains a TAD canister that is loaded with 21 ident ical PW R SN F assemblies Three PWR source term s are analy zed they are the source term s corresponding to the maximum design basis and average PW R SN Fs The characteris tics of the P WR source terms are presented in S ection 627 Each PWR source term has neutron and ga mma radiation sources that require separate MCNP5 runs For each radiation source an axial profile source and a uniform source for the active fuel region are considered The uniform source for the active fuel region is included in this calculation because this approach was used in combination with source peaking factors in certain calculations (Reference 2216 Sections 37 and 39 and Reference 2217 Section 5242)
The total number of MCNP5 runs is 24 which re sults from a com bination of two conceptual casks three PWR source terms two radiation sources and two axia l source distributions for the active fuel region These 24 runs are categorized into four calcula tion sets Each calculation set consists of six runs that is a combination of three PWR source te rms and two radiation sources The characteristics of each calculation set are as follows
1 Cask A with axial profile sources in the active fuel region
2 Cask A with uniform axial sources in the active fuel region
3 Cask B with axial profile sources in the active fuel region
4 Cask B with uniform axial sources in the active fuel region
For each MCNP5 run dose rates are calculated at the exte rior surfaces and at distances 1 and 2 meters from the exterior surfaces Surface tallies and detector tallies (ring and point detectors) as indicated in Figure 1 are e mployed in all runs Figure 1 is used to illustrate the dep loyment of the surface and detector tallies re lative to the so urce regions and it should not be interpreted as an exact geometry of any particular run Surface tallies are deployed at all three distances while ring and point detectors are used only at 1 m and 2 m and not at the cask surfaces Using point detectors near a surface or in any scattering media is not recommended because very large scores can occur f rom collisions close ( less than a f ew centimeters) to the point detecto rs that can lead to resu lts with high r elative e rrors thus m aking the ca lculation d ifficult to o btain r eliable answers
21
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
For the radial direction surface tallies at the three distances (contact 1 m and 2 m) are computed for three su rface segments (cylindrical rings) between the planes at Z = 145 175 2 05 and 235 cm The geometric locations of the segments are shown in Figure 1 The axial locations of these segments correspond to the m iddle of the active fuel region of the PWR SNF assemblies The average dose rates for each of the segm ents are calculated for the outside surface and surfaces at 1 m and 2 m from the cask surface Two ring detectors (instead of point detectors) are deployed at 1 m and 2 m for the radial dire ction Ring detectors instead of point detectors are used in order to capitalize on the symm etry around the cask axis thus im proving the efficiency of the calculations
In the axial direction the average d ose rates within three concentric radial surfaces defined by radii of 40 80 and 120 cm (shown in Figure 1) are calculated for the top and bottom surfaces and at distances 1 m and 2 m from these surfaces Finally point detectors at 1 m and 2 m from the top and bottom axial surfaces are employed
22
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Point Detector at 2 m x
Ring Ring Detector Detector at 2 m at 1 m
x x
Z = 00 cm
Z = 145 cm
Z = 175 cm
Z = 205 cm
Z = 235 cm
R = 80 cm
R = 120 cm
R = 40 cm
Active Fuel
Shield Plug
Top End-Fitting Plenum
Bottom End-Fitting
Ring Detector at 1 m
x
Point Detector at 1 m x
Ring Detector
at 2 m x
D = 26797 cm
H =
610
845
cm
Point Detector at 1 m x
Point Detector at 2 m x
Figure 1 Geometry and Tally Scheme for the TAD Transportation Cask
23
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
62 CALCULATION INPUT
Technical product input and sources of the input used in the deve lopment of this calculation are documented in this section Tables in this docum ent and in th e associated Microsoftreg Excel spreadsheets referenced m ay present num erical values with m any significant figures these values are not to be considered as high precision values since the significant figures are results of calculated values andor unit conversions
621 TAD Canister
The TAD canis ter will contain either 21 P WR or 44 BW R (boiling water reactor) SNF assemblies (Reference 2222 Section 321) While the canister design is iden tical for both PWR and BWR SNF assemblies the internal basket structure is different depending on the SNF assemblies However the internal basket stru cture m aterial is no t in cluded in the calcu lation model (Assumption 326)
The TAD canister is a right-circu lar cylinder with a diam eter of 665 in and a height between 186 and 212 in (Reference 2222 Section 321) The average and maximum total dose rates on the top surf ace of a loaded TAD ca nister must not exceed 800 and 1000 m remhr respectively (Reference 2222 Section 314) The TAD canister used in this calculation is m ade of SS 316 with a radial wall and bottom thickness of 025 in (Assumption 321) The top of the canister has a shield plug that is 11 in thick SS 316 (Ass umption 322) A thick shield plug is needed to keep the maxim um contact dose rate of th e top surface below 1000 m remhr The overall dimensions of the TAD canister are provided in Table 3
Table 3 Dimensions of TAD Canister
Component Dimension
(in) (cm)
Maximum heighta 212 53848
Outer diametera 665 16891
Thickness of bottom lidb 025 0635
Shell thicknessb 025 0635
Lifting Featurec 6 1524
Height without Lifting Feature 206 52324
Thickness of shield plugd 110 2794
aReference 2222 Section 311 bAssumption 321 cReference 2222 p Attachment C-1 dAssumption 322
622 Conceptual TAD Transportation Casks
Two conceptual TAD transportation casks designa ted as Cask A and Cask B are em ployed in this calculation (Assumption 323) They both have a cylindrical geometry with dimensions and materials specified in Tables 1 and 2 of Section 323 Cask A will provide shielding to meet the exterior radiation standards of 10 CFR 7147(b) (Reference 231) when loaded with a TAD
24
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
canister car rying the m aximum PWR SNF Cask B will s atisfy th e sa me radiatio n standa rds when loaded with a TAD canister c arrying the average PWR SNF The reason to analyze both Casks A and B is to cover a broad range of characteristics of the CSNF
The cavity dimensions of the conceptual cask s are 53785 cm (21175 in) in height and 16891 cm (665 in) in diam eter (Tab les 1 and 2) This cav ity will accommoda te the TAD canister described in Table 3 without the lifting feature This is the geometry model used in the MCNP5 calculations
623 Fuel Assembly Selection
PWR and BWR Source Term Sensitivity Study (Reference 2211 Tables 71 through 84) shows that the source terms generated for the Bamp W 15x15 Mark B fuel assembly with 475 kg uranium loading bound the source terms of other PWR assembly types ther efore this assembly type is selected as the representative PWR fuel assembly The gamma and neutron source terms for the BampW 15x15 Mark B assembly are generated in PWR Source Term Generation and Evaluation (Reference 229) and are used in this calculation
624 BampW 15x15 Mark B PWR Fuel Assembly
BampW 15x15 Mark B fuel assembly consists of four regions top end-fitting plenum active fuel and bottom end-fitting The m aterials and ra diation sources of each assem bly region are homogenized inside a volume defined by the region height and the interior diam eter of the TAD canister (Assumption 325) The active fuel region is homogenized with fresh unirradiated fuel (Assumption 324) Since the internal structure (i e basket) design of t he TAD is currently not finalized the com position of the hom ogenized fuel does not include the basket m aterials (Assumption 326) and therefore does not take cred it for any shielding that these m aterials may provide
Table 4 provides the design param eters for the BampW 15x15 Mark B fuel assembly Data provided here are used in Attachment II PWR_fuel compxls worksheet BampWassy
25
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 4 BampW 15x15 Mark B Fuel Assembly Description
Component Material Characteristic Value Specific Reference Array Size 15 x 15
Reference 2227 Table 2-2 Fuel Pins Assembly 208 Guide Tubes Assembly 16 Instrument Tubes Assembly 1
Assembly NA Pin Pellet Diameter 0936244 cm (03686 in) Reference 2220 p 2A-34 Pin Pitch 144272 cm (0568 in)
Reference 2227 Table 2-2 Active Fuel Height 360172 cm (1418 in) Assembly Width 2168144 cm (8536 in)
Reference 2220 p 2A-31 Assembly Height 4206875 cm (165625 in) Mass U assembly 46363 kg
Guide tube Zircaloy-4 Outer Diameter 13462 cm (053 in)
Reference 2227 Table 2-2
Inner Diameter 126492 cm (0498 in)
Instrument tube Zircaloy-4 Outer Diameter 138193 cm (05441 in) Inner Diameter 112014 cm (0441 in)
Cladding` Zircaloy-4 Inner Diameter 095758 cm (0377 in) Outer Diameter 10922 cm (043 in)
Plenum region NA Length 297688 cm (11720 in) Reference 2220 p 2A-34 Top nozzle SS CF3M MassAssembly (Top) 748 kg
Reference 2220 p 2A-32
Bottom nozzle SS CF3M MassAssembly (Bottom) 816 kg Guide tubes Zircaloy-4 MassAssembly (in Core) 80 kg Instrument tube Zircaloy-4 MassAssembly (in Core) 064 kg Spacer-plenum Inconel-718 MassAssembly (Plenum) 104 kg Spacer-bottom Inconel-718 MassAssembly (Bottom) 13 kg Spacer-in core Inconel-718 MassAssembly (in Core) 49 kg Spring retainer SS CF3M MassAssembly (Top) 091 kg Holddown spring Inconel-718 MassAssembly (Top) 18 kg Upper end plug SS 304 MassAssembly (Top) 006 kg Upper nut SS 304L MassAssembly (Top) 051 kg Lower nut SS 304 MassAssembly (Bottom) 015 kg Grid supports Zircaloy-4 MassAssembly (in Core) 064 kg Plenum spring SS 302 MassAssembly (Plenum) 0042 lb (001905 kg) Reference 2220 p 2A-34
Note Som e d ata i n this tab le ar e given i n British u nits in th e r eferences thes e d ata ar e converted into metric units as the inputs to MCNP5 are in metric units
The assem bly region heights as m odeled in MC NP are presented in Table 5 utilizing values from Table 4 Table 5 is taken from Dose Rate Calculation for Exhaust Main Drifts (Reference 2213 Table 3)
26
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 5 PWR Fuel Assembly Regions
Component Height Reference
Plenum 297688 cm (11720 in) Reference 2220 p 2A-34
Active Fuel 360172 cm (1418 in) Table 3
Bottom End-Fitting 1077 cm (424 in) Calculateda
Top End-Fitting 1998 cm (787 in) Calculatedb
Source Reference 2213 Table 3 aCalculated b ased on data Reference 2227 F igures 2-3 an d 2-7
(Region 9 Height [16723 cm] + Region 10 Height [508 cm] ndash Lo wer Fuel Plenum and End Cap [11033 cm])
bCalculated (Assembly Length ndash Active Fuel Length ndash P lenum Length ndash Bottom End-fitting Length)
625 Material Compositions
The TAD transportation cask com ponent m aterial specifications are defined in Table 1 The TAD canister is constructed of SS 316 (Assumpti on 321) The PWR fuel assembly materials used to homogenize the fuel regions are defined in Table 4 Table 6 c ontains the m aterial compositions defining the TAD canister WP and fuel assemblies
27
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 6 Chemical Compositions of Materials
Material Density (gcc)
Isotopic Weight Percent Reference
SS 302 NA
C 0150 Mn 2000 P 0045 S 0030 Si 0750 Cr 18000 Ni 9000 N 0100 Fe 69925
Attachment II PWR_fuel compxls worksheet ferrous Reference 222 SEC II A SA-240 Table 1 for SS 302 SS 304 and SS 304L Reference 222 SEC II A SA-351SA -351M Table 2 for SS CF3M
SS 304 NA
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 9250 N 0100 Fe 68745
SS 304L NA
C 003 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 10000 N 0100 Fe 6804 5
SS CF3M NA
C 0030 Mn 1500 P 0040 S 0040 Si 1500 Cr 19000 Ni 11000 Mo 2500 Fe 64390
Inconel 718 NA
C 0080 Mn 0350 Si 0350 Cr 19000 Ni 52500 Co 1000 Mo 3050 Fe 16809 Nb 5125 Ti 0900 Al 0500 Cu 0300 S 0015 P 0015 B 0006
Attachment II PWR_fuel compxls worksheet alloys aReference 223 p 666 Table 6 Reference 222 SEC II B SB-637 Table 1 for Inconel 718 Reference 224 Table 2 for Zircaloy 4
Zircaloy 4 656a Cr 0100 Fe 0210 O 0125 Sn 1450 Zr 98115
SS 316 798b
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 17000 Ni 12000 Mo 2500 N 0100 Fe 65495
Attachment II PWR_fuel compxls worksheet others Reference 222 SEC II A SA-240 Table 1 for SS 316 bReference 225 Table X1
626 Homogenization Assembly Materials
The atom density of an element or isotope in atomsbmiddotcm in a homogenized region is calculated according to the following equation (Reference 2223 Appendix B)
M i times N AvogadroNi = Equation 1 Ai timesV times K
where Ni = Atom density of elementisotope i (atomsbmiddotcm) Mi = Mass of elementisotope i (g) NAvogadro = Avogadrorsquos constant 06022 x 1024 (atomsmole)
28
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Ai = Atomic weight of elementisotope i (gmole) V = Homogenization volume (cm3) K = Unit transformation constant = 1024 (bmiddotcmcm3)
Equation 1 is used in A ttachment II spreadsheet PWR_fuel compxls worksheet BampWassy to calculate th e atom dens ities for v arious elem ents and iso topes The m ass of elementsisotop es and Avogadrorsquos constant are provided in Reference 2226
Table 7 lists the com position of the hom ogenized assem bly regions (active fuel plenum top end-fitting and bottom end-fitting) for the PWR assembly The active fuel region contains fresh unirradiated fuel (Assumption 324) Since the internal structure (ie basket) design of the TAD is currently not finalized the composition of either homogenized fuel does not include the basket materials and therefore does not tak e credit for any shielding that thes e materials may provide (Assumption 326)
Table 7 Isotopic Compositions of Homogenized PWR Assembly Regions
Element Isotope
Atom Densities for Homogenized Regions (atomsbsdotcm)
Active Fuel Bottom End-Fitting Plenum Top End-Fitting
10B 861E-09 764E-08 221E-08 570E-08 11B 347E-08 307E-07 890E-08 230E-07 C 519E-07 160E-05 138E-06 993E-06 N -- 570E-07 262E-08 117E-06 O 621E-03 -- 142E-05 -- Al 144E-06 128E-05 371E-06 957E-06 Si 971E-07 243E-04 259E-06 139E-04 P 377E-08 606E-06 102E-07 360E-06 S 365E-08 581E-06 971E-08 340E-06 Ti 147E-06 130E-05 376E-06 971E-06 Cr 320E-05 187E-03 779E-05 113E-03 Mn 497E-07 126E-04 141E-06 749E-05 Fe 303E-05 531E-03 717E-05 313E-03 Co 132E-06 117E-05 340E-06 876E-06 Ni 697E-05 144E-03 180E-04 940E-04 Cu 368E-07 327E-06 945E-07 244E-06 Zr 196E-03 -- 195E-03 -- Nb 430E-06 382E-05 110E-05 285E-05 Mo 248E-06 135E-04 636E-06 791E-05 Sn 223E-05 -- 222E-05 -- 234U 139E-06 -- -- -- 235U 157E-04 -- -- -- 236U 719E-07 -- -- -- 238U 294E-03 -- -- -- Total 114E-02 924E-03 235E-03 557E-03
Source Attachment II spreadsheet PWR_fuel compxls worksheet BampWassy
29
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
The isotopic composition of commercially available 235U enriched uranium is determined by the given initial 235U enrichment using the following equations (Reference 226 p 20)
wt235U =235Uenrichment _ of _ the _ associated _ fuel _ batch Equation 2
wt234U = 0007731times (wt235U )10837 Equation 3
wt236U = 00046times (wt235U ) Equation 4
wt238U =100 minus (wt234U + wt235U + wt236U ) Equation 5
The weight percentages of uran ium isotopes for PWR fuel are ca lculated in Attachm ent II spreadsheet PWR_fuel compxls worksheet BampWassy using Equations 2 through 5
627 PWR Source Terms
This calculation uses the following three PWR source terms bull Maximum source (50 wt initial 235U enrichment 80 GWdMTU burnup and 5-year
decay time) (Reference 229 Section 55) Table 8 lists th e gamma source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Design Basis source (4 0 wt initial 235U enrichment 60 GW dMTU burnup and 10-year decay tim e) (Reference 228 Section 552) Table 9 lists the gamm a source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Average source ( 40 wt initial 235U enrichment 48 GWdMTU burnup and 25-year decay time) (Reference 229 Section 55) Table 10 lists the gamma source terms for the fuel and non-fuel regions and the neutron source term for the fuel region
These sources (ie maximum design basis and av erage) are described in this section For dose rate calculations all the fuel assemblies in a transportation cask are of the sam e characteristics Also gamma radiation source term s for the PWR assem bly are prov ided for the f our assembly regions while neutron source term is only present in the active fuel region Gamma radiation sources in the non-active fuel region are distri buted unif ormly within each source region Gamma and neutron sources in the active fuel re gion are modeled as uni form distributions or with axial source profiles
The PWR gamma and neutron axial source profiles for the active fuel region presented in Table 11 are applied to the active fuel region of all three source terms (ie maximum design basis and average) when appropriate
30
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 8 Gamma and Neutron Sources for the Maximum PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting
Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 594E+11 233E+15 528E+11 379E+11 100E-01 000E+00 100E-01 116E+11 644E+14 609E+10 743E+10 400E-01 805E+07 200E-01 283E+10 522E+14 352E+10 179E+10 900E-01 411E+08 300E-01 141E+09 148E+14 196E+09 891E+08 140E+00 376E+08 400E-01 190E+09 985E+13 586E+09 117E+09 185E+00 276E+08 600E-01 191E+09 153E+15 110E+11 741E+07 300E+00 485E+08 800E-01 435E+09 470E+15 595E+10 237E+09 643E+00 443E+08 100E+00 137E+11 708E+14 803E+09 766E+10 200E+01 393E+07 133E+00 338E+13 455E+14 174E+13 217E+13 Total 211E+09 166E+00 953E+12 130E+14 491E+12 612E+12
--
200E+00 187E+03 144E+12 919E+02 113E+03 250E+00 226E+08 249E+12 116E+08 145E+08 300E+00 351E+05 110E+11 181E+05 225E+05 400E+00 766E-08 139E+10 100E-08 416E-08 500E+00 000E+00 709E+07 000E+00 000E+00 650E+00 000E+00 286E+07 000E+00 000E+00 800E+00 000E+00 558E+06 000E+00 000E+00 100E+01 000E+00 119E+06 000E+00 000E+00
Total 442E+13 113E+16 231E+13 284E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE2R2B14cut bWasteStreamE2R1B14cut cWasteStreamE2R3B14cut dWasteStreamE2R4B14cut
31
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 9 Gamma and Neutron Sources for the Design Basis PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary
(MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 273E+11 121E+15 188E+11 175E+11 100E-01 000E+00 100E-01 528E+10 329E+14 277E+10 339E+10 400E-01 316E+07 200E-01 128E+10 245E+14 117E+10 819E+09 900E-01 161E+08 300E-01 639E+08 713E+13 633E+08 407E+08 140E+00 148E+08 400E-01 850E+08 455E+13 164E+09 533E+08 185E+00 109E+08 600E-01 492E+08 226E+14 269E+10 337E+07 300E+00 191E+08 800E-01 291E+09 237E+15 160E+10 186E+09 643E+00 174E+08 100E+00 540E+09 122E+14 248E+09 341E+09 200E+01 154E+07 133E+00 154E+13 195E+14 797E+12 990E+12 Total 830E+08 166E+00 435E+12 450E+13 225E+12 280E+12
--
200E+00 235E+00 152E+11 149E+02 215E-02 250E+00 103E+08 517E+10 534E+07 664E+07 300E+00 160E+05 379E+09 829E+04 103E+05 400E+00 943E-10 497E+08 155E-10 519E-10 500E+00 000E+00 282E+07 000E+00 000E+00 650E+00 000E+00 113E+07 000E+00 000E+00 800E+00 000E+00 222E+06 000E+00 000E+00 100E+01 000E+00 471E+05 000E+00 000E+00
Total 201E+13 486E+15 105E+13 129E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B11cut bWasteStreamE5R1B11cut cWasteStreamE5R3B11cut dWasteStreamE5R4B11cut
32
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 10 Gamma and Neutron Sources for the Average PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 336E+10 670E+14 186E+10 217E+10 100E-01 00000E+00 100E-01 602E+09 199E+14 314E+09 387E+09 400E-01 748E+06 200E-01 146E+09 126E+14 853E+08 936E+08 900E-01 382E+07 300E-01 730E+07 389E+13 439E+07 469E+07 140E+00 352E+07 400E-01 947E+07 263E+13 716E+07 607E+07 185E+00 261E+07 600E-01 141E+07 205E+13 504E+08 383E+06 300E+00 469E+07 800E-01 208E+09 124E+15 192E+09 144E+09 643E+00 418E+07 100E+00 208E+09 110E+13 164E+09 144E+09 200E+01 365E+06 133E+00 175E+12 295E+13 909E+11 112E+12 Total 199E+08 166E+00 494E+11 513E+12 257E+11 318E+11
--
200E+00 973E-01 675E+10 614E+01 872E-03 250E+00 117E+07 353E+09 609E+06 754E+06 300E+00 182E+04 288E+08 944E+03 117E+04 400E+00 186E-11 198E+07 149E-11 127E-11 500E+00 000E+00 669E+06 000E+00 000E+00 650E+00 000E+00 269E+06 000E+00 000E+00 800E+00 000E+00 527E+05 000E+00 000E+00 100E+01 000E+00 112E+05 000E+00 000E+00
Total 229E+12 237E+15 119E+12 147E+12
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B9cut bWasteStreamE5R1B9cut cWasteStreamE5R3B9cut dWasteStreamE5R4B9cut
33
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 11 Gamma and Neutron Axial Source Profiles for a PWR Assembly
Axial boundaries (From midplane)
(cm)
TOP BOTTOM
Neutron Gamma Ne utron Gamma 000 1554 1117 1554 1117 1143 1537 1114 1571 1120 2286 1521 1111 1588 1123 3429 1504 1108 1605 1126 4572 1486 1104 1622 1129 5715 1464 1100 1636 1131 6858 1438 1095 1648 1133 8001 1401 1088 1657 1135 9144 1350 1078 1654 1134
10287 1277 1063 1625 1129 11430 1165 1039 1554 1117 12573 0998 09995 1414 1091 13716 0769 09365 1172 1041 14859 0492 08375 0816 0951 16002 0220 06850 0402 0797 17145 0046 04625 0092 0551 18288 00 00 00 00
Source Reference 2219 Table S445
34
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
63 MCNP SPECIFIC INPUT
631 Source Probability
A linear radial distribution is used for all gamma and neutron sources The linear radial distribution is sam pled usi ng the built-in power function p(x) = xc a with a = 1 for the radial direction This sampling method results in a uniform source distribution over the area bounded by the outer radius of the source
The source axial distributions are unifor m for all four source regions The a xial uni form xp(x) = c distribution is sampled using the built-in power function a with a = 0 for extent
The energy distribu tions of the gamma and neutron sour ce term s are treated as energ y probabilities and are applied in MCNP5 using SISP cards
632 Dose Rate and Flux Tallies
MCNP5 dose rate calculations feature separate runs for the following calculation types
bull a photon transport calculation for prim ary ga mma contribution to the dose rates fr om photon fluxes
bull a coupled neutronphoton transport calculat ion for neutrons a nd secondary gamma (photons generated by neutron be ing captured) contributions to dose rates from neutron and gamma fluxes
The tally type F2 is us ed in th is d esign ca lculation as f lux estim ators The type F2 tally evaluates the flux averaged over a surface in particlescm2s
To generate dose ra tes in te rms of remhr the FM (tally multiplier ) and DEDF (dose energydose conversion factors) cards are used to en ter the tally multiplier f actor (source intensity in particless) energy boundaries in MeV and corresponding dose conversion factors in (remhr)(particlescm2s) respectively These factors were used in the input files
In order for the F2 tally to accum ulate flux ov er a surface a specific s urface area is requ ired The SD cards are used to enter a surface area in cm2 over which the flux will be tallied for an F2 tally
633 Variance Reduction Techniques
Variance reduction technique is usually em ployed in order to increase the efficiency of a calculation and obtain statistically m eaningful results within re asonable com puter tim e In Monte Carlo calculations when variance reduction scheme is employed the weights of particles are adjusted in order to account for the biasing and to preserve a fair game
Geometry splitting and Russian roulette techniques described in Reference 2224 (pp 2-140 ndash 2-142) are useful in shielding calculations and therefore deployed in all the MCNP5 runs
35
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
As particles migrate in an important direction (toward the detector) they are increased in number to provide better sampling by means of geometry splitting across geometric boundaries Russian roulette (the reverse process) is played when particles travel in an unimportant direction to allow termination of unim portant histories The IMP card required for every cel l ca rd is us ed to implement this technique
The other variance reduction technique deployed in the MC NP5 runs is source intensity biasing for the gamma sources from the four source regions (active fuel bottom end-fitting plenum and top end-fitting) The natural total gamma source intensity of comm ercial SNF is dom inated by the gamma source in the active fuel region This active fuel gamma source usually accounts for over 95 o f the total g amma source intens ity In order to im prove the efficiency of the axial dose rate calculations a biased source probability distribution is employed for the prim ary gamma dose rate calculations The biased gamma source probability distribution is chosen to be 005 080 010 and 005 for the bottom end-fitting the active fuel the plenum and the top end-fitting regions respectively
64 DOSE CONVERSION FACTORS
Project Design Criteria Document (Reference 2211 Se ction 41015) requires the use of flux-to-dose rate conversion fact ors from ANSIANS-611-1977 (Reference 221) for dose rate evaluations Table 16 lists the neutron and ga mma dose conversion factors used in the MCNP5 calculations
Table 12 Gamma and Neutron Flux to Dose Conversion Factors
Gamma Neutron Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
001 396E-06 140 251E-06 250E-08 367E-06 003 582E-07 180 299E-06 100E-07 367E-06 005 290E-07 220 342E-06 100E-06 446E-06 007 258E-07 260 382E-06 100E-05 454E-06 010 283E-07 280 401E-06 100E-04 418E-06 015 379E-07 325 441E-06 100E-03 376E-06 020 501E-07 375 483E-06 100E-02 356E-06 025 631E-07 425 523E-06 100E-01 217E-05 030 759E-07 475 560E-06 500E-01 926E-05 035 878E-07 500 580E-06 100E+00 132E-04 040 985E-07 525 601E-06 250E+00 125E-04 045 108E-06 575 637E-06 500E+00 156E-04 050 117E-06 625 674E-06 700E+00 147E-04 055 127E-06 675 711E-06 100E+01 147E-04 060 136E-06 750 766E-06 140E+01 208E-04 065 144E-06 900 877E-06 200E+01 227E-04 070 152E-06 1100 103E-05 080 168E-06 1300 118E-05 100 198E-06 1500 133E-05
Source Reference 221 Tables 1 and 3
36
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION
By def inition (Ref erence 2224 Equation 219) the estimated st atistic relative error of the i component is
Ri = Si
2
Equation 6Ti
where i = tally component index Ri = relative error of the i component S2
i = variance of the i component Ti = tally i component
For a result (ie dose rate) computed as a sum of different tallies the statistical relative error of the computed value is o btained from the variance of the result - S2
total which is th e sum of the estimated variances of the individual tallies S2
i n
2 2STotal = sum Si Equation 7 i=1
where S2Total = total estimated variance
n = total number of components Therefore the total tally value (dose rate) and the associated relative error are derived according to Equations 8 and 9
n TTotal = sumTi Equation 8
i=1
n n
sum (Ri timesTi )2
2 sum Si 2
STotal = i=1 = i=1 Equation 9RTotal = TTotal TTotal TTotal
where RTotal = total estimated relative error TTotal = total estimated tally
Equations 8 and 9 are utilized in Attachm ent II to ev aluate to tal dos e ra tes and their r elative errors
37
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
7 RESULTS AND CONCLUSIONS
71 RESULTS
The following sections summarize the results of this calculation Section 711 presents results for Conceptual Cask A while Section 712 for Conceptual Cask B Section 713 provides comparisons of the dose-rate reduction factors du e to the two conceptual casks and the axial source distributions in the active fuel region Do se rates and relative errors can be found in Attachment II within the output files and Excel files
711 Dose Rates of Conceptual Cask A
This section presents dose-rate results of the calculation sets 1 and 2 as described in Section 61 for Cask A Set 1 has axial p rofile sources in the active fuel region a nd consist of six runs resulting from the three PWR SNF source term s (maximum design basis and average) and the two radiation sources (gammas and neutrons) Set 2 has uniform axial sources in the active fuel region and consists of six run s r esulting f rom the th ree P WR SNF source term s and th e tw o radiation sources
As described in Section 61 dose ra tes are calculated at the three exterior surfaces (radial top and bottom) and at distances 1 m and 2 m from the exterior surfaces The total dose rates for set 1 are presented in Tables 13 14 and 15 for the ra dial top and bottom dire ctions respectively However the com ponents (primary gamma neutr on and secondary gamma) contributing to the total dose rates as well as the re lative error calculations can be found in Attachment II Excel file MCNP-Results1xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 2 are shown in Tables 16 17 and 18 The dose-rate components and the relative errors can be found in A ttachment II Excel file MCNP-Results2xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 13 and 16 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 14 and 17 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 15 and 18 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carrying th e maximum PWR SNF Based on the results in Tables 13 through 18 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask A indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these 6 tables the d ose-rate red uction f actors between the m aximum and the design basis fuels the maxim um and the averag e fuels and th e design basis and the average fuels are a lso presented
38
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 320E-02 00237 116E-02 00222 262E-03 00219 275 1223 445
1 m 133E-02 00164 494E-03 00171 106E-03 00162 269 1261 468 2 m 749E-03 00198 285E-03 00225 584E-04 00162 263 1282 488
Ring Detectors 1 m 133E-02 00116 492E-03 00115 108E-03 00124 271 1229 454 2 m 756E-03 00118 279E-03 00110 605E-04 00128 271 1250 462
Source Attachment II MCNP-Results1xls worksheet Summary
Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 142E-02 00368 628E-03 00446 934E-04 00483 226 1520 672
1 m 570E-03 00289 263E-03 00426 375E-04 00381 217 1520 701 2 m 265E-03 00364 123E-03 00547 169E-04 00374 216 1575 730
Point Detectors 1 m 598E-03 00238 274E-03 00271 402E-04 00354 219 1489 681 2 m 273E-03 00218 123E-03 00245 180E-04 00336 221 1515 684
Source Attachment II MCNP-Results1xls worksheet Summary
Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 653E-03 00298 265E-03 00276 510E-04 00341 247 1278 518
1 m 276E-03 00238 112E-03 00208 207E-04 00249 248 1334 539 2 m 125E-03 00185 508E-04 00199 933E-05 00246 246 1336 544
Point Detectors 1 m 291E-03 00227 118E-03 00203 218E-04 00242 247 1335 540 2 m 130E-03 00209 524E-04 00187 955E-05 00233 247 1357 549
Source Attachment II MCNP-Results1xls worksheet Summary
Tables 13 14 and 15 are results of calculation set 1 for conceptual Cask A with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
39
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 265E-02 00247 990E-03 00222 215E-03 00278 268 1234 461
1 m 116E-02 00178 468E-03 00549 960E-04 00189 248 1208 488 2 m 713E-03 00273 265E-03 00161 602E-04 00360 269 1184 439
Ring Detectors 1 m 117E-02 00120 454E-03 00132 979E-04 00141 259 1199 463 2 m 722E-03 00130 276E-03 00141 589E-04 00153 261 1226 469
Source Attachment II MCNP-Results2xls worksheet Summary
Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 199E-02 00461 827E-03 00455 147E-03 00536 241 1359 564
1 m 849E-03 00564 323E-03 00314 563E-04 00418 263 1507 574 2 m 415E-03 00832 158E-03 00603 253E-04 00501 263 1641 623
Point Detectors 1 m 877E-03 00348 353E-03 00275 615E-04 00391 248 1426 574 2 m 393E-03 00341 160E-03 00278 270E-04 00378 246 1454 590
Source Attachment II MCNP-Results2xls worksheet Summary
Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 879E-03 00374 356E-03 00333 669E-04 00406 247 1315 533
1 m 365E-03 00223 147E-03 00209 269E-04 00253 248 1358 548 2 m 164E-03 00229 674E-04 00205 120E-04 00248 243 1364 560
Point Detectors 1 m 383E-03 00217 155E-03 00204 285E-04 00248 247 1347 546 2 m 172E-03 00197 689E-04 00186 124E-04 00225 249 1391 558
Source Attachment II MCNP-Results2xls worksheet Summary
Tables 16 17 and 18 ar e results of calculation set 2 for conceptual Cask A with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
40
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
bull This software is installed on a persona l com puter running Microsoft W indows XP (central processing unit number 151834)
The user defined for mulas inputs results and gr aphical representations have been verified by hand calculations or visual inspection and are documented in sufficient detail to allow an independent repetition of the com putations Calculations were verifi ed by hand and graphical representations were found accurate by visual inspection
Per Software Management Microsoftreg Excel is not requir ed to be qualif ied due to its commercial availability status (Reference 211 Attachment 4 p 55 bullet 2)
43 CALCULATION APPROACH
This calculation em ploys the qualified so ftware MCNP5 version 140 (Reference 2225) a three-dimensional Monte Carlo code for pe rforming neutron and coupled neutron-gamm a calculations to estim ate dose rates at sele cted locations on and surrounding a conceptual transportation cask containing a loaded TAD canister
431 MCNP5 Program
MCNP5 a general Monte Carlo part icle transport code sim ulates particle transport through a three-dimensional representation of the nuclear system being analyzed During the random walk of particles through the system described by the geom etry the c ode collects inform ation about various events (su rface cross ing collis ions trac k leng th etc) and es timates fluxes in various geometric configurations specified as tallies by the user It also estimates the statistical precision of the results in the form of relative errors (Reference 2224 pp 1-2 to 1-8)
Per Project Design Criteria Document (Reference 2211 Section 41015) the flux estim ates are converted to dose rates using the Am erican Nuclear Society (ANS) flux-to-dose rate conversion factors for gammas and neutrons (R eference 221) The simple variance reduction techniques of Geometry SplittingRussian Roulette and source probability biasing (Sections 631 and 633) are used to enhance computational efficiency
19
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
5 LIST OF ATTACHMENTS
Number of Pages Attachment I List of Electronic Files on the CD 3 Attachment II Compact Disc NA
20
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
6 CALCULATIONS
This sectio n provides inform ation necess ary to perform the calcu lations in this docum ent Section 61 describes the configurations the type of CSNF to be analyzed the number of MCNP runs and the locations where dose rates are ca lculated Section 62 provides the calculation input that includes the details of the geom etry m odel radiation source term s and m aterial compositions Input specific to MCNP dose -rate conversion factors and relative error calculation are described in the later sections
61 DESCRIPTION OF CALCULATIONS
Dose rate calculations are perform ed with the MCNP5 version 140 com puter code (Reference 2225) Two conceptual transportation casks Cask A and Cask B (Assum ption 323) are employed Each cask contains a TAD canister that is loaded with 21 ident ical PW R SN F assemblies Three PWR source term s are analy zed they are the source term s corresponding to the maximum design basis and average PW R SN Fs The characteris tics of the P WR source terms are presented in S ection 627 Each PWR source term has neutron and ga mma radiation sources that require separate MCNP5 runs For each radiation source an axial profile source and a uniform source for the active fuel region are considered The uniform source for the active fuel region is included in this calculation because this approach was used in combination with source peaking factors in certain calculations (Reference 2216 Sections 37 and 39 and Reference 2217 Section 5242)
The total number of MCNP5 runs is 24 which re sults from a com bination of two conceptual casks three PWR source terms two radiation sources and two axia l source distributions for the active fuel region These 24 runs are categorized into four calcula tion sets Each calculation set consists of six runs that is a combination of three PWR source te rms and two radiation sources The characteristics of each calculation set are as follows
1 Cask A with axial profile sources in the active fuel region
2 Cask A with uniform axial sources in the active fuel region
3 Cask B with axial profile sources in the active fuel region
4 Cask B with uniform axial sources in the active fuel region
For each MCNP5 run dose rates are calculated at the exte rior surfaces and at distances 1 and 2 meters from the exterior surfaces Surface tallies and detector tallies (ring and point detectors) as indicated in Figure 1 are e mployed in all runs Figure 1 is used to illustrate the dep loyment of the surface and detector tallies re lative to the so urce regions and it should not be interpreted as an exact geometry of any particular run Surface tallies are deployed at all three distances while ring and point detectors are used only at 1 m and 2 m and not at the cask surfaces Using point detectors near a surface or in any scattering media is not recommended because very large scores can occur f rom collisions close ( less than a f ew centimeters) to the point detecto rs that can lead to resu lts with high r elative e rrors thus m aking the ca lculation d ifficult to o btain r eliable answers
21
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
For the radial direction surface tallies at the three distances (contact 1 m and 2 m) are computed for three su rface segments (cylindrical rings) between the planes at Z = 145 175 2 05 and 235 cm The geometric locations of the segments are shown in Figure 1 The axial locations of these segments correspond to the m iddle of the active fuel region of the PWR SNF assemblies The average dose rates for each of the segm ents are calculated for the outside surface and surfaces at 1 m and 2 m from the cask surface Two ring detectors (instead of point detectors) are deployed at 1 m and 2 m for the radial dire ction Ring detectors instead of point detectors are used in order to capitalize on the symm etry around the cask axis thus im proving the efficiency of the calculations
In the axial direction the average d ose rates within three concentric radial surfaces defined by radii of 40 80 and 120 cm (shown in Figure 1) are calculated for the top and bottom surfaces and at distances 1 m and 2 m from these surfaces Finally point detectors at 1 m and 2 m from the top and bottom axial surfaces are employed
22
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Point Detector at 2 m x
Ring Ring Detector Detector at 2 m at 1 m
x x
Z = 00 cm
Z = 145 cm
Z = 175 cm
Z = 205 cm
Z = 235 cm
R = 80 cm
R = 120 cm
R = 40 cm
Active Fuel
Shield Plug
Top End-Fitting Plenum
Bottom End-Fitting
Ring Detector at 1 m
x
Point Detector at 1 m x
Ring Detector
at 2 m x
D = 26797 cm
H =
610
845
cm
Point Detector at 1 m x
Point Detector at 2 m x
Figure 1 Geometry and Tally Scheme for the TAD Transportation Cask
23
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
62 CALCULATION INPUT
Technical product input and sources of the input used in the deve lopment of this calculation are documented in this section Tables in this docum ent and in th e associated Microsoftreg Excel spreadsheets referenced m ay present num erical values with m any significant figures these values are not to be considered as high precision values since the significant figures are results of calculated values andor unit conversions
621 TAD Canister
The TAD canis ter will contain either 21 P WR or 44 BW R (boiling water reactor) SNF assemblies (Reference 2222 Section 321) While the canister design is iden tical for both PWR and BWR SNF assemblies the internal basket structure is different depending on the SNF assemblies However the internal basket stru cture m aterial is no t in cluded in the calcu lation model (Assumption 326)
The TAD canister is a right-circu lar cylinder with a diam eter of 665 in and a height between 186 and 212 in (Reference 2222 Section 321) The average and maximum total dose rates on the top surf ace of a loaded TAD ca nister must not exceed 800 and 1000 m remhr respectively (Reference 2222 Section 314) The TAD canister used in this calculation is m ade of SS 316 with a radial wall and bottom thickness of 025 in (Assumption 321) The top of the canister has a shield plug that is 11 in thick SS 316 (Ass umption 322) A thick shield plug is needed to keep the maxim um contact dose rate of th e top surface below 1000 m remhr The overall dimensions of the TAD canister are provided in Table 3
Table 3 Dimensions of TAD Canister
Component Dimension
(in) (cm)
Maximum heighta 212 53848
Outer diametera 665 16891
Thickness of bottom lidb 025 0635
Shell thicknessb 025 0635
Lifting Featurec 6 1524
Height without Lifting Feature 206 52324
Thickness of shield plugd 110 2794
aReference 2222 Section 311 bAssumption 321 cReference 2222 p Attachment C-1 dAssumption 322
622 Conceptual TAD Transportation Casks
Two conceptual TAD transportation casks designa ted as Cask A and Cask B are em ployed in this calculation (Assumption 323) They both have a cylindrical geometry with dimensions and materials specified in Tables 1 and 2 of Section 323 Cask A will provide shielding to meet the exterior radiation standards of 10 CFR 7147(b) (Reference 231) when loaded with a TAD
24
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
canister car rying the m aximum PWR SNF Cask B will s atisfy th e sa me radiatio n standa rds when loaded with a TAD canister c arrying the average PWR SNF The reason to analyze both Casks A and B is to cover a broad range of characteristics of the CSNF
The cavity dimensions of the conceptual cask s are 53785 cm (21175 in) in height and 16891 cm (665 in) in diam eter (Tab les 1 and 2) This cav ity will accommoda te the TAD canister described in Table 3 without the lifting feature This is the geometry model used in the MCNP5 calculations
623 Fuel Assembly Selection
PWR and BWR Source Term Sensitivity Study (Reference 2211 Tables 71 through 84) shows that the source terms generated for the Bamp W 15x15 Mark B fuel assembly with 475 kg uranium loading bound the source terms of other PWR assembly types ther efore this assembly type is selected as the representative PWR fuel assembly The gamma and neutron source terms for the BampW 15x15 Mark B assembly are generated in PWR Source Term Generation and Evaluation (Reference 229) and are used in this calculation
624 BampW 15x15 Mark B PWR Fuel Assembly
BampW 15x15 Mark B fuel assembly consists of four regions top end-fitting plenum active fuel and bottom end-fitting The m aterials and ra diation sources of each assem bly region are homogenized inside a volume defined by the region height and the interior diam eter of the TAD canister (Assumption 325) The active fuel region is homogenized with fresh unirradiated fuel (Assumption 324) Since the internal structure (i e basket) design of t he TAD is currently not finalized the com position of the hom ogenized fuel does not include the basket m aterials (Assumption 326) and therefore does not take cred it for any shielding that these m aterials may provide
Table 4 provides the design param eters for the BampW 15x15 Mark B fuel assembly Data provided here are used in Attachment II PWR_fuel compxls worksheet BampWassy
25
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 4 BampW 15x15 Mark B Fuel Assembly Description
Component Material Characteristic Value Specific Reference Array Size 15 x 15
Reference 2227 Table 2-2 Fuel Pins Assembly 208 Guide Tubes Assembly 16 Instrument Tubes Assembly 1
Assembly NA Pin Pellet Diameter 0936244 cm (03686 in) Reference 2220 p 2A-34 Pin Pitch 144272 cm (0568 in)
Reference 2227 Table 2-2 Active Fuel Height 360172 cm (1418 in) Assembly Width 2168144 cm (8536 in)
Reference 2220 p 2A-31 Assembly Height 4206875 cm (165625 in) Mass U assembly 46363 kg
Guide tube Zircaloy-4 Outer Diameter 13462 cm (053 in)
Reference 2227 Table 2-2
Inner Diameter 126492 cm (0498 in)
Instrument tube Zircaloy-4 Outer Diameter 138193 cm (05441 in) Inner Diameter 112014 cm (0441 in)
Cladding` Zircaloy-4 Inner Diameter 095758 cm (0377 in) Outer Diameter 10922 cm (043 in)
Plenum region NA Length 297688 cm (11720 in) Reference 2220 p 2A-34 Top nozzle SS CF3M MassAssembly (Top) 748 kg
Reference 2220 p 2A-32
Bottom nozzle SS CF3M MassAssembly (Bottom) 816 kg Guide tubes Zircaloy-4 MassAssembly (in Core) 80 kg Instrument tube Zircaloy-4 MassAssembly (in Core) 064 kg Spacer-plenum Inconel-718 MassAssembly (Plenum) 104 kg Spacer-bottom Inconel-718 MassAssembly (Bottom) 13 kg Spacer-in core Inconel-718 MassAssembly (in Core) 49 kg Spring retainer SS CF3M MassAssembly (Top) 091 kg Holddown spring Inconel-718 MassAssembly (Top) 18 kg Upper end plug SS 304 MassAssembly (Top) 006 kg Upper nut SS 304L MassAssembly (Top) 051 kg Lower nut SS 304 MassAssembly (Bottom) 015 kg Grid supports Zircaloy-4 MassAssembly (in Core) 064 kg Plenum spring SS 302 MassAssembly (Plenum) 0042 lb (001905 kg) Reference 2220 p 2A-34
Note Som e d ata i n this tab le ar e given i n British u nits in th e r eferences thes e d ata ar e converted into metric units as the inputs to MCNP5 are in metric units
The assem bly region heights as m odeled in MC NP are presented in Table 5 utilizing values from Table 4 Table 5 is taken from Dose Rate Calculation for Exhaust Main Drifts (Reference 2213 Table 3)
26
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 5 PWR Fuel Assembly Regions
Component Height Reference
Plenum 297688 cm (11720 in) Reference 2220 p 2A-34
Active Fuel 360172 cm (1418 in) Table 3
Bottom End-Fitting 1077 cm (424 in) Calculateda
Top End-Fitting 1998 cm (787 in) Calculatedb
Source Reference 2213 Table 3 aCalculated b ased on data Reference 2227 F igures 2-3 an d 2-7
(Region 9 Height [16723 cm] + Region 10 Height [508 cm] ndash Lo wer Fuel Plenum and End Cap [11033 cm])
bCalculated (Assembly Length ndash Active Fuel Length ndash P lenum Length ndash Bottom End-fitting Length)
625 Material Compositions
The TAD transportation cask com ponent m aterial specifications are defined in Table 1 The TAD canister is constructed of SS 316 (Assumpti on 321) The PWR fuel assembly materials used to homogenize the fuel regions are defined in Table 4 Table 6 c ontains the m aterial compositions defining the TAD canister WP and fuel assemblies
27
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 6 Chemical Compositions of Materials
Material Density (gcc)
Isotopic Weight Percent Reference
SS 302 NA
C 0150 Mn 2000 P 0045 S 0030 Si 0750 Cr 18000 Ni 9000 N 0100 Fe 69925
Attachment II PWR_fuel compxls worksheet ferrous Reference 222 SEC II A SA-240 Table 1 for SS 302 SS 304 and SS 304L Reference 222 SEC II A SA-351SA -351M Table 2 for SS CF3M
SS 304 NA
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 9250 N 0100 Fe 68745
SS 304L NA
C 003 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 10000 N 0100 Fe 6804 5
SS CF3M NA
C 0030 Mn 1500 P 0040 S 0040 Si 1500 Cr 19000 Ni 11000 Mo 2500 Fe 64390
Inconel 718 NA
C 0080 Mn 0350 Si 0350 Cr 19000 Ni 52500 Co 1000 Mo 3050 Fe 16809 Nb 5125 Ti 0900 Al 0500 Cu 0300 S 0015 P 0015 B 0006
Attachment II PWR_fuel compxls worksheet alloys aReference 223 p 666 Table 6 Reference 222 SEC II B SB-637 Table 1 for Inconel 718 Reference 224 Table 2 for Zircaloy 4
Zircaloy 4 656a Cr 0100 Fe 0210 O 0125 Sn 1450 Zr 98115
SS 316 798b
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 17000 Ni 12000 Mo 2500 N 0100 Fe 65495
Attachment II PWR_fuel compxls worksheet others Reference 222 SEC II A SA-240 Table 1 for SS 316 bReference 225 Table X1
626 Homogenization Assembly Materials
The atom density of an element or isotope in atomsbmiddotcm in a homogenized region is calculated according to the following equation (Reference 2223 Appendix B)
M i times N AvogadroNi = Equation 1 Ai timesV times K
where Ni = Atom density of elementisotope i (atomsbmiddotcm) Mi = Mass of elementisotope i (g) NAvogadro = Avogadrorsquos constant 06022 x 1024 (atomsmole)
28
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Ai = Atomic weight of elementisotope i (gmole) V = Homogenization volume (cm3) K = Unit transformation constant = 1024 (bmiddotcmcm3)
Equation 1 is used in A ttachment II spreadsheet PWR_fuel compxls worksheet BampWassy to calculate th e atom dens ities for v arious elem ents and iso topes The m ass of elementsisotop es and Avogadrorsquos constant are provided in Reference 2226
Table 7 lists the com position of the hom ogenized assem bly regions (active fuel plenum top end-fitting and bottom end-fitting) for the PWR assembly The active fuel region contains fresh unirradiated fuel (Assumption 324) Since the internal structure (ie basket) design of the TAD is currently not finalized the composition of either homogenized fuel does not include the basket materials and therefore does not tak e credit for any shielding that thes e materials may provide (Assumption 326)
Table 7 Isotopic Compositions of Homogenized PWR Assembly Regions
Element Isotope
Atom Densities for Homogenized Regions (atomsbsdotcm)
Active Fuel Bottom End-Fitting Plenum Top End-Fitting
10B 861E-09 764E-08 221E-08 570E-08 11B 347E-08 307E-07 890E-08 230E-07 C 519E-07 160E-05 138E-06 993E-06 N -- 570E-07 262E-08 117E-06 O 621E-03 -- 142E-05 -- Al 144E-06 128E-05 371E-06 957E-06 Si 971E-07 243E-04 259E-06 139E-04 P 377E-08 606E-06 102E-07 360E-06 S 365E-08 581E-06 971E-08 340E-06 Ti 147E-06 130E-05 376E-06 971E-06 Cr 320E-05 187E-03 779E-05 113E-03 Mn 497E-07 126E-04 141E-06 749E-05 Fe 303E-05 531E-03 717E-05 313E-03 Co 132E-06 117E-05 340E-06 876E-06 Ni 697E-05 144E-03 180E-04 940E-04 Cu 368E-07 327E-06 945E-07 244E-06 Zr 196E-03 -- 195E-03 -- Nb 430E-06 382E-05 110E-05 285E-05 Mo 248E-06 135E-04 636E-06 791E-05 Sn 223E-05 -- 222E-05 -- 234U 139E-06 -- -- -- 235U 157E-04 -- -- -- 236U 719E-07 -- -- -- 238U 294E-03 -- -- -- Total 114E-02 924E-03 235E-03 557E-03
Source Attachment II spreadsheet PWR_fuel compxls worksheet BampWassy
29
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
The isotopic composition of commercially available 235U enriched uranium is determined by the given initial 235U enrichment using the following equations (Reference 226 p 20)
wt235U =235Uenrichment _ of _ the _ associated _ fuel _ batch Equation 2
wt234U = 0007731times (wt235U )10837 Equation 3
wt236U = 00046times (wt235U ) Equation 4
wt238U =100 minus (wt234U + wt235U + wt236U ) Equation 5
The weight percentages of uran ium isotopes for PWR fuel are ca lculated in Attachm ent II spreadsheet PWR_fuel compxls worksheet BampWassy using Equations 2 through 5
627 PWR Source Terms
This calculation uses the following three PWR source terms bull Maximum source (50 wt initial 235U enrichment 80 GWdMTU burnup and 5-year
decay time) (Reference 229 Section 55) Table 8 lists th e gamma source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Design Basis source (4 0 wt initial 235U enrichment 60 GW dMTU burnup and 10-year decay tim e) (Reference 228 Section 552) Table 9 lists the gamm a source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Average source ( 40 wt initial 235U enrichment 48 GWdMTU burnup and 25-year decay time) (Reference 229 Section 55) Table 10 lists the gamma source terms for the fuel and non-fuel regions and the neutron source term for the fuel region
These sources (ie maximum design basis and av erage) are described in this section For dose rate calculations all the fuel assemblies in a transportation cask are of the sam e characteristics Also gamma radiation source term s for the PWR assem bly are prov ided for the f our assembly regions while neutron source term is only present in the active fuel region Gamma radiation sources in the non-active fuel region are distri buted unif ormly within each source region Gamma and neutron sources in the active fuel re gion are modeled as uni form distributions or with axial source profiles
The PWR gamma and neutron axial source profiles for the active fuel region presented in Table 11 are applied to the active fuel region of all three source terms (ie maximum design basis and average) when appropriate
30
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 8 Gamma and Neutron Sources for the Maximum PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting
Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 594E+11 233E+15 528E+11 379E+11 100E-01 000E+00 100E-01 116E+11 644E+14 609E+10 743E+10 400E-01 805E+07 200E-01 283E+10 522E+14 352E+10 179E+10 900E-01 411E+08 300E-01 141E+09 148E+14 196E+09 891E+08 140E+00 376E+08 400E-01 190E+09 985E+13 586E+09 117E+09 185E+00 276E+08 600E-01 191E+09 153E+15 110E+11 741E+07 300E+00 485E+08 800E-01 435E+09 470E+15 595E+10 237E+09 643E+00 443E+08 100E+00 137E+11 708E+14 803E+09 766E+10 200E+01 393E+07 133E+00 338E+13 455E+14 174E+13 217E+13 Total 211E+09 166E+00 953E+12 130E+14 491E+12 612E+12
--
200E+00 187E+03 144E+12 919E+02 113E+03 250E+00 226E+08 249E+12 116E+08 145E+08 300E+00 351E+05 110E+11 181E+05 225E+05 400E+00 766E-08 139E+10 100E-08 416E-08 500E+00 000E+00 709E+07 000E+00 000E+00 650E+00 000E+00 286E+07 000E+00 000E+00 800E+00 000E+00 558E+06 000E+00 000E+00 100E+01 000E+00 119E+06 000E+00 000E+00
Total 442E+13 113E+16 231E+13 284E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE2R2B14cut bWasteStreamE2R1B14cut cWasteStreamE2R3B14cut dWasteStreamE2R4B14cut
31
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 9 Gamma and Neutron Sources for the Design Basis PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary
(MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 273E+11 121E+15 188E+11 175E+11 100E-01 000E+00 100E-01 528E+10 329E+14 277E+10 339E+10 400E-01 316E+07 200E-01 128E+10 245E+14 117E+10 819E+09 900E-01 161E+08 300E-01 639E+08 713E+13 633E+08 407E+08 140E+00 148E+08 400E-01 850E+08 455E+13 164E+09 533E+08 185E+00 109E+08 600E-01 492E+08 226E+14 269E+10 337E+07 300E+00 191E+08 800E-01 291E+09 237E+15 160E+10 186E+09 643E+00 174E+08 100E+00 540E+09 122E+14 248E+09 341E+09 200E+01 154E+07 133E+00 154E+13 195E+14 797E+12 990E+12 Total 830E+08 166E+00 435E+12 450E+13 225E+12 280E+12
--
200E+00 235E+00 152E+11 149E+02 215E-02 250E+00 103E+08 517E+10 534E+07 664E+07 300E+00 160E+05 379E+09 829E+04 103E+05 400E+00 943E-10 497E+08 155E-10 519E-10 500E+00 000E+00 282E+07 000E+00 000E+00 650E+00 000E+00 113E+07 000E+00 000E+00 800E+00 000E+00 222E+06 000E+00 000E+00 100E+01 000E+00 471E+05 000E+00 000E+00
Total 201E+13 486E+15 105E+13 129E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B11cut bWasteStreamE5R1B11cut cWasteStreamE5R3B11cut dWasteStreamE5R4B11cut
32
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 10 Gamma and Neutron Sources for the Average PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 336E+10 670E+14 186E+10 217E+10 100E-01 00000E+00 100E-01 602E+09 199E+14 314E+09 387E+09 400E-01 748E+06 200E-01 146E+09 126E+14 853E+08 936E+08 900E-01 382E+07 300E-01 730E+07 389E+13 439E+07 469E+07 140E+00 352E+07 400E-01 947E+07 263E+13 716E+07 607E+07 185E+00 261E+07 600E-01 141E+07 205E+13 504E+08 383E+06 300E+00 469E+07 800E-01 208E+09 124E+15 192E+09 144E+09 643E+00 418E+07 100E+00 208E+09 110E+13 164E+09 144E+09 200E+01 365E+06 133E+00 175E+12 295E+13 909E+11 112E+12 Total 199E+08 166E+00 494E+11 513E+12 257E+11 318E+11
--
200E+00 973E-01 675E+10 614E+01 872E-03 250E+00 117E+07 353E+09 609E+06 754E+06 300E+00 182E+04 288E+08 944E+03 117E+04 400E+00 186E-11 198E+07 149E-11 127E-11 500E+00 000E+00 669E+06 000E+00 000E+00 650E+00 000E+00 269E+06 000E+00 000E+00 800E+00 000E+00 527E+05 000E+00 000E+00 100E+01 000E+00 112E+05 000E+00 000E+00
Total 229E+12 237E+15 119E+12 147E+12
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B9cut bWasteStreamE5R1B9cut cWasteStreamE5R3B9cut dWasteStreamE5R4B9cut
33
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 11 Gamma and Neutron Axial Source Profiles for a PWR Assembly
Axial boundaries (From midplane)
(cm)
TOP BOTTOM
Neutron Gamma Ne utron Gamma 000 1554 1117 1554 1117 1143 1537 1114 1571 1120 2286 1521 1111 1588 1123 3429 1504 1108 1605 1126 4572 1486 1104 1622 1129 5715 1464 1100 1636 1131 6858 1438 1095 1648 1133 8001 1401 1088 1657 1135 9144 1350 1078 1654 1134
10287 1277 1063 1625 1129 11430 1165 1039 1554 1117 12573 0998 09995 1414 1091 13716 0769 09365 1172 1041 14859 0492 08375 0816 0951 16002 0220 06850 0402 0797 17145 0046 04625 0092 0551 18288 00 00 00 00
Source Reference 2219 Table S445
34
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
63 MCNP SPECIFIC INPUT
631 Source Probability
A linear radial distribution is used for all gamma and neutron sources The linear radial distribution is sam pled usi ng the built-in power function p(x) = xc a with a = 1 for the radial direction This sampling method results in a uniform source distribution over the area bounded by the outer radius of the source
The source axial distributions are unifor m for all four source regions The a xial uni form xp(x) = c distribution is sampled using the built-in power function a with a = 0 for extent
The energy distribu tions of the gamma and neutron sour ce term s are treated as energ y probabilities and are applied in MCNP5 using SISP cards
632 Dose Rate and Flux Tallies
MCNP5 dose rate calculations feature separate runs for the following calculation types
bull a photon transport calculation for prim ary ga mma contribution to the dose rates fr om photon fluxes
bull a coupled neutronphoton transport calculat ion for neutrons a nd secondary gamma (photons generated by neutron be ing captured) contributions to dose rates from neutron and gamma fluxes
The tally type F2 is us ed in th is d esign ca lculation as f lux estim ators The type F2 tally evaluates the flux averaged over a surface in particlescm2s
To generate dose ra tes in te rms of remhr the FM (tally multiplier ) and DEDF (dose energydose conversion factors) cards are used to en ter the tally multiplier f actor (source intensity in particless) energy boundaries in MeV and corresponding dose conversion factors in (remhr)(particlescm2s) respectively These factors were used in the input files
In order for the F2 tally to accum ulate flux ov er a surface a specific s urface area is requ ired The SD cards are used to enter a surface area in cm2 over which the flux will be tallied for an F2 tally
633 Variance Reduction Techniques
Variance reduction technique is usually em ployed in order to increase the efficiency of a calculation and obtain statistically m eaningful results within re asonable com puter tim e In Monte Carlo calculations when variance reduction scheme is employed the weights of particles are adjusted in order to account for the biasing and to preserve a fair game
Geometry splitting and Russian roulette techniques described in Reference 2224 (pp 2-140 ndash 2-142) are useful in shielding calculations and therefore deployed in all the MCNP5 runs
35
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
As particles migrate in an important direction (toward the detector) they are increased in number to provide better sampling by means of geometry splitting across geometric boundaries Russian roulette (the reverse process) is played when particles travel in an unimportant direction to allow termination of unim portant histories The IMP card required for every cel l ca rd is us ed to implement this technique
The other variance reduction technique deployed in the MC NP5 runs is source intensity biasing for the gamma sources from the four source regions (active fuel bottom end-fitting plenum and top end-fitting) The natural total gamma source intensity of comm ercial SNF is dom inated by the gamma source in the active fuel region This active fuel gamma source usually accounts for over 95 o f the total g amma source intens ity In order to im prove the efficiency of the axial dose rate calculations a biased source probability distribution is employed for the prim ary gamma dose rate calculations The biased gamma source probability distribution is chosen to be 005 080 010 and 005 for the bottom end-fitting the active fuel the plenum and the top end-fitting regions respectively
64 DOSE CONVERSION FACTORS
Project Design Criteria Document (Reference 2211 Se ction 41015) requires the use of flux-to-dose rate conversion fact ors from ANSIANS-611-1977 (Reference 221) for dose rate evaluations Table 16 lists the neutron and ga mma dose conversion factors used in the MCNP5 calculations
Table 12 Gamma and Neutron Flux to Dose Conversion Factors
Gamma Neutron Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
001 396E-06 140 251E-06 250E-08 367E-06 003 582E-07 180 299E-06 100E-07 367E-06 005 290E-07 220 342E-06 100E-06 446E-06 007 258E-07 260 382E-06 100E-05 454E-06 010 283E-07 280 401E-06 100E-04 418E-06 015 379E-07 325 441E-06 100E-03 376E-06 020 501E-07 375 483E-06 100E-02 356E-06 025 631E-07 425 523E-06 100E-01 217E-05 030 759E-07 475 560E-06 500E-01 926E-05 035 878E-07 500 580E-06 100E+00 132E-04 040 985E-07 525 601E-06 250E+00 125E-04 045 108E-06 575 637E-06 500E+00 156E-04 050 117E-06 625 674E-06 700E+00 147E-04 055 127E-06 675 711E-06 100E+01 147E-04 060 136E-06 750 766E-06 140E+01 208E-04 065 144E-06 900 877E-06 200E+01 227E-04 070 152E-06 1100 103E-05 080 168E-06 1300 118E-05 100 198E-06 1500 133E-05
Source Reference 221 Tables 1 and 3
36
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION
By def inition (Ref erence 2224 Equation 219) the estimated st atistic relative error of the i component is
Ri = Si
2
Equation 6Ti
where i = tally component index Ri = relative error of the i component S2
i = variance of the i component Ti = tally i component
For a result (ie dose rate) computed as a sum of different tallies the statistical relative error of the computed value is o btained from the variance of the result - S2
total which is th e sum of the estimated variances of the individual tallies S2
i n
2 2STotal = sum Si Equation 7 i=1
where S2Total = total estimated variance
n = total number of components Therefore the total tally value (dose rate) and the associated relative error are derived according to Equations 8 and 9
n TTotal = sumTi Equation 8
i=1
n n
sum (Ri timesTi )2
2 sum Si 2
STotal = i=1 = i=1 Equation 9RTotal = TTotal TTotal TTotal
where RTotal = total estimated relative error TTotal = total estimated tally
Equations 8 and 9 are utilized in Attachm ent II to ev aluate to tal dos e ra tes and their r elative errors
37
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
7 RESULTS AND CONCLUSIONS
71 RESULTS
The following sections summarize the results of this calculation Section 711 presents results for Conceptual Cask A while Section 712 for Conceptual Cask B Section 713 provides comparisons of the dose-rate reduction factors du e to the two conceptual casks and the axial source distributions in the active fuel region Do se rates and relative errors can be found in Attachment II within the output files and Excel files
711 Dose Rates of Conceptual Cask A
This section presents dose-rate results of the calculation sets 1 and 2 as described in Section 61 for Cask A Set 1 has axial p rofile sources in the active fuel region a nd consist of six runs resulting from the three PWR SNF source term s (maximum design basis and average) and the two radiation sources (gammas and neutrons) Set 2 has uniform axial sources in the active fuel region and consists of six run s r esulting f rom the th ree P WR SNF source term s and th e tw o radiation sources
As described in Section 61 dose ra tes are calculated at the three exterior surfaces (radial top and bottom) and at distances 1 m and 2 m from the exterior surfaces The total dose rates for set 1 are presented in Tables 13 14 and 15 for the ra dial top and bottom dire ctions respectively However the com ponents (primary gamma neutr on and secondary gamma) contributing to the total dose rates as well as the re lative error calculations can be found in Attachment II Excel file MCNP-Results1xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 2 are shown in Tables 16 17 and 18 The dose-rate components and the relative errors can be found in A ttachment II Excel file MCNP-Results2xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 13 and 16 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 14 and 17 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 15 and 18 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carrying th e maximum PWR SNF Based on the results in Tables 13 through 18 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask A indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these 6 tables the d ose-rate red uction f actors between the m aximum and the design basis fuels the maxim um and the averag e fuels and th e design basis and the average fuels are a lso presented
38
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 320E-02 00237 116E-02 00222 262E-03 00219 275 1223 445
1 m 133E-02 00164 494E-03 00171 106E-03 00162 269 1261 468 2 m 749E-03 00198 285E-03 00225 584E-04 00162 263 1282 488
Ring Detectors 1 m 133E-02 00116 492E-03 00115 108E-03 00124 271 1229 454 2 m 756E-03 00118 279E-03 00110 605E-04 00128 271 1250 462
Source Attachment II MCNP-Results1xls worksheet Summary
Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 142E-02 00368 628E-03 00446 934E-04 00483 226 1520 672
1 m 570E-03 00289 263E-03 00426 375E-04 00381 217 1520 701 2 m 265E-03 00364 123E-03 00547 169E-04 00374 216 1575 730
Point Detectors 1 m 598E-03 00238 274E-03 00271 402E-04 00354 219 1489 681 2 m 273E-03 00218 123E-03 00245 180E-04 00336 221 1515 684
Source Attachment II MCNP-Results1xls worksheet Summary
Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 653E-03 00298 265E-03 00276 510E-04 00341 247 1278 518
1 m 276E-03 00238 112E-03 00208 207E-04 00249 248 1334 539 2 m 125E-03 00185 508E-04 00199 933E-05 00246 246 1336 544
Point Detectors 1 m 291E-03 00227 118E-03 00203 218E-04 00242 247 1335 540 2 m 130E-03 00209 524E-04 00187 955E-05 00233 247 1357 549
Source Attachment II MCNP-Results1xls worksheet Summary
Tables 13 14 and 15 are results of calculation set 1 for conceptual Cask A with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
39
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 265E-02 00247 990E-03 00222 215E-03 00278 268 1234 461
1 m 116E-02 00178 468E-03 00549 960E-04 00189 248 1208 488 2 m 713E-03 00273 265E-03 00161 602E-04 00360 269 1184 439
Ring Detectors 1 m 117E-02 00120 454E-03 00132 979E-04 00141 259 1199 463 2 m 722E-03 00130 276E-03 00141 589E-04 00153 261 1226 469
Source Attachment II MCNP-Results2xls worksheet Summary
Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 199E-02 00461 827E-03 00455 147E-03 00536 241 1359 564
1 m 849E-03 00564 323E-03 00314 563E-04 00418 263 1507 574 2 m 415E-03 00832 158E-03 00603 253E-04 00501 263 1641 623
Point Detectors 1 m 877E-03 00348 353E-03 00275 615E-04 00391 248 1426 574 2 m 393E-03 00341 160E-03 00278 270E-04 00378 246 1454 590
Source Attachment II MCNP-Results2xls worksheet Summary
Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 879E-03 00374 356E-03 00333 669E-04 00406 247 1315 533
1 m 365E-03 00223 147E-03 00209 269E-04 00253 248 1358 548 2 m 164E-03 00229 674E-04 00205 120E-04 00248 243 1364 560
Point Detectors 1 m 383E-03 00217 155E-03 00204 285E-04 00248 247 1347 546 2 m 172E-03 00197 689E-04 00186 124E-04 00225 249 1391 558
Source Attachment II MCNP-Results2xls worksheet Summary
Tables 16 17 and 18 ar e results of calculation set 2 for conceptual Cask A with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
40
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
5 LIST OF ATTACHMENTS
Number of Pages Attachment I List of Electronic Files on the CD 3 Attachment II Compact Disc NA
20
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
6 CALCULATIONS
This sectio n provides inform ation necess ary to perform the calcu lations in this docum ent Section 61 describes the configurations the type of CSNF to be analyzed the number of MCNP runs and the locations where dose rates are ca lculated Section 62 provides the calculation input that includes the details of the geom etry m odel radiation source term s and m aterial compositions Input specific to MCNP dose -rate conversion factors and relative error calculation are described in the later sections
61 DESCRIPTION OF CALCULATIONS
Dose rate calculations are perform ed with the MCNP5 version 140 com puter code (Reference 2225) Two conceptual transportation casks Cask A and Cask B (Assum ption 323) are employed Each cask contains a TAD canister that is loaded with 21 ident ical PW R SN F assemblies Three PWR source term s are analy zed they are the source term s corresponding to the maximum design basis and average PW R SN Fs The characteris tics of the P WR source terms are presented in S ection 627 Each PWR source term has neutron and ga mma radiation sources that require separate MCNP5 runs For each radiation source an axial profile source and a uniform source for the active fuel region are considered The uniform source for the active fuel region is included in this calculation because this approach was used in combination with source peaking factors in certain calculations (Reference 2216 Sections 37 and 39 and Reference 2217 Section 5242)
The total number of MCNP5 runs is 24 which re sults from a com bination of two conceptual casks three PWR source terms two radiation sources and two axia l source distributions for the active fuel region These 24 runs are categorized into four calcula tion sets Each calculation set consists of six runs that is a combination of three PWR source te rms and two radiation sources The characteristics of each calculation set are as follows
1 Cask A with axial profile sources in the active fuel region
2 Cask A with uniform axial sources in the active fuel region
3 Cask B with axial profile sources in the active fuel region
4 Cask B with uniform axial sources in the active fuel region
For each MCNP5 run dose rates are calculated at the exte rior surfaces and at distances 1 and 2 meters from the exterior surfaces Surface tallies and detector tallies (ring and point detectors) as indicated in Figure 1 are e mployed in all runs Figure 1 is used to illustrate the dep loyment of the surface and detector tallies re lative to the so urce regions and it should not be interpreted as an exact geometry of any particular run Surface tallies are deployed at all three distances while ring and point detectors are used only at 1 m and 2 m and not at the cask surfaces Using point detectors near a surface or in any scattering media is not recommended because very large scores can occur f rom collisions close ( less than a f ew centimeters) to the point detecto rs that can lead to resu lts with high r elative e rrors thus m aking the ca lculation d ifficult to o btain r eliable answers
21
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
For the radial direction surface tallies at the three distances (contact 1 m and 2 m) are computed for three su rface segments (cylindrical rings) between the planes at Z = 145 175 2 05 and 235 cm The geometric locations of the segments are shown in Figure 1 The axial locations of these segments correspond to the m iddle of the active fuel region of the PWR SNF assemblies The average dose rates for each of the segm ents are calculated for the outside surface and surfaces at 1 m and 2 m from the cask surface Two ring detectors (instead of point detectors) are deployed at 1 m and 2 m for the radial dire ction Ring detectors instead of point detectors are used in order to capitalize on the symm etry around the cask axis thus im proving the efficiency of the calculations
In the axial direction the average d ose rates within three concentric radial surfaces defined by radii of 40 80 and 120 cm (shown in Figure 1) are calculated for the top and bottom surfaces and at distances 1 m and 2 m from these surfaces Finally point detectors at 1 m and 2 m from the top and bottom axial surfaces are employed
22
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Point Detector at 2 m x
Ring Ring Detector Detector at 2 m at 1 m
x x
Z = 00 cm
Z = 145 cm
Z = 175 cm
Z = 205 cm
Z = 235 cm
R = 80 cm
R = 120 cm
R = 40 cm
Active Fuel
Shield Plug
Top End-Fitting Plenum
Bottom End-Fitting
Ring Detector at 1 m
x
Point Detector at 1 m x
Ring Detector
at 2 m x
D = 26797 cm
H =
610
845
cm
Point Detector at 1 m x
Point Detector at 2 m x
Figure 1 Geometry and Tally Scheme for the TAD Transportation Cask
23
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
62 CALCULATION INPUT
Technical product input and sources of the input used in the deve lopment of this calculation are documented in this section Tables in this docum ent and in th e associated Microsoftreg Excel spreadsheets referenced m ay present num erical values with m any significant figures these values are not to be considered as high precision values since the significant figures are results of calculated values andor unit conversions
621 TAD Canister
The TAD canis ter will contain either 21 P WR or 44 BW R (boiling water reactor) SNF assemblies (Reference 2222 Section 321) While the canister design is iden tical for both PWR and BWR SNF assemblies the internal basket structure is different depending on the SNF assemblies However the internal basket stru cture m aterial is no t in cluded in the calcu lation model (Assumption 326)
The TAD canister is a right-circu lar cylinder with a diam eter of 665 in and a height between 186 and 212 in (Reference 2222 Section 321) The average and maximum total dose rates on the top surf ace of a loaded TAD ca nister must not exceed 800 and 1000 m remhr respectively (Reference 2222 Section 314) The TAD canister used in this calculation is m ade of SS 316 with a radial wall and bottom thickness of 025 in (Assumption 321) The top of the canister has a shield plug that is 11 in thick SS 316 (Ass umption 322) A thick shield plug is needed to keep the maxim um contact dose rate of th e top surface below 1000 m remhr The overall dimensions of the TAD canister are provided in Table 3
Table 3 Dimensions of TAD Canister
Component Dimension
(in) (cm)
Maximum heighta 212 53848
Outer diametera 665 16891
Thickness of bottom lidb 025 0635
Shell thicknessb 025 0635
Lifting Featurec 6 1524
Height without Lifting Feature 206 52324
Thickness of shield plugd 110 2794
aReference 2222 Section 311 bAssumption 321 cReference 2222 p Attachment C-1 dAssumption 322
622 Conceptual TAD Transportation Casks
Two conceptual TAD transportation casks designa ted as Cask A and Cask B are em ployed in this calculation (Assumption 323) They both have a cylindrical geometry with dimensions and materials specified in Tables 1 and 2 of Section 323 Cask A will provide shielding to meet the exterior radiation standards of 10 CFR 7147(b) (Reference 231) when loaded with a TAD
24
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
canister car rying the m aximum PWR SNF Cask B will s atisfy th e sa me radiatio n standa rds when loaded with a TAD canister c arrying the average PWR SNF The reason to analyze both Casks A and B is to cover a broad range of characteristics of the CSNF
The cavity dimensions of the conceptual cask s are 53785 cm (21175 in) in height and 16891 cm (665 in) in diam eter (Tab les 1 and 2) This cav ity will accommoda te the TAD canister described in Table 3 without the lifting feature This is the geometry model used in the MCNP5 calculations
623 Fuel Assembly Selection
PWR and BWR Source Term Sensitivity Study (Reference 2211 Tables 71 through 84) shows that the source terms generated for the Bamp W 15x15 Mark B fuel assembly with 475 kg uranium loading bound the source terms of other PWR assembly types ther efore this assembly type is selected as the representative PWR fuel assembly The gamma and neutron source terms for the BampW 15x15 Mark B assembly are generated in PWR Source Term Generation and Evaluation (Reference 229) and are used in this calculation
624 BampW 15x15 Mark B PWR Fuel Assembly
BampW 15x15 Mark B fuel assembly consists of four regions top end-fitting plenum active fuel and bottom end-fitting The m aterials and ra diation sources of each assem bly region are homogenized inside a volume defined by the region height and the interior diam eter of the TAD canister (Assumption 325) The active fuel region is homogenized with fresh unirradiated fuel (Assumption 324) Since the internal structure (i e basket) design of t he TAD is currently not finalized the com position of the hom ogenized fuel does not include the basket m aterials (Assumption 326) and therefore does not take cred it for any shielding that these m aterials may provide
Table 4 provides the design param eters for the BampW 15x15 Mark B fuel assembly Data provided here are used in Attachment II PWR_fuel compxls worksheet BampWassy
25
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 4 BampW 15x15 Mark B Fuel Assembly Description
Component Material Characteristic Value Specific Reference Array Size 15 x 15
Reference 2227 Table 2-2 Fuel Pins Assembly 208 Guide Tubes Assembly 16 Instrument Tubes Assembly 1
Assembly NA Pin Pellet Diameter 0936244 cm (03686 in) Reference 2220 p 2A-34 Pin Pitch 144272 cm (0568 in)
Reference 2227 Table 2-2 Active Fuel Height 360172 cm (1418 in) Assembly Width 2168144 cm (8536 in)
Reference 2220 p 2A-31 Assembly Height 4206875 cm (165625 in) Mass U assembly 46363 kg
Guide tube Zircaloy-4 Outer Diameter 13462 cm (053 in)
Reference 2227 Table 2-2
Inner Diameter 126492 cm (0498 in)
Instrument tube Zircaloy-4 Outer Diameter 138193 cm (05441 in) Inner Diameter 112014 cm (0441 in)
Cladding` Zircaloy-4 Inner Diameter 095758 cm (0377 in) Outer Diameter 10922 cm (043 in)
Plenum region NA Length 297688 cm (11720 in) Reference 2220 p 2A-34 Top nozzle SS CF3M MassAssembly (Top) 748 kg
Reference 2220 p 2A-32
Bottom nozzle SS CF3M MassAssembly (Bottom) 816 kg Guide tubes Zircaloy-4 MassAssembly (in Core) 80 kg Instrument tube Zircaloy-4 MassAssembly (in Core) 064 kg Spacer-plenum Inconel-718 MassAssembly (Plenum) 104 kg Spacer-bottom Inconel-718 MassAssembly (Bottom) 13 kg Spacer-in core Inconel-718 MassAssembly (in Core) 49 kg Spring retainer SS CF3M MassAssembly (Top) 091 kg Holddown spring Inconel-718 MassAssembly (Top) 18 kg Upper end plug SS 304 MassAssembly (Top) 006 kg Upper nut SS 304L MassAssembly (Top) 051 kg Lower nut SS 304 MassAssembly (Bottom) 015 kg Grid supports Zircaloy-4 MassAssembly (in Core) 064 kg Plenum spring SS 302 MassAssembly (Plenum) 0042 lb (001905 kg) Reference 2220 p 2A-34
Note Som e d ata i n this tab le ar e given i n British u nits in th e r eferences thes e d ata ar e converted into metric units as the inputs to MCNP5 are in metric units
The assem bly region heights as m odeled in MC NP are presented in Table 5 utilizing values from Table 4 Table 5 is taken from Dose Rate Calculation for Exhaust Main Drifts (Reference 2213 Table 3)
26
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 5 PWR Fuel Assembly Regions
Component Height Reference
Plenum 297688 cm (11720 in) Reference 2220 p 2A-34
Active Fuel 360172 cm (1418 in) Table 3
Bottom End-Fitting 1077 cm (424 in) Calculateda
Top End-Fitting 1998 cm (787 in) Calculatedb
Source Reference 2213 Table 3 aCalculated b ased on data Reference 2227 F igures 2-3 an d 2-7
(Region 9 Height [16723 cm] + Region 10 Height [508 cm] ndash Lo wer Fuel Plenum and End Cap [11033 cm])
bCalculated (Assembly Length ndash Active Fuel Length ndash P lenum Length ndash Bottom End-fitting Length)
625 Material Compositions
The TAD transportation cask com ponent m aterial specifications are defined in Table 1 The TAD canister is constructed of SS 316 (Assumpti on 321) The PWR fuel assembly materials used to homogenize the fuel regions are defined in Table 4 Table 6 c ontains the m aterial compositions defining the TAD canister WP and fuel assemblies
27
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 6 Chemical Compositions of Materials
Material Density (gcc)
Isotopic Weight Percent Reference
SS 302 NA
C 0150 Mn 2000 P 0045 S 0030 Si 0750 Cr 18000 Ni 9000 N 0100 Fe 69925
Attachment II PWR_fuel compxls worksheet ferrous Reference 222 SEC II A SA-240 Table 1 for SS 302 SS 304 and SS 304L Reference 222 SEC II A SA-351SA -351M Table 2 for SS CF3M
SS 304 NA
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 9250 N 0100 Fe 68745
SS 304L NA
C 003 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 10000 N 0100 Fe 6804 5
SS CF3M NA
C 0030 Mn 1500 P 0040 S 0040 Si 1500 Cr 19000 Ni 11000 Mo 2500 Fe 64390
Inconel 718 NA
C 0080 Mn 0350 Si 0350 Cr 19000 Ni 52500 Co 1000 Mo 3050 Fe 16809 Nb 5125 Ti 0900 Al 0500 Cu 0300 S 0015 P 0015 B 0006
Attachment II PWR_fuel compxls worksheet alloys aReference 223 p 666 Table 6 Reference 222 SEC II B SB-637 Table 1 for Inconel 718 Reference 224 Table 2 for Zircaloy 4
Zircaloy 4 656a Cr 0100 Fe 0210 O 0125 Sn 1450 Zr 98115
SS 316 798b
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 17000 Ni 12000 Mo 2500 N 0100 Fe 65495
Attachment II PWR_fuel compxls worksheet others Reference 222 SEC II A SA-240 Table 1 for SS 316 bReference 225 Table X1
626 Homogenization Assembly Materials
The atom density of an element or isotope in atomsbmiddotcm in a homogenized region is calculated according to the following equation (Reference 2223 Appendix B)
M i times N AvogadroNi = Equation 1 Ai timesV times K
where Ni = Atom density of elementisotope i (atomsbmiddotcm) Mi = Mass of elementisotope i (g) NAvogadro = Avogadrorsquos constant 06022 x 1024 (atomsmole)
28
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Ai = Atomic weight of elementisotope i (gmole) V = Homogenization volume (cm3) K = Unit transformation constant = 1024 (bmiddotcmcm3)
Equation 1 is used in A ttachment II spreadsheet PWR_fuel compxls worksheet BampWassy to calculate th e atom dens ities for v arious elem ents and iso topes The m ass of elementsisotop es and Avogadrorsquos constant are provided in Reference 2226
Table 7 lists the com position of the hom ogenized assem bly regions (active fuel plenum top end-fitting and bottom end-fitting) for the PWR assembly The active fuel region contains fresh unirradiated fuel (Assumption 324) Since the internal structure (ie basket) design of the TAD is currently not finalized the composition of either homogenized fuel does not include the basket materials and therefore does not tak e credit for any shielding that thes e materials may provide (Assumption 326)
Table 7 Isotopic Compositions of Homogenized PWR Assembly Regions
Element Isotope
Atom Densities for Homogenized Regions (atomsbsdotcm)
Active Fuel Bottom End-Fitting Plenum Top End-Fitting
10B 861E-09 764E-08 221E-08 570E-08 11B 347E-08 307E-07 890E-08 230E-07 C 519E-07 160E-05 138E-06 993E-06 N -- 570E-07 262E-08 117E-06 O 621E-03 -- 142E-05 -- Al 144E-06 128E-05 371E-06 957E-06 Si 971E-07 243E-04 259E-06 139E-04 P 377E-08 606E-06 102E-07 360E-06 S 365E-08 581E-06 971E-08 340E-06 Ti 147E-06 130E-05 376E-06 971E-06 Cr 320E-05 187E-03 779E-05 113E-03 Mn 497E-07 126E-04 141E-06 749E-05 Fe 303E-05 531E-03 717E-05 313E-03 Co 132E-06 117E-05 340E-06 876E-06 Ni 697E-05 144E-03 180E-04 940E-04 Cu 368E-07 327E-06 945E-07 244E-06 Zr 196E-03 -- 195E-03 -- Nb 430E-06 382E-05 110E-05 285E-05 Mo 248E-06 135E-04 636E-06 791E-05 Sn 223E-05 -- 222E-05 -- 234U 139E-06 -- -- -- 235U 157E-04 -- -- -- 236U 719E-07 -- -- -- 238U 294E-03 -- -- -- Total 114E-02 924E-03 235E-03 557E-03
Source Attachment II spreadsheet PWR_fuel compxls worksheet BampWassy
29
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
The isotopic composition of commercially available 235U enriched uranium is determined by the given initial 235U enrichment using the following equations (Reference 226 p 20)
wt235U =235Uenrichment _ of _ the _ associated _ fuel _ batch Equation 2
wt234U = 0007731times (wt235U )10837 Equation 3
wt236U = 00046times (wt235U ) Equation 4
wt238U =100 minus (wt234U + wt235U + wt236U ) Equation 5
The weight percentages of uran ium isotopes for PWR fuel are ca lculated in Attachm ent II spreadsheet PWR_fuel compxls worksheet BampWassy using Equations 2 through 5
627 PWR Source Terms
This calculation uses the following three PWR source terms bull Maximum source (50 wt initial 235U enrichment 80 GWdMTU burnup and 5-year
decay time) (Reference 229 Section 55) Table 8 lists th e gamma source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Design Basis source (4 0 wt initial 235U enrichment 60 GW dMTU burnup and 10-year decay tim e) (Reference 228 Section 552) Table 9 lists the gamm a source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Average source ( 40 wt initial 235U enrichment 48 GWdMTU burnup and 25-year decay time) (Reference 229 Section 55) Table 10 lists the gamma source terms for the fuel and non-fuel regions and the neutron source term for the fuel region
These sources (ie maximum design basis and av erage) are described in this section For dose rate calculations all the fuel assemblies in a transportation cask are of the sam e characteristics Also gamma radiation source term s for the PWR assem bly are prov ided for the f our assembly regions while neutron source term is only present in the active fuel region Gamma radiation sources in the non-active fuel region are distri buted unif ormly within each source region Gamma and neutron sources in the active fuel re gion are modeled as uni form distributions or with axial source profiles
The PWR gamma and neutron axial source profiles for the active fuel region presented in Table 11 are applied to the active fuel region of all three source terms (ie maximum design basis and average) when appropriate
30
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 8 Gamma and Neutron Sources for the Maximum PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting
Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 594E+11 233E+15 528E+11 379E+11 100E-01 000E+00 100E-01 116E+11 644E+14 609E+10 743E+10 400E-01 805E+07 200E-01 283E+10 522E+14 352E+10 179E+10 900E-01 411E+08 300E-01 141E+09 148E+14 196E+09 891E+08 140E+00 376E+08 400E-01 190E+09 985E+13 586E+09 117E+09 185E+00 276E+08 600E-01 191E+09 153E+15 110E+11 741E+07 300E+00 485E+08 800E-01 435E+09 470E+15 595E+10 237E+09 643E+00 443E+08 100E+00 137E+11 708E+14 803E+09 766E+10 200E+01 393E+07 133E+00 338E+13 455E+14 174E+13 217E+13 Total 211E+09 166E+00 953E+12 130E+14 491E+12 612E+12
--
200E+00 187E+03 144E+12 919E+02 113E+03 250E+00 226E+08 249E+12 116E+08 145E+08 300E+00 351E+05 110E+11 181E+05 225E+05 400E+00 766E-08 139E+10 100E-08 416E-08 500E+00 000E+00 709E+07 000E+00 000E+00 650E+00 000E+00 286E+07 000E+00 000E+00 800E+00 000E+00 558E+06 000E+00 000E+00 100E+01 000E+00 119E+06 000E+00 000E+00
Total 442E+13 113E+16 231E+13 284E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE2R2B14cut bWasteStreamE2R1B14cut cWasteStreamE2R3B14cut dWasteStreamE2R4B14cut
31
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 9 Gamma and Neutron Sources for the Design Basis PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary
(MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 273E+11 121E+15 188E+11 175E+11 100E-01 000E+00 100E-01 528E+10 329E+14 277E+10 339E+10 400E-01 316E+07 200E-01 128E+10 245E+14 117E+10 819E+09 900E-01 161E+08 300E-01 639E+08 713E+13 633E+08 407E+08 140E+00 148E+08 400E-01 850E+08 455E+13 164E+09 533E+08 185E+00 109E+08 600E-01 492E+08 226E+14 269E+10 337E+07 300E+00 191E+08 800E-01 291E+09 237E+15 160E+10 186E+09 643E+00 174E+08 100E+00 540E+09 122E+14 248E+09 341E+09 200E+01 154E+07 133E+00 154E+13 195E+14 797E+12 990E+12 Total 830E+08 166E+00 435E+12 450E+13 225E+12 280E+12
--
200E+00 235E+00 152E+11 149E+02 215E-02 250E+00 103E+08 517E+10 534E+07 664E+07 300E+00 160E+05 379E+09 829E+04 103E+05 400E+00 943E-10 497E+08 155E-10 519E-10 500E+00 000E+00 282E+07 000E+00 000E+00 650E+00 000E+00 113E+07 000E+00 000E+00 800E+00 000E+00 222E+06 000E+00 000E+00 100E+01 000E+00 471E+05 000E+00 000E+00
Total 201E+13 486E+15 105E+13 129E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B11cut bWasteStreamE5R1B11cut cWasteStreamE5R3B11cut dWasteStreamE5R4B11cut
32
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 10 Gamma and Neutron Sources for the Average PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 336E+10 670E+14 186E+10 217E+10 100E-01 00000E+00 100E-01 602E+09 199E+14 314E+09 387E+09 400E-01 748E+06 200E-01 146E+09 126E+14 853E+08 936E+08 900E-01 382E+07 300E-01 730E+07 389E+13 439E+07 469E+07 140E+00 352E+07 400E-01 947E+07 263E+13 716E+07 607E+07 185E+00 261E+07 600E-01 141E+07 205E+13 504E+08 383E+06 300E+00 469E+07 800E-01 208E+09 124E+15 192E+09 144E+09 643E+00 418E+07 100E+00 208E+09 110E+13 164E+09 144E+09 200E+01 365E+06 133E+00 175E+12 295E+13 909E+11 112E+12 Total 199E+08 166E+00 494E+11 513E+12 257E+11 318E+11
--
200E+00 973E-01 675E+10 614E+01 872E-03 250E+00 117E+07 353E+09 609E+06 754E+06 300E+00 182E+04 288E+08 944E+03 117E+04 400E+00 186E-11 198E+07 149E-11 127E-11 500E+00 000E+00 669E+06 000E+00 000E+00 650E+00 000E+00 269E+06 000E+00 000E+00 800E+00 000E+00 527E+05 000E+00 000E+00 100E+01 000E+00 112E+05 000E+00 000E+00
Total 229E+12 237E+15 119E+12 147E+12
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B9cut bWasteStreamE5R1B9cut cWasteStreamE5R3B9cut dWasteStreamE5R4B9cut
33
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 11 Gamma and Neutron Axial Source Profiles for a PWR Assembly
Axial boundaries (From midplane)
(cm)
TOP BOTTOM
Neutron Gamma Ne utron Gamma 000 1554 1117 1554 1117 1143 1537 1114 1571 1120 2286 1521 1111 1588 1123 3429 1504 1108 1605 1126 4572 1486 1104 1622 1129 5715 1464 1100 1636 1131 6858 1438 1095 1648 1133 8001 1401 1088 1657 1135 9144 1350 1078 1654 1134
10287 1277 1063 1625 1129 11430 1165 1039 1554 1117 12573 0998 09995 1414 1091 13716 0769 09365 1172 1041 14859 0492 08375 0816 0951 16002 0220 06850 0402 0797 17145 0046 04625 0092 0551 18288 00 00 00 00
Source Reference 2219 Table S445
34
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
63 MCNP SPECIFIC INPUT
631 Source Probability
A linear radial distribution is used for all gamma and neutron sources The linear radial distribution is sam pled usi ng the built-in power function p(x) = xc a with a = 1 for the radial direction This sampling method results in a uniform source distribution over the area bounded by the outer radius of the source
The source axial distributions are unifor m for all four source regions The a xial uni form xp(x) = c distribution is sampled using the built-in power function a with a = 0 for extent
The energy distribu tions of the gamma and neutron sour ce term s are treated as energ y probabilities and are applied in MCNP5 using SISP cards
632 Dose Rate and Flux Tallies
MCNP5 dose rate calculations feature separate runs for the following calculation types
bull a photon transport calculation for prim ary ga mma contribution to the dose rates fr om photon fluxes
bull a coupled neutronphoton transport calculat ion for neutrons a nd secondary gamma (photons generated by neutron be ing captured) contributions to dose rates from neutron and gamma fluxes
The tally type F2 is us ed in th is d esign ca lculation as f lux estim ators The type F2 tally evaluates the flux averaged over a surface in particlescm2s
To generate dose ra tes in te rms of remhr the FM (tally multiplier ) and DEDF (dose energydose conversion factors) cards are used to en ter the tally multiplier f actor (source intensity in particless) energy boundaries in MeV and corresponding dose conversion factors in (remhr)(particlescm2s) respectively These factors were used in the input files
In order for the F2 tally to accum ulate flux ov er a surface a specific s urface area is requ ired The SD cards are used to enter a surface area in cm2 over which the flux will be tallied for an F2 tally
633 Variance Reduction Techniques
Variance reduction technique is usually em ployed in order to increase the efficiency of a calculation and obtain statistically m eaningful results within re asonable com puter tim e In Monte Carlo calculations when variance reduction scheme is employed the weights of particles are adjusted in order to account for the biasing and to preserve a fair game
Geometry splitting and Russian roulette techniques described in Reference 2224 (pp 2-140 ndash 2-142) are useful in shielding calculations and therefore deployed in all the MCNP5 runs
35
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
As particles migrate in an important direction (toward the detector) they are increased in number to provide better sampling by means of geometry splitting across geometric boundaries Russian roulette (the reverse process) is played when particles travel in an unimportant direction to allow termination of unim portant histories The IMP card required for every cel l ca rd is us ed to implement this technique
The other variance reduction technique deployed in the MC NP5 runs is source intensity biasing for the gamma sources from the four source regions (active fuel bottom end-fitting plenum and top end-fitting) The natural total gamma source intensity of comm ercial SNF is dom inated by the gamma source in the active fuel region This active fuel gamma source usually accounts for over 95 o f the total g amma source intens ity In order to im prove the efficiency of the axial dose rate calculations a biased source probability distribution is employed for the prim ary gamma dose rate calculations The biased gamma source probability distribution is chosen to be 005 080 010 and 005 for the bottom end-fitting the active fuel the plenum and the top end-fitting regions respectively
64 DOSE CONVERSION FACTORS
Project Design Criteria Document (Reference 2211 Se ction 41015) requires the use of flux-to-dose rate conversion fact ors from ANSIANS-611-1977 (Reference 221) for dose rate evaluations Table 16 lists the neutron and ga mma dose conversion factors used in the MCNP5 calculations
Table 12 Gamma and Neutron Flux to Dose Conversion Factors
Gamma Neutron Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
001 396E-06 140 251E-06 250E-08 367E-06 003 582E-07 180 299E-06 100E-07 367E-06 005 290E-07 220 342E-06 100E-06 446E-06 007 258E-07 260 382E-06 100E-05 454E-06 010 283E-07 280 401E-06 100E-04 418E-06 015 379E-07 325 441E-06 100E-03 376E-06 020 501E-07 375 483E-06 100E-02 356E-06 025 631E-07 425 523E-06 100E-01 217E-05 030 759E-07 475 560E-06 500E-01 926E-05 035 878E-07 500 580E-06 100E+00 132E-04 040 985E-07 525 601E-06 250E+00 125E-04 045 108E-06 575 637E-06 500E+00 156E-04 050 117E-06 625 674E-06 700E+00 147E-04 055 127E-06 675 711E-06 100E+01 147E-04 060 136E-06 750 766E-06 140E+01 208E-04 065 144E-06 900 877E-06 200E+01 227E-04 070 152E-06 1100 103E-05 080 168E-06 1300 118E-05 100 198E-06 1500 133E-05
Source Reference 221 Tables 1 and 3
36
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION
By def inition (Ref erence 2224 Equation 219) the estimated st atistic relative error of the i component is
Ri = Si
2
Equation 6Ti
where i = tally component index Ri = relative error of the i component S2
i = variance of the i component Ti = tally i component
For a result (ie dose rate) computed as a sum of different tallies the statistical relative error of the computed value is o btained from the variance of the result - S2
total which is th e sum of the estimated variances of the individual tallies S2
i n
2 2STotal = sum Si Equation 7 i=1
where S2Total = total estimated variance
n = total number of components Therefore the total tally value (dose rate) and the associated relative error are derived according to Equations 8 and 9
n TTotal = sumTi Equation 8
i=1
n n
sum (Ri timesTi )2
2 sum Si 2
STotal = i=1 = i=1 Equation 9RTotal = TTotal TTotal TTotal
where RTotal = total estimated relative error TTotal = total estimated tally
Equations 8 and 9 are utilized in Attachm ent II to ev aluate to tal dos e ra tes and their r elative errors
37
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
7 RESULTS AND CONCLUSIONS
71 RESULTS
The following sections summarize the results of this calculation Section 711 presents results for Conceptual Cask A while Section 712 for Conceptual Cask B Section 713 provides comparisons of the dose-rate reduction factors du e to the two conceptual casks and the axial source distributions in the active fuel region Do se rates and relative errors can be found in Attachment II within the output files and Excel files
711 Dose Rates of Conceptual Cask A
This section presents dose-rate results of the calculation sets 1 and 2 as described in Section 61 for Cask A Set 1 has axial p rofile sources in the active fuel region a nd consist of six runs resulting from the three PWR SNF source term s (maximum design basis and average) and the two radiation sources (gammas and neutrons) Set 2 has uniform axial sources in the active fuel region and consists of six run s r esulting f rom the th ree P WR SNF source term s and th e tw o radiation sources
As described in Section 61 dose ra tes are calculated at the three exterior surfaces (radial top and bottom) and at distances 1 m and 2 m from the exterior surfaces The total dose rates for set 1 are presented in Tables 13 14 and 15 for the ra dial top and bottom dire ctions respectively However the com ponents (primary gamma neutr on and secondary gamma) contributing to the total dose rates as well as the re lative error calculations can be found in Attachment II Excel file MCNP-Results1xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 2 are shown in Tables 16 17 and 18 The dose-rate components and the relative errors can be found in A ttachment II Excel file MCNP-Results2xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 13 and 16 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 14 and 17 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 15 and 18 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carrying th e maximum PWR SNF Based on the results in Tables 13 through 18 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask A indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these 6 tables the d ose-rate red uction f actors between the m aximum and the design basis fuels the maxim um and the averag e fuels and th e design basis and the average fuels are a lso presented
38
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 320E-02 00237 116E-02 00222 262E-03 00219 275 1223 445
1 m 133E-02 00164 494E-03 00171 106E-03 00162 269 1261 468 2 m 749E-03 00198 285E-03 00225 584E-04 00162 263 1282 488
Ring Detectors 1 m 133E-02 00116 492E-03 00115 108E-03 00124 271 1229 454 2 m 756E-03 00118 279E-03 00110 605E-04 00128 271 1250 462
Source Attachment II MCNP-Results1xls worksheet Summary
Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 142E-02 00368 628E-03 00446 934E-04 00483 226 1520 672
1 m 570E-03 00289 263E-03 00426 375E-04 00381 217 1520 701 2 m 265E-03 00364 123E-03 00547 169E-04 00374 216 1575 730
Point Detectors 1 m 598E-03 00238 274E-03 00271 402E-04 00354 219 1489 681 2 m 273E-03 00218 123E-03 00245 180E-04 00336 221 1515 684
Source Attachment II MCNP-Results1xls worksheet Summary
Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 653E-03 00298 265E-03 00276 510E-04 00341 247 1278 518
1 m 276E-03 00238 112E-03 00208 207E-04 00249 248 1334 539 2 m 125E-03 00185 508E-04 00199 933E-05 00246 246 1336 544
Point Detectors 1 m 291E-03 00227 118E-03 00203 218E-04 00242 247 1335 540 2 m 130E-03 00209 524E-04 00187 955E-05 00233 247 1357 549
Source Attachment II MCNP-Results1xls worksheet Summary
Tables 13 14 and 15 are results of calculation set 1 for conceptual Cask A with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
39
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 265E-02 00247 990E-03 00222 215E-03 00278 268 1234 461
1 m 116E-02 00178 468E-03 00549 960E-04 00189 248 1208 488 2 m 713E-03 00273 265E-03 00161 602E-04 00360 269 1184 439
Ring Detectors 1 m 117E-02 00120 454E-03 00132 979E-04 00141 259 1199 463 2 m 722E-03 00130 276E-03 00141 589E-04 00153 261 1226 469
Source Attachment II MCNP-Results2xls worksheet Summary
Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 199E-02 00461 827E-03 00455 147E-03 00536 241 1359 564
1 m 849E-03 00564 323E-03 00314 563E-04 00418 263 1507 574 2 m 415E-03 00832 158E-03 00603 253E-04 00501 263 1641 623
Point Detectors 1 m 877E-03 00348 353E-03 00275 615E-04 00391 248 1426 574 2 m 393E-03 00341 160E-03 00278 270E-04 00378 246 1454 590
Source Attachment II MCNP-Results2xls worksheet Summary
Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 879E-03 00374 356E-03 00333 669E-04 00406 247 1315 533
1 m 365E-03 00223 147E-03 00209 269E-04 00253 248 1358 548 2 m 164E-03 00229 674E-04 00205 120E-04 00248 243 1364 560
Point Detectors 1 m 383E-03 00217 155E-03 00204 285E-04 00248 247 1347 546 2 m 172E-03 00197 689E-04 00186 124E-04 00225 249 1391 558
Source Attachment II MCNP-Results2xls worksheet Summary
Tables 16 17 and 18 ar e results of calculation set 2 for conceptual Cask A with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
40
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
6 CALCULATIONS
This sectio n provides inform ation necess ary to perform the calcu lations in this docum ent Section 61 describes the configurations the type of CSNF to be analyzed the number of MCNP runs and the locations where dose rates are ca lculated Section 62 provides the calculation input that includes the details of the geom etry m odel radiation source term s and m aterial compositions Input specific to MCNP dose -rate conversion factors and relative error calculation are described in the later sections
61 DESCRIPTION OF CALCULATIONS
Dose rate calculations are perform ed with the MCNP5 version 140 com puter code (Reference 2225) Two conceptual transportation casks Cask A and Cask B (Assum ption 323) are employed Each cask contains a TAD canister that is loaded with 21 ident ical PW R SN F assemblies Three PWR source term s are analy zed they are the source term s corresponding to the maximum design basis and average PW R SN Fs The characteris tics of the P WR source terms are presented in S ection 627 Each PWR source term has neutron and ga mma radiation sources that require separate MCNP5 runs For each radiation source an axial profile source and a uniform source for the active fuel region are considered The uniform source for the active fuel region is included in this calculation because this approach was used in combination with source peaking factors in certain calculations (Reference 2216 Sections 37 and 39 and Reference 2217 Section 5242)
The total number of MCNP5 runs is 24 which re sults from a com bination of two conceptual casks three PWR source terms two radiation sources and two axia l source distributions for the active fuel region These 24 runs are categorized into four calcula tion sets Each calculation set consists of six runs that is a combination of three PWR source te rms and two radiation sources The characteristics of each calculation set are as follows
1 Cask A with axial profile sources in the active fuel region
2 Cask A with uniform axial sources in the active fuel region
3 Cask B with axial profile sources in the active fuel region
4 Cask B with uniform axial sources in the active fuel region
For each MCNP5 run dose rates are calculated at the exte rior surfaces and at distances 1 and 2 meters from the exterior surfaces Surface tallies and detector tallies (ring and point detectors) as indicated in Figure 1 are e mployed in all runs Figure 1 is used to illustrate the dep loyment of the surface and detector tallies re lative to the so urce regions and it should not be interpreted as an exact geometry of any particular run Surface tallies are deployed at all three distances while ring and point detectors are used only at 1 m and 2 m and not at the cask surfaces Using point detectors near a surface or in any scattering media is not recommended because very large scores can occur f rom collisions close ( less than a f ew centimeters) to the point detecto rs that can lead to resu lts with high r elative e rrors thus m aking the ca lculation d ifficult to o btain r eliable answers
21
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
For the radial direction surface tallies at the three distances (contact 1 m and 2 m) are computed for three su rface segments (cylindrical rings) between the planes at Z = 145 175 2 05 and 235 cm The geometric locations of the segments are shown in Figure 1 The axial locations of these segments correspond to the m iddle of the active fuel region of the PWR SNF assemblies The average dose rates for each of the segm ents are calculated for the outside surface and surfaces at 1 m and 2 m from the cask surface Two ring detectors (instead of point detectors) are deployed at 1 m and 2 m for the radial dire ction Ring detectors instead of point detectors are used in order to capitalize on the symm etry around the cask axis thus im proving the efficiency of the calculations
In the axial direction the average d ose rates within three concentric radial surfaces defined by radii of 40 80 and 120 cm (shown in Figure 1) are calculated for the top and bottom surfaces and at distances 1 m and 2 m from these surfaces Finally point detectors at 1 m and 2 m from the top and bottom axial surfaces are employed
22
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Point Detector at 2 m x
Ring Ring Detector Detector at 2 m at 1 m
x x
Z = 00 cm
Z = 145 cm
Z = 175 cm
Z = 205 cm
Z = 235 cm
R = 80 cm
R = 120 cm
R = 40 cm
Active Fuel
Shield Plug
Top End-Fitting Plenum
Bottom End-Fitting
Ring Detector at 1 m
x
Point Detector at 1 m x
Ring Detector
at 2 m x
D = 26797 cm
H =
610
845
cm
Point Detector at 1 m x
Point Detector at 2 m x
Figure 1 Geometry and Tally Scheme for the TAD Transportation Cask
23
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
62 CALCULATION INPUT
Technical product input and sources of the input used in the deve lopment of this calculation are documented in this section Tables in this docum ent and in th e associated Microsoftreg Excel spreadsheets referenced m ay present num erical values with m any significant figures these values are not to be considered as high precision values since the significant figures are results of calculated values andor unit conversions
621 TAD Canister
The TAD canis ter will contain either 21 P WR or 44 BW R (boiling water reactor) SNF assemblies (Reference 2222 Section 321) While the canister design is iden tical for both PWR and BWR SNF assemblies the internal basket structure is different depending on the SNF assemblies However the internal basket stru cture m aterial is no t in cluded in the calcu lation model (Assumption 326)
The TAD canister is a right-circu lar cylinder with a diam eter of 665 in and a height between 186 and 212 in (Reference 2222 Section 321) The average and maximum total dose rates on the top surf ace of a loaded TAD ca nister must not exceed 800 and 1000 m remhr respectively (Reference 2222 Section 314) The TAD canister used in this calculation is m ade of SS 316 with a radial wall and bottom thickness of 025 in (Assumption 321) The top of the canister has a shield plug that is 11 in thick SS 316 (Ass umption 322) A thick shield plug is needed to keep the maxim um contact dose rate of th e top surface below 1000 m remhr The overall dimensions of the TAD canister are provided in Table 3
Table 3 Dimensions of TAD Canister
Component Dimension
(in) (cm)
Maximum heighta 212 53848
Outer diametera 665 16891
Thickness of bottom lidb 025 0635
Shell thicknessb 025 0635
Lifting Featurec 6 1524
Height without Lifting Feature 206 52324
Thickness of shield plugd 110 2794
aReference 2222 Section 311 bAssumption 321 cReference 2222 p Attachment C-1 dAssumption 322
622 Conceptual TAD Transportation Casks
Two conceptual TAD transportation casks designa ted as Cask A and Cask B are em ployed in this calculation (Assumption 323) They both have a cylindrical geometry with dimensions and materials specified in Tables 1 and 2 of Section 323 Cask A will provide shielding to meet the exterior radiation standards of 10 CFR 7147(b) (Reference 231) when loaded with a TAD
24
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
canister car rying the m aximum PWR SNF Cask B will s atisfy th e sa me radiatio n standa rds when loaded with a TAD canister c arrying the average PWR SNF The reason to analyze both Casks A and B is to cover a broad range of characteristics of the CSNF
The cavity dimensions of the conceptual cask s are 53785 cm (21175 in) in height and 16891 cm (665 in) in diam eter (Tab les 1 and 2) This cav ity will accommoda te the TAD canister described in Table 3 without the lifting feature This is the geometry model used in the MCNP5 calculations
623 Fuel Assembly Selection
PWR and BWR Source Term Sensitivity Study (Reference 2211 Tables 71 through 84) shows that the source terms generated for the Bamp W 15x15 Mark B fuel assembly with 475 kg uranium loading bound the source terms of other PWR assembly types ther efore this assembly type is selected as the representative PWR fuel assembly The gamma and neutron source terms for the BampW 15x15 Mark B assembly are generated in PWR Source Term Generation and Evaluation (Reference 229) and are used in this calculation
624 BampW 15x15 Mark B PWR Fuel Assembly
BampW 15x15 Mark B fuel assembly consists of four regions top end-fitting plenum active fuel and bottom end-fitting The m aterials and ra diation sources of each assem bly region are homogenized inside a volume defined by the region height and the interior diam eter of the TAD canister (Assumption 325) The active fuel region is homogenized with fresh unirradiated fuel (Assumption 324) Since the internal structure (i e basket) design of t he TAD is currently not finalized the com position of the hom ogenized fuel does not include the basket m aterials (Assumption 326) and therefore does not take cred it for any shielding that these m aterials may provide
Table 4 provides the design param eters for the BampW 15x15 Mark B fuel assembly Data provided here are used in Attachment II PWR_fuel compxls worksheet BampWassy
25
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 4 BampW 15x15 Mark B Fuel Assembly Description
Component Material Characteristic Value Specific Reference Array Size 15 x 15
Reference 2227 Table 2-2 Fuel Pins Assembly 208 Guide Tubes Assembly 16 Instrument Tubes Assembly 1
Assembly NA Pin Pellet Diameter 0936244 cm (03686 in) Reference 2220 p 2A-34 Pin Pitch 144272 cm (0568 in)
Reference 2227 Table 2-2 Active Fuel Height 360172 cm (1418 in) Assembly Width 2168144 cm (8536 in)
Reference 2220 p 2A-31 Assembly Height 4206875 cm (165625 in) Mass U assembly 46363 kg
Guide tube Zircaloy-4 Outer Diameter 13462 cm (053 in)
Reference 2227 Table 2-2
Inner Diameter 126492 cm (0498 in)
Instrument tube Zircaloy-4 Outer Diameter 138193 cm (05441 in) Inner Diameter 112014 cm (0441 in)
Cladding` Zircaloy-4 Inner Diameter 095758 cm (0377 in) Outer Diameter 10922 cm (043 in)
Plenum region NA Length 297688 cm (11720 in) Reference 2220 p 2A-34 Top nozzle SS CF3M MassAssembly (Top) 748 kg
Reference 2220 p 2A-32
Bottom nozzle SS CF3M MassAssembly (Bottom) 816 kg Guide tubes Zircaloy-4 MassAssembly (in Core) 80 kg Instrument tube Zircaloy-4 MassAssembly (in Core) 064 kg Spacer-plenum Inconel-718 MassAssembly (Plenum) 104 kg Spacer-bottom Inconel-718 MassAssembly (Bottom) 13 kg Spacer-in core Inconel-718 MassAssembly (in Core) 49 kg Spring retainer SS CF3M MassAssembly (Top) 091 kg Holddown spring Inconel-718 MassAssembly (Top) 18 kg Upper end plug SS 304 MassAssembly (Top) 006 kg Upper nut SS 304L MassAssembly (Top) 051 kg Lower nut SS 304 MassAssembly (Bottom) 015 kg Grid supports Zircaloy-4 MassAssembly (in Core) 064 kg Plenum spring SS 302 MassAssembly (Plenum) 0042 lb (001905 kg) Reference 2220 p 2A-34
Note Som e d ata i n this tab le ar e given i n British u nits in th e r eferences thes e d ata ar e converted into metric units as the inputs to MCNP5 are in metric units
The assem bly region heights as m odeled in MC NP are presented in Table 5 utilizing values from Table 4 Table 5 is taken from Dose Rate Calculation for Exhaust Main Drifts (Reference 2213 Table 3)
26
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 5 PWR Fuel Assembly Regions
Component Height Reference
Plenum 297688 cm (11720 in) Reference 2220 p 2A-34
Active Fuel 360172 cm (1418 in) Table 3
Bottom End-Fitting 1077 cm (424 in) Calculateda
Top End-Fitting 1998 cm (787 in) Calculatedb
Source Reference 2213 Table 3 aCalculated b ased on data Reference 2227 F igures 2-3 an d 2-7
(Region 9 Height [16723 cm] + Region 10 Height [508 cm] ndash Lo wer Fuel Plenum and End Cap [11033 cm])
bCalculated (Assembly Length ndash Active Fuel Length ndash P lenum Length ndash Bottom End-fitting Length)
625 Material Compositions
The TAD transportation cask com ponent m aterial specifications are defined in Table 1 The TAD canister is constructed of SS 316 (Assumpti on 321) The PWR fuel assembly materials used to homogenize the fuel regions are defined in Table 4 Table 6 c ontains the m aterial compositions defining the TAD canister WP and fuel assemblies
27
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 6 Chemical Compositions of Materials
Material Density (gcc)
Isotopic Weight Percent Reference
SS 302 NA
C 0150 Mn 2000 P 0045 S 0030 Si 0750 Cr 18000 Ni 9000 N 0100 Fe 69925
Attachment II PWR_fuel compxls worksheet ferrous Reference 222 SEC II A SA-240 Table 1 for SS 302 SS 304 and SS 304L Reference 222 SEC II A SA-351SA -351M Table 2 for SS CF3M
SS 304 NA
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 9250 N 0100 Fe 68745
SS 304L NA
C 003 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 10000 N 0100 Fe 6804 5
SS CF3M NA
C 0030 Mn 1500 P 0040 S 0040 Si 1500 Cr 19000 Ni 11000 Mo 2500 Fe 64390
Inconel 718 NA
C 0080 Mn 0350 Si 0350 Cr 19000 Ni 52500 Co 1000 Mo 3050 Fe 16809 Nb 5125 Ti 0900 Al 0500 Cu 0300 S 0015 P 0015 B 0006
Attachment II PWR_fuel compxls worksheet alloys aReference 223 p 666 Table 6 Reference 222 SEC II B SB-637 Table 1 for Inconel 718 Reference 224 Table 2 for Zircaloy 4
Zircaloy 4 656a Cr 0100 Fe 0210 O 0125 Sn 1450 Zr 98115
SS 316 798b
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 17000 Ni 12000 Mo 2500 N 0100 Fe 65495
Attachment II PWR_fuel compxls worksheet others Reference 222 SEC II A SA-240 Table 1 for SS 316 bReference 225 Table X1
626 Homogenization Assembly Materials
The atom density of an element or isotope in atomsbmiddotcm in a homogenized region is calculated according to the following equation (Reference 2223 Appendix B)
M i times N AvogadroNi = Equation 1 Ai timesV times K
where Ni = Atom density of elementisotope i (atomsbmiddotcm) Mi = Mass of elementisotope i (g) NAvogadro = Avogadrorsquos constant 06022 x 1024 (atomsmole)
28
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Ai = Atomic weight of elementisotope i (gmole) V = Homogenization volume (cm3) K = Unit transformation constant = 1024 (bmiddotcmcm3)
Equation 1 is used in A ttachment II spreadsheet PWR_fuel compxls worksheet BampWassy to calculate th e atom dens ities for v arious elem ents and iso topes The m ass of elementsisotop es and Avogadrorsquos constant are provided in Reference 2226
Table 7 lists the com position of the hom ogenized assem bly regions (active fuel plenum top end-fitting and bottom end-fitting) for the PWR assembly The active fuel region contains fresh unirradiated fuel (Assumption 324) Since the internal structure (ie basket) design of the TAD is currently not finalized the composition of either homogenized fuel does not include the basket materials and therefore does not tak e credit for any shielding that thes e materials may provide (Assumption 326)
Table 7 Isotopic Compositions of Homogenized PWR Assembly Regions
Element Isotope
Atom Densities for Homogenized Regions (atomsbsdotcm)
Active Fuel Bottom End-Fitting Plenum Top End-Fitting
10B 861E-09 764E-08 221E-08 570E-08 11B 347E-08 307E-07 890E-08 230E-07 C 519E-07 160E-05 138E-06 993E-06 N -- 570E-07 262E-08 117E-06 O 621E-03 -- 142E-05 -- Al 144E-06 128E-05 371E-06 957E-06 Si 971E-07 243E-04 259E-06 139E-04 P 377E-08 606E-06 102E-07 360E-06 S 365E-08 581E-06 971E-08 340E-06 Ti 147E-06 130E-05 376E-06 971E-06 Cr 320E-05 187E-03 779E-05 113E-03 Mn 497E-07 126E-04 141E-06 749E-05 Fe 303E-05 531E-03 717E-05 313E-03 Co 132E-06 117E-05 340E-06 876E-06 Ni 697E-05 144E-03 180E-04 940E-04 Cu 368E-07 327E-06 945E-07 244E-06 Zr 196E-03 -- 195E-03 -- Nb 430E-06 382E-05 110E-05 285E-05 Mo 248E-06 135E-04 636E-06 791E-05 Sn 223E-05 -- 222E-05 -- 234U 139E-06 -- -- -- 235U 157E-04 -- -- -- 236U 719E-07 -- -- -- 238U 294E-03 -- -- -- Total 114E-02 924E-03 235E-03 557E-03
Source Attachment II spreadsheet PWR_fuel compxls worksheet BampWassy
29
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
The isotopic composition of commercially available 235U enriched uranium is determined by the given initial 235U enrichment using the following equations (Reference 226 p 20)
wt235U =235Uenrichment _ of _ the _ associated _ fuel _ batch Equation 2
wt234U = 0007731times (wt235U )10837 Equation 3
wt236U = 00046times (wt235U ) Equation 4
wt238U =100 minus (wt234U + wt235U + wt236U ) Equation 5
The weight percentages of uran ium isotopes for PWR fuel are ca lculated in Attachm ent II spreadsheet PWR_fuel compxls worksheet BampWassy using Equations 2 through 5
627 PWR Source Terms
This calculation uses the following three PWR source terms bull Maximum source (50 wt initial 235U enrichment 80 GWdMTU burnup and 5-year
decay time) (Reference 229 Section 55) Table 8 lists th e gamma source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Design Basis source (4 0 wt initial 235U enrichment 60 GW dMTU burnup and 10-year decay tim e) (Reference 228 Section 552) Table 9 lists the gamm a source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Average source ( 40 wt initial 235U enrichment 48 GWdMTU burnup and 25-year decay time) (Reference 229 Section 55) Table 10 lists the gamma source terms for the fuel and non-fuel regions and the neutron source term for the fuel region
These sources (ie maximum design basis and av erage) are described in this section For dose rate calculations all the fuel assemblies in a transportation cask are of the sam e characteristics Also gamma radiation source term s for the PWR assem bly are prov ided for the f our assembly regions while neutron source term is only present in the active fuel region Gamma radiation sources in the non-active fuel region are distri buted unif ormly within each source region Gamma and neutron sources in the active fuel re gion are modeled as uni form distributions or with axial source profiles
The PWR gamma and neutron axial source profiles for the active fuel region presented in Table 11 are applied to the active fuel region of all three source terms (ie maximum design basis and average) when appropriate
30
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 8 Gamma and Neutron Sources for the Maximum PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting
Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 594E+11 233E+15 528E+11 379E+11 100E-01 000E+00 100E-01 116E+11 644E+14 609E+10 743E+10 400E-01 805E+07 200E-01 283E+10 522E+14 352E+10 179E+10 900E-01 411E+08 300E-01 141E+09 148E+14 196E+09 891E+08 140E+00 376E+08 400E-01 190E+09 985E+13 586E+09 117E+09 185E+00 276E+08 600E-01 191E+09 153E+15 110E+11 741E+07 300E+00 485E+08 800E-01 435E+09 470E+15 595E+10 237E+09 643E+00 443E+08 100E+00 137E+11 708E+14 803E+09 766E+10 200E+01 393E+07 133E+00 338E+13 455E+14 174E+13 217E+13 Total 211E+09 166E+00 953E+12 130E+14 491E+12 612E+12
--
200E+00 187E+03 144E+12 919E+02 113E+03 250E+00 226E+08 249E+12 116E+08 145E+08 300E+00 351E+05 110E+11 181E+05 225E+05 400E+00 766E-08 139E+10 100E-08 416E-08 500E+00 000E+00 709E+07 000E+00 000E+00 650E+00 000E+00 286E+07 000E+00 000E+00 800E+00 000E+00 558E+06 000E+00 000E+00 100E+01 000E+00 119E+06 000E+00 000E+00
Total 442E+13 113E+16 231E+13 284E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE2R2B14cut bWasteStreamE2R1B14cut cWasteStreamE2R3B14cut dWasteStreamE2R4B14cut
31
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 9 Gamma and Neutron Sources for the Design Basis PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary
(MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 273E+11 121E+15 188E+11 175E+11 100E-01 000E+00 100E-01 528E+10 329E+14 277E+10 339E+10 400E-01 316E+07 200E-01 128E+10 245E+14 117E+10 819E+09 900E-01 161E+08 300E-01 639E+08 713E+13 633E+08 407E+08 140E+00 148E+08 400E-01 850E+08 455E+13 164E+09 533E+08 185E+00 109E+08 600E-01 492E+08 226E+14 269E+10 337E+07 300E+00 191E+08 800E-01 291E+09 237E+15 160E+10 186E+09 643E+00 174E+08 100E+00 540E+09 122E+14 248E+09 341E+09 200E+01 154E+07 133E+00 154E+13 195E+14 797E+12 990E+12 Total 830E+08 166E+00 435E+12 450E+13 225E+12 280E+12
--
200E+00 235E+00 152E+11 149E+02 215E-02 250E+00 103E+08 517E+10 534E+07 664E+07 300E+00 160E+05 379E+09 829E+04 103E+05 400E+00 943E-10 497E+08 155E-10 519E-10 500E+00 000E+00 282E+07 000E+00 000E+00 650E+00 000E+00 113E+07 000E+00 000E+00 800E+00 000E+00 222E+06 000E+00 000E+00 100E+01 000E+00 471E+05 000E+00 000E+00
Total 201E+13 486E+15 105E+13 129E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B11cut bWasteStreamE5R1B11cut cWasteStreamE5R3B11cut dWasteStreamE5R4B11cut
32
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 10 Gamma and Neutron Sources for the Average PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 336E+10 670E+14 186E+10 217E+10 100E-01 00000E+00 100E-01 602E+09 199E+14 314E+09 387E+09 400E-01 748E+06 200E-01 146E+09 126E+14 853E+08 936E+08 900E-01 382E+07 300E-01 730E+07 389E+13 439E+07 469E+07 140E+00 352E+07 400E-01 947E+07 263E+13 716E+07 607E+07 185E+00 261E+07 600E-01 141E+07 205E+13 504E+08 383E+06 300E+00 469E+07 800E-01 208E+09 124E+15 192E+09 144E+09 643E+00 418E+07 100E+00 208E+09 110E+13 164E+09 144E+09 200E+01 365E+06 133E+00 175E+12 295E+13 909E+11 112E+12 Total 199E+08 166E+00 494E+11 513E+12 257E+11 318E+11
--
200E+00 973E-01 675E+10 614E+01 872E-03 250E+00 117E+07 353E+09 609E+06 754E+06 300E+00 182E+04 288E+08 944E+03 117E+04 400E+00 186E-11 198E+07 149E-11 127E-11 500E+00 000E+00 669E+06 000E+00 000E+00 650E+00 000E+00 269E+06 000E+00 000E+00 800E+00 000E+00 527E+05 000E+00 000E+00 100E+01 000E+00 112E+05 000E+00 000E+00
Total 229E+12 237E+15 119E+12 147E+12
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B9cut bWasteStreamE5R1B9cut cWasteStreamE5R3B9cut dWasteStreamE5R4B9cut
33
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 11 Gamma and Neutron Axial Source Profiles for a PWR Assembly
Axial boundaries (From midplane)
(cm)
TOP BOTTOM
Neutron Gamma Ne utron Gamma 000 1554 1117 1554 1117 1143 1537 1114 1571 1120 2286 1521 1111 1588 1123 3429 1504 1108 1605 1126 4572 1486 1104 1622 1129 5715 1464 1100 1636 1131 6858 1438 1095 1648 1133 8001 1401 1088 1657 1135 9144 1350 1078 1654 1134
10287 1277 1063 1625 1129 11430 1165 1039 1554 1117 12573 0998 09995 1414 1091 13716 0769 09365 1172 1041 14859 0492 08375 0816 0951 16002 0220 06850 0402 0797 17145 0046 04625 0092 0551 18288 00 00 00 00
Source Reference 2219 Table S445
34
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
63 MCNP SPECIFIC INPUT
631 Source Probability
A linear radial distribution is used for all gamma and neutron sources The linear radial distribution is sam pled usi ng the built-in power function p(x) = xc a with a = 1 for the radial direction This sampling method results in a uniform source distribution over the area bounded by the outer radius of the source
The source axial distributions are unifor m for all four source regions The a xial uni form xp(x) = c distribution is sampled using the built-in power function a with a = 0 for extent
The energy distribu tions of the gamma and neutron sour ce term s are treated as energ y probabilities and are applied in MCNP5 using SISP cards
632 Dose Rate and Flux Tallies
MCNP5 dose rate calculations feature separate runs for the following calculation types
bull a photon transport calculation for prim ary ga mma contribution to the dose rates fr om photon fluxes
bull a coupled neutronphoton transport calculat ion for neutrons a nd secondary gamma (photons generated by neutron be ing captured) contributions to dose rates from neutron and gamma fluxes
The tally type F2 is us ed in th is d esign ca lculation as f lux estim ators The type F2 tally evaluates the flux averaged over a surface in particlescm2s
To generate dose ra tes in te rms of remhr the FM (tally multiplier ) and DEDF (dose energydose conversion factors) cards are used to en ter the tally multiplier f actor (source intensity in particless) energy boundaries in MeV and corresponding dose conversion factors in (remhr)(particlescm2s) respectively These factors were used in the input files
In order for the F2 tally to accum ulate flux ov er a surface a specific s urface area is requ ired The SD cards are used to enter a surface area in cm2 over which the flux will be tallied for an F2 tally
633 Variance Reduction Techniques
Variance reduction technique is usually em ployed in order to increase the efficiency of a calculation and obtain statistically m eaningful results within re asonable com puter tim e In Monte Carlo calculations when variance reduction scheme is employed the weights of particles are adjusted in order to account for the biasing and to preserve a fair game
Geometry splitting and Russian roulette techniques described in Reference 2224 (pp 2-140 ndash 2-142) are useful in shielding calculations and therefore deployed in all the MCNP5 runs
35
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
As particles migrate in an important direction (toward the detector) they are increased in number to provide better sampling by means of geometry splitting across geometric boundaries Russian roulette (the reverse process) is played when particles travel in an unimportant direction to allow termination of unim portant histories The IMP card required for every cel l ca rd is us ed to implement this technique
The other variance reduction technique deployed in the MC NP5 runs is source intensity biasing for the gamma sources from the four source regions (active fuel bottom end-fitting plenum and top end-fitting) The natural total gamma source intensity of comm ercial SNF is dom inated by the gamma source in the active fuel region This active fuel gamma source usually accounts for over 95 o f the total g amma source intens ity In order to im prove the efficiency of the axial dose rate calculations a biased source probability distribution is employed for the prim ary gamma dose rate calculations The biased gamma source probability distribution is chosen to be 005 080 010 and 005 for the bottom end-fitting the active fuel the plenum and the top end-fitting regions respectively
64 DOSE CONVERSION FACTORS
Project Design Criteria Document (Reference 2211 Se ction 41015) requires the use of flux-to-dose rate conversion fact ors from ANSIANS-611-1977 (Reference 221) for dose rate evaluations Table 16 lists the neutron and ga mma dose conversion factors used in the MCNP5 calculations
Table 12 Gamma and Neutron Flux to Dose Conversion Factors
Gamma Neutron Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
001 396E-06 140 251E-06 250E-08 367E-06 003 582E-07 180 299E-06 100E-07 367E-06 005 290E-07 220 342E-06 100E-06 446E-06 007 258E-07 260 382E-06 100E-05 454E-06 010 283E-07 280 401E-06 100E-04 418E-06 015 379E-07 325 441E-06 100E-03 376E-06 020 501E-07 375 483E-06 100E-02 356E-06 025 631E-07 425 523E-06 100E-01 217E-05 030 759E-07 475 560E-06 500E-01 926E-05 035 878E-07 500 580E-06 100E+00 132E-04 040 985E-07 525 601E-06 250E+00 125E-04 045 108E-06 575 637E-06 500E+00 156E-04 050 117E-06 625 674E-06 700E+00 147E-04 055 127E-06 675 711E-06 100E+01 147E-04 060 136E-06 750 766E-06 140E+01 208E-04 065 144E-06 900 877E-06 200E+01 227E-04 070 152E-06 1100 103E-05 080 168E-06 1300 118E-05 100 198E-06 1500 133E-05
Source Reference 221 Tables 1 and 3
36
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION
By def inition (Ref erence 2224 Equation 219) the estimated st atistic relative error of the i component is
Ri = Si
2
Equation 6Ti
where i = tally component index Ri = relative error of the i component S2
i = variance of the i component Ti = tally i component
For a result (ie dose rate) computed as a sum of different tallies the statistical relative error of the computed value is o btained from the variance of the result - S2
total which is th e sum of the estimated variances of the individual tallies S2
i n
2 2STotal = sum Si Equation 7 i=1
where S2Total = total estimated variance
n = total number of components Therefore the total tally value (dose rate) and the associated relative error are derived according to Equations 8 and 9
n TTotal = sumTi Equation 8
i=1
n n
sum (Ri timesTi )2
2 sum Si 2
STotal = i=1 = i=1 Equation 9RTotal = TTotal TTotal TTotal
where RTotal = total estimated relative error TTotal = total estimated tally
Equations 8 and 9 are utilized in Attachm ent II to ev aluate to tal dos e ra tes and their r elative errors
37
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
7 RESULTS AND CONCLUSIONS
71 RESULTS
The following sections summarize the results of this calculation Section 711 presents results for Conceptual Cask A while Section 712 for Conceptual Cask B Section 713 provides comparisons of the dose-rate reduction factors du e to the two conceptual casks and the axial source distributions in the active fuel region Do se rates and relative errors can be found in Attachment II within the output files and Excel files
711 Dose Rates of Conceptual Cask A
This section presents dose-rate results of the calculation sets 1 and 2 as described in Section 61 for Cask A Set 1 has axial p rofile sources in the active fuel region a nd consist of six runs resulting from the three PWR SNF source term s (maximum design basis and average) and the two radiation sources (gammas and neutrons) Set 2 has uniform axial sources in the active fuel region and consists of six run s r esulting f rom the th ree P WR SNF source term s and th e tw o radiation sources
As described in Section 61 dose ra tes are calculated at the three exterior surfaces (radial top and bottom) and at distances 1 m and 2 m from the exterior surfaces The total dose rates for set 1 are presented in Tables 13 14 and 15 for the ra dial top and bottom dire ctions respectively However the com ponents (primary gamma neutr on and secondary gamma) contributing to the total dose rates as well as the re lative error calculations can be found in Attachment II Excel file MCNP-Results1xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 2 are shown in Tables 16 17 and 18 The dose-rate components and the relative errors can be found in A ttachment II Excel file MCNP-Results2xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 13 and 16 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 14 and 17 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 15 and 18 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carrying th e maximum PWR SNF Based on the results in Tables 13 through 18 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask A indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these 6 tables the d ose-rate red uction f actors between the m aximum and the design basis fuels the maxim um and the averag e fuels and th e design basis and the average fuels are a lso presented
38
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 320E-02 00237 116E-02 00222 262E-03 00219 275 1223 445
1 m 133E-02 00164 494E-03 00171 106E-03 00162 269 1261 468 2 m 749E-03 00198 285E-03 00225 584E-04 00162 263 1282 488
Ring Detectors 1 m 133E-02 00116 492E-03 00115 108E-03 00124 271 1229 454 2 m 756E-03 00118 279E-03 00110 605E-04 00128 271 1250 462
Source Attachment II MCNP-Results1xls worksheet Summary
Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 142E-02 00368 628E-03 00446 934E-04 00483 226 1520 672
1 m 570E-03 00289 263E-03 00426 375E-04 00381 217 1520 701 2 m 265E-03 00364 123E-03 00547 169E-04 00374 216 1575 730
Point Detectors 1 m 598E-03 00238 274E-03 00271 402E-04 00354 219 1489 681 2 m 273E-03 00218 123E-03 00245 180E-04 00336 221 1515 684
Source Attachment II MCNP-Results1xls worksheet Summary
Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 653E-03 00298 265E-03 00276 510E-04 00341 247 1278 518
1 m 276E-03 00238 112E-03 00208 207E-04 00249 248 1334 539 2 m 125E-03 00185 508E-04 00199 933E-05 00246 246 1336 544
Point Detectors 1 m 291E-03 00227 118E-03 00203 218E-04 00242 247 1335 540 2 m 130E-03 00209 524E-04 00187 955E-05 00233 247 1357 549
Source Attachment II MCNP-Results1xls worksheet Summary
Tables 13 14 and 15 are results of calculation set 1 for conceptual Cask A with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
39
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 265E-02 00247 990E-03 00222 215E-03 00278 268 1234 461
1 m 116E-02 00178 468E-03 00549 960E-04 00189 248 1208 488 2 m 713E-03 00273 265E-03 00161 602E-04 00360 269 1184 439
Ring Detectors 1 m 117E-02 00120 454E-03 00132 979E-04 00141 259 1199 463 2 m 722E-03 00130 276E-03 00141 589E-04 00153 261 1226 469
Source Attachment II MCNP-Results2xls worksheet Summary
Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 199E-02 00461 827E-03 00455 147E-03 00536 241 1359 564
1 m 849E-03 00564 323E-03 00314 563E-04 00418 263 1507 574 2 m 415E-03 00832 158E-03 00603 253E-04 00501 263 1641 623
Point Detectors 1 m 877E-03 00348 353E-03 00275 615E-04 00391 248 1426 574 2 m 393E-03 00341 160E-03 00278 270E-04 00378 246 1454 590
Source Attachment II MCNP-Results2xls worksheet Summary
Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 879E-03 00374 356E-03 00333 669E-04 00406 247 1315 533
1 m 365E-03 00223 147E-03 00209 269E-04 00253 248 1358 548 2 m 164E-03 00229 674E-04 00205 120E-04 00248 243 1364 560
Point Detectors 1 m 383E-03 00217 155E-03 00204 285E-04 00248 247 1347 546 2 m 172E-03 00197 689E-04 00186 124E-04 00225 249 1391 558
Source Attachment II MCNP-Results2xls worksheet Summary
Tables 16 17 and 18 ar e results of calculation set 2 for conceptual Cask A with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
40
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
For the radial direction surface tallies at the three distances (contact 1 m and 2 m) are computed for three su rface segments (cylindrical rings) between the planes at Z = 145 175 2 05 and 235 cm The geometric locations of the segments are shown in Figure 1 The axial locations of these segments correspond to the m iddle of the active fuel region of the PWR SNF assemblies The average dose rates for each of the segm ents are calculated for the outside surface and surfaces at 1 m and 2 m from the cask surface Two ring detectors (instead of point detectors) are deployed at 1 m and 2 m for the radial dire ction Ring detectors instead of point detectors are used in order to capitalize on the symm etry around the cask axis thus im proving the efficiency of the calculations
In the axial direction the average d ose rates within three concentric radial surfaces defined by radii of 40 80 and 120 cm (shown in Figure 1) are calculated for the top and bottom surfaces and at distances 1 m and 2 m from these surfaces Finally point detectors at 1 m and 2 m from the top and bottom axial surfaces are employed
22
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Point Detector at 2 m x
Ring Ring Detector Detector at 2 m at 1 m
x x
Z = 00 cm
Z = 145 cm
Z = 175 cm
Z = 205 cm
Z = 235 cm
R = 80 cm
R = 120 cm
R = 40 cm
Active Fuel
Shield Plug
Top End-Fitting Plenum
Bottom End-Fitting
Ring Detector at 1 m
x
Point Detector at 1 m x
Ring Detector
at 2 m x
D = 26797 cm
H =
610
845
cm
Point Detector at 1 m x
Point Detector at 2 m x
Figure 1 Geometry and Tally Scheme for the TAD Transportation Cask
23
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
62 CALCULATION INPUT
Technical product input and sources of the input used in the deve lopment of this calculation are documented in this section Tables in this docum ent and in th e associated Microsoftreg Excel spreadsheets referenced m ay present num erical values with m any significant figures these values are not to be considered as high precision values since the significant figures are results of calculated values andor unit conversions
621 TAD Canister
The TAD canis ter will contain either 21 P WR or 44 BW R (boiling water reactor) SNF assemblies (Reference 2222 Section 321) While the canister design is iden tical for both PWR and BWR SNF assemblies the internal basket structure is different depending on the SNF assemblies However the internal basket stru cture m aterial is no t in cluded in the calcu lation model (Assumption 326)
The TAD canister is a right-circu lar cylinder with a diam eter of 665 in and a height between 186 and 212 in (Reference 2222 Section 321) The average and maximum total dose rates on the top surf ace of a loaded TAD ca nister must not exceed 800 and 1000 m remhr respectively (Reference 2222 Section 314) The TAD canister used in this calculation is m ade of SS 316 with a radial wall and bottom thickness of 025 in (Assumption 321) The top of the canister has a shield plug that is 11 in thick SS 316 (Ass umption 322) A thick shield plug is needed to keep the maxim um contact dose rate of th e top surface below 1000 m remhr The overall dimensions of the TAD canister are provided in Table 3
Table 3 Dimensions of TAD Canister
Component Dimension
(in) (cm)
Maximum heighta 212 53848
Outer diametera 665 16891
Thickness of bottom lidb 025 0635
Shell thicknessb 025 0635
Lifting Featurec 6 1524
Height without Lifting Feature 206 52324
Thickness of shield plugd 110 2794
aReference 2222 Section 311 bAssumption 321 cReference 2222 p Attachment C-1 dAssumption 322
622 Conceptual TAD Transportation Casks
Two conceptual TAD transportation casks designa ted as Cask A and Cask B are em ployed in this calculation (Assumption 323) They both have a cylindrical geometry with dimensions and materials specified in Tables 1 and 2 of Section 323 Cask A will provide shielding to meet the exterior radiation standards of 10 CFR 7147(b) (Reference 231) when loaded with a TAD
24
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
canister car rying the m aximum PWR SNF Cask B will s atisfy th e sa me radiatio n standa rds when loaded with a TAD canister c arrying the average PWR SNF The reason to analyze both Casks A and B is to cover a broad range of characteristics of the CSNF
The cavity dimensions of the conceptual cask s are 53785 cm (21175 in) in height and 16891 cm (665 in) in diam eter (Tab les 1 and 2) This cav ity will accommoda te the TAD canister described in Table 3 without the lifting feature This is the geometry model used in the MCNP5 calculations
623 Fuel Assembly Selection
PWR and BWR Source Term Sensitivity Study (Reference 2211 Tables 71 through 84) shows that the source terms generated for the Bamp W 15x15 Mark B fuel assembly with 475 kg uranium loading bound the source terms of other PWR assembly types ther efore this assembly type is selected as the representative PWR fuel assembly The gamma and neutron source terms for the BampW 15x15 Mark B assembly are generated in PWR Source Term Generation and Evaluation (Reference 229) and are used in this calculation
624 BampW 15x15 Mark B PWR Fuel Assembly
BampW 15x15 Mark B fuel assembly consists of four regions top end-fitting plenum active fuel and bottom end-fitting The m aterials and ra diation sources of each assem bly region are homogenized inside a volume defined by the region height and the interior diam eter of the TAD canister (Assumption 325) The active fuel region is homogenized with fresh unirradiated fuel (Assumption 324) Since the internal structure (i e basket) design of t he TAD is currently not finalized the com position of the hom ogenized fuel does not include the basket m aterials (Assumption 326) and therefore does not take cred it for any shielding that these m aterials may provide
Table 4 provides the design param eters for the BampW 15x15 Mark B fuel assembly Data provided here are used in Attachment II PWR_fuel compxls worksheet BampWassy
25
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 4 BampW 15x15 Mark B Fuel Assembly Description
Component Material Characteristic Value Specific Reference Array Size 15 x 15
Reference 2227 Table 2-2 Fuel Pins Assembly 208 Guide Tubes Assembly 16 Instrument Tubes Assembly 1
Assembly NA Pin Pellet Diameter 0936244 cm (03686 in) Reference 2220 p 2A-34 Pin Pitch 144272 cm (0568 in)
Reference 2227 Table 2-2 Active Fuel Height 360172 cm (1418 in) Assembly Width 2168144 cm (8536 in)
Reference 2220 p 2A-31 Assembly Height 4206875 cm (165625 in) Mass U assembly 46363 kg
Guide tube Zircaloy-4 Outer Diameter 13462 cm (053 in)
Reference 2227 Table 2-2
Inner Diameter 126492 cm (0498 in)
Instrument tube Zircaloy-4 Outer Diameter 138193 cm (05441 in) Inner Diameter 112014 cm (0441 in)
Cladding` Zircaloy-4 Inner Diameter 095758 cm (0377 in) Outer Diameter 10922 cm (043 in)
Plenum region NA Length 297688 cm (11720 in) Reference 2220 p 2A-34 Top nozzle SS CF3M MassAssembly (Top) 748 kg
Reference 2220 p 2A-32
Bottom nozzle SS CF3M MassAssembly (Bottom) 816 kg Guide tubes Zircaloy-4 MassAssembly (in Core) 80 kg Instrument tube Zircaloy-4 MassAssembly (in Core) 064 kg Spacer-plenum Inconel-718 MassAssembly (Plenum) 104 kg Spacer-bottom Inconel-718 MassAssembly (Bottom) 13 kg Spacer-in core Inconel-718 MassAssembly (in Core) 49 kg Spring retainer SS CF3M MassAssembly (Top) 091 kg Holddown spring Inconel-718 MassAssembly (Top) 18 kg Upper end plug SS 304 MassAssembly (Top) 006 kg Upper nut SS 304L MassAssembly (Top) 051 kg Lower nut SS 304 MassAssembly (Bottom) 015 kg Grid supports Zircaloy-4 MassAssembly (in Core) 064 kg Plenum spring SS 302 MassAssembly (Plenum) 0042 lb (001905 kg) Reference 2220 p 2A-34
Note Som e d ata i n this tab le ar e given i n British u nits in th e r eferences thes e d ata ar e converted into metric units as the inputs to MCNP5 are in metric units
The assem bly region heights as m odeled in MC NP are presented in Table 5 utilizing values from Table 4 Table 5 is taken from Dose Rate Calculation for Exhaust Main Drifts (Reference 2213 Table 3)
26
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 5 PWR Fuel Assembly Regions
Component Height Reference
Plenum 297688 cm (11720 in) Reference 2220 p 2A-34
Active Fuel 360172 cm (1418 in) Table 3
Bottom End-Fitting 1077 cm (424 in) Calculateda
Top End-Fitting 1998 cm (787 in) Calculatedb
Source Reference 2213 Table 3 aCalculated b ased on data Reference 2227 F igures 2-3 an d 2-7
(Region 9 Height [16723 cm] + Region 10 Height [508 cm] ndash Lo wer Fuel Plenum and End Cap [11033 cm])
bCalculated (Assembly Length ndash Active Fuel Length ndash P lenum Length ndash Bottom End-fitting Length)
625 Material Compositions
The TAD transportation cask com ponent m aterial specifications are defined in Table 1 The TAD canister is constructed of SS 316 (Assumpti on 321) The PWR fuel assembly materials used to homogenize the fuel regions are defined in Table 4 Table 6 c ontains the m aterial compositions defining the TAD canister WP and fuel assemblies
27
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 6 Chemical Compositions of Materials
Material Density (gcc)
Isotopic Weight Percent Reference
SS 302 NA
C 0150 Mn 2000 P 0045 S 0030 Si 0750 Cr 18000 Ni 9000 N 0100 Fe 69925
Attachment II PWR_fuel compxls worksheet ferrous Reference 222 SEC II A SA-240 Table 1 for SS 302 SS 304 and SS 304L Reference 222 SEC II A SA-351SA -351M Table 2 for SS CF3M
SS 304 NA
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 9250 N 0100 Fe 68745
SS 304L NA
C 003 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 10000 N 0100 Fe 6804 5
SS CF3M NA
C 0030 Mn 1500 P 0040 S 0040 Si 1500 Cr 19000 Ni 11000 Mo 2500 Fe 64390
Inconel 718 NA
C 0080 Mn 0350 Si 0350 Cr 19000 Ni 52500 Co 1000 Mo 3050 Fe 16809 Nb 5125 Ti 0900 Al 0500 Cu 0300 S 0015 P 0015 B 0006
Attachment II PWR_fuel compxls worksheet alloys aReference 223 p 666 Table 6 Reference 222 SEC II B SB-637 Table 1 for Inconel 718 Reference 224 Table 2 for Zircaloy 4
Zircaloy 4 656a Cr 0100 Fe 0210 O 0125 Sn 1450 Zr 98115
SS 316 798b
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 17000 Ni 12000 Mo 2500 N 0100 Fe 65495
Attachment II PWR_fuel compxls worksheet others Reference 222 SEC II A SA-240 Table 1 for SS 316 bReference 225 Table X1
626 Homogenization Assembly Materials
The atom density of an element or isotope in atomsbmiddotcm in a homogenized region is calculated according to the following equation (Reference 2223 Appendix B)
M i times N AvogadroNi = Equation 1 Ai timesV times K
where Ni = Atom density of elementisotope i (atomsbmiddotcm) Mi = Mass of elementisotope i (g) NAvogadro = Avogadrorsquos constant 06022 x 1024 (atomsmole)
28
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Ai = Atomic weight of elementisotope i (gmole) V = Homogenization volume (cm3) K = Unit transformation constant = 1024 (bmiddotcmcm3)
Equation 1 is used in A ttachment II spreadsheet PWR_fuel compxls worksheet BampWassy to calculate th e atom dens ities for v arious elem ents and iso topes The m ass of elementsisotop es and Avogadrorsquos constant are provided in Reference 2226
Table 7 lists the com position of the hom ogenized assem bly regions (active fuel plenum top end-fitting and bottom end-fitting) for the PWR assembly The active fuel region contains fresh unirradiated fuel (Assumption 324) Since the internal structure (ie basket) design of the TAD is currently not finalized the composition of either homogenized fuel does not include the basket materials and therefore does not tak e credit for any shielding that thes e materials may provide (Assumption 326)
Table 7 Isotopic Compositions of Homogenized PWR Assembly Regions
Element Isotope
Atom Densities for Homogenized Regions (atomsbsdotcm)
Active Fuel Bottom End-Fitting Plenum Top End-Fitting
10B 861E-09 764E-08 221E-08 570E-08 11B 347E-08 307E-07 890E-08 230E-07 C 519E-07 160E-05 138E-06 993E-06 N -- 570E-07 262E-08 117E-06 O 621E-03 -- 142E-05 -- Al 144E-06 128E-05 371E-06 957E-06 Si 971E-07 243E-04 259E-06 139E-04 P 377E-08 606E-06 102E-07 360E-06 S 365E-08 581E-06 971E-08 340E-06 Ti 147E-06 130E-05 376E-06 971E-06 Cr 320E-05 187E-03 779E-05 113E-03 Mn 497E-07 126E-04 141E-06 749E-05 Fe 303E-05 531E-03 717E-05 313E-03 Co 132E-06 117E-05 340E-06 876E-06 Ni 697E-05 144E-03 180E-04 940E-04 Cu 368E-07 327E-06 945E-07 244E-06 Zr 196E-03 -- 195E-03 -- Nb 430E-06 382E-05 110E-05 285E-05 Mo 248E-06 135E-04 636E-06 791E-05 Sn 223E-05 -- 222E-05 -- 234U 139E-06 -- -- -- 235U 157E-04 -- -- -- 236U 719E-07 -- -- -- 238U 294E-03 -- -- -- Total 114E-02 924E-03 235E-03 557E-03
Source Attachment II spreadsheet PWR_fuel compxls worksheet BampWassy
29
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
The isotopic composition of commercially available 235U enriched uranium is determined by the given initial 235U enrichment using the following equations (Reference 226 p 20)
wt235U =235Uenrichment _ of _ the _ associated _ fuel _ batch Equation 2
wt234U = 0007731times (wt235U )10837 Equation 3
wt236U = 00046times (wt235U ) Equation 4
wt238U =100 minus (wt234U + wt235U + wt236U ) Equation 5
The weight percentages of uran ium isotopes for PWR fuel are ca lculated in Attachm ent II spreadsheet PWR_fuel compxls worksheet BampWassy using Equations 2 through 5
627 PWR Source Terms
This calculation uses the following three PWR source terms bull Maximum source (50 wt initial 235U enrichment 80 GWdMTU burnup and 5-year
decay time) (Reference 229 Section 55) Table 8 lists th e gamma source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Design Basis source (4 0 wt initial 235U enrichment 60 GW dMTU burnup and 10-year decay tim e) (Reference 228 Section 552) Table 9 lists the gamm a source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Average source ( 40 wt initial 235U enrichment 48 GWdMTU burnup and 25-year decay time) (Reference 229 Section 55) Table 10 lists the gamma source terms for the fuel and non-fuel regions and the neutron source term for the fuel region
These sources (ie maximum design basis and av erage) are described in this section For dose rate calculations all the fuel assemblies in a transportation cask are of the sam e characteristics Also gamma radiation source term s for the PWR assem bly are prov ided for the f our assembly regions while neutron source term is only present in the active fuel region Gamma radiation sources in the non-active fuel region are distri buted unif ormly within each source region Gamma and neutron sources in the active fuel re gion are modeled as uni form distributions or with axial source profiles
The PWR gamma and neutron axial source profiles for the active fuel region presented in Table 11 are applied to the active fuel region of all three source terms (ie maximum design basis and average) when appropriate
30
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 8 Gamma and Neutron Sources for the Maximum PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting
Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 594E+11 233E+15 528E+11 379E+11 100E-01 000E+00 100E-01 116E+11 644E+14 609E+10 743E+10 400E-01 805E+07 200E-01 283E+10 522E+14 352E+10 179E+10 900E-01 411E+08 300E-01 141E+09 148E+14 196E+09 891E+08 140E+00 376E+08 400E-01 190E+09 985E+13 586E+09 117E+09 185E+00 276E+08 600E-01 191E+09 153E+15 110E+11 741E+07 300E+00 485E+08 800E-01 435E+09 470E+15 595E+10 237E+09 643E+00 443E+08 100E+00 137E+11 708E+14 803E+09 766E+10 200E+01 393E+07 133E+00 338E+13 455E+14 174E+13 217E+13 Total 211E+09 166E+00 953E+12 130E+14 491E+12 612E+12
--
200E+00 187E+03 144E+12 919E+02 113E+03 250E+00 226E+08 249E+12 116E+08 145E+08 300E+00 351E+05 110E+11 181E+05 225E+05 400E+00 766E-08 139E+10 100E-08 416E-08 500E+00 000E+00 709E+07 000E+00 000E+00 650E+00 000E+00 286E+07 000E+00 000E+00 800E+00 000E+00 558E+06 000E+00 000E+00 100E+01 000E+00 119E+06 000E+00 000E+00
Total 442E+13 113E+16 231E+13 284E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE2R2B14cut bWasteStreamE2R1B14cut cWasteStreamE2R3B14cut dWasteStreamE2R4B14cut
31
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 9 Gamma and Neutron Sources for the Design Basis PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary
(MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 273E+11 121E+15 188E+11 175E+11 100E-01 000E+00 100E-01 528E+10 329E+14 277E+10 339E+10 400E-01 316E+07 200E-01 128E+10 245E+14 117E+10 819E+09 900E-01 161E+08 300E-01 639E+08 713E+13 633E+08 407E+08 140E+00 148E+08 400E-01 850E+08 455E+13 164E+09 533E+08 185E+00 109E+08 600E-01 492E+08 226E+14 269E+10 337E+07 300E+00 191E+08 800E-01 291E+09 237E+15 160E+10 186E+09 643E+00 174E+08 100E+00 540E+09 122E+14 248E+09 341E+09 200E+01 154E+07 133E+00 154E+13 195E+14 797E+12 990E+12 Total 830E+08 166E+00 435E+12 450E+13 225E+12 280E+12
--
200E+00 235E+00 152E+11 149E+02 215E-02 250E+00 103E+08 517E+10 534E+07 664E+07 300E+00 160E+05 379E+09 829E+04 103E+05 400E+00 943E-10 497E+08 155E-10 519E-10 500E+00 000E+00 282E+07 000E+00 000E+00 650E+00 000E+00 113E+07 000E+00 000E+00 800E+00 000E+00 222E+06 000E+00 000E+00 100E+01 000E+00 471E+05 000E+00 000E+00
Total 201E+13 486E+15 105E+13 129E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B11cut bWasteStreamE5R1B11cut cWasteStreamE5R3B11cut dWasteStreamE5R4B11cut
32
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 10 Gamma and Neutron Sources for the Average PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 336E+10 670E+14 186E+10 217E+10 100E-01 00000E+00 100E-01 602E+09 199E+14 314E+09 387E+09 400E-01 748E+06 200E-01 146E+09 126E+14 853E+08 936E+08 900E-01 382E+07 300E-01 730E+07 389E+13 439E+07 469E+07 140E+00 352E+07 400E-01 947E+07 263E+13 716E+07 607E+07 185E+00 261E+07 600E-01 141E+07 205E+13 504E+08 383E+06 300E+00 469E+07 800E-01 208E+09 124E+15 192E+09 144E+09 643E+00 418E+07 100E+00 208E+09 110E+13 164E+09 144E+09 200E+01 365E+06 133E+00 175E+12 295E+13 909E+11 112E+12 Total 199E+08 166E+00 494E+11 513E+12 257E+11 318E+11
--
200E+00 973E-01 675E+10 614E+01 872E-03 250E+00 117E+07 353E+09 609E+06 754E+06 300E+00 182E+04 288E+08 944E+03 117E+04 400E+00 186E-11 198E+07 149E-11 127E-11 500E+00 000E+00 669E+06 000E+00 000E+00 650E+00 000E+00 269E+06 000E+00 000E+00 800E+00 000E+00 527E+05 000E+00 000E+00 100E+01 000E+00 112E+05 000E+00 000E+00
Total 229E+12 237E+15 119E+12 147E+12
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B9cut bWasteStreamE5R1B9cut cWasteStreamE5R3B9cut dWasteStreamE5R4B9cut
33
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 11 Gamma and Neutron Axial Source Profiles for a PWR Assembly
Axial boundaries (From midplane)
(cm)
TOP BOTTOM
Neutron Gamma Ne utron Gamma 000 1554 1117 1554 1117 1143 1537 1114 1571 1120 2286 1521 1111 1588 1123 3429 1504 1108 1605 1126 4572 1486 1104 1622 1129 5715 1464 1100 1636 1131 6858 1438 1095 1648 1133 8001 1401 1088 1657 1135 9144 1350 1078 1654 1134
10287 1277 1063 1625 1129 11430 1165 1039 1554 1117 12573 0998 09995 1414 1091 13716 0769 09365 1172 1041 14859 0492 08375 0816 0951 16002 0220 06850 0402 0797 17145 0046 04625 0092 0551 18288 00 00 00 00
Source Reference 2219 Table S445
34
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
63 MCNP SPECIFIC INPUT
631 Source Probability
A linear radial distribution is used for all gamma and neutron sources The linear radial distribution is sam pled usi ng the built-in power function p(x) = xc a with a = 1 for the radial direction This sampling method results in a uniform source distribution over the area bounded by the outer radius of the source
The source axial distributions are unifor m for all four source regions The a xial uni form xp(x) = c distribution is sampled using the built-in power function a with a = 0 for extent
The energy distribu tions of the gamma and neutron sour ce term s are treated as energ y probabilities and are applied in MCNP5 using SISP cards
632 Dose Rate and Flux Tallies
MCNP5 dose rate calculations feature separate runs for the following calculation types
bull a photon transport calculation for prim ary ga mma contribution to the dose rates fr om photon fluxes
bull a coupled neutronphoton transport calculat ion for neutrons a nd secondary gamma (photons generated by neutron be ing captured) contributions to dose rates from neutron and gamma fluxes
The tally type F2 is us ed in th is d esign ca lculation as f lux estim ators The type F2 tally evaluates the flux averaged over a surface in particlescm2s
To generate dose ra tes in te rms of remhr the FM (tally multiplier ) and DEDF (dose energydose conversion factors) cards are used to en ter the tally multiplier f actor (source intensity in particless) energy boundaries in MeV and corresponding dose conversion factors in (remhr)(particlescm2s) respectively These factors were used in the input files
In order for the F2 tally to accum ulate flux ov er a surface a specific s urface area is requ ired The SD cards are used to enter a surface area in cm2 over which the flux will be tallied for an F2 tally
633 Variance Reduction Techniques
Variance reduction technique is usually em ployed in order to increase the efficiency of a calculation and obtain statistically m eaningful results within re asonable com puter tim e In Monte Carlo calculations when variance reduction scheme is employed the weights of particles are adjusted in order to account for the biasing and to preserve a fair game
Geometry splitting and Russian roulette techniques described in Reference 2224 (pp 2-140 ndash 2-142) are useful in shielding calculations and therefore deployed in all the MCNP5 runs
35
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
As particles migrate in an important direction (toward the detector) they are increased in number to provide better sampling by means of geometry splitting across geometric boundaries Russian roulette (the reverse process) is played when particles travel in an unimportant direction to allow termination of unim portant histories The IMP card required for every cel l ca rd is us ed to implement this technique
The other variance reduction technique deployed in the MC NP5 runs is source intensity biasing for the gamma sources from the four source regions (active fuel bottom end-fitting plenum and top end-fitting) The natural total gamma source intensity of comm ercial SNF is dom inated by the gamma source in the active fuel region This active fuel gamma source usually accounts for over 95 o f the total g amma source intens ity In order to im prove the efficiency of the axial dose rate calculations a biased source probability distribution is employed for the prim ary gamma dose rate calculations The biased gamma source probability distribution is chosen to be 005 080 010 and 005 for the bottom end-fitting the active fuel the plenum and the top end-fitting regions respectively
64 DOSE CONVERSION FACTORS
Project Design Criteria Document (Reference 2211 Se ction 41015) requires the use of flux-to-dose rate conversion fact ors from ANSIANS-611-1977 (Reference 221) for dose rate evaluations Table 16 lists the neutron and ga mma dose conversion factors used in the MCNP5 calculations
Table 12 Gamma and Neutron Flux to Dose Conversion Factors
Gamma Neutron Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
001 396E-06 140 251E-06 250E-08 367E-06 003 582E-07 180 299E-06 100E-07 367E-06 005 290E-07 220 342E-06 100E-06 446E-06 007 258E-07 260 382E-06 100E-05 454E-06 010 283E-07 280 401E-06 100E-04 418E-06 015 379E-07 325 441E-06 100E-03 376E-06 020 501E-07 375 483E-06 100E-02 356E-06 025 631E-07 425 523E-06 100E-01 217E-05 030 759E-07 475 560E-06 500E-01 926E-05 035 878E-07 500 580E-06 100E+00 132E-04 040 985E-07 525 601E-06 250E+00 125E-04 045 108E-06 575 637E-06 500E+00 156E-04 050 117E-06 625 674E-06 700E+00 147E-04 055 127E-06 675 711E-06 100E+01 147E-04 060 136E-06 750 766E-06 140E+01 208E-04 065 144E-06 900 877E-06 200E+01 227E-04 070 152E-06 1100 103E-05 080 168E-06 1300 118E-05 100 198E-06 1500 133E-05
Source Reference 221 Tables 1 and 3
36
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION
By def inition (Ref erence 2224 Equation 219) the estimated st atistic relative error of the i component is
Ri = Si
2
Equation 6Ti
where i = tally component index Ri = relative error of the i component S2
i = variance of the i component Ti = tally i component
For a result (ie dose rate) computed as a sum of different tallies the statistical relative error of the computed value is o btained from the variance of the result - S2
total which is th e sum of the estimated variances of the individual tallies S2
i n
2 2STotal = sum Si Equation 7 i=1
where S2Total = total estimated variance
n = total number of components Therefore the total tally value (dose rate) and the associated relative error are derived according to Equations 8 and 9
n TTotal = sumTi Equation 8
i=1
n n
sum (Ri timesTi )2
2 sum Si 2
STotal = i=1 = i=1 Equation 9RTotal = TTotal TTotal TTotal
where RTotal = total estimated relative error TTotal = total estimated tally
Equations 8 and 9 are utilized in Attachm ent II to ev aluate to tal dos e ra tes and their r elative errors
37
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
7 RESULTS AND CONCLUSIONS
71 RESULTS
The following sections summarize the results of this calculation Section 711 presents results for Conceptual Cask A while Section 712 for Conceptual Cask B Section 713 provides comparisons of the dose-rate reduction factors du e to the two conceptual casks and the axial source distributions in the active fuel region Do se rates and relative errors can be found in Attachment II within the output files and Excel files
711 Dose Rates of Conceptual Cask A
This section presents dose-rate results of the calculation sets 1 and 2 as described in Section 61 for Cask A Set 1 has axial p rofile sources in the active fuel region a nd consist of six runs resulting from the three PWR SNF source term s (maximum design basis and average) and the two radiation sources (gammas and neutrons) Set 2 has uniform axial sources in the active fuel region and consists of six run s r esulting f rom the th ree P WR SNF source term s and th e tw o radiation sources
As described in Section 61 dose ra tes are calculated at the three exterior surfaces (radial top and bottom) and at distances 1 m and 2 m from the exterior surfaces The total dose rates for set 1 are presented in Tables 13 14 and 15 for the ra dial top and bottom dire ctions respectively However the com ponents (primary gamma neutr on and secondary gamma) contributing to the total dose rates as well as the re lative error calculations can be found in Attachment II Excel file MCNP-Results1xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 2 are shown in Tables 16 17 and 18 The dose-rate components and the relative errors can be found in A ttachment II Excel file MCNP-Results2xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 13 and 16 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 14 and 17 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 15 and 18 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carrying th e maximum PWR SNF Based on the results in Tables 13 through 18 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask A indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these 6 tables the d ose-rate red uction f actors between the m aximum and the design basis fuels the maxim um and the averag e fuels and th e design basis and the average fuels are a lso presented
38
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 320E-02 00237 116E-02 00222 262E-03 00219 275 1223 445
1 m 133E-02 00164 494E-03 00171 106E-03 00162 269 1261 468 2 m 749E-03 00198 285E-03 00225 584E-04 00162 263 1282 488
Ring Detectors 1 m 133E-02 00116 492E-03 00115 108E-03 00124 271 1229 454 2 m 756E-03 00118 279E-03 00110 605E-04 00128 271 1250 462
Source Attachment II MCNP-Results1xls worksheet Summary
Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 142E-02 00368 628E-03 00446 934E-04 00483 226 1520 672
1 m 570E-03 00289 263E-03 00426 375E-04 00381 217 1520 701 2 m 265E-03 00364 123E-03 00547 169E-04 00374 216 1575 730
Point Detectors 1 m 598E-03 00238 274E-03 00271 402E-04 00354 219 1489 681 2 m 273E-03 00218 123E-03 00245 180E-04 00336 221 1515 684
Source Attachment II MCNP-Results1xls worksheet Summary
Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 653E-03 00298 265E-03 00276 510E-04 00341 247 1278 518
1 m 276E-03 00238 112E-03 00208 207E-04 00249 248 1334 539 2 m 125E-03 00185 508E-04 00199 933E-05 00246 246 1336 544
Point Detectors 1 m 291E-03 00227 118E-03 00203 218E-04 00242 247 1335 540 2 m 130E-03 00209 524E-04 00187 955E-05 00233 247 1357 549
Source Attachment II MCNP-Results1xls worksheet Summary
Tables 13 14 and 15 are results of calculation set 1 for conceptual Cask A with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
39
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 265E-02 00247 990E-03 00222 215E-03 00278 268 1234 461
1 m 116E-02 00178 468E-03 00549 960E-04 00189 248 1208 488 2 m 713E-03 00273 265E-03 00161 602E-04 00360 269 1184 439
Ring Detectors 1 m 117E-02 00120 454E-03 00132 979E-04 00141 259 1199 463 2 m 722E-03 00130 276E-03 00141 589E-04 00153 261 1226 469
Source Attachment II MCNP-Results2xls worksheet Summary
Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 199E-02 00461 827E-03 00455 147E-03 00536 241 1359 564
1 m 849E-03 00564 323E-03 00314 563E-04 00418 263 1507 574 2 m 415E-03 00832 158E-03 00603 253E-04 00501 263 1641 623
Point Detectors 1 m 877E-03 00348 353E-03 00275 615E-04 00391 248 1426 574 2 m 393E-03 00341 160E-03 00278 270E-04 00378 246 1454 590
Source Attachment II MCNP-Results2xls worksheet Summary
Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 879E-03 00374 356E-03 00333 669E-04 00406 247 1315 533
1 m 365E-03 00223 147E-03 00209 269E-04 00253 248 1358 548 2 m 164E-03 00229 674E-04 00205 120E-04 00248 243 1364 560
Point Detectors 1 m 383E-03 00217 155E-03 00204 285E-04 00248 247 1347 546 2 m 172E-03 00197 689E-04 00186 124E-04 00225 249 1391 558
Source Attachment II MCNP-Results2xls worksheet Summary
Tables 16 17 and 18 ar e results of calculation set 2 for conceptual Cask A with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
40
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Point Detector at 2 m x
Ring Ring Detector Detector at 2 m at 1 m
x x
Z = 00 cm
Z = 145 cm
Z = 175 cm
Z = 205 cm
Z = 235 cm
R = 80 cm
R = 120 cm
R = 40 cm
Active Fuel
Shield Plug
Top End-Fitting Plenum
Bottom End-Fitting
Ring Detector at 1 m
x
Point Detector at 1 m x
Ring Detector
at 2 m x
D = 26797 cm
H =
610
845
cm
Point Detector at 1 m x
Point Detector at 2 m x
Figure 1 Geometry and Tally Scheme for the TAD Transportation Cask
23
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
62 CALCULATION INPUT
Technical product input and sources of the input used in the deve lopment of this calculation are documented in this section Tables in this docum ent and in th e associated Microsoftreg Excel spreadsheets referenced m ay present num erical values with m any significant figures these values are not to be considered as high precision values since the significant figures are results of calculated values andor unit conversions
621 TAD Canister
The TAD canis ter will contain either 21 P WR or 44 BW R (boiling water reactor) SNF assemblies (Reference 2222 Section 321) While the canister design is iden tical for both PWR and BWR SNF assemblies the internal basket structure is different depending on the SNF assemblies However the internal basket stru cture m aterial is no t in cluded in the calcu lation model (Assumption 326)
The TAD canister is a right-circu lar cylinder with a diam eter of 665 in and a height between 186 and 212 in (Reference 2222 Section 321) The average and maximum total dose rates on the top surf ace of a loaded TAD ca nister must not exceed 800 and 1000 m remhr respectively (Reference 2222 Section 314) The TAD canister used in this calculation is m ade of SS 316 with a radial wall and bottom thickness of 025 in (Assumption 321) The top of the canister has a shield plug that is 11 in thick SS 316 (Ass umption 322) A thick shield plug is needed to keep the maxim um contact dose rate of th e top surface below 1000 m remhr The overall dimensions of the TAD canister are provided in Table 3
Table 3 Dimensions of TAD Canister
Component Dimension
(in) (cm)
Maximum heighta 212 53848
Outer diametera 665 16891
Thickness of bottom lidb 025 0635
Shell thicknessb 025 0635
Lifting Featurec 6 1524
Height without Lifting Feature 206 52324
Thickness of shield plugd 110 2794
aReference 2222 Section 311 bAssumption 321 cReference 2222 p Attachment C-1 dAssumption 322
622 Conceptual TAD Transportation Casks
Two conceptual TAD transportation casks designa ted as Cask A and Cask B are em ployed in this calculation (Assumption 323) They both have a cylindrical geometry with dimensions and materials specified in Tables 1 and 2 of Section 323 Cask A will provide shielding to meet the exterior radiation standards of 10 CFR 7147(b) (Reference 231) when loaded with a TAD
24
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
canister car rying the m aximum PWR SNF Cask B will s atisfy th e sa me radiatio n standa rds when loaded with a TAD canister c arrying the average PWR SNF The reason to analyze both Casks A and B is to cover a broad range of characteristics of the CSNF
The cavity dimensions of the conceptual cask s are 53785 cm (21175 in) in height and 16891 cm (665 in) in diam eter (Tab les 1 and 2) This cav ity will accommoda te the TAD canister described in Table 3 without the lifting feature This is the geometry model used in the MCNP5 calculations
623 Fuel Assembly Selection
PWR and BWR Source Term Sensitivity Study (Reference 2211 Tables 71 through 84) shows that the source terms generated for the Bamp W 15x15 Mark B fuel assembly with 475 kg uranium loading bound the source terms of other PWR assembly types ther efore this assembly type is selected as the representative PWR fuel assembly The gamma and neutron source terms for the BampW 15x15 Mark B assembly are generated in PWR Source Term Generation and Evaluation (Reference 229) and are used in this calculation
624 BampW 15x15 Mark B PWR Fuel Assembly
BampW 15x15 Mark B fuel assembly consists of four regions top end-fitting plenum active fuel and bottom end-fitting The m aterials and ra diation sources of each assem bly region are homogenized inside a volume defined by the region height and the interior diam eter of the TAD canister (Assumption 325) The active fuel region is homogenized with fresh unirradiated fuel (Assumption 324) Since the internal structure (i e basket) design of t he TAD is currently not finalized the com position of the hom ogenized fuel does not include the basket m aterials (Assumption 326) and therefore does not take cred it for any shielding that these m aterials may provide
Table 4 provides the design param eters for the BampW 15x15 Mark B fuel assembly Data provided here are used in Attachment II PWR_fuel compxls worksheet BampWassy
25
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 4 BampW 15x15 Mark B Fuel Assembly Description
Component Material Characteristic Value Specific Reference Array Size 15 x 15
Reference 2227 Table 2-2 Fuel Pins Assembly 208 Guide Tubes Assembly 16 Instrument Tubes Assembly 1
Assembly NA Pin Pellet Diameter 0936244 cm (03686 in) Reference 2220 p 2A-34 Pin Pitch 144272 cm (0568 in)
Reference 2227 Table 2-2 Active Fuel Height 360172 cm (1418 in) Assembly Width 2168144 cm (8536 in)
Reference 2220 p 2A-31 Assembly Height 4206875 cm (165625 in) Mass U assembly 46363 kg
Guide tube Zircaloy-4 Outer Diameter 13462 cm (053 in)
Reference 2227 Table 2-2
Inner Diameter 126492 cm (0498 in)
Instrument tube Zircaloy-4 Outer Diameter 138193 cm (05441 in) Inner Diameter 112014 cm (0441 in)
Cladding` Zircaloy-4 Inner Diameter 095758 cm (0377 in) Outer Diameter 10922 cm (043 in)
Plenum region NA Length 297688 cm (11720 in) Reference 2220 p 2A-34 Top nozzle SS CF3M MassAssembly (Top) 748 kg
Reference 2220 p 2A-32
Bottom nozzle SS CF3M MassAssembly (Bottom) 816 kg Guide tubes Zircaloy-4 MassAssembly (in Core) 80 kg Instrument tube Zircaloy-4 MassAssembly (in Core) 064 kg Spacer-plenum Inconel-718 MassAssembly (Plenum) 104 kg Spacer-bottom Inconel-718 MassAssembly (Bottom) 13 kg Spacer-in core Inconel-718 MassAssembly (in Core) 49 kg Spring retainer SS CF3M MassAssembly (Top) 091 kg Holddown spring Inconel-718 MassAssembly (Top) 18 kg Upper end plug SS 304 MassAssembly (Top) 006 kg Upper nut SS 304L MassAssembly (Top) 051 kg Lower nut SS 304 MassAssembly (Bottom) 015 kg Grid supports Zircaloy-4 MassAssembly (in Core) 064 kg Plenum spring SS 302 MassAssembly (Plenum) 0042 lb (001905 kg) Reference 2220 p 2A-34
Note Som e d ata i n this tab le ar e given i n British u nits in th e r eferences thes e d ata ar e converted into metric units as the inputs to MCNP5 are in metric units
The assem bly region heights as m odeled in MC NP are presented in Table 5 utilizing values from Table 4 Table 5 is taken from Dose Rate Calculation for Exhaust Main Drifts (Reference 2213 Table 3)
26
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 5 PWR Fuel Assembly Regions
Component Height Reference
Plenum 297688 cm (11720 in) Reference 2220 p 2A-34
Active Fuel 360172 cm (1418 in) Table 3
Bottom End-Fitting 1077 cm (424 in) Calculateda
Top End-Fitting 1998 cm (787 in) Calculatedb
Source Reference 2213 Table 3 aCalculated b ased on data Reference 2227 F igures 2-3 an d 2-7
(Region 9 Height [16723 cm] + Region 10 Height [508 cm] ndash Lo wer Fuel Plenum and End Cap [11033 cm])
bCalculated (Assembly Length ndash Active Fuel Length ndash P lenum Length ndash Bottom End-fitting Length)
625 Material Compositions
The TAD transportation cask com ponent m aterial specifications are defined in Table 1 The TAD canister is constructed of SS 316 (Assumpti on 321) The PWR fuel assembly materials used to homogenize the fuel regions are defined in Table 4 Table 6 c ontains the m aterial compositions defining the TAD canister WP and fuel assemblies
27
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 6 Chemical Compositions of Materials
Material Density (gcc)
Isotopic Weight Percent Reference
SS 302 NA
C 0150 Mn 2000 P 0045 S 0030 Si 0750 Cr 18000 Ni 9000 N 0100 Fe 69925
Attachment II PWR_fuel compxls worksheet ferrous Reference 222 SEC II A SA-240 Table 1 for SS 302 SS 304 and SS 304L Reference 222 SEC II A SA-351SA -351M Table 2 for SS CF3M
SS 304 NA
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 9250 N 0100 Fe 68745
SS 304L NA
C 003 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 10000 N 0100 Fe 6804 5
SS CF3M NA
C 0030 Mn 1500 P 0040 S 0040 Si 1500 Cr 19000 Ni 11000 Mo 2500 Fe 64390
Inconel 718 NA
C 0080 Mn 0350 Si 0350 Cr 19000 Ni 52500 Co 1000 Mo 3050 Fe 16809 Nb 5125 Ti 0900 Al 0500 Cu 0300 S 0015 P 0015 B 0006
Attachment II PWR_fuel compxls worksheet alloys aReference 223 p 666 Table 6 Reference 222 SEC II B SB-637 Table 1 for Inconel 718 Reference 224 Table 2 for Zircaloy 4
Zircaloy 4 656a Cr 0100 Fe 0210 O 0125 Sn 1450 Zr 98115
SS 316 798b
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 17000 Ni 12000 Mo 2500 N 0100 Fe 65495
Attachment II PWR_fuel compxls worksheet others Reference 222 SEC II A SA-240 Table 1 for SS 316 bReference 225 Table X1
626 Homogenization Assembly Materials
The atom density of an element or isotope in atomsbmiddotcm in a homogenized region is calculated according to the following equation (Reference 2223 Appendix B)
M i times N AvogadroNi = Equation 1 Ai timesV times K
where Ni = Atom density of elementisotope i (atomsbmiddotcm) Mi = Mass of elementisotope i (g) NAvogadro = Avogadrorsquos constant 06022 x 1024 (atomsmole)
28
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Ai = Atomic weight of elementisotope i (gmole) V = Homogenization volume (cm3) K = Unit transformation constant = 1024 (bmiddotcmcm3)
Equation 1 is used in A ttachment II spreadsheet PWR_fuel compxls worksheet BampWassy to calculate th e atom dens ities for v arious elem ents and iso topes The m ass of elementsisotop es and Avogadrorsquos constant are provided in Reference 2226
Table 7 lists the com position of the hom ogenized assem bly regions (active fuel plenum top end-fitting and bottom end-fitting) for the PWR assembly The active fuel region contains fresh unirradiated fuel (Assumption 324) Since the internal structure (ie basket) design of the TAD is currently not finalized the composition of either homogenized fuel does not include the basket materials and therefore does not tak e credit for any shielding that thes e materials may provide (Assumption 326)
Table 7 Isotopic Compositions of Homogenized PWR Assembly Regions
Element Isotope
Atom Densities for Homogenized Regions (atomsbsdotcm)
Active Fuel Bottom End-Fitting Plenum Top End-Fitting
10B 861E-09 764E-08 221E-08 570E-08 11B 347E-08 307E-07 890E-08 230E-07 C 519E-07 160E-05 138E-06 993E-06 N -- 570E-07 262E-08 117E-06 O 621E-03 -- 142E-05 -- Al 144E-06 128E-05 371E-06 957E-06 Si 971E-07 243E-04 259E-06 139E-04 P 377E-08 606E-06 102E-07 360E-06 S 365E-08 581E-06 971E-08 340E-06 Ti 147E-06 130E-05 376E-06 971E-06 Cr 320E-05 187E-03 779E-05 113E-03 Mn 497E-07 126E-04 141E-06 749E-05 Fe 303E-05 531E-03 717E-05 313E-03 Co 132E-06 117E-05 340E-06 876E-06 Ni 697E-05 144E-03 180E-04 940E-04 Cu 368E-07 327E-06 945E-07 244E-06 Zr 196E-03 -- 195E-03 -- Nb 430E-06 382E-05 110E-05 285E-05 Mo 248E-06 135E-04 636E-06 791E-05 Sn 223E-05 -- 222E-05 -- 234U 139E-06 -- -- -- 235U 157E-04 -- -- -- 236U 719E-07 -- -- -- 238U 294E-03 -- -- -- Total 114E-02 924E-03 235E-03 557E-03
Source Attachment II spreadsheet PWR_fuel compxls worksheet BampWassy
29
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
The isotopic composition of commercially available 235U enriched uranium is determined by the given initial 235U enrichment using the following equations (Reference 226 p 20)
wt235U =235Uenrichment _ of _ the _ associated _ fuel _ batch Equation 2
wt234U = 0007731times (wt235U )10837 Equation 3
wt236U = 00046times (wt235U ) Equation 4
wt238U =100 minus (wt234U + wt235U + wt236U ) Equation 5
The weight percentages of uran ium isotopes for PWR fuel are ca lculated in Attachm ent II spreadsheet PWR_fuel compxls worksheet BampWassy using Equations 2 through 5
627 PWR Source Terms
This calculation uses the following three PWR source terms bull Maximum source (50 wt initial 235U enrichment 80 GWdMTU burnup and 5-year
decay time) (Reference 229 Section 55) Table 8 lists th e gamma source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Design Basis source (4 0 wt initial 235U enrichment 60 GW dMTU burnup and 10-year decay tim e) (Reference 228 Section 552) Table 9 lists the gamm a source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Average source ( 40 wt initial 235U enrichment 48 GWdMTU burnup and 25-year decay time) (Reference 229 Section 55) Table 10 lists the gamma source terms for the fuel and non-fuel regions and the neutron source term for the fuel region
These sources (ie maximum design basis and av erage) are described in this section For dose rate calculations all the fuel assemblies in a transportation cask are of the sam e characteristics Also gamma radiation source term s for the PWR assem bly are prov ided for the f our assembly regions while neutron source term is only present in the active fuel region Gamma radiation sources in the non-active fuel region are distri buted unif ormly within each source region Gamma and neutron sources in the active fuel re gion are modeled as uni form distributions or with axial source profiles
The PWR gamma and neutron axial source profiles for the active fuel region presented in Table 11 are applied to the active fuel region of all three source terms (ie maximum design basis and average) when appropriate
30
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 8 Gamma and Neutron Sources for the Maximum PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting
Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 594E+11 233E+15 528E+11 379E+11 100E-01 000E+00 100E-01 116E+11 644E+14 609E+10 743E+10 400E-01 805E+07 200E-01 283E+10 522E+14 352E+10 179E+10 900E-01 411E+08 300E-01 141E+09 148E+14 196E+09 891E+08 140E+00 376E+08 400E-01 190E+09 985E+13 586E+09 117E+09 185E+00 276E+08 600E-01 191E+09 153E+15 110E+11 741E+07 300E+00 485E+08 800E-01 435E+09 470E+15 595E+10 237E+09 643E+00 443E+08 100E+00 137E+11 708E+14 803E+09 766E+10 200E+01 393E+07 133E+00 338E+13 455E+14 174E+13 217E+13 Total 211E+09 166E+00 953E+12 130E+14 491E+12 612E+12
--
200E+00 187E+03 144E+12 919E+02 113E+03 250E+00 226E+08 249E+12 116E+08 145E+08 300E+00 351E+05 110E+11 181E+05 225E+05 400E+00 766E-08 139E+10 100E-08 416E-08 500E+00 000E+00 709E+07 000E+00 000E+00 650E+00 000E+00 286E+07 000E+00 000E+00 800E+00 000E+00 558E+06 000E+00 000E+00 100E+01 000E+00 119E+06 000E+00 000E+00
Total 442E+13 113E+16 231E+13 284E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE2R2B14cut bWasteStreamE2R1B14cut cWasteStreamE2R3B14cut dWasteStreamE2R4B14cut
31
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 9 Gamma and Neutron Sources for the Design Basis PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary
(MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 273E+11 121E+15 188E+11 175E+11 100E-01 000E+00 100E-01 528E+10 329E+14 277E+10 339E+10 400E-01 316E+07 200E-01 128E+10 245E+14 117E+10 819E+09 900E-01 161E+08 300E-01 639E+08 713E+13 633E+08 407E+08 140E+00 148E+08 400E-01 850E+08 455E+13 164E+09 533E+08 185E+00 109E+08 600E-01 492E+08 226E+14 269E+10 337E+07 300E+00 191E+08 800E-01 291E+09 237E+15 160E+10 186E+09 643E+00 174E+08 100E+00 540E+09 122E+14 248E+09 341E+09 200E+01 154E+07 133E+00 154E+13 195E+14 797E+12 990E+12 Total 830E+08 166E+00 435E+12 450E+13 225E+12 280E+12
--
200E+00 235E+00 152E+11 149E+02 215E-02 250E+00 103E+08 517E+10 534E+07 664E+07 300E+00 160E+05 379E+09 829E+04 103E+05 400E+00 943E-10 497E+08 155E-10 519E-10 500E+00 000E+00 282E+07 000E+00 000E+00 650E+00 000E+00 113E+07 000E+00 000E+00 800E+00 000E+00 222E+06 000E+00 000E+00 100E+01 000E+00 471E+05 000E+00 000E+00
Total 201E+13 486E+15 105E+13 129E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B11cut bWasteStreamE5R1B11cut cWasteStreamE5R3B11cut dWasteStreamE5R4B11cut
32
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 10 Gamma and Neutron Sources for the Average PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 336E+10 670E+14 186E+10 217E+10 100E-01 00000E+00 100E-01 602E+09 199E+14 314E+09 387E+09 400E-01 748E+06 200E-01 146E+09 126E+14 853E+08 936E+08 900E-01 382E+07 300E-01 730E+07 389E+13 439E+07 469E+07 140E+00 352E+07 400E-01 947E+07 263E+13 716E+07 607E+07 185E+00 261E+07 600E-01 141E+07 205E+13 504E+08 383E+06 300E+00 469E+07 800E-01 208E+09 124E+15 192E+09 144E+09 643E+00 418E+07 100E+00 208E+09 110E+13 164E+09 144E+09 200E+01 365E+06 133E+00 175E+12 295E+13 909E+11 112E+12 Total 199E+08 166E+00 494E+11 513E+12 257E+11 318E+11
--
200E+00 973E-01 675E+10 614E+01 872E-03 250E+00 117E+07 353E+09 609E+06 754E+06 300E+00 182E+04 288E+08 944E+03 117E+04 400E+00 186E-11 198E+07 149E-11 127E-11 500E+00 000E+00 669E+06 000E+00 000E+00 650E+00 000E+00 269E+06 000E+00 000E+00 800E+00 000E+00 527E+05 000E+00 000E+00 100E+01 000E+00 112E+05 000E+00 000E+00
Total 229E+12 237E+15 119E+12 147E+12
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B9cut bWasteStreamE5R1B9cut cWasteStreamE5R3B9cut dWasteStreamE5R4B9cut
33
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 11 Gamma and Neutron Axial Source Profiles for a PWR Assembly
Axial boundaries (From midplane)
(cm)
TOP BOTTOM
Neutron Gamma Ne utron Gamma 000 1554 1117 1554 1117 1143 1537 1114 1571 1120 2286 1521 1111 1588 1123 3429 1504 1108 1605 1126 4572 1486 1104 1622 1129 5715 1464 1100 1636 1131 6858 1438 1095 1648 1133 8001 1401 1088 1657 1135 9144 1350 1078 1654 1134
10287 1277 1063 1625 1129 11430 1165 1039 1554 1117 12573 0998 09995 1414 1091 13716 0769 09365 1172 1041 14859 0492 08375 0816 0951 16002 0220 06850 0402 0797 17145 0046 04625 0092 0551 18288 00 00 00 00
Source Reference 2219 Table S445
34
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
63 MCNP SPECIFIC INPUT
631 Source Probability
A linear radial distribution is used for all gamma and neutron sources The linear radial distribution is sam pled usi ng the built-in power function p(x) = xc a with a = 1 for the radial direction This sampling method results in a uniform source distribution over the area bounded by the outer radius of the source
The source axial distributions are unifor m for all four source regions The a xial uni form xp(x) = c distribution is sampled using the built-in power function a with a = 0 for extent
The energy distribu tions of the gamma and neutron sour ce term s are treated as energ y probabilities and are applied in MCNP5 using SISP cards
632 Dose Rate and Flux Tallies
MCNP5 dose rate calculations feature separate runs for the following calculation types
bull a photon transport calculation for prim ary ga mma contribution to the dose rates fr om photon fluxes
bull a coupled neutronphoton transport calculat ion for neutrons a nd secondary gamma (photons generated by neutron be ing captured) contributions to dose rates from neutron and gamma fluxes
The tally type F2 is us ed in th is d esign ca lculation as f lux estim ators The type F2 tally evaluates the flux averaged over a surface in particlescm2s
To generate dose ra tes in te rms of remhr the FM (tally multiplier ) and DEDF (dose energydose conversion factors) cards are used to en ter the tally multiplier f actor (source intensity in particless) energy boundaries in MeV and corresponding dose conversion factors in (remhr)(particlescm2s) respectively These factors were used in the input files
In order for the F2 tally to accum ulate flux ov er a surface a specific s urface area is requ ired The SD cards are used to enter a surface area in cm2 over which the flux will be tallied for an F2 tally
633 Variance Reduction Techniques
Variance reduction technique is usually em ployed in order to increase the efficiency of a calculation and obtain statistically m eaningful results within re asonable com puter tim e In Monte Carlo calculations when variance reduction scheme is employed the weights of particles are adjusted in order to account for the biasing and to preserve a fair game
Geometry splitting and Russian roulette techniques described in Reference 2224 (pp 2-140 ndash 2-142) are useful in shielding calculations and therefore deployed in all the MCNP5 runs
35
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
As particles migrate in an important direction (toward the detector) they are increased in number to provide better sampling by means of geometry splitting across geometric boundaries Russian roulette (the reverse process) is played when particles travel in an unimportant direction to allow termination of unim portant histories The IMP card required for every cel l ca rd is us ed to implement this technique
The other variance reduction technique deployed in the MC NP5 runs is source intensity biasing for the gamma sources from the four source regions (active fuel bottom end-fitting plenum and top end-fitting) The natural total gamma source intensity of comm ercial SNF is dom inated by the gamma source in the active fuel region This active fuel gamma source usually accounts for over 95 o f the total g amma source intens ity In order to im prove the efficiency of the axial dose rate calculations a biased source probability distribution is employed for the prim ary gamma dose rate calculations The biased gamma source probability distribution is chosen to be 005 080 010 and 005 for the bottom end-fitting the active fuel the plenum and the top end-fitting regions respectively
64 DOSE CONVERSION FACTORS
Project Design Criteria Document (Reference 2211 Se ction 41015) requires the use of flux-to-dose rate conversion fact ors from ANSIANS-611-1977 (Reference 221) for dose rate evaluations Table 16 lists the neutron and ga mma dose conversion factors used in the MCNP5 calculations
Table 12 Gamma and Neutron Flux to Dose Conversion Factors
Gamma Neutron Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
001 396E-06 140 251E-06 250E-08 367E-06 003 582E-07 180 299E-06 100E-07 367E-06 005 290E-07 220 342E-06 100E-06 446E-06 007 258E-07 260 382E-06 100E-05 454E-06 010 283E-07 280 401E-06 100E-04 418E-06 015 379E-07 325 441E-06 100E-03 376E-06 020 501E-07 375 483E-06 100E-02 356E-06 025 631E-07 425 523E-06 100E-01 217E-05 030 759E-07 475 560E-06 500E-01 926E-05 035 878E-07 500 580E-06 100E+00 132E-04 040 985E-07 525 601E-06 250E+00 125E-04 045 108E-06 575 637E-06 500E+00 156E-04 050 117E-06 625 674E-06 700E+00 147E-04 055 127E-06 675 711E-06 100E+01 147E-04 060 136E-06 750 766E-06 140E+01 208E-04 065 144E-06 900 877E-06 200E+01 227E-04 070 152E-06 1100 103E-05 080 168E-06 1300 118E-05 100 198E-06 1500 133E-05
Source Reference 221 Tables 1 and 3
36
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION
By def inition (Ref erence 2224 Equation 219) the estimated st atistic relative error of the i component is
Ri = Si
2
Equation 6Ti
where i = tally component index Ri = relative error of the i component S2
i = variance of the i component Ti = tally i component
For a result (ie dose rate) computed as a sum of different tallies the statistical relative error of the computed value is o btained from the variance of the result - S2
total which is th e sum of the estimated variances of the individual tallies S2
i n
2 2STotal = sum Si Equation 7 i=1
where S2Total = total estimated variance
n = total number of components Therefore the total tally value (dose rate) and the associated relative error are derived according to Equations 8 and 9
n TTotal = sumTi Equation 8
i=1
n n
sum (Ri timesTi )2
2 sum Si 2
STotal = i=1 = i=1 Equation 9RTotal = TTotal TTotal TTotal
where RTotal = total estimated relative error TTotal = total estimated tally
Equations 8 and 9 are utilized in Attachm ent II to ev aluate to tal dos e ra tes and their r elative errors
37
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
7 RESULTS AND CONCLUSIONS
71 RESULTS
The following sections summarize the results of this calculation Section 711 presents results for Conceptual Cask A while Section 712 for Conceptual Cask B Section 713 provides comparisons of the dose-rate reduction factors du e to the two conceptual casks and the axial source distributions in the active fuel region Do se rates and relative errors can be found in Attachment II within the output files and Excel files
711 Dose Rates of Conceptual Cask A
This section presents dose-rate results of the calculation sets 1 and 2 as described in Section 61 for Cask A Set 1 has axial p rofile sources in the active fuel region a nd consist of six runs resulting from the three PWR SNF source term s (maximum design basis and average) and the two radiation sources (gammas and neutrons) Set 2 has uniform axial sources in the active fuel region and consists of six run s r esulting f rom the th ree P WR SNF source term s and th e tw o radiation sources
As described in Section 61 dose ra tes are calculated at the three exterior surfaces (radial top and bottom) and at distances 1 m and 2 m from the exterior surfaces The total dose rates for set 1 are presented in Tables 13 14 and 15 for the ra dial top and bottom dire ctions respectively However the com ponents (primary gamma neutr on and secondary gamma) contributing to the total dose rates as well as the re lative error calculations can be found in Attachment II Excel file MCNP-Results1xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 2 are shown in Tables 16 17 and 18 The dose-rate components and the relative errors can be found in A ttachment II Excel file MCNP-Results2xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 13 and 16 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 14 and 17 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 15 and 18 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carrying th e maximum PWR SNF Based on the results in Tables 13 through 18 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask A indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these 6 tables the d ose-rate red uction f actors between the m aximum and the design basis fuels the maxim um and the averag e fuels and th e design basis and the average fuels are a lso presented
38
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 320E-02 00237 116E-02 00222 262E-03 00219 275 1223 445
1 m 133E-02 00164 494E-03 00171 106E-03 00162 269 1261 468 2 m 749E-03 00198 285E-03 00225 584E-04 00162 263 1282 488
Ring Detectors 1 m 133E-02 00116 492E-03 00115 108E-03 00124 271 1229 454 2 m 756E-03 00118 279E-03 00110 605E-04 00128 271 1250 462
Source Attachment II MCNP-Results1xls worksheet Summary
Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 142E-02 00368 628E-03 00446 934E-04 00483 226 1520 672
1 m 570E-03 00289 263E-03 00426 375E-04 00381 217 1520 701 2 m 265E-03 00364 123E-03 00547 169E-04 00374 216 1575 730
Point Detectors 1 m 598E-03 00238 274E-03 00271 402E-04 00354 219 1489 681 2 m 273E-03 00218 123E-03 00245 180E-04 00336 221 1515 684
Source Attachment II MCNP-Results1xls worksheet Summary
Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 653E-03 00298 265E-03 00276 510E-04 00341 247 1278 518
1 m 276E-03 00238 112E-03 00208 207E-04 00249 248 1334 539 2 m 125E-03 00185 508E-04 00199 933E-05 00246 246 1336 544
Point Detectors 1 m 291E-03 00227 118E-03 00203 218E-04 00242 247 1335 540 2 m 130E-03 00209 524E-04 00187 955E-05 00233 247 1357 549
Source Attachment II MCNP-Results1xls worksheet Summary
Tables 13 14 and 15 are results of calculation set 1 for conceptual Cask A with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
39
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 265E-02 00247 990E-03 00222 215E-03 00278 268 1234 461
1 m 116E-02 00178 468E-03 00549 960E-04 00189 248 1208 488 2 m 713E-03 00273 265E-03 00161 602E-04 00360 269 1184 439
Ring Detectors 1 m 117E-02 00120 454E-03 00132 979E-04 00141 259 1199 463 2 m 722E-03 00130 276E-03 00141 589E-04 00153 261 1226 469
Source Attachment II MCNP-Results2xls worksheet Summary
Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 199E-02 00461 827E-03 00455 147E-03 00536 241 1359 564
1 m 849E-03 00564 323E-03 00314 563E-04 00418 263 1507 574 2 m 415E-03 00832 158E-03 00603 253E-04 00501 263 1641 623
Point Detectors 1 m 877E-03 00348 353E-03 00275 615E-04 00391 248 1426 574 2 m 393E-03 00341 160E-03 00278 270E-04 00378 246 1454 590
Source Attachment II MCNP-Results2xls worksheet Summary
Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 879E-03 00374 356E-03 00333 669E-04 00406 247 1315 533
1 m 365E-03 00223 147E-03 00209 269E-04 00253 248 1358 548 2 m 164E-03 00229 674E-04 00205 120E-04 00248 243 1364 560
Point Detectors 1 m 383E-03 00217 155E-03 00204 285E-04 00248 247 1347 546 2 m 172E-03 00197 689E-04 00186 124E-04 00225 249 1391 558
Source Attachment II MCNP-Results2xls worksheet Summary
Tables 16 17 and 18 ar e results of calculation set 2 for conceptual Cask A with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
40
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
62 CALCULATION INPUT
Technical product input and sources of the input used in the deve lopment of this calculation are documented in this section Tables in this docum ent and in th e associated Microsoftreg Excel spreadsheets referenced m ay present num erical values with m any significant figures these values are not to be considered as high precision values since the significant figures are results of calculated values andor unit conversions
621 TAD Canister
The TAD canis ter will contain either 21 P WR or 44 BW R (boiling water reactor) SNF assemblies (Reference 2222 Section 321) While the canister design is iden tical for both PWR and BWR SNF assemblies the internal basket structure is different depending on the SNF assemblies However the internal basket stru cture m aterial is no t in cluded in the calcu lation model (Assumption 326)
The TAD canister is a right-circu lar cylinder with a diam eter of 665 in and a height between 186 and 212 in (Reference 2222 Section 321) The average and maximum total dose rates on the top surf ace of a loaded TAD ca nister must not exceed 800 and 1000 m remhr respectively (Reference 2222 Section 314) The TAD canister used in this calculation is m ade of SS 316 with a radial wall and bottom thickness of 025 in (Assumption 321) The top of the canister has a shield plug that is 11 in thick SS 316 (Ass umption 322) A thick shield plug is needed to keep the maxim um contact dose rate of th e top surface below 1000 m remhr The overall dimensions of the TAD canister are provided in Table 3
Table 3 Dimensions of TAD Canister
Component Dimension
(in) (cm)
Maximum heighta 212 53848
Outer diametera 665 16891
Thickness of bottom lidb 025 0635
Shell thicknessb 025 0635
Lifting Featurec 6 1524
Height without Lifting Feature 206 52324
Thickness of shield plugd 110 2794
aReference 2222 Section 311 bAssumption 321 cReference 2222 p Attachment C-1 dAssumption 322
622 Conceptual TAD Transportation Casks
Two conceptual TAD transportation casks designa ted as Cask A and Cask B are em ployed in this calculation (Assumption 323) They both have a cylindrical geometry with dimensions and materials specified in Tables 1 and 2 of Section 323 Cask A will provide shielding to meet the exterior radiation standards of 10 CFR 7147(b) (Reference 231) when loaded with a TAD
24
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
canister car rying the m aximum PWR SNF Cask B will s atisfy th e sa me radiatio n standa rds when loaded with a TAD canister c arrying the average PWR SNF The reason to analyze both Casks A and B is to cover a broad range of characteristics of the CSNF
The cavity dimensions of the conceptual cask s are 53785 cm (21175 in) in height and 16891 cm (665 in) in diam eter (Tab les 1 and 2) This cav ity will accommoda te the TAD canister described in Table 3 without the lifting feature This is the geometry model used in the MCNP5 calculations
623 Fuel Assembly Selection
PWR and BWR Source Term Sensitivity Study (Reference 2211 Tables 71 through 84) shows that the source terms generated for the Bamp W 15x15 Mark B fuel assembly with 475 kg uranium loading bound the source terms of other PWR assembly types ther efore this assembly type is selected as the representative PWR fuel assembly The gamma and neutron source terms for the BampW 15x15 Mark B assembly are generated in PWR Source Term Generation and Evaluation (Reference 229) and are used in this calculation
624 BampW 15x15 Mark B PWR Fuel Assembly
BampW 15x15 Mark B fuel assembly consists of four regions top end-fitting plenum active fuel and bottom end-fitting The m aterials and ra diation sources of each assem bly region are homogenized inside a volume defined by the region height and the interior diam eter of the TAD canister (Assumption 325) The active fuel region is homogenized with fresh unirradiated fuel (Assumption 324) Since the internal structure (i e basket) design of t he TAD is currently not finalized the com position of the hom ogenized fuel does not include the basket m aterials (Assumption 326) and therefore does not take cred it for any shielding that these m aterials may provide
Table 4 provides the design param eters for the BampW 15x15 Mark B fuel assembly Data provided here are used in Attachment II PWR_fuel compxls worksheet BampWassy
25
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 4 BampW 15x15 Mark B Fuel Assembly Description
Component Material Characteristic Value Specific Reference Array Size 15 x 15
Reference 2227 Table 2-2 Fuel Pins Assembly 208 Guide Tubes Assembly 16 Instrument Tubes Assembly 1
Assembly NA Pin Pellet Diameter 0936244 cm (03686 in) Reference 2220 p 2A-34 Pin Pitch 144272 cm (0568 in)
Reference 2227 Table 2-2 Active Fuel Height 360172 cm (1418 in) Assembly Width 2168144 cm (8536 in)
Reference 2220 p 2A-31 Assembly Height 4206875 cm (165625 in) Mass U assembly 46363 kg
Guide tube Zircaloy-4 Outer Diameter 13462 cm (053 in)
Reference 2227 Table 2-2
Inner Diameter 126492 cm (0498 in)
Instrument tube Zircaloy-4 Outer Diameter 138193 cm (05441 in) Inner Diameter 112014 cm (0441 in)
Cladding` Zircaloy-4 Inner Diameter 095758 cm (0377 in) Outer Diameter 10922 cm (043 in)
Plenum region NA Length 297688 cm (11720 in) Reference 2220 p 2A-34 Top nozzle SS CF3M MassAssembly (Top) 748 kg
Reference 2220 p 2A-32
Bottom nozzle SS CF3M MassAssembly (Bottom) 816 kg Guide tubes Zircaloy-4 MassAssembly (in Core) 80 kg Instrument tube Zircaloy-4 MassAssembly (in Core) 064 kg Spacer-plenum Inconel-718 MassAssembly (Plenum) 104 kg Spacer-bottom Inconel-718 MassAssembly (Bottom) 13 kg Spacer-in core Inconel-718 MassAssembly (in Core) 49 kg Spring retainer SS CF3M MassAssembly (Top) 091 kg Holddown spring Inconel-718 MassAssembly (Top) 18 kg Upper end plug SS 304 MassAssembly (Top) 006 kg Upper nut SS 304L MassAssembly (Top) 051 kg Lower nut SS 304 MassAssembly (Bottom) 015 kg Grid supports Zircaloy-4 MassAssembly (in Core) 064 kg Plenum spring SS 302 MassAssembly (Plenum) 0042 lb (001905 kg) Reference 2220 p 2A-34
Note Som e d ata i n this tab le ar e given i n British u nits in th e r eferences thes e d ata ar e converted into metric units as the inputs to MCNP5 are in metric units
The assem bly region heights as m odeled in MC NP are presented in Table 5 utilizing values from Table 4 Table 5 is taken from Dose Rate Calculation for Exhaust Main Drifts (Reference 2213 Table 3)
26
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 5 PWR Fuel Assembly Regions
Component Height Reference
Plenum 297688 cm (11720 in) Reference 2220 p 2A-34
Active Fuel 360172 cm (1418 in) Table 3
Bottom End-Fitting 1077 cm (424 in) Calculateda
Top End-Fitting 1998 cm (787 in) Calculatedb
Source Reference 2213 Table 3 aCalculated b ased on data Reference 2227 F igures 2-3 an d 2-7
(Region 9 Height [16723 cm] + Region 10 Height [508 cm] ndash Lo wer Fuel Plenum and End Cap [11033 cm])
bCalculated (Assembly Length ndash Active Fuel Length ndash P lenum Length ndash Bottom End-fitting Length)
625 Material Compositions
The TAD transportation cask com ponent m aterial specifications are defined in Table 1 The TAD canister is constructed of SS 316 (Assumpti on 321) The PWR fuel assembly materials used to homogenize the fuel regions are defined in Table 4 Table 6 c ontains the m aterial compositions defining the TAD canister WP and fuel assemblies
27
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 6 Chemical Compositions of Materials
Material Density (gcc)
Isotopic Weight Percent Reference
SS 302 NA
C 0150 Mn 2000 P 0045 S 0030 Si 0750 Cr 18000 Ni 9000 N 0100 Fe 69925
Attachment II PWR_fuel compxls worksheet ferrous Reference 222 SEC II A SA-240 Table 1 for SS 302 SS 304 and SS 304L Reference 222 SEC II A SA-351SA -351M Table 2 for SS CF3M
SS 304 NA
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 9250 N 0100 Fe 68745
SS 304L NA
C 003 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 10000 N 0100 Fe 6804 5
SS CF3M NA
C 0030 Mn 1500 P 0040 S 0040 Si 1500 Cr 19000 Ni 11000 Mo 2500 Fe 64390
Inconel 718 NA
C 0080 Mn 0350 Si 0350 Cr 19000 Ni 52500 Co 1000 Mo 3050 Fe 16809 Nb 5125 Ti 0900 Al 0500 Cu 0300 S 0015 P 0015 B 0006
Attachment II PWR_fuel compxls worksheet alloys aReference 223 p 666 Table 6 Reference 222 SEC II B SB-637 Table 1 for Inconel 718 Reference 224 Table 2 for Zircaloy 4
Zircaloy 4 656a Cr 0100 Fe 0210 O 0125 Sn 1450 Zr 98115
SS 316 798b
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 17000 Ni 12000 Mo 2500 N 0100 Fe 65495
Attachment II PWR_fuel compxls worksheet others Reference 222 SEC II A SA-240 Table 1 for SS 316 bReference 225 Table X1
626 Homogenization Assembly Materials
The atom density of an element or isotope in atomsbmiddotcm in a homogenized region is calculated according to the following equation (Reference 2223 Appendix B)
M i times N AvogadroNi = Equation 1 Ai timesV times K
where Ni = Atom density of elementisotope i (atomsbmiddotcm) Mi = Mass of elementisotope i (g) NAvogadro = Avogadrorsquos constant 06022 x 1024 (atomsmole)
28
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Ai = Atomic weight of elementisotope i (gmole) V = Homogenization volume (cm3) K = Unit transformation constant = 1024 (bmiddotcmcm3)
Equation 1 is used in A ttachment II spreadsheet PWR_fuel compxls worksheet BampWassy to calculate th e atom dens ities for v arious elem ents and iso topes The m ass of elementsisotop es and Avogadrorsquos constant are provided in Reference 2226
Table 7 lists the com position of the hom ogenized assem bly regions (active fuel plenum top end-fitting and bottom end-fitting) for the PWR assembly The active fuel region contains fresh unirradiated fuel (Assumption 324) Since the internal structure (ie basket) design of the TAD is currently not finalized the composition of either homogenized fuel does not include the basket materials and therefore does not tak e credit for any shielding that thes e materials may provide (Assumption 326)
Table 7 Isotopic Compositions of Homogenized PWR Assembly Regions
Element Isotope
Atom Densities for Homogenized Regions (atomsbsdotcm)
Active Fuel Bottom End-Fitting Plenum Top End-Fitting
10B 861E-09 764E-08 221E-08 570E-08 11B 347E-08 307E-07 890E-08 230E-07 C 519E-07 160E-05 138E-06 993E-06 N -- 570E-07 262E-08 117E-06 O 621E-03 -- 142E-05 -- Al 144E-06 128E-05 371E-06 957E-06 Si 971E-07 243E-04 259E-06 139E-04 P 377E-08 606E-06 102E-07 360E-06 S 365E-08 581E-06 971E-08 340E-06 Ti 147E-06 130E-05 376E-06 971E-06 Cr 320E-05 187E-03 779E-05 113E-03 Mn 497E-07 126E-04 141E-06 749E-05 Fe 303E-05 531E-03 717E-05 313E-03 Co 132E-06 117E-05 340E-06 876E-06 Ni 697E-05 144E-03 180E-04 940E-04 Cu 368E-07 327E-06 945E-07 244E-06 Zr 196E-03 -- 195E-03 -- Nb 430E-06 382E-05 110E-05 285E-05 Mo 248E-06 135E-04 636E-06 791E-05 Sn 223E-05 -- 222E-05 -- 234U 139E-06 -- -- -- 235U 157E-04 -- -- -- 236U 719E-07 -- -- -- 238U 294E-03 -- -- -- Total 114E-02 924E-03 235E-03 557E-03
Source Attachment II spreadsheet PWR_fuel compxls worksheet BampWassy
29
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
The isotopic composition of commercially available 235U enriched uranium is determined by the given initial 235U enrichment using the following equations (Reference 226 p 20)
wt235U =235Uenrichment _ of _ the _ associated _ fuel _ batch Equation 2
wt234U = 0007731times (wt235U )10837 Equation 3
wt236U = 00046times (wt235U ) Equation 4
wt238U =100 minus (wt234U + wt235U + wt236U ) Equation 5
The weight percentages of uran ium isotopes for PWR fuel are ca lculated in Attachm ent II spreadsheet PWR_fuel compxls worksheet BampWassy using Equations 2 through 5
627 PWR Source Terms
This calculation uses the following three PWR source terms bull Maximum source (50 wt initial 235U enrichment 80 GWdMTU burnup and 5-year
decay time) (Reference 229 Section 55) Table 8 lists th e gamma source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Design Basis source (4 0 wt initial 235U enrichment 60 GW dMTU burnup and 10-year decay tim e) (Reference 228 Section 552) Table 9 lists the gamm a source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Average source ( 40 wt initial 235U enrichment 48 GWdMTU burnup and 25-year decay time) (Reference 229 Section 55) Table 10 lists the gamma source terms for the fuel and non-fuel regions and the neutron source term for the fuel region
These sources (ie maximum design basis and av erage) are described in this section For dose rate calculations all the fuel assemblies in a transportation cask are of the sam e characteristics Also gamma radiation source term s for the PWR assem bly are prov ided for the f our assembly regions while neutron source term is only present in the active fuel region Gamma radiation sources in the non-active fuel region are distri buted unif ormly within each source region Gamma and neutron sources in the active fuel re gion are modeled as uni form distributions or with axial source profiles
The PWR gamma and neutron axial source profiles for the active fuel region presented in Table 11 are applied to the active fuel region of all three source terms (ie maximum design basis and average) when appropriate
30
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 8 Gamma and Neutron Sources for the Maximum PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting
Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 594E+11 233E+15 528E+11 379E+11 100E-01 000E+00 100E-01 116E+11 644E+14 609E+10 743E+10 400E-01 805E+07 200E-01 283E+10 522E+14 352E+10 179E+10 900E-01 411E+08 300E-01 141E+09 148E+14 196E+09 891E+08 140E+00 376E+08 400E-01 190E+09 985E+13 586E+09 117E+09 185E+00 276E+08 600E-01 191E+09 153E+15 110E+11 741E+07 300E+00 485E+08 800E-01 435E+09 470E+15 595E+10 237E+09 643E+00 443E+08 100E+00 137E+11 708E+14 803E+09 766E+10 200E+01 393E+07 133E+00 338E+13 455E+14 174E+13 217E+13 Total 211E+09 166E+00 953E+12 130E+14 491E+12 612E+12
--
200E+00 187E+03 144E+12 919E+02 113E+03 250E+00 226E+08 249E+12 116E+08 145E+08 300E+00 351E+05 110E+11 181E+05 225E+05 400E+00 766E-08 139E+10 100E-08 416E-08 500E+00 000E+00 709E+07 000E+00 000E+00 650E+00 000E+00 286E+07 000E+00 000E+00 800E+00 000E+00 558E+06 000E+00 000E+00 100E+01 000E+00 119E+06 000E+00 000E+00
Total 442E+13 113E+16 231E+13 284E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE2R2B14cut bWasteStreamE2R1B14cut cWasteStreamE2R3B14cut dWasteStreamE2R4B14cut
31
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 9 Gamma and Neutron Sources for the Design Basis PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary
(MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 273E+11 121E+15 188E+11 175E+11 100E-01 000E+00 100E-01 528E+10 329E+14 277E+10 339E+10 400E-01 316E+07 200E-01 128E+10 245E+14 117E+10 819E+09 900E-01 161E+08 300E-01 639E+08 713E+13 633E+08 407E+08 140E+00 148E+08 400E-01 850E+08 455E+13 164E+09 533E+08 185E+00 109E+08 600E-01 492E+08 226E+14 269E+10 337E+07 300E+00 191E+08 800E-01 291E+09 237E+15 160E+10 186E+09 643E+00 174E+08 100E+00 540E+09 122E+14 248E+09 341E+09 200E+01 154E+07 133E+00 154E+13 195E+14 797E+12 990E+12 Total 830E+08 166E+00 435E+12 450E+13 225E+12 280E+12
--
200E+00 235E+00 152E+11 149E+02 215E-02 250E+00 103E+08 517E+10 534E+07 664E+07 300E+00 160E+05 379E+09 829E+04 103E+05 400E+00 943E-10 497E+08 155E-10 519E-10 500E+00 000E+00 282E+07 000E+00 000E+00 650E+00 000E+00 113E+07 000E+00 000E+00 800E+00 000E+00 222E+06 000E+00 000E+00 100E+01 000E+00 471E+05 000E+00 000E+00
Total 201E+13 486E+15 105E+13 129E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B11cut bWasteStreamE5R1B11cut cWasteStreamE5R3B11cut dWasteStreamE5R4B11cut
32
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 10 Gamma and Neutron Sources for the Average PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 336E+10 670E+14 186E+10 217E+10 100E-01 00000E+00 100E-01 602E+09 199E+14 314E+09 387E+09 400E-01 748E+06 200E-01 146E+09 126E+14 853E+08 936E+08 900E-01 382E+07 300E-01 730E+07 389E+13 439E+07 469E+07 140E+00 352E+07 400E-01 947E+07 263E+13 716E+07 607E+07 185E+00 261E+07 600E-01 141E+07 205E+13 504E+08 383E+06 300E+00 469E+07 800E-01 208E+09 124E+15 192E+09 144E+09 643E+00 418E+07 100E+00 208E+09 110E+13 164E+09 144E+09 200E+01 365E+06 133E+00 175E+12 295E+13 909E+11 112E+12 Total 199E+08 166E+00 494E+11 513E+12 257E+11 318E+11
--
200E+00 973E-01 675E+10 614E+01 872E-03 250E+00 117E+07 353E+09 609E+06 754E+06 300E+00 182E+04 288E+08 944E+03 117E+04 400E+00 186E-11 198E+07 149E-11 127E-11 500E+00 000E+00 669E+06 000E+00 000E+00 650E+00 000E+00 269E+06 000E+00 000E+00 800E+00 000E+00 527E+05 000E+00 000E+00 100E+01 000E+00 112E+05 000E+00 000E+00
Total 229E+12 237E+15 119E+12 147E+12
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B9cut bWasteStreamE5R1B9cut cWasteStreamE5R3B9cut dWasteStreamE5R4B9cut
33
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 11 Gamma and Neutron Axial Source Profiles for a PWR Assembly
Axial boundaries (From midplane)
(cm)
TOP BOTTOM
Neutron Gamma Ne utron Gamma 000 1554 1117 1554 1117 1143 1537 1114 1571 1120 2286 1521 1111 1588 1123 3429 1504 1108 1605 1126 4572 1486 1104 1622 1129 5715 1464 1100 1636 1131 6858 1438 1095 1648 1133 8001 1401 1088 1657 1135 9144 1350 1078 1654 1134
10287 1277 1063 1625 1129 11430 1165 1039 1554 1117 12573 0998 09995 1414 1091 13716 0769 09365 1172 1041 14859 0492 08375 0816 0951 16002 0220 06850 0402 0797 17145 0046 04625 0092 0551 18288 00 00 00 00
Source Reference 2219 Table S445
34
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
63 MCNP SPECIFIC INPUT
631 Source Probability
A linear radial distribution is used for all gamma and neutron sources The linear radial distribution is sam pled usi ng the built-in power function p(x) = xc a with a = 1 for the radial direction This sampling method results in a uniform source distribution over the area bounded by the outer radius of the source
The source axial distributions are unifor m for all four source regions The a xial uni form xp(x) = c distribution is sampled using the built-in power function a with a = 0 for extent
The energy distribu tions of the gamma and neutron sour ce term s are treated as energ y probabilities and are applied in MCNP5 using SISP cards
632 Dose Rate and Flux Tallies
MCNP5 dose rate calculations feature separate runs for the following calculation types
bull a photon transport calculation for prim ary ga mma contribution to the dose rates fr om photon fluxes
bull a coupled neutronphoton transport calculat ion for neutrons a nd secondary gamma (photons generated by neutron be ing captured) contributions to dose rates from neutron and gamma fluxes
The tally type F2 is us ed in th is d esign ca lculation as f lux estim ators The type F2 tally evaluates the flux averaged over a surface in particlescm2s
To generate dose ra tes in te rms of remhr the FM (tally multiplier ) and DEDF (dose energydose conversion factors) cards are used to en ter the tally multiplier f actor (source intensity in particless) energy boundaries in MeV and corresponding dose conversion factors in (remhr)(particlescm2s) respectively These factors were used in the input files
In order for the F2 tally to accum ulate flux ov er a surface a specific s urface area is requ ired The SD cards are used to enter a surface area in cm2 over which the flux will be tallied for an F2 tally
633 Variance Reduction Techniques
Variance reduction technique is usually em ployed in order to increase the efficiency of a calculation and obtain statistically m eaningful results within re asonable com puter tim e In Monte Carlo calculations when variance reduction scheme is employed the weights of particles are adjusted in order to account for the biasing and to preserve a fair game
Geometry splitting and Russian roulette techniques described in Reference 2224 (pp 2-140 ndash 2-142) are useful in shielding calculations and therefore deployed in all the MCNP5 runs
35
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
As particles migrate in an important direction (toward the detector) they are increased in number to provide better sampling by means of geometry splitting across geometric boundaries Russian roulette (the reverse process) is played when particles travel in an unimportant direction to allow termination of unim portant histories The IMP card required for every cel l ca rd is us ed to implement this technique
The other variance reduction technique deployed in the MC NP5 runs is source intensity biasing for the gamma sources from the four source regions (active fuel bottom end-fitting plenum and top end-fitting) The natural total gamma source intensity of comm ercial SNF is dom inated by the gamma source in the active fuel region This active fuel gamma source usually accounts for over 95 o f the total g amma source intens ity In order to im prove the efficiency of the axial dose rate calculations a biased source probability distribution is employed for the prim ary gamma dose rate calculations The biased gamma source probability distribution is chosen to be 005 080 010 and 005 for the bottom end-fitting the active fuel the plenum and the top end-fitting regions respectively
64 DOSE CONVERSION FACTORS
Project Design Criteria Document (Reference 2211 Se ction 41015) requires the use of flux-to-dose rate conversion fact ors from ANSIANS-611-1977 (Reference 221) for dose rate evaluations Table 16 lists the neutron and ga mma dose conversion factors used in the MCNP5 calculations
Table 12 Gamma and Neutron Flux to Dose Conversion Factors
Gamma Neutron Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
001 396E-06 140 251E-06 250E-08 367E-06 003 582E-07 180 299E-06 100E-07 367E-06 005 290E-07 220 342E-06 100E-06 446E-06 007 258E-07 260 382E-06 100E-05 454E-06 010 283E-07 280 401E-06 100E-04 418E-06 015 379E-07 325 441E-06 100E-03 376E-06 020 501E-07 375 483E-06 100E-02 356E-06 025 631E-07 425 523E-06 100E-01 217E-05 030 759E-07 475 560E-06 500E-01 926E-05 035 878E-07 500 580E-06 100E+00 132E-04 040 985E-07 525 601E-06 250E+00 125E-04 045 108E-06 575 637E-06 500E+00 156E-04 050 117E-06 625 674E-06 700E+00 147E-04 055 127E-06 675 711E-06 100E+01 147E-04 060 136E-06 750 766E-06 140E+01 208E-04 065 144E-06 900 877E-06 200E+01 227E-04 070 152E-06 1100 103E-05 080 168E-06 1300 118E-05 100 198E-06 1500 133E-05
Source Reference 221 Tables 1 and 3
36
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION
By def inition (Ref erence 2224 Equation 219) the estimated st atistic relative error of the i component is
Ri = Si
2
Equation 6Ti
where i = tally component index Ri = relative error of the i component S2
i = variance of the i component Ti = tally i component
For a result (ie dose rate) computed as a sum of different tallies the statistical relative error of the computed value is o btained from the variance of the result - S2
total which is th e sum of the estimated variances of the individual tallies S2
i n
2 2STotal = sum Si Equation 7 i=1
where S2Total = total estimated variance
n = total number of components Therefore the total tally value (dose rate) and the associated relative error are derived according to Equations 8 and 9
n TTotal = sumTi Equation 8
i=1
n n
sum (Ri timesTi )2
2 sum Si 2
STotal = i=1 = i=1 Equation 9RTotal = TTotal TTotal TTotal
where RTotal = total estimated relative error TTotal = total estimated tally
Equations 8 and 9 are utilized in Attachm ent II to ev aluate to tal dos e ra tes and their r elative errors
37
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
7 RESULTS AND CONCLUSIONS
71 RESULTS
The following sections summarize the results of this calculation Section 711 presents results for Conceptual Cask A while Section 712 for Conceptual Cask B Section 713 provides comparisons of the dose-rate reduction factors du e to the two conceptual casks and the axial source distributions in the active fuel region Do se rates and relative errors can be found in Attachment II within the output files and Excel files
711 Dose Rates of Conceptual Cask A
This section presents dose-rate results of the calculation sets 1 and 2 as described in Section 61 for Cask A Set 1 has axial p rofile sources in the active fuel region a nd consist of six runs resulting from the three PWR SNF source term s (maximum design basis and average) and the two radiation sources (gammas and neutrons) Set 2 has uniform axial sources in the active fuel region and consists of six run s r esulting f rom the th ree P WR SNF source term s and th e tw o radiation sources
As described in Section 61 dose ra tes are calculated at the three exterior surfaces (radial top and bottom) and at distances 1 m and 2 m from the exterior surfaces The total dose rates for set 1 are presented in Tables 13 14 and 15 for the ra dial top and bottom dire ctions respectively However the com ponents (primary gamma neutr on and secondary gamma) contributing to the total dose rates as well as the re lative error calculations can be found in Attachment II Excel file MCNP-Results1xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 2 are shown in Tables 16 17 and 18 The dose-rate components and the relative errors can be found in A ttachment II Excel file MCNP-Results2xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 13 and 16 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 14 and 17 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 15 and 18 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carrying th e maximum PWR SNF Based on the results in Tables 13 through 18 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask A indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these 6 tables the d ose-rate red uction f actors between the m aximum and the design basis fuels the maxim um and the averag e fuels and th e design basis and the average fuels are a lso presented
38
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 320E-02 00237 116E-02 00222 262E-03 00219 275 1223 445
1 m 133E-02 00164 494E-03 00171 106E-03 00162 269 1261 468 2 m 749E-03 00198 285E-03 00225 584E-04 00162 263 1282 488
Ring Detectors 1 m 133E-02 00116 492E-03 00115 108E-03 00124 271 1229 454 2 m 756E-03 00118 279E-03 00110 605E-04 00128 271 1250 462
Source Attachment II MCNP-Results1xls worksheet Summary
Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 142E-02 00368 628E-03 00446 934E-04 00483 226 1520 672
1 m 570E-03 00289 263E-03 00426 375E-04 00381 217 1520 701 2 m 265E-03 00364 123E-03 00547 169E-04 00374 216 1575 730
Point Detectors 1 m 598E-03 00238 274E-03 00271 402E-04 00354 219 1489 681 2 m 273E-03 00218 123E-03 00245 180E-04 00336 221 1515 684
Source Attachment II MCNP-Results1xls worksheet Summary
Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 653E-03 00298 265E-03 00276 510E-04 00341 247 1278 518
1 m 276E-03 00238 112E-03 00208 207E-04 00249 248 1334 539 2 m 125E-03 00185 508E-04 00199 933E-05 00246 246 1336 544
Point Detectors 1 m 291E-03 00227 118E-03 00203 218E-04 00242 247 1335 540 2 m 130E-03 00209 524E-04 00187 955E-05 00233 247 1357 549
Source Attachment II MCNP-Results1xls worksheet Summary
Tables 13 14 and 15 are results of calculation set 1 for conceptual Cask A with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
39
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 265E-02 00247 990E-03 00222 215E-03 00278 268 1234 461
1 m 116E-02 00178 468E-03 00549 960E-04 00189 248 1208 488 2 m 713E-03 00273 265E-03 00161 602E-04 00360 269 1184 439
Ring Detectors 1 m 117E-02 00120 454E-03 00132 979E-04 00141 259 1199 463 2 m 722E-03 00130 276E-03 00141 589E-04 00153 261 1226 469
Source Attachment II MCNP-Results2xls worksheet Summary
Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 199E-02 00461 827E-03 00455 147E-03 00536 241 1359 564
1 m 849E-03 00564 323E-03 00314 563E-04 00418 263 1507 574 2 m 415E-03 00832 158E-03 00603 253E-04 00501 263 1641 623
Point Detectors 1 m 877E-03 00348 353E-03 00275 615E-04 00391 248 1426 574 2 m 393E-03 00341 160E-03 00278 270E-04 00378 246 1454 590
Source Attachment II MCNP-Results2xls worksheet Summary
Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 879E-03 00374 356E-03 00333 669E-04 00406 247 1315 533
1 m 365E-03 00223 147E-03 00209 269E-04 00253 248 1358 548 2 m 164E-03 00229 674E-04 00205 120E-04 00248 243 1364 560
Point Detectors 1 m 383E-03 00217 155E-03 00204 285E-04 00248 247 1347 546 2 m 172E-03 00197 689E-04 00186 124E-04 00225 249 1391 558
Source Attachment II MCNP-Results2xls worksheet Summary
Tables 16 17 and 18 ar e results of calculation set 2 for conceptual Cask A with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
40
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
canister car rying the m aximum PWR SNF Cask B will s atisfy th e sa me radiatio n standa rds when loaded with a TAD canister c arrying the average PWR SNF The reason to analyze both Casks A and B is to cover a broad range of characteristics of the CSNF
The cavity dimensions of the conceptual cask s are 53785 cm (21175 in) in height and 16891 cm (665 in) in diam eter (Tab les 1 and 2) This cav ity will accommoda te the TAD canister described in Table 3 without the lifting feature This is the geometry model used in the MCNP5 calculations
623 Fuel Assembly Selection
PWR and BWR Source Term Sensitivity Study (Reference 2211 Tables 71 through 84) shows that the source terms generated for the Bamp W 15x15 Mark B fuel assembly with 475 kg uranium loading bound the source terms of other PWR assembly types ther efore this assembly type is selected as the representative PWR fuel assembly The gamma and neutron source terms for the BampW 15x15 Mark B assembly are generated in PWR Source Term Generation and Evaluation (Reference 229) and are used in this calculation
624 BampW 15x15 Mark B PWR Fuel Assembly
BampW 15x15 Mark B fuel assembly consists of four regions top end-fitting plenum active fuel and bottom end-fitting The m aterials and ra diation sources of each assem bly region are homogenized inside a volume defined by the region height and the interior diam eter of the TAD canister (Assumption 325) The active fuel region is homogenized with fresh unirradiated fuel (Assumption 324) Since the internal structure (i e basket) design of t he TAD is currently not finalized the com position of the hom ogenized fuel does not include the basket m aterials (Assumption 326) and therefore does not take cred it for any shielding that these m aterials may provide
Table 4 provides the design param eters for the BampW 15x15 Mark B fuel assembly Data provided here are used in Attachment II PWR_fuel compxls worksheet BampWassy
25
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 4 BampW 15x15 Mark B Fuel Assembly Description
Component Material Characteristic Value Specific Reference Array Size 15 x 15
Reference 2227 Table 2-2 Fuel Pins Assembly 208 Guide Tubes Assembly 16 Instrument Tubes Assembly 1
Assembly NA Pin Pellet Diameter 0936244 cm (03686 in) Reference 2220 p 2A-34 Pin Pitch 144272 cm (0568 in)
Reference 2227 Table 2-2 Active Fuel Height 360172 cm (1418 in) Assembly Width 2168144 cm (8536 in)
Reference 2220 p 2A-31 Assembly Height 4206875 cm (165625 in) Mass U assembly 46363 kg
Guide tube Zircaloy-4 Outer Diameter 13462 cm (053 in)
Reference 2227 Table 2-2
Inner Diameter 126492 cm (0498 in)
Instrument tube Zircaloy-4 Outer Diameter 138193 cm (05441 in) Inner Diameter 112014 cm (0441 in)
Cladding` Zircaloy-4 Inner Diameter 095758 cm (0377 in) Outer Diameter 10922 cm (043 in)
Plenum region NA Length 297688 cm (11720 in) Reference 2220 p 2A-34 Top nozzle SS CF3M MassAssembly (Top) 748 kg
Reference 2220 p 2A-32
Bottom nozzle SS CF3M MassAssembly (Bottom) 816 kg Guide tubes Zircaloy-4 MassAssembly (in Core) 80 kg Instrument tube Zircaloy-4 MassAssembly (in Core) 064 kg Spacer-plenum Inconel-718 MassAssembly (Plenum) 104 kg Spacer-bottom Inconel-718 MassAssembly (Bottom) 13 kg Spacer-in core Inconel-718 MassAssembly (in Core) 49 kg Spring retainer SS CF3M MassAssembly (Top) 091 kg Holddown spring Inconel-718 MassAssembly (Top) 18 kg Upper end plug SS 304 MassAssembly (Top) 006 kg Upper nut SS 304L MassAssembly (Top) 051 kg Lower nut SS 304 MassAssembly (Bottom) 015 kg Grid supports Zircaloy-4 MassAssembly (in Core) 064 kg Plenum spring SS 302 MassAssembly (Plenum) 0042 lb (001905 kg) Reference 2220 p 2A-34
Note Som e d ata i n this tab le ar e given i n British u nits in th e r eferences thes e d ata ar e converted into metric units as the inputs to MCNP5 are in metric units
The assem bly region heights as m odeled in MC NP are presented in Table 5 utilizing values from Table 4 Table 5 is taken from Dose Rate Calculation for Exhaust Main Drifts (Reference 2213 Table 3)
26
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 5 PWR Fuel Assembly Regions
Component Height Reference
Plenum 297688 cm (11720 in) Reference 2220 p 2A-34
Active Fuel 360172 cm (1418 in) Table 3
Bottom End-Fitting 1077 cm (424 in) Calculateda
Top End-Fitting 1998 cm (787 in) Calculatedb
Source Reference 2213 Table 3 aCalculated b ased on data Reference 2227 F igures 2-3 an d 2-7
(Region 9 Height [16723 cm] + Region 10 Height [508 cm] ndash Lo wer Fuel Plenum and End Cap [11033 cm])
bCalculated (Assembly Length ndash Active Fuel Length ndash P lenum Length ndash Bottom End-fitting Length)
625 Material Compositions
The TAD transportation cask com ponent m aterial specifications are defined in Table 1 The TAD canister is constructed of SS 316 (Assumpti on 321) The PWR fuel assembly materials used to homogenize the fuel regions are defined in Table 4 Table 6 c ontains the m aterial compositions defining the TAD canister WP and fuel assemblies
27
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 6 Chemical Compositions of Materials
Material Density (gcc)
Isotopic Weight Percent Reference
SS 302 NA
C 0150 Mn 2000 P 0045 S 0030 Si 0750 Cr 18000 Ni 9000 N 0100 Fe 69925
Attachment II PWR_fuel compxls worksheet ferrous Reference 222 SEC II A SA-240 Table 1 for SS 302 SS 304 and SS 304L Reference 222 SEC II A SA-351SA -351M Table 2 for SS CF3M
SS 304 NA
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 9250 N 0100 Fe 68745
SS 304L NA
C 003 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 10000 N 0100 Fe 6804 5
SS CF3M NA
C 0030 Mn 1500 P 0040 S 0040 Si 1500 Cr 19000 Ni 11000 Mo 2500 Fe 64390
Inconel 718 NA
C 0080 Mn 0350 Si 0350 Cr 19000 Ni 52500 Co 1000 Mo 3050 Fe 16809 Nb 5125 Ti 0900 Al 0500 Cu 0300 S 0015 P 0015 B 0006
Attachment II PWR_fuel compxls worksheet alloys aReference 223 p 666 Table 6 Reference 222 SEC II B SB-637 Table 1 for Inconel 718 Reference 224 Table 2 for Zircaloy 4
Zircaloy 4 656a Cr 0100 Fe 0210 O 0125 Sn 1450 Zr 98115
SS 316 798b
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 17000 Ni 12000 Mo 2500 N 0100 Fe 65495
Attachment II PWR_fuel compxls worksheet others Reference 222 SEC II A SA-240 Table 1 for SS 316 bReference 225 Table X1
626 Homogenization Assembly Materials
The atom density of an element or isotope in atomsbmiddotcm in a homogenized region is calculated according to the following equation (Reference 2223 Appendix B)
M i times N AvogadroNi = Equation 1 Ai timesV times K
where Ni = Atom density of elementisotope i (atomsbmiddotcm) Mi = Mass of elementisotope i (g) NAvogadro = Avogadrorsquos constant 06022 x 1024 (atomsmole)
28
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Ai = Atomic weight of elementisotope i (gmole) V = Homogenization volume (cm3) K = Unit transformation constant = 1024 (bmiddotcmcm3)
Equation 1 is used in A ttachment II spreadsheet PWR_fuel compxls worksheet BampWassy to calculate th e atom dens ities for v arious elem ents and iso topes The m ass of elementsisotop es and Avogadrorsquos constant are provided in Reference 2226
Table 7 lists the com position of the hom ogenized assem bly regions (active fuel plenum top end-fitting and bottom end-fitting) for the PWR assembly The active fuel region contains fresh unirradiated fuel (Assumption 324) Since the internal structure (ie basket) design of the TAD is currently not finalized the composition of either homogenized fuel does not include the basket materials and therefore does not tak e credit for any shielding that thes e materials may provide (Assumption 326)
Table 7 Isotopic Compositions of Homogenized PWR Assembly Regions
Element Isotope
Atom Densities for Homogenized Regions (atomsbsdotcm)
Active Fuel Bottom End-Fitting Plenum Top End-Fitting
10B 861E-09 764E-08 221E-08 570E-08 11B 347E-08 307E-07 890E-08 230E-07 C 519E-07 160E-05 138E-06 993E-06 N -- 570E-07 262E-08 117E-06 O 621E-03 -- 142E-05 -- Al 144E-06 128E-05 371E-06 957E-06 Si 971E-07 243E-04 259E-06 139E-04 P 377E-08 606E-06 102E-07 360E-06 S 365E-08 581E-06 971E-08 340E-06 Ti 147E-06 130E-05 376E-06 971E-06 Cr 320E-05 187E-03 779E-05 113E-03 Mn 497E-07 126E-04 141E-06 749E-05 Fe 303E-05 531E-03 717E-05 313E-03 Co 132E-06 117E-05 340E-06 876E-06 Ni 697E-05 144E-03 180E-04 940E-04 Cu 368E-07 327E-06 945E-07 244E-06 Zr 196E-03 -- 195E-03 -- Nb 430E-06 382E-05 110E-05 285E-05 Mo 248E-06 135E-04 636E-06 791E-05 Sn 223E-05 -- 222E-05 -- 234U 139E-06 -- -- -- 235U 157E-04 -- -- -- 236U 719E-07 -- -- -- 238U 294E-03 -- -- -- Total 114E-02 924E-03 235E-03 557E-03
Source Attachment II spreadsheet PWR_fuel compxls worksheet BampWassy
29
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
The isotopic composition of commercially available 235U enriched uranium is determined by the given initial 235U enrichment using the following equations (Reference 226 p 20)
wt235U =235Uenrichment _ of _ the _ associated _ fuel _ batch Equation 2
wt234U = 0007731times (wt235U )10837 Equation 3
wt236U = 00046times (wt235U ) Equation 4
wt238U =100 minus (wt234U + wt235U + wt236U ) Equation 5
The weight percentages of uran ium isotopes for PWR fuel are ca lculated in Attachm ent II spreadsheet PWR_fuel compxls worksheet BampWassy using Equations 2 through 5
627 PWR Source Terms
This calculation uses the following three PWR source terms bull Maximum source (50 wt initial 235U enrichment 80 GWdMTU burnup and 5-year
decay time) (Reference 229 Section 55) Table 8 lists th e gamma source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Design Basis source (4 0 wt initial 235U enrichment 60 GW dMTU burnup and 10-year decay tim e) (Reference 228 Section 552) Table 9 lists the gamm a source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Average source ( 40 wt initial 235U enrichment 48 GWdMTU burnup and 25-year decay time) (Reference 229 Section 55) Table 10 lists the gamma source terms for the fuel and non-fuel regions and the neutron source term for the fuel region
These sources (ie maximum design basis and av erage) are described in this section For dose rate calculations all the fuel assemblies in a transportation cask are of the sam e characteristics Also gamma radiation source term s for the PWR assem bly are prov ided for the f our assembly regions while neutron source term is only present in the active fuel region Gamma radiation sources in the non-active fuel region are distri buted unif ormly within each source region Gamma and neutron sources in the active fuel re gion are modeled as uni form distributions or with axial source profiles
The PWR gamma and neutron axial source profiles for the active fuel region presented in Table 11 are applied to the active fuel region of all three source terms (ie maximum design basis and average) when appropriate
30
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 8 Gamma and Neutron Sources for the Maximum PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting
Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 594E+11 233E+15 528E+11 379E+11 100E-01 000E+00 100E-01 116E+11 644E+14 609E+10 743E+10 400E-01 805E+07 200E-01 283E+10 522E+14 352E+10 179E+10 900E-01 411E+08 300E-01 141E+09 148E+14 196E+09 891E+08 140E+00 376E+08 400E-01 190E+09 985E+13 586E+09 117E+09 185E+00 276E+08 600E-01 191E+09 153E+15 110E+11 741E+07 300E+00 485E+08 800E-01 435E+09 470E+15 595E+10 237E+09 643E+00 443E+08 100E+00 137E+11 708E+14 803E+09 766E+10 200E+01 393E+07 133E+00 338E+13 455E+14 174E+13 217E+13 Total 211E+09 166E+00 953E+12 130E+14 491E+12 612E+12
--
200E+00 187E+03 144E+12 919E+02 113E+03 250E+00 226E+08 249E+12 116E+08 145E+08 300E+00 351E+05 110E+11 181E+05 225E+05 400E+00 766E-08 139E+10 100E-08 416E-08 500E+00 000E+00 709E+07 000E+00 000E+00 650E+00 000E+00 286E+07 000E+00 000E+00 800E+00 000E+00 558E+06 000E+00 000E+00 100E+01 000E+00 119E+06 000E+00 000E+00
Total 442E+13 113E+16 231E+13 284E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE2R2B14cut bWasteStreamE2R1B14cut cWasteStreamE2R3B14cut dWasteStreamE2R4B14cut
31
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 9 Gamma and Neutron Sources for the Design Basis PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary
(MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 273E+11 121E+15 188E+11 175E+11 100E-01 000E+00 100E-01 528E+10 329E+14 277E+10 339E+10 400E-01 316E+07 200E-01 128E+10 245E+14 117E+10 819E+09 900E-01 161E+08 300E-01 639E+08 713E+13 633E+08 407E+08 140E+00 148E+08 400E-01 850E+08 455E+13 164E+09 533E+08 185E+00 109E+08 600E-01 492E+08 226E+14 269E+10 337E+07 300E+00 191E+08 800E-01 291E+09 237E+15 160E+10 186E+09 643E+00 174E+08 100E+00 540E+09 122E+14 248E+09 341E+09 200E+01 154E+07 133E+00 154E+13 195E+14 797E+12 990E+12 Total 830E+08 166E+00 435E+12 450E+13 225E+12 280E+12
--
200E+00 235E+00 152E+11 149E+02 215E-02 250E+00 103E+08 517E+10 534E+07 664E+07 300E+00 160E+05 379E+09 829E+04 103E+05 400E+00 943E-10 497E+08 155E-10 519E-10 500E+00 000E+00 282E+07 000E+00 000E+00 650E+00 000E+00 113E+07 000E+00 000E+00 800E+00 000E+00 222E+06 000E+00 000E+00 100E+01 000E+00 471E+05 000E+00 000E+00
Total 201E+13 486E+15 105E+13 129E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B11cut bWasteStreamE5R1B11cut cWasteStreamE5R3B11cut dWasteStreamE5R4B11cut
32
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 10 Gamma and Neutron Sources for the Average PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 336E+10 670E+14 186E+10 217E+10 100E-01 00000E+00 100E-01 602E+09 199E+14 314E+09 387E+09 400E-01 748E+06 200E-01 146E+09 126E+14 853E+08 936E+08 900E-01 382E+07 300E-01 730E+07 389E+13 439E+07 469E+07 140E+00 352E+07 400E-01 947E+07 263E+13 716E+07 607E+07 185E+00 261E+07 600E-01 141E+07 205E+13 504E+08 383E+06 300E+00 469E+07 800E-01 208E+09 124E+15 192E+09 144E+09 643E+00 418E+07 100E+00 208E+09 110E+13 164E+09 144E+09 200E+01 365E+06 133E+00 175E+12 295E+13 909E+11 112E+12 Total 199E+08 166E+00 494E+11 513E+12 257E+11 318E+11
--
200E+00 973E-01 675E+10 614E+01 872E-03 250E+00 117E+07 353E+09 609E+06 754E+06 300E+00 182E+04 288E+08 944E+03 117E+04 400E+00 186E-11 198E+07 149E-11 127E-11 500E+00 000E+00 669E+06 000E+00 000E+00 650E+00 000E+00 269E+06 000E+00 000E+00 800E+00 000E+00 527E+05 000E+00 000E+00 100E+01 000E+00 112E+05 000E+00 000E+00
Total 229E+12 237E+15 119E+12 147E+12
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B9cut bWasteStreamE5R1B9cut cWasteStreamE5R3B9cut dWasteStreamE5R4B9cut
33
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 11 Gamma and Neutron Axial Source Profiles for a PWR Assembly
Axial boundaries (From midplane)
(cm)
TOP BOTTOM
Neutron Gamma Ne utron Gamma 000 1554 1117 1554 1117 1143 1537 1114 1571 1120 2286 1521 1111 1588 1123 3429 1504 1108 1605 1126 4572 1486 1104 1622 1129 5715 1464 1100 1636 1131 6858 1438 1095 1648 1133 8001 1401 1088 1657 1135 9144 1350 1078 1654 1134
10287 1277 1063 1625 1129 11430 1165 1039 1554 1117 12573 0998 09995 1414 1091 13716 0769 09365 1172 1041 14859 0492 08375 0816 0951 16002 0220 06850 0402 0797 17145 0046 04625 0092 0551 18288 00 00 00 00
Source Reference 2219 Table S445
34
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
63 MCNP SPECIFIC INPUT
631 Source Probability
A linear radial distribution is used for all gamma and neutron sources The linear radial distribution is sam pled usi ng the built-in power function p(x) = xc a with a = 1 for the radial direction This sampling method results in a uniform source distribution over the area bounded by the outer radius of the source
The source axial distributions are unifor m for all four source regions The a xial uni form xp(x) = c distribution is sampled using the built-in power function a with a = 0 for extent
The energy distribu tions of the gamma and neutron sour ce term s are treated as energ y probabilities and are applied in MCNP5 using SISP cards
632 Dose Rate and Flux Tallies
MCNP5 dose rate calculations feature separate runs for the following calculation types
bull a photon transport calculation for prim ary ga mma contribution to the dose rates fr om photon fluxes
bull a coupled neutronphoton transport calculat ion for neutrons a nd secondary gamma (photons generated by neutron be ing captured) contributions to dose rates from neutron and gamma fluxes
The tally type F2 is us ed in th is d esign ca lculation as f lux estim ators The type F2 tally evaluates the flux averaged over a surface in particlescm2s
To generate dose ra tes in te rms of remhr the FM (tally multiplier ) and DEDF (dose energydose conversion factors) cards are used to en ter the tally multiplier f actor (source intensity in particless) energy boundaries in MeV and corresponding dose conversion factors in (remhr)(particlescm2s) respectively These factors were used in the input files
In order for the F2 tally to accum ulate flux ov er a surface a specific s urface area is requ ired The SD cards are used to enter a surface area in cm2 over which the flux will be tallied for an F2 tally
633 Variance Reduction Techniques
Variance reduction technique is usually em ployed in order to increase the efficiency of a calculation and obtain statistically m eaningful results within re asonable com puter tim e In Monte Carlo calculations when variance reduction scheme is employed the weights of particles are adjusted in order to account for the biasing and to preserve a fair game
Geometry splitting and Russian roulette techniques described in Reference 2224 (pp 2-140 ndash 2-142) are useful in shielding calculations and therefore deployed in all the MCNP5 runs
35
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
As particles migrate in an important direction (toward the detector) they are increased in number to provide better sampling by means of geometry splitting across geometric boundaries Russian roulette (the reverse process) is played when particles travel in an unimportant direction to allow termination of unim portant histories The IMP card required for every cel l ca rd is us ed to implement this technique
The other variance reduction technique deployed in the MC NP5 runs is source intensity biasing for the gamma sources from the four source regions (active fuel bottom end-fitting plenum and top end-fitting) The natural total gamma source intensity of comm ercial SNF is dom inated by the gamma source in the active fuel region This active fuel gamma source usually accounts for over 95 o f the total g amma source intens ity In order to im prove the efficiency of the axial dose rate calculations a biased source probability distribution is employed for the prim ary gamma dose rate calculations The biased gamma source probability distribution is chosen to be 005 080 010 and 005 for the bottom end-fitting the active fuel the plenum and the top end-fitting regions respectively
64 DOSE CONVERSION FACTORS
Project Design Criteria Document (Reference 2211 Se ction 41015) requires the use of flux-to-dose rate conversion fact ors from ANSIANS-611-1977 (Reference 221) for dose rate evaluations Table 16 lists the neutron and ga mma dose conversion factors used in the MCNP5 calculations
Table 12 Gamma and Neutron Flux to Dose Conversion Factors
Gamma Neutron Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
001 396E-06 140 251E-06 250E-08 367E-06 003 582E-07 180 299E-06 100E-07 367E-06 005 290E-07 220 342E-06 100E-06 446E-06 007 258E-07 260 382E-06 100E-05 454E-06 010 283E-07 280 401E-06 100E-04 418E-06 015 379E-07 325 441E-06 100E-03 376E-06 020 501E-07 375 483E-06 100E-02 356E-06 025 631E-07 425 523E-06 100E-01 217E-05 030 759E-07 475 560E-06 500E-01 926E-05 035 878E-07 500 580E-06 100E+00 132E-04 040 985E-07 525 601E-06 250E+00 125E-04 045 108E-06 575 637E-06 500E+00 156E-04 050 117E-06 625 674E-06 700E+00 147E-04 055 127E-06 675 711E-06 100E+01 147E-04 060 136E-06 750 766E-06 140E+01 208E-04 065 144E-06 900 877E-06 200E+01 227E-04 070 152E-06 1100 103E-05 080 168E-06 1300 118E-05 100 198E-06 1500 133E-05
Source Reference 221 Tables 1 and 3
36
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION
By def inition (Ref erence 2224 Equation 219) the estimated st atistic relative error of the i component is
Ri = Si
2
Equation 6Ti
where i = tally component index Ri = relative error of the i component S2
i = variance of the i component Ti = tally i component
For a result (ie dose rate) computed as a sum of different tallies the statistical relative error of the computed value is o btained from the variance of the result - S2
total which is th e sum of the estimated variances of the individual tallies S2
i n
2 2STotal = sum Si Equation 7 i=1
where S2Total = total estimated variance
n = total number of components Therefore the total tally value (dose rate) and the associated relative error are derived according to Equations 8 and 9
n TTotal = sumTi Equation 8
i=1
n n
sum (Ri timesTi )2
2 sum Si 2
STotal = i=1 = i=1 Equation 9RTotal = TTotal TTotal TTotal
where RTotal = total estimated relative error TTotal = total estimated tally
Equations 8 and 9 are utilized in Attachm ent II to ev aluate to tal dos e ra tes and their r elative errors
37
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
7 RESULTS AND CONCLUSIONS
71 RESULTS
The following sections summarize the results of this calculation Section 711 presents results for Conceptual Cask A while Section 712 for Conceptual Cask B Section 713 provides comparisons of the dose-rate reduction factors du e to the two conceptual casks and the axial source distributions in the active fuel region Do se rates and relative errors can be found in Attachment II within the output files and Excel files
711 Dose Rates of Conceptual Cask A
This section presents dose-rate results of the calculation sets 1 and 2 as described in Section 61 for Cask A Set 1 has axial p rofile sources in the active fuel region a nd consist of six runs resulting from the three PWR SNF source term s (maximum design basis and average) and the two radiation sources (gammas and neutrons) Set 2 has uniform axial sources in the active fuel region and consists of six run s r esulting f rom the th ree P WR SNF source term s and th e tw o radiation sources
As described in Section 61 dose ra tes are calculated at the three exterior surfaces (radial top and bottom) and at distances 1 m and 2 m from the exterior surfaces The total dose rates for set 1 are presented in Tables 13 14 and 15 for the ra dial top and bottom dire ctions respectively However the com ponents (primary gamma neutr on and secondary gamma) contributing to the total dose rates as well as the re lative error calculations can be found in Attachment II Excel file MCNP-Results1xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 2 are shown in Tables 16 17 and 18 The dose-rate components and the relative errors can be found in A ttachment II Excel file MCNP-Results2xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 13 and 16 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 14 and 17 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 15 and 18 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carrying th e maximum PWR SNF Based on the results in Tables 13 through 18 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask A indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these 6 tables the d ose-rate red uction f actors between the m aximum and the design basis fuels the maxim um and the averag e fuels and th e design basis and the average fuels are a lso presented
38
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 320E-02 00237 116E-02 00222 262E-03 00219 275 1223 445
1 m 133E-02 00164 494E-03 00171 106E-03 00162 269 1261 468 2 m 749E-03 00198 285E-03 00225 584E-04 00162 263 1282 488
Ring Detectors 1 m 133E-02 00116 492E-03 00115 108E-03 00124 271 1229 454 2 m 756E-03 00118 279E-03 00110 605E-04 00128 271 1250 462
Source Attachment II MCNP-Results1xls worksheet Summary
Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 142E-02 00368 628E-03 00446 934E-04 00483 226 1520 672
1 m 570E-03 00289 263E-03 00426 375E-04 00381 217 1520 701 2 m 265E-03 00364 123E-03 00547 169E-04 00374 216 1575 730
Point Detectors 1 m 598E-03 00238 274E-03 00271 402E-04 00354 219 1489 681 2 m 273E-03 00218 123E-03 00245 180E-04 00336 221 1515 684
Source Attachment II MCNP-Results1xls worksheet Summary
Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 653E-03 00298 265E-03 00276 510E-04 00341 247 1278 518
1 m 276E-03 00238 112E-03 00208 207E-04 00249 248 1334 539 2 m 125E-03 00185 508E-04 00199 933E-05 00246 246 1336 544
Point Detectors 1 m 291E-03 00227 118E-03 00203 218E-04 00242 247 1335 540 2 m 130E-03 00209 524E-04 00187 955E-05 00233 247 1357 549
Source Attachment II MCNP-Results1xls worksheet Summary
Tables 13 14 and 15 are results of calculation set 1 for conceptual Cask A with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
39
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 265E-02 00247 990E-03 00222 215E-03 00278 268 1234 461
1 m 116E-02 00178 468E-03 00549 960E-04 00189 248 1208 488 2 m 713E-03 00273 265E-03 00161 602E-04 00360 269 1184 439
Ring Detectors 1 m 117E-02 00120 454E-03 00132 979E-04 00141 259 1199 463 2 m 722E-03 00130 276E-03 00141 589E-04 00153 261 1226 469
Source Attachment II MCNP-Results2xls worksheet Summary
Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 199E-02 00461 827E-03 00455 147E-03 00536 241 1359 564
1 m 849E-03 00564 323E-03 00314 563E-04 00418 263 1507 574 2 m 415E-03 00832 158E-03 00603 253E-04 00501 263 1641 623
Point Detectors 1 m 877E-03 00348 353E-03 00275 615E-04 00391 248 1426 574 2 m 393E-03 00341 160E-03 00278 270E-04 00378 246 1454 590
Source Attachment II MCNP-Results2xls worksheet Summary
Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 879E-03 00374 356E-03 00333 669E-04 00406 247 1315 533
1 m 365E-03 00223 147E-03 00209 269E-04 00253 248 1358 548 2 m 164E-03 00229 674E-04 00205 120E-04 00248 243 1364 560
Point Detectors 1 m 383E-03 00217 155E-03 00204 285E-04 00248 247 1347 546 2 m 172E-03 00197 689E-04 00186 124E-04 00225 249 1391 558
Source Attachment II MCNP-Results2xls worksheet Summary
Tables 16 17 and 18 ar e results of calculation set 2 for conceptual Cask A with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
40
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 4 BampW 15x15 Mark B Fuel Assembly Description
Component Material Characteristic Value Specific Reference Array Size 15 x 15
Reference 2227 Table 2-2 Fuel Pins Assembly 208 Guide Tubes Assembly 16 Instrument Tubes Assembly 1
Assembly NA Pin Pellet Diameter 0936244 cm (03686 in) Reference 2220 p 2A-34 Pin Pitch 144272 cm (0568 in)
Reference 2227 Table 2-2 Active Fuel Height 360172 cm (1418 in) Assembly Width 2168144 cm (8536 in)
Reference 2220 p 2A-31 Assembly Height 4206875 cm (165625 in) Mass U assembly 46363 kg
Guide tube Zircaloy-4 Outer Diameter 13462 cm (053 in)
Reference 2227 Table 2-2
Inner Diameter 126492 cm (0498 in)
Instrument tube Zircaloy-4 Outer Diameter 138193 cm (05441 in) Inner Diameter 112014 cm (0441 in)
Cladding` Zircaloy-4 Inner Diameter 095758 cm (0377 in) Outer Diameter 10922 cm (043 in)
Plenum region NA Length 297688 cm (11720 in) Reference 2220 p 2A-34 Top nozzle SS CF3M MassAssembly (Top) 748 kg
Reference 2220 p 2A-32
Bottom nozzle SS CF3M MassAssembly (Bottom) 816 kg Guide tubes Zircaloy-4 MassAssembly (in Core) 80 kg Instrument tube Zircaloy-4 MassAssembly (in Core) 064 kg Spacer-plenum Inconel-718 MassAssembly (Plenum) 104 kg Spacer-bottom Inconel-718 MassAssembly (Bottom) 13 kg Spacer-in core Inconel-718 MassAssembly (in Core) 49 kg Spring retainer SS CF3M MassAssembly (Top) 091 kg Holddown spring Inconel-718 MassAssembly (Top) 18 kg Upper end plug SS 304 MassAssembly (Top) 006 kg Upper nut SS 304L MassAssembly (Top) 051 kg Lower nut SS 304 MassAssembly (Bottom) 015 kg Grid supports Zircaloy-4 MassAssembly (in Core) 064 kg Plenum spring SS 302 MassAssembly (Plenum) 0042 lb (001905 kg) Reference 2220 p 2A-34
Note Som e d ata i n this tab le ar e given i n British u nits in th e r eferences thes e d ata ar e converted into metric units as the inputs to MCNP5 are in metric units
The assem bly region heights as m odeled in MC NP are presented in Table 5 utilizing values from Table 4 Table 5 is taken from Dose Rate Calculation for Exhaust Main Drifts (Reference 2213 Table 3)
26
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 5 PWR Fuel Assembly Regions
Component Height Reference
Plenum 297688 cm (11720 in) Reference 2220 p 2A-34
Active Fuel 360172 cm (1418 in) Table 3
Bottom End-Fitting 1077 cm (424 in) Calculateda
Top End-Fitting 1998 cm (787 in) Calculatedb
Source Reference 2213 Table 3 aCalculated b ased on data Reference 2227 F igures 2-3 an d 2-7
(Region 9 Height [16723 cm] + Region 10 Height [508 cm] ndash Lo wer Fuel Plenum and End Cap [11033 cm])
bCalculated (Assembly Length ndash Active Fuel Length ndash P lenum Length ndash Bottom End-fitting Length)
625 Material Compositions
The TAD transportation cask com ponent m aterial specifications are defined in Table 1 The TAD canister is constructed of SS 316 (Assumpti on 321) The PWR fuel assembly materials used to homogenize the fuel regions are defined in Table 4 Table 6 c ontains the m aterial compositions defining the TAD canister WP and fuel assemblies
27
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 6 Chemical Compositions of Materials
Material Density (gcc)
Isotopic Weight Percent Reference
SS 302 NA
C 0150 Mn 2000 P 0045 S 0030 Si 0750 Cr 18000 Ni 9000 N 0100 Fe 69925
Attachment II PWR_fuel compxls worksheet ferrous Reference 222 SEC II A SA-240 Table 1 for SS 302 SS 304 and SS 304L Reference 222 SEC II A SA-351SA -351M Table 2 for SS CF3M
SS 304 NA
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 9250 N 0100 Fe 68745
SS 304L NA
C 003 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 10000 N 0100 Fe 6804 5
SS CF3M NA
C 0030 Mn 1500 P 0040 S 0040 Si 1500 Cr 19000 Ni 11000 Mo 2500 Fe 64390
Inconel 718 NA
C 0080 Mn 0350 Si 0350 Cr 19000 Ni 52500 Co 1000 Mo 3050 Fe 16809 Nb 5125 Ti 0900 Al 0500 Cu 0300 S 0015 P 0015 B 0006
Attachment II PWR_fuel compxls worksheet alloys aReference 223 p 666 Table 6 Reference 222 SEC II B SB-637 Table 1 for Inconel 718 Reference 224 Table 2 for Zircaloy 4
Zircaloy 4 656a Cr 0100 Fe 0210 O 0125 Sn 1450 Zr 98115
SS 316 798b
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 17000 Ni 12000 Mo 2500 N 0100 Fe 65495
Attachment II PWR_fuel compxls worksheet others Reference 222 SEC II A SA-240 Table 1 for SS 316 bReference 225 Table X1
626 Homogenization Assembly Materials
The atom density of an element or isotope in atomsbmiddotcm in a homogenized region is calculated according to the following equation (Reference 2223 Appendix B)
M i times N AvogadroNi = Equation 1 Ai timesV times K
where Ni = Atom density of elementisotope i (atomsbmiddotcm) Mi = Mass of elementisotope i (g) NAvogadro = Avogadrorsquos constant 06022 x 1024 (atomsmole)
28
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Ai = Atomic weight of elementisotope i (gmole) V = Homogenization volume (cm3) K = Unit transformation constant = 1024 (bmiddotcmcm3)
Equation 1 is used in A ttachment II spreadsheet PWR_fuel compxls worksheet BampWassy to calculate th e atom dens ities for v arious elem ents and iso topes The m ass of elementsisotop es and Avogadrorsquos constant are provided in Reference 2226
Table 7 lists the com position of the hom ogenized assem bly regions (active fuel plenum top end-fitting and bottom end-fitting) for the PWR assembly The active fuel region contains fresh unirradiated fuel (Assumption 324) Since the internal structure (ie basket) design of the TAD is currently not finalized the composition of either homogenized fuel does not include the basket materials and therefore does not tak e credit for any shielding that thes e materials may provide (Assumption 326)
Table 7 Isotopic Compositions of Homogenized PWR Assembly Regions
Element Isotope
Atom Densities for Homogenized Regions (atomsbsdotcm)
Active Fuel Bottom End-Fitting Plenum Top End-Fitting
10B 861E-09 764E-08 221E-08 570E-08 11B 347E-08 307E-07 890E-08 230E-07 C 519E-07 160E-05 138E-06 993E-06 N -- 570E-07 262E-08 117E-06 O 621E-03 -- 142E-05 -- Al 144E-06 128E-05 371E-06 957E-06 Si 971E-07 243E-04 259E-06 139E-04 P 377E-08 606E-06 102E-07 360E-06 S 365E-08 581E-06 971E-08 340E-06 Ti 147E-06 130E-05 376E-06 971E-06 Cr 320E-05 187E-03 779E-05 113E-03 Mn 497E-07 126E-04 141E-06 749E-05 Fe 303E-05 531E-03 717E-05 313E-03 Co 132E-06 117E-05 340E-06 876E-06 Ni 697E-05 144E-03 180E-04 940E-04 Cu 368E-07 327E-06 945E-07 244E-06 Zr 196E-03 -- 195E-03 -- Nb 430E-06 382E-05 110E-05 285E-05 Mo 248E-06 135E-04 636E-06 791E-05 Sn 223E-05 -- 222E-05 -- 234U 139E-06 -- -- -- 235U 157E-04 -- -- -- 236U 719E-07 -- -- -- 238U 294E-03 -- -- -- Total 114E-02 924E-03 235E-03 557E-03
Source Attachment II spreadsheet PWR_fuel compxls worksheet BampWassy
29
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
The isotopic composition of commercially available 235U enriched uranium is determined by the given initial 235U enrichment using the following equations (Reference 226 p 20)
wt235U =235Uenrichment _ of _ the _ associated _ fuel _ batch Equation 2
wt234U = 0007731times (wt235U )10837 Equation 3
wt236U = 00046times (wt235U ) Equation 4
wt238U =100 minus (wt234U + wt235U + wt236U ) Equation 5
The weight percentages of uran ium isotopes for PWR fuel are ca lculated in Attachm ent II spreadsheet PWR_fuel compxls worksheet BampWassy using Equations 2 through 5
627 PWR Source Terms
This calculation uses the following three PWR source terms bull Maximum source (50 wt initial 235U enrichment 80 GWdMTU burnup and 5-year
decay time) (Reference 229 Section 55) Table 8 lists th e gamma source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Design Basis source (4 0 wt initial 235U enrichment 60 GW dMTU burnup and 10-year decay tim e) (Reference 228 Section 552) Table 9 lists the gamm a source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Average source ( 40 wt initial 235U enrichment 48 GWdMTU burnup and 25-year decay time) (Reference 229 Section 55) Table 10 lists the gamma source terms for the fuel and non-fuel regions and the neutron source term for the fuel region
These sources (ie maximum design basis and av erage) are described in this section For dose rate calculations all the fuel assemblies in a transportation cask are of the sam e characteristics Also gamma radiation source term s for the PWR assem bly are prov ided for the f our assembly regions while neutron source term is only present in the active fuel region Gamma radiation sources in the non-active fuel region are distri buted unif ormly within each source region Gamma and neutron sources in the active fuel re gion are modeled as uni form distributions or with axial source profiles
The PWR gamma and neutron axial source profiles for the active fuel region presented in Table 11 are applied to the active fuel region of all three source terms (ie maximum design basis and average) when appropriate
30
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 8 Gamma and Neutron Sources for the Maximum PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting
Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 594E+11 233E+15 528E+11 379E+11 100E-01 000E+00 100E-01 116E+11 644E+14 609E+10 743E+10 400E-01 805E+07 200E-01 283E+10 522E+14 352E+10 179E+10 900E-01 411E+08 300E-01 141E+09 148E+14 196E+09 891E+08 140E+00 376E+08 400E-01 190E+09 985E+13 586E+09 117E+09 185E+00 276E+08 600E-01 191E+09 153E+15 110E+11 741E+07 300E+00 485E+08 800E-01 435E+09 470E+15 595E+10 237E+09 643E+00 443E+08 100E+00 137E+11 708E+14 803E+09 766E+10 200E+01 393E+07 133E+00 338E+13 455E+14 174E+13 217E+13 Total 211E+09 166E+00 953E+12 130E+14 491E+12 612E+12
--
200E+00 187E+03 144E+12 919E+02 113E+03 250E+00 226E+08 249E+12 116E+08 145E+08 300E+00 351E+05 110E+11 181E+05 225E+05 400E+00 766E-08 139E+10 100E-08 416E-08 500E+00 000E+00 709E+07 000E+00 000E+00 650E+00 000E+00 286E+07 000E+00 000E+00 800E+00 000E+00 558E+06 000E+00 000E+00 100E+01 000E+00 119E+06 000E+00 000E+00
Total 442E+13 113E+16 231E+13 284E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE2R2B14cut bWasteStreamE2R1B14cut cWasteStreamE2R3B14cut dWasteStreamE2R4B14cut
31
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 9 Gamma and Neutron Sources for the Design Basis PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary
(MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 273E+11 121E+15 188E+11 175E+11 100E-01 000E+00 100E-01 528E+10 329E+14 277E+10 339E+10 400E-01 316E+07 200E-01 128E+10 245E+14 117E+10 819E+09 900E-01 161E+08 300E-01 639E+08 713E+13 633E+08 407E+08 140E+00 148E+08 400E-01 850E+08 455E+13 164E+09 533E+08 185E+00 109E+08 600E-01 492E+08 226E+14 269E+10 337E+07 300E+00 191E+08 800E-01 291E+09 237E+15 160E+10 186E+09 643E+00 174E+08 100E+00 540E+09 122E+14 248E+09 341E+09 200E+01 154E+07 133E+00 154E+13 195E+14 797E+12 990E+12 Total 830E+08 166E+00 435E+12 450E+13 225E+12 280E+12
--
200E+00 235E+00 152E+11 149E+02 215E-02 250E+00 103E+08 517E+10 534E+07 664E+07 300E+00 160E+05 379E+09 829E+04 103E+05 400E+00 943E-10 497E+08 155E-10 519E-10 500E+00 000E+00 282E+07 000E+00 000E+00 650E+00 000E+00 113E+07 000E+00 000E+00 800E+00 000E+00 222E+06 000E+00 000E+00 100E+01 000E+00 471E+05 000E+00 000E+00
Total 201E+13 486E+15 105E+13 129E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B11cut bWasteStreamE5R1B11cut cWasteStreamE5R3B11cut dWasteStreamE5R4B11cut
32
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 10 Gamma and Neutron Sources for the Average PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 336E+10 670E+14 186E+10 217E+10 100E-01 00000E+00 100E-01 602E+09 199E+14 314E+09 387E+09 400E-01 748E+06 200E-01 146E+09 126E+14 853E+08 936E+08 900E-01 382E+07 300E-01 730E+07 389E+13 439E+07 469E+07 140E+00 352E+07 400E-01 947E+07 263E+13 716E+07 607E+07 185E+00 261E+07 600E-01 141E+07 205E+13 504E+08 383E+06 300E+00 469E+07 800E-01 208E+09 124E+15 192E+09 144E+09 643E+00 418E+07 100E+00 208E+09 110E+13 164E+09 144E+09 200E+01 365E+06 133E+00 175E+12 295E+13 909E+11 112E+12 Total 199E+08 166E+00 494E+11 513E+12 257E+11 318E+11
--
200E+00 973E-01 675E+10 614E+01 872E-03 250E+00 117E+07 353E+09 609E+06 754E+06 300E+00 182E+04 288E+08 944E+03 117E+04 400E+00 186E-11 198E+07 149E-11 127E-11 500E+00 000E+00 669E+06 000E+00 000E+00 650E+00 000E+00 269E+06 000E+00 000E+00 800E+00 000E+00 527E+05 000E+00 000E+00 100E+01 000E+00 112E+05 000E+00 000E+00
Total 229E+12 237E+15 119E+12 147E+12
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B9cut bWasteStreamE5R1B9cut cWasteStreamE5R3B9cut dWasteStreamE5R4B9cut
33
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 11 Gamma and Neutron Axial Source Profiles for a PWR Assembly
Axial boundaries (From midplane)
(cm)
TOP BOTTOM
Neutron Gamma Ne utron Gamma 000 1554 1117 1554 1117 1143 1537 1114 1571 1120 2286 1521 1111 1588 1123 3429 1504 1108 1605 1126 4572 1486 1104 1622 1129 5715 1464 1100 1636 1131 6858 1438 1095 1648 1133 8001 1401 1088 1657 1135 9144 1350 1078 1654 1134
10287 1277 1063 1625 1129 11430 1165 1039 1554 1117 12573 0998 09995 1414 1091 13716 0769 09365 1172 1041 14859 0492 08375 0816 0951 16002 0220 06850 0402 0797 17145 0046 04625 0092 0551 18288 00 00 00 00
Source Reference 2219 Table S445
34
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
63 MCNP SPECIFIC INPUT
631 Source Probability
A linear radial distribution is used for all gamma and neutron sources The linear radial distribution is sam pled usi ng the built-in power function p(x) = xc a with a = 1 for the radial direction This sampling method results in a uniform source distribution over the area bounded by the outer radius of the source
The source axial distributions are unifor m for all four source regions The a xial uni form xp(x) = c distribution is sampled using the built-in power function a with a = 0 for extent
The energy distribu tions of the gamma and neutron sour ce term s are treated as energ y probabilities and are applied in MCNP5 using SISP cards
632 Dose Rate and Flux Tallies
MCNP5 dose rate calculations feature separate runs for the following calculation types
bull a photon transport calculation for prim ary ga mma contribution to the dose rates fr om photon fluxes
bull a coupled neutronphoton transport calculat ion for neutrons a nd secondary gamma (photons generated by neutron be ing captured) contributions to dose rates from neutron and gamma fluxes
The tally type F2 is us ed in th is d esign ca lculation as f lux estim ators The type F2 tally evaluates the flux averaged over a surface in particlescm2s
To generate dose ra tes in te rms of remhr the FM (tally multiplier ) and DEDF (dose energydose conversion factors) cards are used to en ter the tally multiplier f actor (source intensity in particless) energy boundaries in MeV and corresponding dose conversion factors in (remhr)(particlescm2s) respectively These factors were used in the input files
In order for the F2 tally to accum ulate flux ov er a surface a specific s urface area is requ ired The SD cards are used to enter a surface area in cm2 over which the flux will be tallied for an F2 tally
633 Variance Reduction Techniques
Variance reduction technique is usually em ployed in order to increase the efficiency of a calculation and obtain statistically m eaningful results within re asonable com puter tim e In Monte Carlo calculations when variance reduction scheme is employed the weights of particles are adjusted in order to account for the biasing and to preserve a fair game
Geometry splitting and Russian roulette techniques described in Reference 2224 (pp 2-140 ndash 2-142) are useful in shielding calculations and therefore deployed in all the MCNP5 runs
35
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
As particles migrate in an important direction (toward the detector) they are increased in number to provide better sampling by means of geometry splitting across geometric boundaries Russian roulette (the reverse process) is played when particles travel in an unimportant direction to allow termination of unim portant histories The IMP card required for every cel l ca rd is us ed to implement this technique
The other variance reduction technique deployed in the MC NP5 runs is source intensity biasing for the gamma sources from the four source regions (active fuel bottom end-fitting plenum and top end-fitting) The natural total gamma source intensity of comm ercial SNF is dom inated by the gamma source in the active fuel region This active fuel gamma source usually accounts for over 95 o f the total g amma source intens ity In order to im prove the efficiency of the axial dose rate calculations a biased source probability distribution is employed for the prim ary gamma dose rate calculations The biased gamma source probability distribution is chosen to be 005 080 010 and 005 for the bottom end-fitting the active fuel the plenum and the top end-fitting regions respectively
64 DOSE CONVERSION FACTORS
Project Design Criteria Document (Reference 2211 Se ction 41015) requires the use of flux-to-dose rate conversion fact ors from ANSIANS-611-1977 (Reference 221) for dose rate evaluations Table 16 lists the neutron and ga mma dose conversion factors used in the MCNP5 calculations
Table 12 Gamma and Neutron Flux to Dose Conversion Factors
Gamma Neutron Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
001 396E-06 140 251E-06 250E-08 367E-06 003 582E-07 180 299E-06 100E-07 367E-06 005 290E-07 220 342E-06 100E-06 446E-06 007 258E-07 260 382E-06 100E-05 454E-06 010 283E-07 280 401E-06 100E-04 418E-06 015 379E-07 325 441E-06 100E-03 376E-06 020 501E-07 375 483E-06 100E-02 356E-06 025 631E-07 425 523E-06 100E-01 217E-05 030 759E-07 475 560E-06 500E-01 926E-05 035 878E-07 500 580E-06 100E+00 132E-04 040 985E-07 525 601E-06 250E+00 125E-04 045 108E-06 575 637E-06 500E+00 156E-04 050 117E-06 625 674E-06 700E+00 147E-04 055 127E-06 675 711E-06 100E+01 147E-04 060 136E-06 750 766E-06 140E+01 208E-04 065 144E-06 900 877E-06 200E+01 227E-04 070 152E-06 1100 103E-05 080 168E-06 1300 118E-05 100 198E-06 1500 133E-05
Source Reference 221 Tables 1 and 3
36
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION
By def inition (Ref erence 2224 Equation 219) the estimated st atistic relative error of the i component is
Ri = Si
2
Equation 6Ti
where i = tally component index Ri = relative error of the i component S2
i = variance of the i component Ti = tally i component
For a result (ie dose rate) computed as a sum of different tallies the statistical relative error of the computed value is o btained from the variance of the result - S2
total which is th e sum of the estimated variances of the individual tallies S2
i n
2 2STotal = sum Si Equation 7 i=1
where S2Total = total estimated variance
n = total number of components Therefore the total tally value (dose rate) and the associated relative error are derived according to Equations 8 and 9
n TTotal = sumTi Equation 8
i=1
n n
sum (Ri timesTi )2
2 sum Si 2
STotal = i=1 = i=1 Equation 9RTotal = TTotal TTotal TTotal
where RTotal = total estimated relative error TTotal = total estimated tally
Equations 8 and 9 are utilized in Attachm ent II to ev aluate to tal dos e ra tes and their r elative errors
37
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
7 RESULTS AND CONCLUSIONS
71 RESULTS
The following sections summarize the results of this calculation Section 711 presents results for Conceptual Cask A while Section 712 for Conceptual Cask B Section 713 provides comparisons of the dose-rate reduction factors du e to the two conceptual casks and the axial source distributions in the active fuel region Do se rates and relative errors can be found in Attachment II within the output files and Excel files
711 Dose Rates of Conceptual Cask A
This section presents dose-rate results of the calculation sets 1 and 2 as described in Section 61 for Cask A Set 1 has axial p rofile sources in the active fuel region a nd consist of six runs resulting from the three PWR SNF source term s (maximum design basis and average) and the two radiation sources (gammas and neutrons) Set 2 has uniform axial sources in the active fuel region and consists of six run s r esulting f rom the th ree P WR SNF source term s and th e tw o radiation sources
As described in Section 61 dose ra tes are calculated at the three exterior surfaces (radial top and bottom) and at distances 1 m and 2 m from the exterior surfaces The total dose rates for set 1 are presented in Tables 13 14 and 15 for the ra dial top and bottom dire ctions respectively However the com ponents (primary gamma neutr on and secondary gamma) contributing to the total dose rates as well as the re lative error calculations can be found in Attachment II Excel file MCNP-Results1xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 2 are shown in Tables 16 17 and 18 The dose-rate components and the relative errors can be found in A ttachment II Excel file MCNP-Results2xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 13 and 16 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 14 and 17 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 15 and 18 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carrying th e maximum PWR SNF Based on the results in Tables 13 through 18 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask A indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these 6 tables the d ose-rate red uction f actors between the m aximum and the design basis fuels the maxim um and the averag e fuels and th e design basis and the average fuels are a lso presented
38
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 320E-02 00237 116E-02 00222 262E-03 00219 275 1223 445
1 m 133E-02 00164 494E-03 00171 106E-03 00162 269 1261 468 2 m 749E-03 00198 285E-03 00225 584E-04 00162 263 1282 488
Ring Detectors 1 m 133E-02 00116 492E-03 00115 108E-03 00124 271 1229 454 2 m 756E-03 00118 279E-03 00110 605E-04 00128 271 1250 462
Source Attachment II MCNP-Results1xls worksheet Summary
Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 142E-02 00368 628E-03 00446 934E-04 00483 226 1520 672
1 m 570E-03 00289 263E-03 00426 375E-04 00381 217 1520 701 2 m 265E-03 00364 123E-03 00547 169E-04 00374 216 1575 730
Point Detectors 1 m 598E-03 00238 274E-03 00271 402E-04 00354 219 1489 681 2 m 273E-03 00218 123E-03 00245 180E-04 00336 221 1515 684
Source Attachment II MCNP-Results1xls worksheet Summary
Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 653E-03 00298 265E-03 00276 510E-04 00341 247 1278 518
1 m 276E-03 00238 112E-03 00208 207E-04 00249 248 1334 539 2 m 125E-03 00185 508E-04 00199 933E-05 00246 246 1336 544
Point Detectors 1 m 291E-03 00227 118E-03 00203 218E-04 00242 247 1335 540 2 m 130E-03 00209 524E-04 00187 955E-05 00233 247 1357 549
Source Attachment II MCNP-Results1xls worksheet Summary
Tables 13 14 and 15 are results of calculation set 1 for conceptual Cask A with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
39
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 265E-02 00247 990E-03 00222 215E-03 00278 268 1234 461
1 m 116E-02 00178 468E-03 00549 960E-04 00189 248 1208 488 2 m 713E-03 00273 265E-03 00161 602E-04 00360 269 1184 439
Ring Detectors 1 m 117E-02 00120 454E-03 00132 979E-04 00141 259 1199 463 2 m 722E-03 00130 276E-03 00141 589E-04 00153 261 1226 469
Source Attachment II MCNP-Results2xls worksheet Summary
Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 199E-02 00461 827E-03 00455 147E-03 00536 241 1359 564
1 m 849E-03 00564 323E-03 00314 563E-04 00418 263 1507 574 2 m 415E-03 00832 158E-03 00603 253E-04 00501 263 1641 623
Point Detectors 1 m 877E-03 00348 353E-03 00275 615E-04 00391 248 1426 574 2 m 393E-03 00341 160E-03 00278 270E-04 00378 246 1454 590
Source Attachment II MCNP-Results2xls worksheet Summary
Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 879E-03 00374 356E-03 00333 669E-04 00406 247 1315 533
1 m 365E-03 00223 147E-03 00209 269E-04 00253 248 1358 548 2 m 164E-03 00229 674E-04 00205 120E-04 00248 243 1364 560
Point Detectors 1 m 383E-03 00217 155E-03 00204 285E-04 00248 247 1347 546 2 m 172E-03 00197 689E-04 00186 124E-04 00225 249 1391 558
Source Attachment II MCNP-Results2xls worksheet Summary
Tables 16 17 and 18 ar e results of calculation set 2 for conceptual Cask A with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
40
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 5 PWR Fuel Assembly Regions
Component Height Reference
Plenum 297688 cm (11720 in) Reference 2220 p 2A-34
Active Fuel 360172 cm (1418 in) Table 3
Bottom End-Fitting 1077 cm (424 in) Calculateda
Top End-Fitting 1998 cm (787 in) Calculatedb
Source Reference 2213 Table 3 aCalculated b ased on data Reference 2227 F igures 2-3 an d 2-7
(Region 9 Height [16723 cm] + Region 10 Height [508 cm] ndash Lo wer Fuel Plenum and End Cap [11033 cm])
bCalculated (Assembly Length ndash Active Fuel Length ndash P lenum Length ndash Bottom End-fitting Length)
625 Material Compositions
The TAD transportation cask com ponent m aterial specifications are defined in Table 1 The TAD canister is constructed of SS 316 (Assumpti on 321) The PWR fuel assembly materials used to homogenize the fuel regions are defined in Table 4 Table 6 c ontains the m aterial compositions defining the TAD canister WP and fuel assemblies
27
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 6 Chemical Compositions of Materials
Material Density (gcc)
Isotopic Weight Percent Reference
SS 302 NA
C 0150 Mn 2000 P 0045 S 0030 Si 0750 Cr 18000 Ni 9000 N 0100 Fe 69925
Attachment II PWR_fuel compxls worksheet ferrous Reference 222 SEC II A SA-240 Table 1 for SS 302 SS 304 and SS 304L Reference 222 SEC II A SA-351SA -351M Table 2 for SS CF3M
SS 304 NA
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 9250 N 0100 Fe 68745
SS 304L NA
C 003 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 10000 N 0100 Fe 6804 5
SS CF3M NA
C 0030 Mn 1500 P 0040 S 0040 Si 1500 Cr 19000 Ni 11000 Mo 2500 Fe 64390
Inconel 718 NA
C 0080 Mn 0350 Si 0350 Cr 19000 Ni 52500 Co 1000 Mo 3050 Fe 16809 Nb 5125 Ti 0900 Al 0500 Cu 0300 S 0015 P 0015 B 0006
Attachment II PWR_fuel compxls worksheet alloys aReference 223 p 666 Table 6 Reference 222 SEC II B SB-637 Table 1 for Inconel 718 Reference 224 Table 2 for Zircaloy 4
Zircaloy 4 656a Cr 0100 Fe 0210 O 0125 Sn 1450 Zr 98115
SS 316 798b
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 17000 Ni 12000 Mo 2500 N 0100 Fe 65495
Attachment II PWR_fuel compxls worksheet others Reference 222 SEC II A SA-240 Table 1 for SS 316 bReference 225 Table X1
626 Homogenization Assembly Materials
The atom density of an element or isotope in atomsbmiddotcm in a homogenized region is calculated according to the following equation (Reference 2223 Appendix B)
M i times N AvogadroNi = Equation 1 Ai timesV times K
where Ni = Atom density of elementisotope i (atomsbmiddotcm) Mi = Mass of elementisotope i (g) NAvogadro = Avogadrorsquos constant 06022 x 1024 (atomsmole)
28
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Ai = Atomic weight of elementisotope i (gmole) V = Homogenization volume (cm3) K = Unit transformation constant = 1024 (bmiddotcmcm3)
Equation 1 is used in A ttachment II spreadsheet PWR_fuel compxls worksheet BampWassy to calculate th e atom dens ities for v arious elem ents and iso topes The m ass of elementsisotop es and Avogadrorsquos constant are provided in Reference 2226
Table 7 lists the com position of the hom ogenized assem bly regions (active fuel plenum top end-fitting and bottom end-fitting) for the PWR assembly The active fuel region contains fresh unirradiated fuel (Assumption 324) Since the internal structure (ie basket) design of the TAD is currently not finalized the composition of either homogenized fuel does not include the basket materials and therefore does not tak e credit for any shielding that thes e materials may provide (Assumption 326)
Table 7 Isotopic Compositions of Homogenized PWR Assembly Regions
Element Isotope
Atom Densities for Homogenized Regions (atomsbsdotcm)
Active Fuel Bottom End-Fitting Plenum Top End-Fitting
10B 861E-09 764E-08 221E-08 570E-08 11B 347E-08 307E-07 890E-08 230E-07 C 519E-07 160E-05 138E-06 993E-06 N -- 570E-07 262E-08 117E-06 O 621E-03 -- 142E-05 -- Al 144E-06 128E-05 371E-06 957E-06 Si 971E-07 243E-04 259E-06 139E-04 P 377E-08 606E-06 102E-07 360E-06 S 365E-08 581E-06 971E-08 340E-06 Ti 147E-06 130E-05 376E-06 971E-06 Cr 320E-05 187E-03 779E-05 113E-03 Mn 497E-07 126E-04 141E-06 749E-05 Fe 303E-05 531E-03 717E-05 313E-03 Co 132E-06 117E-05 340E-06 876E-06 Ni 697E-05 144E-03 180E-04 940E-04 Cu 368E-07 327E-06 945E-07 244E-06 Zr 196E-03 -- 195E-03 -- Nb 430E-06 382E-05 110E-05 285E-05 Mo 248E-06 135E-04 636E-06 791E-05 Sn 223E-05 -- 222E-05 -- 234U 139E-06 -- -- -- 235U 157E-04 -- -- -- 236U 719E-07 -- -- -- 238U 294E-03 -- -- -- Total 114E-02 924E-03 235E-03 557E-03
Source Attachment II spreadsheet PWR_fuel compxls worksheet BampWassy
29
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
The isotopic composition of commercially available 235U enriched uranium is determined by the given initial 235U enrichment using the following equations (Reference 226 p 20)
wt235U =235Uenrichment _ of _ the _ associated _ fuel _ batch Equation 2
wt234U = 0007731times (wt235U )10837 Equation 3
wt236U = 00046times (wt235U ) Equation 4
wt238U =100 minus (wt234U + wt235U + wt236U ) Equation 5
The weight percentages of uran ium isotopes for PWR fuel are ca lculated in Attachm ent II spreadsheet PWR_fuel compxls worksheet BampWassy using Equations 2 through 5
627 PWR Source Terms
This calculation uses the following three PWR source terms bull Maximum source (50 wt initial 235U enrichment 80 GWdMTU burnup and 5-year
decay time) (Reference 229 Section 55) Table 8 lists th e gamma source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Design Basis source (4 0 wt initial 235U enrichment 60 GW dMTU burnup and 10-year decay tim e) (Reference 228 Section 552) Table 9 lists the gamm a source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Average source ( 40 wt initial 235U enrichment 48 GWdMTU burnup and 25-year decay time) (Reference 229 Section 55) Table 10 lists the gamma source terms for the fuel and non-fuel regions and the neutron source term for the fuel region
These sources (ie maximum design basis and av erage) are described in this section For dose rate calculations all the fuel assemblies in a transportation cask are of the sam e characteristics Also gamma radiation source term s for the PWR assem bly are prov ided for the f our assembly regions while neutron source term is only present in the active fuel region Gamma radiation sources in the non-active fuel region are distri buted unif ormly within each source region Gamma and neutron sources in the active fuel re gion are modeled as uni form distributions or with axial source profiles
The PWR gamma and neutron axial source profiles for the active fuel region presented in Table 11 are applied to the active fuel region of all three source terms (ie maximum design basis and average) when appropriate
30
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 8 Gamma and Neutron Sources for the Maximum PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting
Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 594E+11 233E+15 528E+11 379E+11 100E-01 000E+00 100E-01 116E+11 644E+14 609E+10 743E+10 400E-01 805E+07 200E-01 283E+10 522E+14 352E+10 179E+10 900E-01 411E+08 300E-01 141E+09 148E+14 196E+09 891E+08 140E+00 376E+08 400E-01 190E+09 985E+13 586E+09 117E+09 185E+00 276E+08 600E-01 191E+09 153E+15 110E+11 741E+07 300E+00 485E+08 800E-01 435E+09 470E+15 595E+10 237E+09 643E+00 443E+08 100E+00 137E+11 708E+14 803E+09 766E+10 200E+01 393E+07 133E+00 338E+13 455E+14 174E+13 217E+13 Total 211E+09 166E+00 953E+12 130E+14 491E+12 612E+12
--
200E+00 187E+03 144E+12 919E+02 113E+03 250E+00 226E+08 249E+12 116E+08 145E+08 300E+00 351E+05 110E+11 181E+05 225E+05 400E+00 766E-08 139E+10 100E-08 416E-08 500E+00 000E+00 709E+07 000E+00 000E+00 650E+00 000E+00 286E+07 000E+00 000E+00 800E+00 000E+00 558E+06 000E+00 000E+00 100E+01 000E+00 119E+06 000E+00 000E+00
Total 442E+13 113E+16 231E+13 284E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE2R2B14cut bWasteStreamE2R1B14cut cWasteStreamE2R3B14cut dWasteStreamE2R4B14cut
31
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 9 Gamma and Neutron Sources for the Design Basis PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary
(MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 273E+11 121E+15 188E+11 175E+11 100E-01 000E+00 100E-01 528E+10 329E+14 277E+10 339E+10 400E-01 316E+07 200E-01 128E+10 245E+14 117E+10 819E+09 900E-01 161E+08 300E-01 639E+08 713E+13 633E+08 407E+08 140E+00 148E+08 400E-01 850E+08 455E+13 164E+09 533E+08 185E+00 109E+08 600E-01 492E+08 226E+14 269E+10 337E+07 300E+00 191E+08 800E-01 291E+09 237E+15 160E+10 186E+09 643E+00 174E+08 100E+00 540E+09 122E+14 248E+09 341E+09 200E+01 154E+07 133E+00 154E+13 195E+14 797E+12 990E+12 Total 830E+08 166E+00 435E+12 450E+13 225E+12 280E+12
--
200E+00 235E+00 152E+11 149E+02 215E-02 250E+00 103E+08 517E+10 534E+07 664E+07 300E+00 160E+05 379E+09 829E+04 103E+05 400E+00 943E-10 497E+08 155E-10 519E-10 500E+00 000E+00 282E+07 000E+00 000E+00 650E+00 000E+00 113E+07 000E+00 000E+00 800E+00 000E+00 222E+06 000E+00 000E+00 100E+01 000E+00 471E+05 000E+00 000E+00
Total 201E+13 486E+15 105E+13 129E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B11cut bWasteStreamE5R1B11cut cWasteStreamE5R3B11cut dWasteStreamE5R4B11cut
32
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 10 Gamma and Neutron Sources for the Average PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 336E+10 670E+14 186E+10 217E+10 100E-01 00000E+00 100E-01 602E+09 199E+14 314E+09 387E+09 400E-01 748E+06 200E-01 146E+09 126E+14 853E+08 936E+08 900E-01 382E+07 300E-01 730E+07 389E+13 439E+07 469E+07 140E+00 352E+07 400E-01 947E+07 263E+13 716E+07 607E+07 185E+00 261E+07 600E-01 141E+07 205E+13 504E+08 383E+06 300E+00 469E+07 800E-01 208E+09 124E+15 192E+09 144E+09 643E+00 418E+07 100E+00 208E+09 110E+13 164E+09 144E+09 200E+01 365E+06 133E+00 175E+12 295E+13 909E+11 112E+12 Total 199E+08 166E+00 494E+11 513E+12 257E+11 318E+11
--
200E+00 973E-01 675E+10 614E+01 872E-03 250E+00 117E+07 353E+09 609E+06 754E+06 300E+00 182E+04 288E+08 944E+03 117E+04 400E+00 186E-11 198E+07 149E-11 127E-11 500E+00 000E+00 669E+06 000E+00 000E+00 650E+00 000E+00 269E+06 000E+00 000E+00 800E+00 000E+00 527E+05 000E+00 000E+00 100E+01 000E+00 112E+05 000E+00 000E+00
Total 229E+12 237E+15 119E+12 147E+12
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B9cut bWasteStreamE5R1B9cut cWasteStreamE5R3B9cut dWasteStreamE5R4B9cut
33
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 11 Gamma and Neutron Axial Source Profiles for a PWR Assembly
Axial boundaries (From midplane)
(cm)
TOP BOTTOM
Neutron Gamma Ne utron Gamma 000 1554 1117 1554 1117 1143 1537 1114 1571 1120 2286 1521 1111 1588 1123 3429 1504 1108 1605 1126 4572 1486 1104 1622 1129 5715 1464 1100 1636 1131 6858 1438 1095 1648 1133 8001 1401 1088 1657 1135 9144 1350 1078 1654 1134
10287 1277 1063 1625 1129 11430 1165 1039 1554 1117 12573 0998 09995 1414 1091 13716 0769 09365 1172 1041 14859 0492 08375 0816 0951 16002 0220 06850 0402 0797 17145 0046 04625 0092 0551 18288 00 00 00 00
Source Reference 2219 Table S445
34
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
63 MCNP SPECIFIC INPUT
631 Source Probability
A linear radial distribution is used for all gamma and neutron sources The linear radial distribution is sam pled usi ng the built-in power function p(x) = xc a with a = 1 for the radial direction This sampling method results in a uniform source distribution over the area bounded by the outer radius of the source
The source axial distributions are unifor m for all four source regions The a xial uni form xp(x) = c distribution is sampled using the built-in power function a with a = 0 for extent
The energy distribu tions of the gamma and neutron sour ce term s are treated as energ y probabilities and are applied in MCNP5 using SISP cards
632 Dose Rate and Flux Tallies
MCNP5 dose rate calculations feature separate runs for the following calculation types
bull a photon transport calculation for prim ary ga mma contribution to the dose rates fr om photon fluxes
bull a coupled neutronphoton transport calculat ion for neutrons a nd secondary gamma (photons generated by neutron be ing captured) contributions to dose rates from neutron and gamma fluxes
The tally type F2 is us ed in th is d esign ca lculation as f lux estim ators The type F2 tally evaluates the flux averaged over a surface in particlescm2s
To generate dose ra tes in te rms of remhr the FM (tally multiplier ) and DEDF (dose energydose conversion factors) cards are used to en ter the tally multiplier f actor (source intensity in particless) energy boundaries in MeV and corresponding dose conversion factors in (remhr)(particlescm2s) respectively These factors were used in the input files
In order for the F2 tally to accum ulate flux ov er a surface a specific s urface area is requ ired The SD cards are used to enter a surface area in cm2 over which the flux will be tallied for an F2 tally
633 Variance Reduction Techniques
Variance reduction technique is usually em ployed in order to increase the efficiency of a calculation and obtain statistically m eaningful results within re asonable com puter tim e In Monte Carlo calculations when variance reduction scheme is employed the weights of particles are adjusted in order to account for the biasing and to preserve a fair game
Geometry splitting and Russian roulette techniques described in Reference 2224 (pp 2-140 ndash 2-142) are useful in shielding calculations and therefore deployed in all the MCNP5 runs
35
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
As particles migrate in an important direction (toward the detector) they are increased in number to provide better sampling by means of geometry splitting across geometric boundaries Russian roulette (the reverse process) is played when particles travel in an unimportant direction to allow termination of unim portant histories The IMP card required for every cel l ca rd is us ed to implement this technique
The other variance reduction technique deployed in the MC NP5 runs is source intensity biasing for the gamma sources from the four source regions (active fuel bottom end-fitting plenum and top end-fitting) The natural total gamma source intensity of comm ercial SNF is dom inated by the gamma source in the active fuel region This active fuel gamma source usually accounts for over 95 o f the total g amma source intens ity In order to im prove the efficiency of the axial dose rate calculations a biased source probability distribution is employed for the prim ary gamma dose rate calculations The biased gamma source probability distribution is chosen to be 005 080 010 and 005 for the bottom end-fitting the active fuel the plenum and the top end-fitting regions respectively
64 DOSE CONVERSION FACTORS
Project Design Criteria Document (Reference 2211 Se ction 41015) requires the use of flux-to-dose rate conversion fact ors from ANSIANS-611-1977 (Reference 221) for dose rate evaluations Table 16 lists the neutron and ga mma dose conversion factors used in the MCNP5 calculations
Table 12 Gamma and Neutron Flux to Dose Conversion Factors
Gamma Neutron Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
001 396E-06 140 251E-06 250E-08 367E-06 003 582E-07 180 299E-06 100E-07 367E-06 005 290E-07 220 342E-06 100E-06 446E-06 007 258E-07 260 382E-06 100E-05 454E-06 010 283E-07 280 401E-06 100E-04 418E-06 015 379E-07 325 441E-06 100E-03 376E-06 020 501E-07 375 483E-06 100E-02 356E-06 025 631E-07 425 523E-06 100E-01 217E-05 030 759E-07 475 560E-06 500E-01 926E-05 035 878E-07 500 580E-06 100E+00 132E-04 040 985E-07 525 601E-06 250E+00 125E-04 045 108E-06 575 637E-06 500E+00 156E-04 050 117E-06 625 674E-06 700E+00 147E-04 055 127E-06 675 711E-06 100E+01 147E-04 060 136E-06 750 766E-06 140E+01 208E-04 065 144E-06 900 877E-06 200E+01 227E-04 070 152E-06 1100 103E-05 080 168E-06 1300 118E-05 100 198E-06 1500 133E-05
Source Reference 221 Tables 1 and 3
36
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION
By def inition (Ref erence 2224 Equation 219) the estimated st atistic relative error of the i component is
Ri = Si
2
Equation 6Ti
where i = tally component index Ri = relative error of the i component S2
i = variance of the i component Ti = tally i component
For a result (ie dose rate) computed as a sum of different tallies the statistical relative error of the computed value is o btained from the variance of the result - S2
total which is th e sum of the estimated variances of the individual tallies S2
i n
2 2STotal = sum Si Equation 7 i=1
where S2Total = total estimated variance
n = total number of components Therefore the total tally value (dose rate) and the associated relative error are derived according to Equations 8 and 9
n TTotal = sumTi Equation 8
i=1
n n
sum (Ri timesTi )2
2 sum Si 2
STotal = i=1 = i=1 Equation 9RTotal = TTotal TTotal TTotal
where RTotal = total estimated relative error TTotal = total estimated tally
Equations 8 and 9 are utilized in Attachm ent II to ev aluate to tal dos e ra tes and their r elative errors
37
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
7 RESULTS AND CONCLUSIONS
71 RESULTS
The following sections summarize the results of this calculation Section 711 presents results for Conceptual Cask A while Section 712 for Conceptual Cask B Section 713 provides comparisons of the dose-rate reduction factors du e to the two conceptual casks and the axial source distributions in the active fuel region Do se rates and relative errors can be found in Attachment II within the output files and Excel files
711 Dose Rates of Conceptual Cask A
This section presents dose-rate results of the calculation sets 1 and 2 as described in Section 61 for Cask A Set 1 has axial p rofile sources in the active fuel region a nd consist of six runs resulting from the three PWR SNF source term s (maximum design basis and average) and the two radiation sources (gammas and neutrons) Set 2 has uniform axial sources in the active fuel region and consists of six run s r esulting f rom the th ree P WR SNF source term s and th e tw o radiation sources
As described in Section 61 dose ra tes are calculated at the three exterior surfaces (radial top and bottom) and at distances 1 m and 2 m from the exterior surfaces The total dose rates for set 1 are presented in Tables 13 14 and 15 for the ra dial top and bottom dire ctions respectively However the com ponents (primary gamma neutr on and secondary gamma) contributing to the total dose rates as well as the re lative error calculations can be found in Attachment II Excel file MCNP-Results1xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 2 are shown in Tables 16 17 and 18 The dose-rate components and the relative errors can be found in A ttachment II Excel file MCNP-Results2xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 13 and 16 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 14 and 17 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 15 and 18 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carrying th e maximum PWR SNF Based on the results in Tables 13 through 18 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask A indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these 6 tables the d ose-rate red uction f actors between the m aximum and the design basis fuels the maxim um and the averag e fuels and th e design basis and the average fuels are a lso presented
38
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 320E-02 00237 116E-02 00222 262E-03 00219 275 1223 445
1 m 133E-02 00164 494E-03 00171 106E-03 00162 269 1261 468 2 m 749E-03 00198 285E-03 00225 584E-04 00162 263 1282 488
Ring Detectors 1 m 133E-02 00116 492E-03 00115 108E-03 00124 271 1229 454 2 m 756E-03 00118 279E-03 00110 605E-04 00128 271 1250 462
Source Attachment II MCNP-Results1xls worksheet Summary
Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 142E-02 00368 628E-03 00446 934E-04 00483 226 1520 672
1 m 570E-03 00289 263E-03 00426 375E-04 00381 217 1520 701 2 m 265E-03 00364 123E-03 00547 169E-04 00374 216 1575 730
Point Detectors 1 m 598E-03 00238 274E-03 00271 402E-04 00354 219 1489 681 2 m 273E-03 00218 123E-03 00245 180E-04 00336 221 1515 684
Source Attachment II MCNP-Results1xls worksheet Summary
Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 653E-03 00298 265E-03 00276 510E-04 00341 247 1278 518
1 m 276E-03 00238 112E-03 00208 207E-04 00249 248 1334 539 2 m 125E-03 00185 508E-04 00199 933E-05 00246 246 1336 544
Point Detectors 1 m 291E-03 00227 118E-03 00203 218E-04 00242 247 1335 540 2 m 130E-03 00209 524E-04 00187 955E-05 00233 247 1357 549
Source Attachment II MCNP-Results1xls worksheet Summary
Tables 13 14 and 15 are results of calculation set 1 for conceptual Cask A with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
39
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 265E-02 00247 990E-03 00222 215E-03 00278 268 1234 461
1 m 116E-02 00178 468E-03 00549 960E-04 00189 248 1208 488 2 m 713E-03 00273 265E-03 00161 602E-04 00360 269 1184 439
Ring Detectors 1 m 117E-02 00120 454E-03 00132 979E-04 00141 259 1199 463 2 m 722E-03 00130 276E-03 00141 589E-04 00153 261 1226 469
Source Attachment II MCNP-Results2xls worksheet Summary
Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 199E-02 00461 827E-03 00455 147E-03 00536 241 1359 564
1 m 849E-03 00564 323E-03 00314 563E-04 00418 263 1507 574 2 m 415E-03 00832 158E-03 00603 253E-04 00501 263 1641 623
Point Detectors 1 m 877E-03 00348 353E-03 00275 615E-04 00391 248 1426 574 2 m 393E-03 00341 160E-03 00278 270E-04 00378 246 1454 590
Source Attachment II MCNP-Results2xls worksheet Summary
Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 879E-03 00374 356E-03 00333 669E-04 00406 247 1315 533
1 m 365E-03 00223 147E-03 00209 269E-04 00253 248 1358 548 2 m 164E-03 00229 674E-04 00205 120E-04 00248 243 1364 560
Point Detectors 1 m 383E-03 00217 155E-03 00204 285E-04 00248 247 1347 546 2 m 172E-03 00197 689E-04 00186 124E-04 00225 249 1391 558
Source Attachment II MCNP-Results2xls worksheet Summary
Tables 16 17 and 18 ar e results of calculation set 2 for conceptual Cask A with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
40
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
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11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
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000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 6 Chemical Compositions of Materials
Material Density (gcc)
Isotopic Weight Percent Reference
SS 302 NA
C 0150 Mn 2000 P 0045 S 0030 Si 0750 Cr 18000 Ni 9000 N 0100 Fe 69925
Attachment II PWR_fuel compxls worksheet ferrous Reference 222 SEC II A SA-240 Table 1 for SS 302 SS 304 and SS 304L Reference 222 SEC II A SA-351SA -351M Table 2 for SS CF3M
SS 304 NA
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 9250 N 0100 Fe 68745
SS 304L NA
C 003 Mn 2000 P 0045 S 0030 Si 0750 Cr 19000 Ni 10000 N 0100 Fe 6804 5
SS CF3M NA
C 0030 Mn 1500 P 0040 S 0040 Si 1500 Cr 19000 Ni 11000 Mo 2500 Fe 64390
Inconel 718 NA
C 0080 Mn 0350 Si 0350 Cr 19000 Ni 52500 Co 1000 Mo 3050 Fe 16809 Nb 5125 Ti 0900 Al 0500 Cu 0300 S 0015 P 0015 B 0006
Attachment II PWR_fuel compxls worksheet alloys aReference 223 p 666 Table 6 Reference 222 SEC II B SB-637 Table 1 for Inconel 718 Reference 224 Table 2 for Zircaloy 4
Zircaloy 4 656a Cr 0100 Fe 0210 O 0125 Sn 1450 Zr 98115
SS 316 798b
C 0080 Mn 2000 P 0045 S 0030 Si 0750 Cr 17000 Ni 12000 Mo 2500 N 0100 Fe 65495
Attachment II PWR_fuel compxls worksheet others Reference 222 SEC II A SA-240 Table 1 for SS 316 bReference 225 Table X1
626 Homogenization Assembly Materials
The atom density of an element or isotope in atomsbmiddotcm in a homogenized region is calculated according to the following equation (Reference 2223 Appendix B)
M i times N AvogadroNi = Equation 1 Ai timesV times K
where Ni = Atom density of elementisotope i (atomsbmiddotcm) Mi = Mass of elementisotope i (g) NAvogadro = Avogadrorsquos constant 06022 x 1024 (atomsmole)
28
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Ai = Atomic weight of elementisotope i (gmole) V = Homogenization volume (cm3) K = Unit transformation constant = 1024 (bmiddotcmcm3)
Equation 1 is used in A ttachment II spreadsheet PWR_fuel compxls worksheet BampWassy to calculate th e atom dens ities for v arious elem ents and iso topes The m ass of elementsisotop es and Avogadrorsquos constant are provided in Reference 2226
Table 7 lists the com position of the hom ogenized assem bly regions (active fuel plenum top end-fitting and bottom end-fitting) for the PWR assembly The active fuel region contains fresh unirradiated fuel (Assumption 324) Since the internal structure (ie basket) design of the TAD is currently not finalized the composition of either homogenized fuel does not include the basket materials and therefore does not tak e credit for any shielding that thes e materials may provide (Assumption 326)
Table 7 Isotopic Compositions of Homogenized PWR Assembly Regions
Element Isotope
Atom Densities for Homogenized Regions (atomsbsdotcm)
Active Fuel Bottom End-Fitting Plenum Top End-Fitting
10B 861E-09 764E-08 221E-08 570E-08 11B 347E-08 307E-07 890E-08 230E-07 C 519E-07 160E-05 138E-06 993E-06 N -- 570E-07 262E-08 117E-06 O 621E-03 -- 142E-05 -- Al 144E-06 128E-05 371E-06 957E-06 Si 971E-07 243E-04 259E-06 139E-04 P 377E-08 606E-06 102E-07 360E-06 S 365E-08 581E-06 971E-08 340E-06 Ti 147E-06 130E-05 376E-06 971E-06 Cr 320E-05 187E-03 779E-05 113E-03 Mn 497E-07 126E-04 141E-06 749E-05 Fe 303E-05 531E-03 717E-05 313E-03 Co 132E-06 117E-05 340E-06 876E-06 Ni 697E-05 144E-03 180E-04 940E-04 Cu 368E-07 327E-06 945E-07 244E-06 Zr 196E-03 -- 195E-03 -- Nb 430E-06 382E-05 110E-05 285E-05 Mo 248E-06 135E-04 636E-06 791E-05 Sn 223E-05 -- 222E-05 -- 234U 139E-06 -- -- -- 235U 157E-04 -- -- -- 236U 719E-07 -- -- -- 238U 294E-03 -- -- -- Total 114E-02 924E-03 235E-03 557E-03
Source Attachment II spreadsheet PWR_fuel compxls worksheet BampWassy
29
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
The isotopic composition of commercially available 235U enriched uranium is determined by the given initial 235U enrichment using the following equations (Reference 226 p 20)
wt235U =235Uenrichment _ of _ the _ associated _ fuel _ batch Equation 2
wt234U = 0007731times (wt235U )10837 Equation 3
wt236U = 00046times (wt235U ) Equation 4
wt238U =100 minus (wt234U + wt235U + wt236U ) Equation 5
The weight percentages of uran ium isotopes for PWR fuel are ca lculated in Attachm ent II spreadsheet PWR_fuel compxls worksheet BampWassy using Equations 2 through 5
627 PWR Source Terms
This calculation uses the following three PWR source terms bull Maximum source (50 wt initial 235U enrichment 80 GWdMTU burnup and 5-year
decay time) (Reference 229 Section 55) Table 8 lists th e gamma source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Design Basis source (4 0 wt initial 235U enrichment 60 GW dMTU burnup and 10-year decay tim e) (Reference 228 Section 552) Table 9 lists the gamm a source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Average source ( 40 wt initial 235U enrichment 48 GWdMTU burnup and 25-year decay time) (Reference 229 Section 55) Table 10 lists the gamma source terms for the fuel and non-fuel regions and the neutron source term for the fuel region
These sources (ie maximum design basis and av erage) are described in this section For dose rate calculations all the fuel assemblies in a transportation cask are of the sam e characteristics Also gamma radiation source term s for the PWR assem bly are prov ided for the f our assembly regions while neutron source term is only present in the active fuel region Gamma radiation sources in the non-active fuel region are distri buted unif ormly within each source region Gamma and neutron sources in the active fuel re gion are modeled as uni form distributions or with axial source profiles
The PWR gamma and neutron axial source profiles for the active fuel region presented in Table 11 are applied to the active fuel region of all three source terms (ie maximum design basis and average) when appropriate
30
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 8 Gamma and Neutron Sources for the Maximum PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting
Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 594E+11 233E+15 528E+11 379E+11 100E-01 000E+00 100E-01 116E+11 644E+14 609E+10 743E+10 400E-01 805E+07 200E-01 283E+10 522E+14 352E+10 179E+10 900E-01 411E+08 300E-01 141E+09 148E+14 196E+09 891E+08 140E+00 376E+08 400E-01 190E+09 985E+13 586E+09 117E+09 185E+00 276E+08 600E-01 191E+09 153E+15 110E+11 741E+07 300E+00 485E+08 800E-01 435E+09 470E+15 595E+10 237E+09 643E+00 443E+08 100E+00 137E+11 708E+14 803E+09 766E+10 200E+01 393E+07 133E+00 338E+13 455E+14 174E+13 217E+13 Total 211E+09 166E+00 953E+12 130E+14 491E+12 612E+12
--
200E+00 187E+03 144E+12 919E+02 113E+03 250E+00 226E+08 249E+12 116E+08 145E+08 300E+00 351E+05 110E+11 181E+05 225E+05 400E+00 766E-08 139E+10 100E-08 416E-08 500E+00 000E+00 709E+07 000E+00 000E+00 650E+00 000E+00 286E+07 000E+00 000E+00 800E+00 000E+00 558E+06 000E+00 000E+00 100E+01 000E+00 119E+06 000E+00 000E+00
Total 442E+13 113E+16 231E+13 284E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE2R2B14cut bWasteStreamE2R1B14cut cWasteStreamE2R3B14cut dWasteStreamE2R4B14cut
31
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 9 Gamma and Neutron Sources for the Design Basis PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary
(MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 273E+11 121E+15 188E+11 175E+11 100E-01 000E+00 100E-01 528E+10 329E+14 277E+10 339E+10 400E-01 316E+07 200E-01 128E+10 245E+14 117E+10 819E+09 900E-01 161E+08 300E-01 639E+08 713E+13 633E+08 407E+08 140E+00 148E+08 400E-01 850E+08 455E+13 164E+09 533E+08 185E+00 109E+08 600E-01 492E+08 226E+14 269E+10 337E+07 300E+00 191E+08 800E-01 291E+09 237E+15 160E+10 186E+09 643E+00 174E+08 100E+00 540E+09 122E+14 248E+09 341E+09 200E+01 154E+07 133E+00 154E+13 195E+14 797E+12 990E+12 Total 830E+08 166E+00 435E+12 450E+13 225E+12 280E+12
--
200E+00 235E+00 152E+11 149E+02 215E-02 250E+00 103E+08 517E+10 534E+07 664E+07 300E+00 160E+05 379E+09 829E+04 103E+05 400E+00 943E-10 497E+08 155E-10 519E-10 500E+00 000E+00 282E+07 000E+00 000E+00 650E+00 000E+00 113E+07 000E+00 000E+00 800E+00 000E+00 222E+06 000E+00 000E+00 100E+01 000E+00 471E+05 000E+00 000E+00
Total 201E+13 486E+15 105E+13 129E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B11cut bWasteStreamE5R1B11cut cWasteStreamE5R3B11cut dWasteStreamE5R4B11cut
32
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 10 Gamma and Neutron Sources for the Average PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 336E+10 670E+14 186E+10 217E+10 100E-01 00000E+00 100E-01 602E+09 199E+14 314E+09 387E+09 400E-01 748E+06 200E-01 146E+09 126E+14 853E+08 936E+08 900E-01 382E+07 300E-01 730E+07 389E+13 439E+07 469E+07 140E+00 352E+07 400E-01 947E+07 263E+13 716E+07 607E+07 185E+00 261E+07 600E-01 141E+07 205E+13 504E+08 383E+06 300E+00 469E+07 800E-01 208E+09 124E+15 192E+09 144E+09 643E+00 418E+07 100E+00 208E+09 110E+13 164E+09 144E+09 200E+01 365E+06 133E+00 175E+12 295E+13 909E+11 112E+12 Total 199E+08 166E+00 494E+11 513E+12 257E+11 318E+11
--
200E+00 973E-01 675E+10 614E+01 872E-03 250E+00 117E+07 353E+09 609E+06 754E+06 300E+00 182E+04 288E+08 944E+03 117E+04 400E+00 186E-11 198E+07 149E-11 127E-11 500E+00 000E+00 669E+06 000E+00 000E+00 650E+00 000E+00 269E+06 000E+00 000E+00 800E+00 000E+00 527E+05 000E+00 000E+00 100E+01 000E+00 112E+05 000E+00 000E+00
Total 229E+12 237E+15 119E+12 147E+12
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B9cut bWasteStreamE5R1B9cut cWasteStreamE5R3B9cut dWasteStreamE5R4B9cut
33
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 11 Gamma and Neutron Axial Source Profiles for a PWR Assembly
Axial boundaries (From midplane)
(cm)
TOP BOTTOM
Neutron Gamma Ne utron Gamma 000 1554 1117 1554 1117 1143 1537 1114 1571 1120 2286 1521 1111 1588 1123 3429 1504 1108 1605 1126 4572 1486 1104 1622 1129 5715 1464 1100 1636 1131 6858 1438 1095 1648 1133 8001 1401 1088 1657 1135 9144 1350 1078 1654 1134
10287 1277 1063 1625 1129 11430 1165 1039 1554 1117 12573 0998 09995 1414 1091 13716 0769 09365 1172 1041 14859 0492 08375 0816 0951 16002 0220 06850 0402 0797 17145 0046 04625 0092 0551 18288 00 00 00 00
Source Reference 2219 Table S445
34
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
63 MCNP SPECIFIC INPUT
631 Source Probability
A linear radial distribution is used for all gamma and neutron sources The linear radial distribution is sam pled usi ng the built-in power function p(x) = xc a with a = 1 for the radial direction This sampling method results in a uniform source distribution over the area bounded by the outer radius of the source
The source axial distributions are unifor m for all four source regions The a xial uni form xp(x) = c distribution is sampled using the built-in power function a with a = 0 for extent
The energy distribu tions of the gamma and neutron sour ce term s are treated as energ y probabilities and are applied in MCNP5 using SISP cards
632 Dose Rate and Flux Tallies
MCNP5 dose rate calculations feature separate runs for the following calculation types
bull a photon transport calculation for prim ary ga mma contribution to the dose rates fr om photon fluxes
bull a coupled neutronphoton transport calculat ion for neutrons a nd secondary gamma (photons generated by neutron be ing captured) contributions to dose rates from neutron and gamma fluxes
The tally type F2 is us ed in th is d esign ca lculation as f lux estim ators The type F2 tally evaluates the flux averaged over a surface in particlescm2s
To generate dose ra tes in te rms of remhr the FM (tally multiplier ) and DEDF (dose energydose conversion factors) cards are used to en ter the tally multiplier f actor (source intensity in particless) energy boundaries in MeV and corresponding dose conversion factors in (remhr)(particlescm2s) respectively These factors were used in the input files
In order for the F2 tally to accum ulate flux ov er a surface a specific s urface area is requ ired The SD cards are used to enter a surface area in cm2 over which the flux will be tallied for an F2 tally
633 Variance Reduction Techniques
Variance reduction technique is usually em ployed in order to increase the efficiency of a calculation and obtain statistically m eaningful results within re asonable com puter tim e In Monte Carlo calculations when variance reduction scheme is employed the weights of particles are adjusted in order to account for the biasing and to preserve a fair game
Geometry splitting and Russian roulette techniques described in Reference 2224 (pp 2-140 ndash 2-142) are useful in shielding calculations and therefore deployed in all the MCNP5 runs
35
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
As particles migrate in an important direction (toward the detector) they are increased in number to provide better sampling by means of geometry splitting across geometric boundaries Russian roulette (the reverse process) is played when particles travel in an unimportant direction to allow termination of unim portant histories The IMP card required for every cel l ca rd is us ed to implement this technique
The other variance reduction technique deployed in the MC NP5 runs is source intensity biasing for the gamma sources from the four source regions (active fuel bottom end-fitting plenum and top end-fitting) The natural total gamma source intensity of comm ercial SNF is dom inated by the gamma source in the active fuel region This active fuel gamma source usually accounts for over 95 o f the total g amma source intens ity In order to im prove the efficiency of the axial dose rate calculations a biased source probability distribution is employed for the prim ary gamma dose rate calculations The biased gamma source probability distribution is chosen to be 005 080 010 and 005 for the bottom end-fitting the active fuel the plenum and the top end-fitting regions respectively
64 DOSE CONVERSION FACTORS
Project Design Criteria Document (Reference 2211 Se ction 41015) requires the use of flux-to-dose rate conversion fact ors from ANSIANS-611-1977 (Reference 221) for dose rate evaluations Table 16 lists the neutron and ga mma dose conversion factors used in the MCNP5 calculations
Table 12 Gamma and Neutron Flux to Dose Conversion Factors
Gamma Neutron Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
001 396E-06 140 251E-06 250E-08 367E-06 003 582E-07 180 299E-06 100E-07 367E-06 005 290E-07 220 342E-06 100E-06 446E-06 007 258E-07 260 382E-06 100E-05 454E-06 010 283E-07 280 401E-06 100E-04 418E-06 015 379E-07 325 441E-06 100E-03 376E-06 020 501E-07 375 483E-06 100E-02 356E-06 025 631E-07 425 523E-06 100E-01 217E-05 030 759E-07 475 560E-06 500E-01 926E-05 035 878E-07 500 580E-06 100E+00 132E-04 040 985E-07 525 601E-06 250E+00 125E-04 045 108E-06 575 637E-06 500E+00 156E-04 050 117E-06 625 674E-06 700E+00 147E-04 055 127E-06 675 711E-06 100E+01 147E-04 060 136E-06 750 766E-06 140E+01 208E-04 065 144E-06 900 877E-06 200E+01 227E-04 070 152E-06 1100 103E-05 080 168E-06 1300 118E-05 100 198E-06 1500 133E-05
Source Reference 221 Tables 1 and 3
36
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION
By def inition (Ref erence 2224 Equation 219) the estimated st atistic relative error of the i component is
Ri = Si
2
Equation 6Ti
where i = tally component index Ri = relative error of the i component S2
i = variance of the i component Ti = tally i component
For a result (ie dose rate) computed as a sum of different tallies the statistical relative error of the computed value is o btained from the variance of the result - S2
total which is th e sum of the estimated variances of the individual tallies S2
i n
2 2STotal = sum Si Equation 7 i=1
where S2Total = total estimated variance
n = total number of components Therefore the total tally value (dose rate) and the associated relative error are derived according to Equations 8 and 9
n TTotal = sumTi Equation 8
i=1
n n
sum (Ri timesTi )2
2 sum Si 2
STotal = i=1 = i=1 Equation 9RTotal = TTotal TTotal TTotal
where RTotal = total estimated relative error TTotal = total estimated tally
Equations 8 and 9 are utilized in Attachm ent II to ev aluate to tal dos e ra tes and their r elative errors
37
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
7 RESULTS AND CONCLUSIONS
71 RESULTS
The following sections summarize the results of this calculation Section 711 presents results for Conceptual Cask A while Section 712 for Conceptual Cask B Section 713 provides comparisons of the dose-rate reduction factors du e to the two conceptual casks and the axial source distributions in the active fuel region Do se rates and relative errors can be found in Attachment II within the output files and Excel files
711 Dose Rates of Conceptual Cask A
This section presents dose-rate results of the calculation sets 1 and 2 as described in Section 61 for Cask A Set 1 has axial p rofile sources in the active fuel region a nd consist of six runs resulting from the three PWR SNF source term s (maximum design basis and average) and the two radiation sources (gammas and neutrons) Set 2 has uniform axial sources in the active fuel region and consists of six run s r esulting f rom the th ree P WR SNF source term s and th e tw o radiation sources
As described in Section 61 dose ra tes are calculated at the three exterior surfaces (radial top and bottom) and at distances 1 m and 2 m from the exterior surfaces The total dose rates for set 1 are presented in Tables 13 14 and 15 for the ra dial top and bottom dire ctions respectively However the com ponents (primary gamma neutr on and secondary gamma) contributing to the total dose rates as well as the re lative error calculations can be found in Attachment II Excel file MCNP-Results1xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 2 are shown in Tables 16 17 and 18 The dose-rate components and the relative errors can be found in A ttachment II Excel file MCNP-Results2xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 13 and 16 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 14 and 17 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 15 and 18 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carrying th e maximum PWR SNF Based on the results in Tables 13 through 18 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask A indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these 6 tables the d ose-rate red uction f actors between the m aximum and the design basis fuels the maxim um and the averag e fuels and th e design basis and the average fuels are a lso presented
38
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 320E-02 00237 116E-02 00222 262E-03 00219 275 1223 445
1 m 133E-02 00164 494E-03 00171 106E-03 00162 269 1261 468 2 m 749E-03 00198 285E-03 00225 584E-04 00162 263 1282 488
Ring Detectors 1 m 133E-02 00116 492E-03 00115 108E-03 00124 271 1229 454 2 m 756E-03 00118 279E-03 00110 605E-04 00128 271 1250 462
Source Attachment II MCNP-Results1xls worksheet Summary
Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 142E-02 00368 628E-03 00446 934E-04 00483 226 1520 672
1 m 570E-03 00289 263E-03 00426 375E-04 00381 217 1520 701 2 m 265E-03 00364 123E-03 00547 169E-04 00374 216 1575 730
Point Detectors 1 m 598E-03 00238 274E-03 00271 402E-04 00354 219 1489 681 2 m 273E-03 00218 123E-03 00245 180E-04 00336 221 1515 684
Source Attachment II MCNP-Results1xls worksheet Summary
Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 653E-03 00298 265E-03 00276 510E-04 00341 247 1278 518
1 m 276E-03 00238 112E-03 00208 207E-04 00249 248 1334 539 2 m 125E-03 00185 508E-04 00199 933E-05 00246 246 1336 544
Point Detectors 1 m 291E-03 00227 118E-03 00203 218E-04 00242 247 1335 540 2 m 130E-03 00209 524E-04 00187 955E-05 00233 247 1357 549
Source Attachment II MCNP-Results1xls worksheet Summary
Tables 13 14 and 15 are results of calculation set 1 for conceptual Cask A with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
39
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 265E-02 00247 990E-03 00222 215E-03 00278 268 1234 461
1 m 116E-02 00178 468E-03 00549 960E-04 00189 248 1208 488 2 m 713E-03 00273 265E-03 00161 602E-04 00360 269 1184 439
Ring Detectors 1 m 117E-02 00120 454E-03 00132 979E-04 00141 259 1199 463 2 m 722E-03 00130 276E-03 00141 589E-04 00153 261 1226 469
Source Attachment II MCNP-Results2xls worksheet Summary
Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 199E-02 00461 827E-03 00455 147E-03 00536 241 1359 564
1 m 849E-03 00564 323E-03 00314 563E-04 00418 263 1507 574 2 m 415E-03 00832 158E-03 00603 253E-04 00501 263 1641 623
Point Detectors 1 m 877E-03 00348 353E-03 00275 615E-04 00391 248 1426 574 2 m 393E-03 00341 160E-03 00278 270E-04 00378 246 1454 590
Source Attachment II MCNP-Results2xls worksheet Summary
Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 879E-03 00374 356E-03 00333 669E-04 00406 247 1315 533
1 m 365E-03 00223 147E-03 00209 269E-04 00253 248 1358 548 2 m 164E-03 00229 674E-04 00205 120E-04 00248 243 1364 560
Point Detectors 1 m 383E-03 00217 155E-03 00204 285E-04 00248 247 1347 546 2 m 172E-03 00197 689E-04 00186 124E-04 00225 249 1391 558
Source Attachment II MCNP-Results2xls worksheet Summary
Tables 16 17 and 18 ar e results of calculation set 2 for conceptual Cask A with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
40
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Ai = Atomic weight of elementisotope i (gmole) V = Homogenization volume (cm3) K = Unit transformation constant = 1024 (bmiddotcmcm3)
Equation 1 is used in A ttachment II spreadsheet PWR_fuel compxls worksheet BampWassy to calculate th e atom dens ities for v arious elem ents and iso topes The m ass of elementsisotop es and Avogadrorsquos constant are provided in Reference 2226
Table 7 lists the com position of the hom ogenized assem bly regions (active fuel plenum top end-fitting and bottom end-fitting) for the PWR assembly The active fuel region contains fresh unirradiated fuel (Assumption 324) Since the internal structure (ie basket) design of the TAD is currently not finalized the composition of either homogenized fuel does not include the basket materials and therefore does not tak e credit for any shielding that thes e materials may provide (Assumption 326)
Table 7 Isotopic Compositions of Homogenized PWR Assembly Regions
Element Isotope
Atom Densities for Homogenized Regions (atomsbsdotcm)
Active Fuel Bottom End-Fitting Plenum Top End-Fitting
10B 861E-09 764E-08 221E-08 570E-08 11B 347E-08 307E-07 890E-08 230E-07 C 519E-07 160E-05 138E-06 993E-06 N -- 570E-07 262E-08 117E-06 O 621E-03 -- 142E-05 -- Al 144E-06 128E-05 371E-06 957E-06 Si 971E-07 243E-04 259E-06 139E-04 P 377E-08 606E-06 102E-07 360E-06 S 365E-08 581E-06 971E-08 340E-06 Ti 147E-06 130E-05 376E-06 971E-06 Cr 320E-05 187E-03 779E-05 113E-03 Mn 497E-07 126E-04 141E-06 749E-05 Fe 303E-05 531E-03 717E-05 313E-03 Co 132E-06 117E-05 340E-06 876E-06 Ni 697E-05 144E-03 180E-04 940E-04 Cu 368E-07 327E-06 945E-07 244E-06 Zr 196E-03 -- 195E-03 -- Nb 430E-06 382E-05 110E-05 285E-05 Mo 248E-06 135E-04 636E-06 791E-05 Sn 223E-05 -- 222E-05 -- 234U 139E-06 -- -- -- 235U 157E-04 -- -- -- 236U 719E-07 -- -- -- 238U 294E-03 -- -- -- Total 114E-02 924E-03 235E-03 557E-03
Source Attachment II spreadsheet PWR_fuel compxls worksheet BampWassy
29
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
The isotopic composition of commercially available 235U enriched uranium is determined by the given initial 235U enrichment using the following equations (Reference 226 p 20)
wt235U =235Uenrichment _ of _ the _ associated _ fuel _ batch Equation 2
wt234U = 0007731times (wt235U )10837 Equation 3
wt236U = 00046times (wt235U ) Equation 4
wt238U =100 minus (wt234U + wt235U + wt236U ) Equation 5
The weight percentages of uran ium isotopes for PWR fuel are ca lculated in Attachm ent II spreadsheet PWR_fuel compxls worksheet BampWassy using Equations 2 through 5
627 PWR Source Terms
This calculation uses the following three PWR source terms bull Maximum source (50 wt initial 235U enrichment 80 GWdMTU burnup and 5-year
decay time) (Reference 229 Section 55) Table 8 lists th e gamma source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Design Basis source (4 0 wt initial 235U enrichment 60 GW dMTU burnup and 10-year decay tim e) (Reference 228 Section 552) Table 9 lists the gamm a source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Average source ( 40 wt initial 235U enrichment 48 GWdMTU burnup and 25-year decay time) (Reference 229 Section 55) Table 10 lists the gamma source terms for the fuel and non-fuel regions and the neutron source term for the fuel region
These sources (ie maximum design basis and av erage) are described in this section For dose rate calculations all the fuel assemblies in a transportation cask are of the sam e characteristics Also gamma radiation source term s for the PWR assem bly are prov ided for the f our assembly regions while neutron source term is only present in the active fuel region Gamma radiation sources in the non-active fuel region are distri buted unif ormly within each source region Gamma and neutron sources in the active fuel re gion are modeled as uni form distributions or with axial source profiles
The PWR gamma and neutron axial source profiles for the active fuel region presented in Table 11 are applied to the active fuel region of all three source terms (ie maximum design basis and average) when appropriate
30
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 8 Gamma and Neutron Sources for the Maximum PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting
Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 594E+11 233E+15 528E+11 379E+11 100E-01 000E+00 100E-01 116E+11 644E+14 609E+10 743E+10 400E-01 805E+07 200E-01 283E+10 522E+14 352E+10 179E+10 900E-01 411E+08 300E-01 141E+09 148E+14 196E+09 891E+08 140E+00 376E+08 400E-01 190E+09 985E+13 586E+09 117E+09 185E+00 276E+08 600E-01 191E+09 153E+15 110E+11 741E+07 300E+00 485E+08 800E-01 435E+09 470E+15 595E+10 237E+09 643E+00 443E+08 100E+00 137E+11 708E+14 803E+09 766E+10 200E+01 393E+07 133E+00 338E+13 455E+14 174E+13 217E+13 Total 211E+09 166E+00 953E+12 130E+14 491E+12 612E+12
--
200E+00 187E+03 144E+12 919E+02 113E+03 250E+00 226E+08 249E+12 116E+08 145E+08 300E+00 351E+05 110E+11 181E+05 225E+05 400E+00 766E-08 139E+10 100E-08 416E-08 500E+00 000E+00 709E+07 000E+00 000E+00 650E+00 000E+00 286E+07 000E+00 000E+00 800E+00 000E+00 558E+06 000E+00 000E+00 100E+01 000E+00 119E+06 000E+00 000E+00
Total 442E+13 113E+16 231E+13 284E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE2R2B14cut bWasteStreamE2R1B14cut cWasteStreamE2R3B14cut dWasteStreamE2R4B14cut
31
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 9 Gamma and Neutron Sources for the Design Basis PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary
(MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 273E+11 121E+15 188E+11 175E+11 100E-01 000E+00 100E-01 528E+10 329E+14 277E+10 339E+10 400E-01 316E+07 200E-01 128E+10 245E+14 117E+10 819E+09 900E-01 161E+08 300E-01 639E+08 713E+13 633E+08 407E+08 140E+00 148E+08 400E-01 850E+08 455E+13 164E+09 533E+08 185E+00 109E+08 600E-01 492E+08 226E+14 269E+10 337E+07 300E+00 191E+08 800E-01 291E+09 237E+15 160E+10 186E+09 643E+00 174E+08 100E+00 540E+09 122E+14 248E+09 341E+09 200E+01 154E+07 133E+00 154E+13 195E+14 797E+12 990E+12 Total 830E+08 166E+00 435E+12 450E+13 225E+12 280E+12
--
200E+00 235E+00 152E+11 149E+02 215E-02 250E+00 103E+08 517E+10 534E+07 664E+07 300E+00 160E+05 379E+09 829E+04 103E+05 400E+00 943E-10 497E+08 155E-10 519E-10 500E+00 000E+00 282E+07 000E+00 000E+00 650E+00 000E+00 113E+07 000E+00 000E+00 800E+00 000E+00 222E+06 000E+00 000E+00 100E+01 000E+00 471E+05 000E+00 000E+00
Total 201E+13 486E+15 105E+13 129E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B11cut bWasteStreamE5R1B11cut cWasteStreamE5R3B11cut dWasteStreamE5R4B11cut
32
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 10 Gamma and Neutron Sources for the Average PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 336E+10 670E+14 186E+10 217E+10 100E-01 00000E+00 100E-01 602E+09 199E+14 314E+09 387E+09 400E-01 748E+06 200E-01 146E+09 126E+14 853E+08 936E+08 900E-01 382E+07 300E-01 730E+07 389E+13 439E+07 469E+07 140E+00 352E+07 400E-01 947E+07 263E+13 716E+07 607E+07 185E+00 261E+07 600E-01 141E+07 205E+13 504E+08 383E+06 300E+00 469E+07 800E-01 208E+09 124E+15 192E+09 144E+09 643E+00 418E+07 100E+00 208E+09 110E+13 164E+09 144E+09 200E+01 365E+06 133E+00 175E+12 295E+13 909E+11 112E+12 Total 199E+08 166E+00 494E+11 513E+12 257E+11 318E+11
--
200E+00 973E-01 675E+10 614E+01 872E-03 250E+00 117E+07 353E+09 609E+06 754E+06 300E+00 182E+04 288E+08 944E+03 117E+04 400E+00 186E-11 198E+07 149E-11 127E-11 500E+00 000E+00 669E+06 000E+00 000E+00 650E+00 000E+00 269E+06 000E+00 000E+00 800E+00 000E+00 527E+05 000E+00 000E+00 100E+01 000E+00 112E+05 000E+00 000E+00
Total 229E+12 237E+15 119E+12 147E+12
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B9cut bWasteStreamE5R1B9cut cWasteStreamE5R3B9cut dWasteStreamE5R4B9cut
33
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 11 Gamma and Neutron Axial Source Profiles for a PWR Assembly
Axial boundaries (From midplane)
(cm)
TOP BOTTOM
Neutron Gamma Ne utron Gamma 000 1554 1117 1554 1117 1143 1537 1114 1571 1120 2286 1521 1111 1588 1123 3429 1504 1108 1605 1126 4572 1486 1104 1622 1129 5715 1464 1100 1636 1131 6858 1438 1095 1648 1133 8001 1401 1088 1657 1135 9144 1350 1078 1654 1134
10287 1277 1063 1625 1129 11430 1165 1039 1554 1117 12573 0998 09995 1414 1091 13716 0769 09365 1172 1041 14859 0492 08375 0816 0951 16002 0220 06850 0402 0797 17145 0046 04625 0092 0551 18288 00 00 00 00
Source Reference 2219 Table S445
34
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
63 MCNP SPECIFIC INPUT
631 Source Probability
A linear radial distribution is used for all gamma and neutron sources The linear radial distribution is sam pled usi ng the built-in power function p(x) = xc a with a = 1 for the radial direction This sampling method results in a uniform source distribution over the area bounded by the outer radius of the source
The source axial distributions are unifor m for all four source regions The a xial uni form xp(x) = c distribution is sampled using the built-in power function a with a = 0 for extent
The energy distribu tions of the gamma and neutron sour ce term s are treated as energ y probabilities and are applied in MCNP5 using SISP cards
632 Dose Rate and Flux Tallies
MCNP5 dose rate calculations feature separate runs for the following calculation types
bull a photon transport calculation for prim ary ga mma contribution to the dose rates fr om photon fluxes
bull a coupled neutronphoton transport calculat ion for neutrons a nd secondary gamma (photons generated by neutron be ing captured) contributions to dose rates from neutron and gamma fluxes
The tally type F2 is us ed in th is d esign ca lculation as f lux estim ators The type F2 tally evaluates the flux averaged over a surface in particlescm2s
To generate dose ra tes in te rms of remhr the FM (tally multiplier ) and DEDF (dose energydose conversion factors) cards are used to en ter the tally multiplier f actor (source intensity in particless) energy boundaries in MeV and corresponding dose conversion factors in (remhr)(particlescm2s) respectively These factors were used in the input files
In order for the F2 tally to accum ulate flux ov er a surface a specific s urface area is requ ired The SD cards are used to enter a surface area in cm2 over which the flux will be tallied for an F2 tally
633 Variance Reduction Techniques
Variance reduction technique is usually em ployed in order to increase the efficiency of a calculation and obtain statistically m eaningful results within re asonable com puter tim e In Monte Carlo calculations when variance reduction scheme is employed the weights of particles are adjusted in order to account for the biasing and to preserve a fair game
Geometry splitting and Russian roulette techniques described in Reference 2224 (pp 2-140 ndash 2-142) are useful in shielding calculations and therefore deployed in all the MCNP5 runs
35
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
As particles migrate in an important direction (toward the detector) they are increased in number to provide better sampling by means of geometry splitting across geometric boundaries Russian roulette (the reverse process) is played when particles travel in an unimportant direction to allow termination of unim portant histories The IMP card required for every cel l ca rd is us ed to implement this technique
The other variance reduction technique deployed in the MC NP5 runs is source intensity biasing for the gamma sources from the four source regions (active fuel bottom end-fitting plenum and top end-fitting) The natural total gamma source intensity of comm ercial SNF is dom inated by the gamma source in the active fuel region This active fuel gamma source usually accounts for over 95 o f the total g amma source intens ity In order to im prove the efficiency of the axial dose rate calculations a biased source probability distribution is employed for the prim ary gamma dose rate calculations The biased gamma source probability distribution is chosen to be 005 080 010 and 005 for the bottom end-fitting the active fuel the plenum and the top end-fitting regions respectively
64 DOSE CONVERSION FACTORS
Project Design Criteria Document (Reference 2211 Se ction 41015) requires the use of flux-to-dose rate conversion fact ors from ANSIANS-611-1977 (Reference 221) for dose rate evaluations Table 16 lists the neutron and ga mma dose conversion factors used in the MCNP5 calculations
Table 12 Gamma and Neutron Flux to Dose Conversion Factors
Gamma Neutron Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
001 396E-06 140 251E-06 250E-08 367E-06 003 582E-07 180 299E-06 100E-07 367E-06 005 290E-07 220 342E-06 100E-06 446E-06 007 258E-07 260 382E-06 100E-05 454E-06 010 283E-07 280 401E-06 100E-04 418E-06 015 379E-07 325 441E-06 100E-03 376E-06 020 501E-07 375 483E-06 100E-02 356E-06 025 631E-07 425 523E-06 100E-01 217E-05 030 759E-07 475 560E-06 500E-01 926E-05 035 878E-07 500 580E-06 100E+00 132E-04 040 985E-07 525 601E-06 250E+00 125E-04 045 108E-06 575 637E-06 500E+00 156E-04 050 117E-06 625 674E-06 700E+00 147E-04 055 127E-06 675 711E-06 100E+01 147E-04 060 136E-06 750 766E-06 140E+01 208E-04 065 144E-06 900 877E-06 200E+01 227E-04 070 152E-06 1100 103E-05 080 168E-06 1300 118E-05 100 198E-06 1500 133E-05
Source Reference 221 Tables 1 and 3
36
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION
By def inition (Ref erence 2224 Equation 219) the estimated st atistic relative error of the i component is
Ri = Si
2
Equation 6Ti
where i = tally component index Ri = relative error of the i component S2
i = variance of the i component Ti = tally i component
For a result (ie dose rate) computed as a sum of different tallies the statistical relative error of the computed value is o btained from the variance of the result - S2
total which is th e sum of the estimated variances of the individual tallies S2
i n
2 2STotal = sum Si Equation 7 i=1
where S2Total = total estimated variance
n = total number of components Therefore the total tally value (dose rate) and the associated relative error are derived according to Equations 8 and 9
n TTotal = sumTi Equation 8
i=1
n n
sum (Ri timesTi )2
2 sum Si 2
STotal = i=1 = i=1 Equation 9RTotal = TTotal TTotal TTotal
where RTotal = total estimated relative error TTotal = total estimated tally
Equations 8 and 9 are utilized in Attachm ent II to ev aluate to tal dos e ra tes and their r elative errors
37
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
7 RESULTS AND CONCLUSIONS
71 RESULTS
The following sections summarize the results of this calculation Section 711 presents results for Conceptual Cask A while Section 712 for Conceptual Cask B Section 713 provides comparisons of the dose-rate reduction factors du e to the two conceptual casks and the axial source distributions in the active fuel region Do se rates and relative errors can be found in Attachment II within the output files and Excel files
711 Dose Rates of Conceptual Cask A
This section presents dose-rate results of the calculation sets 1 and 2 as described in Section 61 for Cask A Set 1 has axial p rofile sources in the active fuel region a nd consist of six runs resulting from the three PWR SNF source term s (maximum design basis and average) and the two radiation sources (gammas and neutrons) Set 2 has uniform axial sources in the active fuel region and consists of six run s r esulting f rom the th ree P WR SNF source term s and th e tw o radiation sources
As described in Section 61 dose ra tes are calculated at the three exterior surfaces (radial top and bottom) and at distances 1 m and 2 m from the exterior surfaces The total dose rates for set 1 are presented in Tables 13 14 and 15 for the ra dial top and bottom dire ctions respectively However the com ponents (primary gamma neutr on and secondary gamma) contributing to the total dose rates as well as the re lative error calculations can be found in Attachment II Excel file MCNP-Results1xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 2 are shown in Tables 16 17 and 18 The dose-rate components and the relative errors can be found in A ttachment II Excel file MCNP-Results2xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 13 and 16 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 14 and 17 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 15 and 18 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carrying th e maximum PWR SNF Based on the results in Tables 13 through 18 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask A indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these 6 tables the d ose-rate red uction f actors between the m aximum and the design basis fuels the maxim um and the averag e fuels and th e design basis and the average fuels are a lso presented
38
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 320E-02 00237 116E-02 00222 262E-03 00219 275 1223 445
1 m 133E-02 00164 494E-03 00171 106E-03 00162 269 1261 468 2 m 749E-03 00198 285E-03 00225 584E-04 00162 263 1282 488
Ring Detectors 1 m 133E-02 00116 492E-03 00115 108E-03 00124 271 1229 454 2 m 756E-03 00118 279E-03 00110 605E-04 00128 271 1250 462
Source Attachment II MCNP-Results1xls worksheet Summary
Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 142E-02 00368 628E-03 00446 934E-04 00483 226 1520 672
1 m 570E-03 00289 263E-03 00426 375E-04 00381 217 1520 701 2 m 265E-03 00364 123E-03 00547 169E-04 00374 216 1575 730
Point Detectors 1 m 598E-03 00238 274E-03 00271 402E-04 00354 219 1489 681 2 m 273E-03 00218 123E-03 00245 180E-04 00336 221 1515 684
Source Attachment II MCNP-Results1xls worksheet Summary
Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 653E-03 00298 265E-03 00276 510E-04 00341 247 1278 518
1 m 276E-03 00238 112E-03 00208 207E-04 00249 248 1334 539 2 m 125E-03 00185 508E-04 00199 933E-05 00246 246 1336 544
Point Detectors 1 m 291E-03 00227 118E-03 00203 218E-04 00242 247 1335 540 2 m 130E-03 00209 524E-04 00187 955E-05 00233 247 1357 549
Source Attachment II MCNP-Results1xls worksheet Summary
Tables 13 14 and 15 are results of calculation set 1 for conceptual Cask A with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
39
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 265E-02 00247 990E-03 00222 215E-03 00278 268 1234 461
1 m 116E-02 00178 468E-03 00549 960E-04 00189 248 1208 488 2 m 713E-03 00273 265E-03 00161 602E-04 00360 269 1184 439
Ring Detectors 1 m 117E-02 00120 454E-03 00132 979E-04 00141 259 1199 463 2 m 722E-03 00130 276E-03 00141 589E-04 00153 261 1226 469
Source Attachment II MCNP-Results2xls worksheet Summary
Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 199E-02 00461 827E-03 00455 147E-03 00536 241 1359 564
1 m 849E-03 00564 323E-03 00314 563E-04 00418 263 1507 574 2 m 415E-03 00832 158E-03 00603 253E-04 00501 263 1641 623
Point Detectors 1 m 877E-03 00348 353E-03 00275 615E-04 00391 248 1426 574 2 m 393E-03 00341 160E-03 00278 270E-04 00378 246 1454 590
Source Attachment II MCNP-Results2xls worksheet Summary
Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 879E-03 00374 356E-03 00333 669E-04 00406 247 1315 533
1 m 365E-03 00223 147E-03 00209 269E-04 00253 248 1358 548 2 m 164E-03 00229 674E-04 00205 120E-04 00248 243 1364 560
Point Detectors 1 m 383E-03 00217 155E-03 00204 285E-04 00248 247 1347 546 2 m 172E-03 00197 689E-04 00186 124E-04 00225 249 1391 558
Source Attachment II MCNP-Results2xls worksheet Summary
Tables 16 17 and 18 ar e results of calculation set 2 for conceptual Cask A with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
40
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
The isotopic composition of commercially available 235U enriched uranium is determined by the given initial 235U enrichment using the following equations (Reference 226 p 20)
wt235U =235Uenrichment _ of _ the _ associated _ fuel _ batch Equation 2
wt234U = 0007731times (wt235U )10837 Equation 3
wt236U = 00046times (wt235U ) Equation 4
wt238U =100 minus (wt234U + wt235U + wt236U ) Equation 5
The weight percentages of uran ium isotopes for PWR fuel are ca lculated in Attachm ent II spreadsheet PWR_fuel compxls worksheet BampWassy using Equations 2 through 5
627 PWR Source Terms
This calculation uses the following three PWR source terms bull Maximum source (50 wt initial 235U enrichment 80 GWdMTU burnup and 5-year
decay time) (Reference 229 Section 55) Table 8 lists th e gamma source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Design Basis source (4 0 wt initial 235U enrichment 60 GW dMTU burnup and 10-year decay tim e) (Reference 228 Section 552) Table 9 lists the gamm a source term s for the fuel and non-fuel regions and the neutron source term for the fuel region
bull Average source ( 40 wt initial 235U enrichment 48 GWdMTU burnup and 25-year decay time) (Reference 229 Section 55) Table 10 lists the gamma source terms for the fuel and non-fuel regions and the neutron source term for the fuel region
These sources (ie maximum design basis and av erage) are described in this section For dose rate calculations all the fuel assemblies in a transportation cask are of the sam e characteristics Also gamma radiation source term s for the PWR assem bly are prov ided for the f our assembly regions while neutron source term is only present in the active fuel region Gamma radiation sources in the non-active fuel region are distri buted unif ormly within each source region Gamma and neutron sources in the active fuel re gion are modeled as uni form distributions or with axial source profiles
The PWR gamma and neutron axial source profiles for the active fuel region presented in Table 11 are applied to the active fuel region of all three source terms (ie maximum design basis and average) when appropriate
30
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 8 Gamma and Neutron Sources for the Maximum PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting
Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 594E+11 233E+15 528E+11 379E+11 100E-01 000E+00 100E-01 116E+11 644E+14 609E+10 743E+10 400E-01 805E+07 200E-01 283E+10 522E+14 352E+10 179E+10 900E-01 411E+08 300E-01 141E+09 148E+14 196E+09 891E+08 140E+00 376E+08 400E-01 190E+09 985E+13 586E+09 117E+09 185E+00 276E+08 600E-01 191E+09 153E+15 110E+11 741E+07 300E+00 485E+08 800E-01 435E+09 470E+15 595E+10 237E+09 643E+00 443E+08 100E+00 137E+11 708E+14 803E+09 766E+10 200E+01 393E+07 133E+00 338E+13 455E+14 174E+13 217E+13 Total 211E+09 166E+00 953E+12 130E+14 491E+12 612E+12
--
200E+00 187E+03 144E+12 919E+02 113E+03 250E+00 226E+08 249E+12 116E+08 145E+08 300E+00 351E+05 110E+11 181E+05 225E+05 400E+00 766E-08 139E+10 100E-08 416E-08 500E+00 000E+00 709E+07 000E+00 000E+00 650E+00 000E+00 286E+07 000E+00 000E+00 800E+00 000E+00 558E+06 000E+00 000E+00 100E+01 000E+00 119E+06 000E+00 000E+00
Total 442E+13 113E+16 231E+13 284E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE2R2B14cut bWasteStreamE2R1B14cut cWasteStreamE2R3B14cut dWasteStreamE2R4B14cut
31
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 9 Gamma and Neutron Sources for the Design Basis PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary
(MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 273E+11 121E+15 188E+11 175E+11 100E-01 000E+00 100E-01 528E+10 329E+14 277E+10 339E+10 400E-01 316E+07 200E-01 128E+10 245E+14 117E+10 819E+09 900E-01 161E+08 300E-01 639E+08 713E+13 633E+08 407E+08 140E+00 148E+08 400E-01 850E+08 455E+13 164E+09 533E+08 185E+00 109E+08 600E-01 492E+08 226E+14 269E+10 337E+07 300E+00 191E+08 800E-01 291E+09 237E+15 160E+10 186E+09 643E+00 174E+08 100E+00 540E+09 122E+14 248E+09 341E+09 200E+01 154E+07 133E+00 154E+13 195E+14 797E+12 990E+12 Total 830E+08 166E+00 435E+12 450E+13 225E+12 280E+12
--
200E+00 235E+00 152E+11 149E+02 215E-02 250E+00 103E+08 517E+10 534E+07 664E+07 300E+00 160E+05 379E+09 829E+04 103E+05 400E+00 943E-10 497E+08 155E-10 519E-10 500E+00 000E+00 282E+07 000E+00 000E+00 650E+00 000E+00 113E+07 000E+00 000E+00 800E+00 000E+00 222E+06 000E+00 000E+00 100E+01 000E+00 471E+05 000E+00 000E+00
Total 201E+13 486E+15 105E+13 129E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B11cut bWasteStreamE5R1B11cut cWasteStreamE5R3B11cut dWasteStreamE5R4B11cut
32
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 10 Gamma and Neutron Sources for the Average PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 336E+10 670E+14 186E+10 217E+10 100E-01 00000E+00 100E-01 602E+09 199E+14 314E+09 387E+09 400E-01 748E+06 200E-01 146E+09 126E+14 853E+08 936E+08 900E-01 382E+07 300E-01 730E+07 389E+13 439E+07 469E+07 140E+00 352E+07 400E-01 947E+07 263E+13 716E+07 607E+07 185E+00 261E+07 600E-01 141E+07 205E+13 504E+08 383E+06 300E+00 469E+07 800E-01 208E+09 124E+15 192E+09 144E+09 643E+00 418E+07 100E+00 208E+09 110E+13 164E+09 144E+09 200E+01 365E+06 133E+00 175E+12 295E+13 909E+11 112E+12 Total 199E+08 166E+00 494E+11 513E+12 257E+11 318E+11
--
200E+00 973E-01 675E+10 614E+01 872E-03 250E+00 117E+07 353E+09 609E+06 754E+06 300E+00 182E+04 288E+08 944E+03 117E+04 400E+00 186E-11 198E+07 149E-11 127E-11 500E+00 000E+00 669E+06 000E+00 000E+00 650E+00 000E+00 269E+06 000E+00 000E+00 800E+00 000E+00 527E+05 000E+00 000E+00 100E+01 000E+00 112E+05 000E+00 000E+00
Total 229E+12 237E+15 119E+12 147E+12
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B9cut bWasteStreamE5R1B9cut cWasteStreamE5R3B9cut dWasteStreamE5R4B9cut
33
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 11 Gamma and Neutron Axial Source Profiles for a PWR Assembly
Axial boundaries (From midplane)
(cm)
TOP BOTTOM
Neutron Gamma Ne utron Gamma 000 1554 1117 1554 1117 1143 1537 1114 1571 1120 2286 1521 1111 1588 1123 3429 1504 1108 1605 1126 4572 1486 1104 1622 1129 5715 1464 1100 1636 1131 6858 1438 1095 1648 1133 8001 1401 1088 1657 1135 9144 1350 1078 1654 1134
10287 1277 1063 1625 1129 11430 1165 1039 1554 1117 12573 0998 09995 1414 1091 13716 0769 09365 1172 1041 14859 0492 08375 0816 0951 16002 0220 06850 0402 0797 17145 0046 04625 0092 0551 18288 00 00 00 00
Source Reference 2219 Table S445
34
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
63 MCNP SPECIFIC INPUT
631 Source Probability
A linear radial distribution is used for all gamma and neutron sources The linear radial distribution is sam pled usi ng the built-in power function p(x) = xc a with a = 1 for the radial direction This sampling method results in a uniform source distribution over the area bounded by the outer radius of the source
The source axial distributions are unifor m for all four source regions The a xial uni form xp(x) = c distribution is sampled using the built-in power function a with a = 0 for extent
The energy distribu tions of the gamma and neutron sour ce term s are treated as energ y probabilities and are applied in MCNP5 using SISP cards
632 Dose Rate and Flux Tallies
MCNP5 dose rate calculations feature separate runs for the following calculation types
bull a photon transport calculation for prim ary ga mma contribution to the dose rates fr om photon fluxes
bull a coupled neutronphoton transport calculat ion for neutrons a nd secondary gamma (photons generated by neutron be ing captured) contributions to dose rates from neutron and gamma fluxes
The tally type F2 is us ed in th is d esign ca lculation as f lux estim ators The type F2 tally evaluates the flux averaged over a surface in particlescm2s
To generate dose ra tes in te rms of remhr the FM (tally multiplier ) and DEDF (dose energydose conversion factors) cards are used to en ter the tally multiplier f actor (source intensity in particless) energy boundaries in MeV and corresponding dose conversion factors in (remhr)(particlescm2s) respectively These factors were used in the input files
In order for the F2 tally to accum ulate flux ov er a surface a specific s urface area is requ ired The SD cards are used to enter a surface area in cm2 over which the flux will be tallied for an F2 tally
633 Variance Reduction Techniques
Variance reduction technique is usually em ployed in order to increase the efficiency of a calculation and obtain statistically m eaningful results within re asonable com puter tim e In Monte Carlo calculations when variance reduction scheme is employed the weights of particles are adjusted in order to account for the biasing and to preserve a fair game
Geometry splitting and Russian roulette techniques described in Reference 2224 (pp 2-140 ndash 2-142) are useful in shielding calculations and therefore deployed in all the MCNP5 runs
35
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
As particles migrate in an important direction (toward the detector) they are increased in number to provide better sampling by means of geometry splitting across geometric boundaries Russian roulette (the reverse process) is played when particles travel in an unimportant direction to allow termination of unim portant histories The IMP card required for every cel l ca rd is us ed to implement this technique
The other variance reduction technique deployed in the MC NP5 runs is source intensity biasing for the gamma sources from the four source regions (active fuel bottom end-fitting plenum and top end-fitting) The natural total gamma source intensity of comm ercial SNF is dom inated by the gamma source in the active fuel region This active fuel gamma source usually accounts for over 95 o f the total g amma source intens ity In order to im prove the efficiency of the axial dose rate calculations a biased source probability distribution is employed for the prim ary gamma dose rate calculations The biased gamma source probability distribution is chosen to be 005 080 010 and 005 for the bottom end-fitting the active fuel the plenum and the top end-fitting regions respectively
64 DOSE CONVERSION FACTORS
Project Design Criteria Document (Reference 2211 Se ction 41015) requires the use of flux-to-dose rate conversion fact ors from ANSIANS-611-1977 (Reference 221) for dose rate evaluations Table 16 lists the neutron and ga mma dose conversion factors used in the MCNP5 calculations
Table 12 Gamma and Neutron Flux to Dose Conversion Factors
Gamma Neutron Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
001 396E-06 140 251E-06 250E-08 367E-06 003 582E-07 180 299E-06 100E-07 367E-06 005 290E-07 220 342E-06 100E-06 446E-06 007 258E-07 260 382E-06 100E-05 454E-06 010 283E-07 280 401E-06 100E-04 418E-06 015 379E-07 325 441E-06 100E-03 376E-06 020 501E-07 375 483E-06 100E-02 356E-06 025 631E-07 425 523E-06 100E-01 217E-05 030 759E-07 475 560E-06 500E-01 926E-05 035 878E-07 500 580E-06 100E+00 132E-04 040 985E-07 525 601E-06 250E+00 125E-04 045 108E-06 575 637E-06 500E+00 156E-04 050 117E-06 625 674E-06 700E+00 147E-04 055 127E-06 675 711E-06 100E+01 147E-04 060 136E-06 750 766E-06 140E+01 208E-04 065 144E-06 900 877E-06 200E+01 227E-04 070 152E-06 1100 103E-05 080 168E-06 1300 118E-05 100 198E-06 1500 133E-05
Source Reference 221 Tables 1 and 3
36
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION
By def inition (Ref erence 2224 Equation 219) the estimated st atistic relative error of the i component is
Ri = Si
2
Equation 6Ti
where i = tally component index Ri = relative error of the i component S2
i = variance of the i component Ti = tally i component
For a result (ie dose rate) computed as a sum of different tallies the statistical relative error of the computed value is o btained from the variance of the result - S2
total which is th e sum of the estimated variances of the individual tallies S2
i n
2 2STotal = sum Si Equation 7 i=1
where S2Total = total estimated variance
n = total number of components Therefore the total tally value (dose rate) and the associated relative error are derived according to Equations 8 and 9
n TTotal = sumTi Equation 8
i=1
n n
sum (Ri timesTi )2
2 sum Si 2
STotal = i=1 = i=1 Equation 9RTotal = TTotal TTotal TTotal
where RTotal = total estimated relative error TTotal = total estimated tally
Equations 8 and 9 are utilized in Attachm ent II to ev aluate to tal dos e ra tes and their r elative errors
37
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
7 RESULTS AND CONCLUSIONS
71 RESULTS
The following sections summarize the results of this calculation Section 711 presents results for Conceptual Cask A while Section 712 for Conceptual Cask B Section 713 provides comparisons of the dose-rate reduction factors du e to the two conceptual casks and the axial source distributions in the active fuel region Do se rates and relative errors can be found in Attachment II within the output files and Excel files
711 Dose Rates of Conceptual Cask A
This section presents dose-rate results of the calculation sets 1 and 2 as described in Section 61 for Cask A Set 1 has axial p rofile sources in the active fuel region a nd consist of six runs resulting from the three PWR SNF source term s (maximum design basis and average) and the two radiation sources (gammas and neutrons) Set 2 has uniform axial sources in the active fuel region and consists of six run s r esulting f rom the th ree P WR SNF source term s and th e tw o radiation sources
As described in Section 61 dose ra tes are calculated at the three exterior surfaces (radial top and bottom) and at distances 1 m and 2 m from the exterior surfaces The total dose rates for set 1 are presented in Tables 13 14 and 15 for the ra dial top and bottom dire ctions respectively However the com ponents (primary gamma neutr on and secondary gamma) contributing to the total dose rates as well as the re lative error calculations can be found in Attachment II Excel file MCNP-Results1xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 2 are shown in Tables 16 17 and 18 The dose-rate components and the relative errors can be found in A ttachment II Excel file MCNP-Results2xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 13 and 16 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 14 and 17 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 15 and 18 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carrying th e maximum PWR SNF Based on the results in Tables 13 through 18 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask A indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these 6 tables the d ose-rate red uction f actors between the m aximum and the design basis fuels the maxim um and the averag e fuels and th e design basis and the average fuels are a lso presented
38
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 320E-02 00237 116E-02 00222 262E-03 00219 275 1223 445
1 m 133E-02 00164 494E-03 00171 106E-03 00162 269 1261 468 2 m 749E-03 00198 285E-03 00225 584E-04 00162 263 1282 488
Ring Detectors 1 m 133E-02 00116 492E-03 00115 108E-03 00124 271 1229 454 2 m 756E-03 00118 279E-03 00110 605E-04 00128 271 1250 462
Source Attachment II MCNP-Results1xls worksheet Summary
Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 142E-02 00368 628E-03 00446 934E-04 00483 226 1520 672
1 m 570E-03 00289 263E-03 00426 375E-04 00381 217 1520 701 2 m 265E-03 00364 123E-03 00547 169E-04 00374 216 1575 730
Point Detectors 1 m 598E-03 00238 274E-03 00271 402E-04 00354 219 1489 681 2 m 273E-03 00218 123E-03 00245 180E-04 00336 221 1515 684
Source Attachment II MCNP-Results1xls worksheet Summary
Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 653E-03 00298 265E-03 00276 510E-04 00341 247 1278 518
1 m 276E-03 00238 112E-03 00208 207E-04 00249 248 1334 539 2 m 125E-03 00185 508E-04 00199 933E-05 00246 246 1336 544
Point Detectors 1 m 291E-03 00227 118E-03 00203 218E-04 00242 247 1335 540 2 m 130E-03 00209 524E-04 00187 955E-05 00233 247 1357 549
Source Attachment II MCNP-Results1xls worksheet Summary
Tables 13 14 and 15 are results of calculation set 1 for conceptual Cask A with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
39
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 265E-02 00247 990E-03 00222 215E-03 00278 268 1234 461
1 m 116E-02 00178 468E-03 00549 960E-04 00189 248 1208 488 2 m 713E-03 00273 265E-03 00161 602E-04 00360 269 1184 439
Ring Detectors 1 m 117E-02 00120 454E-03 00132 979E-04 00141 259 1199 463 2 m 722E-03 00130 276E-03 00141 589E-04 00153 261 1226 469
Source Attachment II MCNP-Results2xls worksheet Summary
Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 199E-02 00461 827E-03 00455 147E-03 00536 241 1359 564
1 m 849E-03 00564 323E-03 00314 563E-04 00418 263 1507 574 2 m 415E-03 00832 158E-03 00603 253E-04 00501 263 1641 623
Point Detectors 1 m 877E-03 00348 353E-03 00275 615E-04 00391 248 1426 574 2 m 393E-03 00341 160E-03 00278 270E-04 00378 246 1454 590
Source Attachment II MCNP-Results2xls worksheet Summary
Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 879E-03 00374 356E-03 00333 669E-04 00406 247 1315 533
1 m 365E-03 00223 147E-03 00209 269E-04 00253 248 1358 548 2 m 164E-03 00229 674E-04 00205 120E-04 00248 243 1364 560
Point Detectors 1 m 383E-03 00217 155E-03 00204 285E-04 00248 247 1347 546 2 m 172E-03 00197 689E-04 00186 124E-04 00225 249 1391 558
Source Attachment II MCNP-Results2xls worksheet Summary
Tables 16 17 and 18 ar e results of calculation set 2 for conceptual Cask A with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
40
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
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I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
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I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
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000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
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- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
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- 43 CALCULATION APPROACH
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- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
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- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
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- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
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- 72 CONCLUSIONS
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- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 8 Gamma and Neutron Sources for the Maximum PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting
Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 594E+11 233E+15 528E+11 379E+11 100E-01 000E+00 100E-01 116E+11 644E+14 609E+10 743E+10 400E-01 805E+07 200E-01 283E+10 522E+14 352E+10 179E+10 900E-01 411E+08 300E-01 141E+09 148E+14 196E+09 891E+08 140E+00 376E+08 400E-01 190E+09 985E+13 586E+09 117E+09 185E+00 276E+08 600E-01 191E+09 153E+15 110E+11 741E+07 300E+00 485E+08 800E-01 435E+09 470E+15 595E+10 237E+09 643E+00 443E+08 100E+00 137E+11 708E+14 803E+09 766E+10 200E+01 393E+07 133E+00 338E+13 455E+14 174E+13 217E+13 Total 211E+09 166E+00 953E+12 130E+14 491E+12 612E+12
--
200E+00 187E+03 144E+12 919E+02 113E+03 250E+00 226E+08 249E+12 116E+08 145E+08 300E+00 351E+05 110E+11 181E+05 225E+05 400E+00 766E-08 139E+10 100E-08 416E-08 500E+00 000E+00 709E+07 000E+00 000E+00 650E+00 000E+00 286E+07 000E+00 000E+00 800E+00 000E+00 558E+06 000E+00 000E+00 100E+01 000E+00 119E+06 000E+00 000E+00
Total 442E+13 113E+16 231E+13 284E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE2R2B14cut bWasteStreamE2R1B14cut cWasteStreamE2R3B14cut dWasteStreamE2R4B14cut
31
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 9 Gamma and Neutron Sources for the Design Basis PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary
(MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 273E+11 121E+15 188E+11 175E+11 100E-01 000E+00 100E-01 528E+10 329E+14 277E+10 339E+10 400E-01 316E+07 200E-01 128E+10 245E+14 117E+10 819E+09 900E-01 161E+08 300E-01 639E+08 713E+13 633E+08 407E+08 140E+00 148E+08 400E-01 850E+08 455E+13 164E+09 533E+08 185E+00 109E+08 600E-01 492E+08 226E+14 269E+10 337E+07 300E+00 191E+08 800E-01 291E+09 237E+15 160E+10 186E+09 643E+00 174E+08 100E+00 540E+09 122E+14 248E+09 341E+09 200E+01 154E+07 133E+00 154E+13 195E+14 797E+12 990E+12 Total 830E+08 166E+00 435E+12 450E+13 225E+12 280E+12
--
200E+00 235E+00 152E+11 149E+02 215E-02 250E+00 103E+08 517E+10 534E+07 664E+07 300E+00 160E+05 379E+09 829E+04 103E+05 400E+00 943E-10 497E+08 155E-10 519E-10 500E+00 000E+00 282E+07 000E+00 000E+00 650E+00 000E+00 113E+07 000E+00 000E+00 800E+00 000E+00 222E+06 000E+00 000E+00 100E+01 000E+00 471E+05 000E+00 000E+00
Total 201E+13 486E+15 105E+13 129E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B11cut bWasteStreamE5R1B11cut cWasteStreamE5R3B11cut dWasteStreamE5R4B11cut
32
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 10 Gamma and Neutron Sources for the Average PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 336E+10 670E+14 186E+10 217E+10 100E-01 00000E+00 100E-01 602E+09 199E+14 314E+09 387E+09 400E-01 748E+06 200E-01 146E+09 126E+14 853E+08 936E+08 900E-01 382E+07 300E-01 730E+07 389E+13 439E+07 469E+07 140E+00 352E+07 400E-01 947E+07 263E+13 716E+07 607E+07 185E+00 261E+07 600E-01 141E+07 205E+13 504E+08 383E+06 300E+00 469E+07 800E-01 208E+09 124E+15 192E+09 144E+09 643E+00 418E+07 100E+00 208E+09 110E+13 164E+09 144E+09 200E+01 365E+06 133E+00 175E+12 295E+13 909E+11 112E+12 Total 199E+08 166E+00 494E+11 513E+12 257E+11 318E+11
--
200E+00 973E-01 675E+10 614E+01 872E-03 250E+00 117E+07 353E+09 609E+06 754E+06 300E+00 182E+04 288E+08 944E+03 117E+04 400E+00 186E-11 198E+07 149E-11 127E-11 500E+00 000E+00 669E+06 000E+00 000E+00 650E+00 000E+00 269E+06 000E+00 000E+00 800E+00 000E+00 527E+05 000E+00 000E+00 100E+01 000E+00 112E+05 000E+00 000E+00
Total 229E+12 237E+15 119E+12 147E+12
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B9cut bWasteStreamE5R1B9cut cWasteStreamE5R3B9cut dWasteStreamE5R4B9cut
33
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 11 Gamma and Neutron Axial Source Profiles for a PWR Assembly
Axial boundaries (From midplane)
(cm)
TOP BOTTOM
Neutron Gamma Ne utron Gamma 000 1554 1117 1554 1117 1143 1537 1114 1571 1120 2286 1521 1111 1588 1123 3429 1504 1108 1605 1126 4572 1486 1104 1622 1129 5715 1464 1100 1636 1131 6858 1438 1095 1648 1133 8001 1401 1088 1657 1135 9144 1350 1078 1654 1134
10287 1277 1063 1625 1129 11430 1165 1039 1554 1117 12573 0998 09995 1414 1091 13716 0769 09365 1172 1041 14859 0492 08375 0816 0951 16002 0220 06850 0402 0797 17145 0046 04625 0092 0551 18288 00 00 00 00
Source Reference 2219 Table S445
34
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
63 MCNP SPECIFIC INPUT
631 Source Probability
A linear radial distribution is used for all gamma and neutron sources The linear radial distribution is sam pled usi ng the built-in power function p(x) = xc a with a = 1 for the radial direction This sampling method results in a uniform source distribution over the area bounded by the outer radius of the source
The source axial distributions are unifor m for all four source regions The a xial uni form xp(x) = c distribution is sampled using the built-in power function a with a = 0 for extent
The energy distribu tions of the gamma and neutron sour ce term s are treated as energ y probabilities and are applied in MCNP5 using SISP cards
632 Dose Rate and Flux Tallies
MCNP5 dose rate calculations feature separate runs for the following calculation types
bull a photon transport calculation for prim ary ga mma contribution to the dose rates fr om photon fluxes
bull a coupled neutronphoton transport calculat ion for neutrons a nd secondary gamma (photons generated by neutron be ing captured) contributions to dose rates from neutron and gamma fluxes
The tally type F2 is us ed in th is d esign ca lculation as f lux estim ators The type F2 tally evaluates the flux averaged over a surface in particlescm2s
To generate dose ra tes in te rms of remhr the FM (tally multiplier ) and DEDF (dose energydose conversion factors) cards are used to en ter the tally multiplier f actor (source intensity in particless) energy boundaries in MeV and corresponding dose conversion factors in (remhr)(particlescm2s) respectively These factors were used in the input files
In order for the F2 tally to accum ulate flux ov er a surface a specific s urface area is requ ired The SD cards are used to enter a surface area in cm2 over which the flux will be tallied for an F2 tally
633 Variance Reduction Techniques
Variance reduction technique is usually em ployed in order to increase the efficiency of a calculation and obtain statistically m eaningful results within re asonable com puter tim e In Monte Carlo calculations when variance reduction scheme is employed the weights of particles are adjusted in order to account for the biasing and to preserve a fair game
Geometry splitting and Russian roulette techniques described in Reference 2224 (pp 2-140 ndash 2-142) are useful in shielding calculations and therefore deployed in all the MCNP5 runs
35
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
As particles migrate in an important direction (toward the detector) they are increased in number to provide better sampling by means of geometry splitting across geometric boundaries Russian roulette (the reverse process) is played when particles travel in an unimportant direction to allow termination of unim portant histories The IMP card required for every cel l ca rd is us ed to implement this technique
The other variance reduction technique deployed in the MC NP5 runs is source intensity biasing for the gamma sources from the four source regions (active fuel bottom end-fitting plenum and top end-fitting) The natural total gamma source intensity of comm ercial SNF is dom inated by the gamma source in the active fuel region This active fuel gamma source usually accounts for over 95 o f the total g amma source intens ity In order to im prove the efficiency of the axial dose rate calculations a biased source probability distribution is employed for the prim ary gamma dose rate calculations The biased gamma source probability distribution is chosen to be 005 080 010 and 005 for the bottom end-fitting the active fuel the plenum and the top end-fitting regions respectively
64 DOSE CONVERSION FACTORS
Project Design Criteria Document (Reference 2211 Se ction 41015) requires the use of flux-to-dose rate conversion fact ors from ANSIANS-611-1977 (Reference 221) for dose rate evaluations Table 16 lists the neutron and ga mma dose conversion factors used in the MCNP5 calculations
Table 12 Gamma and Neutron Flux to Dose Conversion Factors
Gamma Neutron Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
001 396E-06 140 251E-06 250E-08 367E-06 003 582E-07 180 299E-06 100E-07 367E-06 005 290E-07 220 342E-06 100E-06 446E-06 007 258E-07 260 382E-06 100E-05 454E-06 010 283E-07 280 401E-06 100E-04 418E-06 015 379E-07 325 441E-06 100E-03 376E-06 020 501E-07 375 483E-06 100E-02 356E-06 025 631E-07 425 523E-06 100E-01 217E-05 030 759E-07 475 560E-06 500E-01 926E-05 035 878E-07 500 580E-06 100E+00 132E-04 040 985E-07 525 601E-06 250E+00 125E-04 045 108E-06 575 637E-06 500E+00 156E-04 050 117E-06 625 674E-06 700E+00 147E-04 055 127E-06 675 711E-06 100E+01 147E-04 060 136E-06 750 766E-06 140E+01 208E-04 065 144E-06 900 877E-06 200E+01 227E-04 070 152E-06 1100 103E-05 080 168E-06 1300 118E-05 100 198E-06 1500 133E-05
Source Reference 221 Tables 1 and 3
36
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION
By def inition (Ref erence 2224 Equation 219) the estimated st atistic relative error of the i component is
Ri = Si
2
Equation 6Ti
where i = tally component index Ri = relative error of the i component S2
i = variance of the i component Ti = tally i component
For a result (ie dose rate) computed as a sum of different tallies the statistical relative error of the computed value is o btained from the variance of the result - S2
total which is th e sum of the estimated variances of the individual tallies S2
i n
2 2STotal = sum Si Equation 7 i=1
where S2Total = total estimated variance
n = total number of components Therefore the total tally value (dose rate) and the associated relative error are derived according to Equations 8 and 9
n TTotal = sumTi Equation 8
i=1
n n
sum (Ri timesTi )2
2 sum Si 2
STotal = i=1 = i=1 Equation 9RTotal = TTotal TTotal TTotal
where RTotal = total estimated relative error TTotal = total estimated tally
Equations 8 and 9 are utilized in Attachm ent II to ev aluate to tal dos e ra tes and their r elative errors
37
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
7 RESULTS AND CONCLUSIONS
71 RESULTS
The following sections summarize the results of this calculation Section 711 presents results for Conceptual Cask A while Section 712 for Conceptual Cask B Section 713 provides comparisons of the dose-rate reduction factors du e to the two conceptual casks and the axial source distributions in the active fuel region Do se rates and relative errors can be found in Attachment II within the output files and Excel files
711 Dose Rates of Conceptual Cask A
This section presents dose-rate results of the calculation sets 1 and 2 as described in Section 61 for Cask A Set 1 has axial p rofile sources in the active fuel region a nd consist of six runs resulting from the three PWR SNF source term s (maximum design basis and average) and the two radiation sources (gammas and neutrons) Set 2 has uniform axial sources in the active fuel region and consists of six run s r esulting f rom the th ree P WR SNF source term s and th e tw o radiation sources
As described in Section 61 dose ra tes are calculated at the three exterior surfaces (radial top and bottom) and at distances 1 m and 2 m from the exterior surfaces The total dose rates for set 1 are presented in Tables 13 14 and 15 for the ra dial top and bottom dire ctions respectively However the com ponents (primary gamma neutr on and secondary gamma) contributing to the total dose rates as well as the re lative error calculations can be found in Attachment II Excel file MCNP-Results1xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 2 are shown in Tables 16 17 and 18 The dose-rate components and the relative errors can be found in A ttachment II Excel file MCNP-Results2xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 13 and 16 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 14 and 17 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 15 and 18 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carrying th e maximum PWR SNF Based on the results in Tables 13 through 18 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask A indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these 6 tables the d ose-rate red uction f actors between the m aximum and the design basis fuels the maxim um and the averag e fuels and th e design basis and the average fuels are a lso presented
38
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 320E-02 00237 116E-02 00222 262E-03 00219 275 1223 445
1 m 133E-02 00164 494E-03 00171 106E-03 00162 269 1261 468 2 m 749E-03 00198 285E-03 00225 584E-04 00162 263 1282 488
Ring Detectors 1 m 133E-02 00116 492E-03 00115 108E-03 00124 271 1229 454 2 m 756E-03 00118 279E-03 00110 605E-04 00128 271 1250 462
Source Attachment II MCNP-Results1xls worksheet Summary
Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 142E-02 00368 628E-03 00446 934E-04 00483 226 1520 672
1 m 570E-03 00289 263E-03 00426 375E-04 00381 217 1520 701 2 m 265E-03 00364 123E-03 00547 169E-04 00374 216 1575 730
Point Detectors 1 m 598E-03 00238 274E-03 00271 402E-04 00354 219 1489 681 2 m 273E-03 00218 123E-03 00245 180E-04 00336 221 1515 684
Source Attachment II MCNP-Results1xls worksheet Summary
Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 653E-03 00298 265E-03 00276 510E-04 00341 247 1278 518
1 m 276E-03 00238 112E-03 00208 207E-04 00249 248 1334 539 2 m 125E-03 00185 508E-04 00199 933E-05 00246 246 1336 544
Point Detectors 1 m 291E-03 00227 118E-03 00203 218E-04 00242 247 1335 540 2 m 130E-03 00209 524E-04 00187 955E-05 00233 247 1357 549
Source Attachment II MCNP-Results1xls worksheet Summary
Tables 13 14 and 15 are results of calculation set 1 for conceptual Cask A with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
39
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 265E-02 00247 990E-03 00222 215E-03 00278 268 1234 461
1 m 116E-02 00178 468E-03 00549 960E-04 00189 248 1208 488 2 m 713E-03 00273 265E-03 00161 602E-04 00360 269 1184 439
Ring Detectors 1 m 117E-02 00120 454E-03 00132 979E-04 00141 259 1199 463 2 m 722E-03 00130 276E-03 00141 589E-04 00153 261 1226 469
Source Attachment II MCNP-Results2xls worksheet Summary
Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 199E-02 00461 827E-03 00455 147E-03 00536 241 1359 564
1 m 849E-03 00564 323E-03 00314 563E-04 00418 263 1507 574 2 m 415E-03 00832 158E-03 00603 253E-04 00501 263 1641 623
Point Detectors 1 m 877E-03 00348 353E-03 00275 615E-04 00391 248 1426 574 2 m 393E-03 00341 160E-03 00278 270E-04 00378 246 1454 590
Source Attachment II MCNP-Results2xls worksheet Summary
Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 879E-03 00374 356E-03 00333 669E-04 00406 247 1315 533
1 m 365E-03 00223 147E-03 00209 269E-04 00253 248 1358 548 2 m 164E-03 00229 674E-04 00205 120E-04 00248 243 1364 560
Point Detectors 1 m 383E-03 00217 155E-03 00204 285E-04 00248 247 1347 546 2 m 172E-03 00197 689E-04 00186 124E-04 00225 249 1391 558
Source Attachment II MCNP-Results2xls worksheet Summary
Tables 16 17 and 18 ar e results of calculation set 2 for conceptual Cask A with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
40
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 9 Gamma and Neutron Sources for the Design Basis PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary
(MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 273E+11 121E+15 188E+11 175E+11 100E-01 000E+00 100E-01 528E+10 329E+14 277E+10 339E+10 400E-01 316E+07 200E-01 128E+10 245E+14 117E+10 819E+09 900E-01 161E+08 300E-01 639E+08 713E+13 633E+08 407E+08 140E+00 148E+08 400E-01 850E+08 455E+13 164E+09 533E+08 185E+00 109E+08 600E-01 492E+08 226E+14 269E+10 337E+07 300E+00 191E+08 800E-01 291E+09 237E+15 160E+10 186E+09 643E+00 174E+08 100E+00 540E+09 122E+14 248E+09 341E+09 200E+01 154E+07 133E+00 154E+13 195E+14 797E+12 990E+12 Total 830E+08 166E+00 435E+12 450E+13 225E+12 280E+12
--
200E+00 235E+00 152E+11 149E+02 215E-02 250E+00 103E+08 517E+10 534E+07 664E+07 300E+00 160E+05 379E+09 829E+04 103E+05 400E+00 943E-10 497E+08 155E-10 519E-10 500E+00 000E+00 282E+07 000E+00 000E+00 650E+00 000E+00 113E+07 000E+00 000E+00 800E+00 000E+00 222E+06 000E+00 000E+00 100E+01 000E+00 471E+05 000E+00 000E+00
Total 201E+13 486E+15 105E+13 129E+13
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B11cut bWasteStreamE5R1B11cut cWasteStreamE5R3B11cut dWasteStreamE5R4B11cut
32
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 10 Gamma and Neutron Sources for the Average PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 336E+10 670E+14 186E+10 217E+10 100E-01 00000E+00 100E-01 602E+09 199E+14 314E+09 387E+09 400E-01 748E+06 200E-01 146E+09 126E+14 853E+08 936E+08 900E-01 382E+07 300E-01 730E+07 389E+13 439E+07 469E+07 140E+00 352E+07 400E-01 947E+07 263E+13 716E+07 607E+07 185E+00 261E+07 600E-01 141E+07 205E+13 504E+08 383E+06 300E+00 469E+07 800E-01 208E+09 124E+15 192E+09 144E+09 643E+00 418E+07 100E+00 208E+09 110E+13 164E+09 144E+09 200E+01 365E+06 133E+00 175E+12 295E+13 909E+11 112E+12 Total 199E+08 166E+00 494E+11 513E+12 257E+11 318E+11
--
200E+00 973E-01 675E+10 614E+01 872E-03 250E+00 117E+07 353E+09 609E+06 754E+06 300E+00 182E+04 288E+08 944E+03 117E+04 400E+00 186E-11 198E+07 149E-11 127E-11 500E+00 000E+00 669E+06 000E+00 000E+00 650E+00 000E+00 269E+06 000E+00 000E+00 800E+00 000E+00 527E+05 000E+00 000E+00 100E+01 000E+00 112E+05 000E+00 000E+00
Total 229E+12 237E+15 119E+12 147E+12
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B9cut bWasteStreamE5R1B9cut cWasteStreamE5R3B9cut dWasteStreamE5R4B9cut
33
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 11 Gamma and Neutron Axial Source Profiles for a PWR Assembly
Axial boundaries (From midplane)
(cm)
TOP BOTTOM
Neutron Gamma Ne utron Gamma 000 1554 1117 1554 1117 1143 1537 1114 1571 1120 2286 1521 1111 1588 1123 3429 1504 1108 1605 1126 4572 1486 1104 1622 1129 5715 1464 1100 1636 1131 6858 1438 1095 1648 1133 8001 1401 1088 1657 1135 9144 1350 1078 1654 1134
10287 1277 1063 1625 1129 11430 1165 1039 1554 1117 12573 0998 09995 1414 1091 13716 0769 09365 1172 1041 14859 0492 08375 0816 0951 16002 0220 06850 0402 0797 17145 0046 04625 0092 0551 18288 00 00 00 00
Source Reference 2219 Table S445
34
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
63 MCNP SPECIFIC INPUT
631 Source Probability
A linear radial distribution is used for all gamma and neutron sources The linear radial distribution is sam pled usi ng the built-in power function p(x) = xc a with a = 1 for the radial direction This sampling method results in a uniform source distribution over the area bounded by the outer radius of the source
The source axial distributions are unifor m for all four source regions The a xial uni form xp(x) = c distribution is sampled using the built-in power function a with a = 0 for extent
The energy distribu tions of the gamma and neutron sour ce term s are treated as energ y probabilities and are applied in MCNP5 using SISP cards
632 Dose Rate and Flux Tallies
MCNP5 dose rate calculations feature separate runs for the following calculation types
bull a photon transport calculation for prim ary ga mma contribution to the dose rates fr om photon fluxes
bull a coupled neutronphoton transport calculat ion for neutrons a nd secondary gamma (photons generated by neutron be ing captured) contributions to dose rates from neutron and gamma fluxes
The tally type F2 is us ed in th is d esign ca lculation as f lux estim ators The type F2 tally evaluates the flux averaged over a surface in particlescm2s
To generate dose ra tes in te rms of remhr the FM (tally multiplier ) and DEDF (dose energydose conversion factors) cards are used to en ter the tally multiplier f actor (source intensity in particless) energy boundaries in MeV and corresponding dose conversion factors in (remhr)(particlescm2s) respectively These factors were used in the input files
In order for the F2 tally to accum ulate flux ov er a surface a specific s urface area is requ ired The SD cards are used to enter a surface area in cm2 over which the flux will be tallied for an F2 tally
633 Variance Reduction Techniques
Variance reduction technique is usually em ployed in order to increase the efficiency of a calculation and obtain statistically m eaningful results within re asonable com puter tim e In Monte Carlo calculations when variance reduction scheme is employed the weights of particles are adjusted in order to account for the biasing and to preserve a fair game
Geometry splitting and Russian roulette techniques described in Reference 2224 (pp 2-140 ndash 2-142) are useful in shielding calculations and therefore deployed in all the MCNP5 runs
35
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
As particles migrate in an important direction (toward the detector) they are increased in number to provide better sampling by means of geometry splitting across geometric boundaries Russian roulette (the reverse process) is played when particles travel in an unimportant direction to allow termination of unim portant histories The IMP card required for every cel l ca rd is us ed to implement this technique
The other variance reduction technique deployed in the MC NP5 runs is source intensity biasing for the gamma sources from the four source regions (active fuel bottom end-fitting plenum and top end-fitting) The natural total gamma source intensity of comm ercial SNF is dom inated by the gamma source in the active fuel region This active fuel gamma source usually accounts for over 95 o f the total g amma source intens ity In order to im prove the efficiency of the axial dose rate calculations a biased source probability distribution is employed for the prim ary gamma dose rate calculations The biased gamma source probability distribution is chosen to be 005 080 010 and 005 for the bottom end-fitting the active fuel the plenum and the top end-fitting regions respectively
64 DOSE CONVERSION FACTORS
Project Design Criteria Document (Reference 2211 Se ction 41015) requires the use of flux-to-dose rate conversion fact ors from ANSIANS-611-1977 (Reference 221) for dose rate evaluations Table 16 lists the neutron and ga mma dose conversion factors used in the MCNP5 calculations
Table 12 Gamma and Neutron Flux to Dose Conversion Factors
Gamma Neutron Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
001 396E-06 140 251E-06 250E-08 367E-06 003 582E-07 180 299E-06 100E-07 367E-06 005 290E-07 220 342E-06 100E-06 446E-06 007 258E-07 260 382E-06 100E-05 454E-06 010 283E-07 280 401E-06 100E-04 418E-06 015 379E-07 325 441E-06 100E-03 376E-06 020 501E-07 375 483E-06 100E-02 356E-06 025 631E-07 425 523E-06 100E-01 217E-05 030 759E-07 475 560E-06 500E-01 926E-05 035 878E-07 500 580E-06 100E+00 132E-04 040 985E-07 525 601E-06 250E+00 125E-04 045 108E-06 575 637E-06 500E+00 156E-04 050 117E-06 625 674E-06 700E+00 147E-04 055 127E-06 675 711E-06 100E+01 147E-04 060 136E-06 750 766E-06 140E+01 208E-04 065 144E-06 900 877E-06 200E+01 227E-04 070 152E-06 1100 103E-05 080 168E-06 1300 118E-05 100 198E-06 1500 133E-05
Source Reference 221 Tables 1 and 3
36
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION
By def inition (Ref erence 2224 Equation 219) the estimated st atistic relative error of the i component is
Ri = Si
2
Equation 6Ti
where i = tally component index Ri = relative error of the i component S2
i = variance of the i component Ti = tally i component
For a result (ie dose rate) computed as a sum of different tallies the statistical relative error of the computed value is o btained from the variance of the result - S2
total which is th e sum of the estimated variances of the individual tallies S2
i n
2 2STotal = sum Si Equation 7 i=1
where S2Total = total estimated variance
n = total number of components Therefore the total tally value (dose rate) and the associated relative error are derived according to Equations 8 and 9
n TTotal = sumTi Equation 8
i=1
n n
sum (Ri timesTi )2
2 sum Si 2
STotal = i=1 = i=1 Equation 9RTotal = TTotal TTotal TTotal
where RTotal = total estimated relative error TTotal = total estimated tally
Equations 8 and 9 are utilized in Attachm ent II to ev aluate to tal dos e ra tes and their r elative errors
37
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
7 RESULTS AND CONCLUSIONS
71 RESULTS
The following sections summarize the results of this calculation Section 711 presents results for Conceptual Cask A while Section 712 for Conceptual Cask B Section 713 provides comparisons of the dose-rate reduction factors du e to the two conceptual casks and the axial source distributions in the active fuel region Do se rates and relative errors can be found in Attachment II within the output files and Excel files
711 Dose Rates of Conceptual Cask A
This section presents dose-rate results of the calculation sets 1 and 2 as described in Section 61 for Cask A Set 1 has axial p rofile sources in the active fuel region a nd consist of six runs resulting from the three PWR SNF source term s (maximum design basis and average) and the two radiation sources (gammas and neutrons) Set 2 has uniform axial sources in the active fuel region and consists of six run s r esulting f rom the th ree P WR SNF source term s and th e tw o radiation sources
As described in Section 61 dose ra tes are calculated at the three exterior surfaces (radial top and bottom) and at distances 1 m and 2 m from the exterior surfaces The total dose rates for set 1 are presented in Tables 13 14 and 15 for the ra dial top and bottom dire ctions respectively However the com ponents (primary gamma neutr on and secondary gamma) contributing to the total dose rates as well as the re lative error calculations can be found in Attachment II Excel file MCNP-Results1xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 2 are shown in Tables 16 17 and 18 The dose-rate components and the relative errors can be found in A ttachment II Excel file MCNP-Results2xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 13 and 16 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 14 and 17 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 15 and 18 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carrying th e maximum PWR SNF Based on the results in Tables 13 through 18 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask A indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these 6 tables the d ose-rate red uction f actors between the m aximum and the design basis fuels the maxim um and the averag e fuels and th e design basis and the average fuels are a lso presented
38
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 320E-02 00237 116E-02 00222 262E-03 00219 275 1223 445
1 m 133E-02 00164 494E-03 00171 106E-03 00162 269 1261 468 2 m 749E-03 00198 285E-03 00225 584E-04 00162 263 1282 488
Ring Detectors 1 m 133E-02 00116 492E-03 00115 108E-03 00124 271 1229 454 2 m 756E-03 00118 279E-03 00110 605E-04 00128 271 1250 462
Source Attachment II MCNP-Results1xls worksheet Summary
Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 142E-02 00368 628E-03 00446 934E-04 00483 226 1520 672
1 m 570E-03 00289 263E-03 00426 375E-04 00381 217 1520 701 2 m 265E-03 00364 123E-03 00547 169E-04 00374 216 1575 730
Point Detectors 1 m 598E-03 00238 274E-03 00271 402E-04 00354 219 1489 681 2 m 273E-03 00218 123E-03 00245 180E-04 00336 221 1515 684
Source Attachment II MCNP-Results1xls worksheet Summary
Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 653E-03 00298 265E-03 00276 510E-04 00341 247 1278 518
1 m 276E-03 00238 112E-03 00208 207E-04 00249 248 1334 539 2 m 125E-03 00185 508E-04 00199 933E-05 00246 246 1336 544
Point Detectors 1 m 291E-03 00227 118E-03 00203 218E-04 00242 247 1335 540 2 m 130E-03 00209 524E-04 00187 955E-05 00233 247 1357 549
Source Attachment II MCNP-Results1xls worksheet Summary
Tables 13 14 and 15 are results of calculation set 1 for conceptual Cask A with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
39
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 265E-02 00247 990E-03 00222 215E-03 00278 268 1234 461
1 m 116E-02 00178 468E-03 00549 960E-04 00189 248 1208 488 2 m 713E-03 00273 265E-03 00161 602E-04 00360 269 1184 439
Ring Detectors 1 m 117E-02 00120 454E-03 00132 979E-04 00141 259 1199 463 2 m 722E-03 00130 276E-03 00141 589E-04 00153 261 1226 469
Source Attachment II MCNP-Results2xls worksheet Summary
Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 199E-02 00461 827E-03 00455 147E-03 00536 241 1359 564
1 m 849E-03 00564 323E-03 00314 563E-04 00418 263 1507 574 2 m 415E-03 00832 158E-03 00603 253E-04 00501 263 1641 623
Point Detectors 1 m 877E-03 00348 353E-03 00275 615E-04 00391 248 1426 574 2 m 393E-03 00341 160E-03 00278 270E-04 00378 246 1454 590
Source Attachment II MCNP-Results2xls worksheet Summary
Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 879E-03 00374 356E-03 00333 669E-04 00406 247 1315 533
1 m 365E-03 00223 147E-03 00209 269E-04 00253 248 1358 548 2 m 164E-03 00229 674E-04 00205 120E-04 00248 243 1364 560
Point Detectors 1 m 383E-03 00217 155E-03 00204 285E-04 00248 247 1347 546 2 m 172E-03 00197 689E-04 00186 124E-04 00225 249 1391 558
Source Attachment II MCNP-Results2xls worksheet Summary
Tables 16 17 and 18 ar e results of calculation set 2 for conceptual Cask A with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
40
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
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I- 1
Dose Reduction Factors between Different Source Terms in a Cask
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I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
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000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 10 Gamma and Neutron Sources for the Average PWR SNF Assembly
Gamma Intensity (photonss) Neutron Intensity (neutronss)
Upper Energy Boundary (MeV)
Bottom End-Fitting
Regiona
Active Fuel Regionb
Plenum Fuel Regionc
Top End-Fitting Regiond
Upper Energy Boundary
(MeV) Active Fuel
Regionb
500E-02 336E+10 670E+14 186E+10 217E+10 100E-01 00000E+00 100E-01 602E+09 199E+14 314E+09 387E+09 400E-01 748E+06 200E-01 146E+09 126E+14 853E+08 936E+08 900E-01 382E+07 300E-01 730E+07 389E+13 439E+07 469E+07 140E+00 352E+07 400E-01 947E+07 263E+13 716E+07 607E+07 185E+00 261E+07 600E-01 141E+07 205E+13 504E+08 383E+06 300E+00 469E+07 800E-01 208E+09 124E+15 192E+09 144E+09 643E+00 418E+07 100E+00 208E+09 110E+13 164E+09 144E+09 200E+01 365E+06 133E+00 175E+12 295E+13 909E+11 112E+12 Total 199E+08 166E+00 494E+11 513E+12 257E+11 318E+11
--
200E+00 973E-01 675E+10 614E+01 872E-03 250E+00 117E+07 353E+09 609E+06 754E+06 300E+00 182E+04 288E+08 944E+03 117E+04 400E+00 186E-11 198E+07 149E-11 127E-11 500E+00 000E+00 669E+06 000E+00 000E+00 650E+00 000E+00 269E+06 000E+00 000E+00 800E+00 000E+00 527E+05 000E+00 000E+00 100E+01 000E+00 112E+05 000E+00 000E+00
Total 229E+12 237E+15 119E+12 147E+12
Source Reference 229 Attachment X (compact disc) aWasteStreamE5R2B9cut bWasteStreamE5R1B9cut cWasteStreamE5R3B9cut dWasteStreamE5R4B9cut
33
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 11 Gamma and Neutron Axial Source Profiles for a PWR Assembly
Axial boundaries (From midplane)
(cm)
TOP BOTTOM
Neutron Gamma Ne utron Gamma 000 1554 1117 1554 1117 1143 1537 1114 1571 1120 2286 1521 1111 1588 1123 3429 1504 1108 1605 1126 4572 1486 1104 1622 1129 5715 1464 1100 1636 1131 6858 1438 1095 1648 1133 8001 1401 1088 1657 1135 9144 1350 1078 1654 1134
10287 1277 1063 1625 1129 11430 1165 1039 1554 1117 12573 0998 09995 1414 1091 13716 0769 09365 1172 1041 14859 0492 08375 0816 0951 16002 0220 06850 0402 0797 17145 0046 04625 0092 0551 18288 00 00 00 00
Source Reference 2219 Table S445
34
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
63 MCNP SPECIFIC INPUT
631 Source Probability
A linear radial distribution is used for all gamma and neutron sources The linear radial distribution is sam pled usi ng the built-in power function p(x) = xc a with a = 1 for the radial direction This sampling method results in a uniform source distribution over the area bounded by the outer radius of the source
The source axial distributions are unifor m for all four source regions The a xial uni form xp(x) = c distribution is sampled using the built-in power function a with a = 0 for extent
The energy distribu tions of the gamma and neutron sour ce term s are treated as energ y probabilities and are applied in MCNP5 using SISP cards
632 Dose Rate and Flux Tallies
MCNP5 dose rate calculations feature separate runs for the following calculation types
bull a photon transport calculation for prim ary ga mma contribution to the dose rates fr om photon fluxes
bull a coupled neutronphoton transport calculat ion for neutrons a nd secondary gamma (photons generated by neutron be ing captured) contributions to dose rates from neutron and gamma fluxes
The tally type F2 is us ed in th is d esign ca lculation as f lux estim ators The type F2 tally evaluates the flux averaged over a surface in particlescm2s
To generate dose ra tes in te rms of remhr the FM (tally multiplier ) and DEDF (dose energydose conversion factors) cards are used to en ter the tally multiplier f actor (source intensity in particless) energy boundaries in MeV and corresponding dose conversion factors in (remhr)(particlescm2s) respectively These factors were used in the input files
In order for the F2 tally to accum ulate flux ov er a surface a specific s urface area is requ ired The SD cards are used to enter a surface area in cm2 over which the flux will be tallied for an F2 tally
633 Variance Reduction Techniques
Variance reduction technique is usually em ployed in order to increase the efficiency of a calculation and obtain statistically m eaningful results within re asonable com puter tim e In Monte Carlo calculations when variance reduction scheme is employed the weights of particles are adjusted in order to account for the biasing and to preserve a fair game
Geometry splitting and Russian roulette techniques described in Reference 2224 (pp 2-140 ndash 2-142) are useful in shielding calculations and therefore deployed in all the MCNP5 runs
35
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
As particles migrate in an important direction (toward the detector) they are increased in number to provide better sampling by means of geometry splitting across geometric boundaries Russian roulette (the reverse process) is played when particles travel in an unimportant direction to allow termination of unim portant histories The IMP card required for every cel l ca rd is us ed to implement this technique
The other variance reduction technique deployed in the MC NP5 runs is source intensity biasing for the gamma sources from the four source regions (active fuel bottom end-fitting plenum and top end-fitting) The natural total gamma source intensity of comm ercial SNF is dom inated by the gamma source in the active fuel region This active fuel gamma source usually accounts for over 95 o f the total g amma source intens ity In order to im prove the efficiency of the axial dose rate calculations a biased source probability distribution is employed for the prim ary gamma dose rate calculations The biased gamma source probability distribution is chosen to be 005 080 010 and 005 for the bottom end-fitting the active fuel the plenum and the top end-fitting regions respectively
64 DOSE CONVERSION FACTORS
Project Design Criteria Document (Reference 2211 Se ction 41015) requires the use of flux-to-dose rate conversion fact ors from ANSIANS-611-1977 (Reference 221) for dose rate evaluations Table 16 lists the neutron and ga mma dose conversion factors used in the MCNP5 calculations
Table 12 Gamma and Neutron Flux to Dose Conversion Factors
Gamma Neutron Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
001 396E-06 140 251E-06 250E-08 367E-06 003 582E-07 180 299E-06 100E-07 367E-06 005 290E-07 220 342E-06 100E-06 446E-06 007 258E-07 260 382E-06 100E-05 454E-06 010 283E-07 280 401E-06 100E-04 418E-06 015 379E-07 325 441E-06 100E-03 376E-06 020 501E-07 375 483E-06 100E-02 356E-06 025 631E-07 425 523E-06 100E-01 217E-05 030 759E-07 475 560E-06 500E-01 926E-05 035 878E-07 500 580E-06 100E+00 132E-04 040 985E-07 525 601E-06 250E+00 125E-04 045 108E-06 575 637E-06 500E+00 156E-04 050 117E-06 625 674E-06 700E+00 147E-04 055 127E-06 675 711E-06 100E+01 147E-04 060 136E-06 750 766E-06 140E+01 208E-04 065 144E-06 900 877E-06 200E+01 227E-04 070 152E-06 1100 103E-05 080 168E-06 1300 118E-05 100 198E-06 1500 133E-05
Source Reference 221 Tables 1 and 3
36
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION
By def inition (Ref erence 2224 Equation 219) the estimated st atistic relative error of the i component is
Ri = Si
2
Equation 6Ti
where i = tally component index Ri = relative error of the i component S2
i = variance of the i component Ti = tally i component
For a result (ie dose rate) computed as a sum of different tallies the statistical relative error of the computed value is o btained from the variance of the result - S2
total which is th e sum of the estimated variances of the individual tallies S2
i n
2 2STotal = sum Si Equation 7 i=1
where S2Total = total estimated variance
n = total number of components Therefore the total tally value (dose rate) and the associated relative error are derived according to Equations 8 and 9
n TTotal = sumTi Equation 8
i=1
n n
sum (Ri timesTi )2
2 sum Si 2
STotal = i=1 = i=1 Equation 9RTotal = TTotal TTotal TTotal
where RTotal = total estimated relative error TTotal = total estimated tally
Equations 8 and 9 are utilized in Attachm ent II to ev aluate to tal dos e ra tes and their r elative errors
37
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
7 RESULTS AND CONCLUSIONS
71 RESULTS
The following sections summarize the results of this calculation Section 711 presents results for Conceptual Cask A while Section 712 for Conceptual Cask B Section 713 provides comparisons of the dose-rate reduction factors du e to the two conceptual casks and the axial source distributions in the active fuel region Do se rates and relative errors can be found in Attachment II within the output files and Excel files
711 Dose Rates of Conceptual Cask A
This section presents dose-rate results of the calculation sets 1 and 2 as described in Section 61 for Cask A Set 1 has axial p rofile sources in the active fuel region a nd consist of six runs resulting from the three PWR SNF source term s (maximum design basis and average) and the two radiation sources (gammas and neutrons) Set 2 has uniform axial sources in the active fuel region and consists of six run s r esulting f rom the th ree P WR SNF source term s and th e tw o radiation sources
As described in Section 61 dose ra tes are calculated at the three exterior surfaces (radial top and bottom) and at distances 1 m and 2 m from the exterior surfaces The total dose rates for set 1 are presented in Tables 13 14 and 15 for the ra dial top and bottom dire ctions respectively However the com ponents (primary gamma neutr on and secondary gamma) contributing to the total dose rates as well as the re lative error calculations can be found in Attachment II Excel file MCNP-Results1xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 2 are shown in Tables 16 17 and 18 The dose-rate components and the relative errors can be found in A ttachment II Excel file MCNP-Results2xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 13 and 16 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 14 and 17 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 15 and 18 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carrying th e maximum PWR SNF Based on the results in Tables 13 through 18 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask A indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these 6 tables the d ose-rate red uction f actors between the m aximum and the design basis fuels the maxim um and the averag e fuels and th e design basis and the average fuels are a lso presented
38
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 320E-02 00237 116E-02 00222 262E-03 00219 275 1223 445
1 m 133E-02 00164 494E-03 00171 106E-03 00162 269 1261 468 2 m 749E-03 00198 285E-03 00225 584E-04 00162 263 1282 488
Ring Detectors 1 m 133E-02 00116 492E-03 00115 108E-03 00124 271 1229 454 2 m 756E-03 00118 279E-03 00110 605E-04 00128 271 1250 462
Source Attachment II MCNP-Results1xls worksheet Summary
Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 142E-02 00368 628E-03 00446 934E-04 00483 226 1520 672
1 m 570E-03 00289 263E-03 00426 375E-04 00381 217 1520 701 2 m 265E-03 00364 123E-03 00547 169E-04 00374 216 1575 730
Point Detectors 1 m 598E-03 00238 274E-03 00271 402E-04 00354 219 1489 681 2 m 273E-03 00218 123E-03 00245 180E-04 00336 221 1515 684
Source Attachment II MCNP-Results1xls worksheet Summary
Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 653E-03 00298 265E-03 00276 510E-04 00341 247 1278 518
1 m 276E-03 00238 112E-03 00208 207E-04 00249 248 1334 539 2 m 125E-03 00185 508E-04 00199 933E-05 00246 246 1336 544
Point Detectors 1 m 291E-03 00227 118E-03 00203 218E-04 00242 247 1335 540 2 m 130E-03 00209 524E-04 00187 955E-05 00233 247 1357 549
Source Attachment II MCNP-Results1xls worksheet Summary
Tables 13 14 and 15 are results of calculation set 1 for conceptual Cask A with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
39
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 265E-02 00247 990E-03 00222 215E-03 00278 268 1234 461
1 m 116E-02 00178 468E-03 00549 960E-04 00189 248 1208 488 2 m 713E-03 00273 265E-03 00161 602E-04 00360 269 1184 439
Ring Detectors 1 m 117E-02 00120 454E-03 00132 979E-04 00141 259 1199 463 2 m 722E-03 00130 276E-03 00141 589E-04 00153 261 1226 469
Source Attachment II MCNP-Results2xls worksheet Summary
Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 199E-02 00461 827E-03 00455 147E-03 00536 241 1359 564
1 m 849E-03 00564 323E-03 00314 563E-04 00418 263 1507 574 2 m 415E-03 00832 158E-03 00603 253E-04 00501 263 1641 623
Point Detectors 1 m 877E-03 00348 353E-03 00275 615E-04 00391 248 1426 574 2 m 393E-03 00341 160E-03 00278 270E-04 00378 246 1454 590
Source Attachment II MCNP-Results2xls worksheet Summary
Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 879E-03 00374 356E-03 00333 669E-04 00406 247 1315 533
1 m 365E-03 00223 147E-03 00209 269E-04 00253 248 1358 548 2 m 164E-03 00229 674E-04 00205 120E-04 00248 243 1364 560
Point Detectors 1 m 383E-03 00217 155E-03 00204 285E-04 00248 247 1347 546 2 m 172E-03 00197 689E-04 00186 124E-04 00225 249 1391 558
Source Attachment II MCNP-Results2xls worksheet Summary
Tables 16 17 and 18 ar e results of calculation set 2 for conceptual Cask A with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
40
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 11 Gamma and Neutron Axial Source Profiles for a PWR Assembly
Axial boundaries (From midplane)
(cm)
TOP BOTTOM
Neutron Gamma Ne utron Gamma 000 1554 1117 1554 1117 1143 1537 1114 1571 1120 2286 1521 1111 1588 1123 3429 1504 1108 1605 1126 4572 1486 1104 1622 1129 5715 1464 1100 1636 1131 6858 1438 1095 1648 1133 8001 1401 1088 1657 1135 9144 1350 1078 1654 1134
10287 1277 1063 1625 1129 11430 1165 1039 1554 1117 12573 0998 09995 1414 1091 13716 0769 09365 1172 1041 14859 0492 08375 0816 0951 16002 0220 06850 0402 0797 17145 0046 04625 0092 0551 18288 00 00 00 00
Source Reference 2219 Table S445
34
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
63 MCNP SPECIFIC INPUT
631 Source Probability
A linear radial distribution is used for all gamma and neutron sources The linear radial distribution is sam pled usi ng the built-in power function p(x) = xc a with a = 1 for the radial direction This sampling method results in a uniform source distribution over the area bounded by the outer radius of the source
The source axial distributions are unifor m for all four source regions The a xial uni form xp(x) = c distribution is sampled using the built-in power function a with a = 0 for extent
The energy distribu tions of the gamma and neutron sour ce term s are treated as energ y probabilities and are applied in MCNP5 using SISP cards
632 Dose Rate and Flux Tallies
MCNP5 dose rate calculations feature separate runs for the following calculation types
bull a photon transport calculation for prim ary ga mma contribution to the dose rates fr om photon fluxes
bull a coupled neutronphoton transport calculat ion for neutrons a nd secondary gamma (photons generated by neutron be ing captured) contributions to dose rates from neutron and gamma fluxes
The tally type F2 is us ed in th is d esign ca lculation as f lux estim ators The type F2 tally evaluates the flux averaged over a surface in particlescm2s
To generate dose ra tes in te rms of remhr the FM (tally multiplier ) and DEDF (dose energydose conversion factors) cards are used to en ter the tally multiplier f actor (source intensity in particless) energy boundaries in MeV and corresponding dose conversion factors in (remhr)(particlescm2s) respectively These factors were used in the input files
In order for the F2 tally to accum ulate flux ov er a surface a specific s urface area is requ ired The SD cards are used to enter a surface area in cm2 over which the flux will be tallied for an F2 tally
633 Variance Reduction Techniques
Variance reduction technique is usually em ployed in order to increase the efficiency of a calculation and obtain statistically m eaningful results within re asonable com puter tim e In Monte Carlo calculations when variance reduction scheme is employed the weights of particles are adjusted in order to account for the biasing and to preserve a fair game
Geometry splitting and Russian roulette techniques described in Reference 2224 (pp 2-140 ndash 2-142) are useful in shielding calculations and therefore deployed in all the MCNP5 runs
35
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
As particles migrate in an important direction (toward the detector) they are increased in number to provide better sampling by means of geometry splitting across geometric boundaries Russian roulette (the reverse process) is played when particles travel in an unimportant direction to allow termination of unim portant histories The IMP card required for every cel l ca rd is us ed to implement this technique
The other variance reduction technique deployed in the MC NP5 runs is source intensity biasing for the gamma sources from the four source regions (active fuel bottom end-fitting plenum and top end-fitting) The natural total gamma source intensity of comm ercial SNF is dom inated by the gamma source in the active fuel region This active fuel gamma source usually accounts for over 95 o f the total g amma source intens ity In order to im prove the efficiency of the axial dose rate calculations a biased source probability distribution is employed for the prim ary gamma dose rate calculations The biased gamma source probability distribution is chosen to be 005 080 010 and 005 for the bottom end-fitting the active fuel the plenum and the top end-fitting regions respectively
64 DOSE CONVERSION FACTORS
Project Design Criteria Document (Reference 2211 Se ction 41015) requires the use of flux-to-dose rate conversion fact ors from ANSIANS-611-1977 (Reference 221) for dose rate evaluations Table 16 lists the neutron and ga mma dose conversion factors used in the MCNP5 calculations
Table 12 Gamma and Neutron Flux to Dose Conversion Factors
Gamma Neutron Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
001 396E-06 140 251E-06 250E-08 367E-06 003 582E-07 180 299E-06 100E-07 367E-06 005 290E-07 220 342E-06 100E-06 446E-06 007 258E-07 260 382E-06 100E-05 454E-06 010 283E-07 280 401E-06 100E-04 418E-06 015 379E-07 325 441E-06 100E-03 376E-06 020 501E-07 375 483E-06 100E-02 356E-06 025 631E-07 425 523E-06 100E-01 217E-05 030 759E-07 475 560E-06 500E-01 926E-05 035 878E-07 500 580E-06 100E+00 132E-04 040 985E-07 525 601E-06 250E+00 125E-04 045 108E-06 575 637E-06 500E+00 156E-04 050 117E-06 625 674E-06 700E+00 147E-04 055 127E-06 675 711E-06 100E+01 147E-04 060 136E-06 750 766E-06 140E+01 208E-04 065 144E-06 900 877E-06 200E+01 227E-04 070 152E-06 1100 103E-05 080 168E-06 1300 118E-05 100 198E-06 1500 133E-05
Source Reference 221 Tables 1 and 3
36
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION
By def inition (Ref erence 2224 Equation 219) the estimated st atistic relative error of the i component is
Ri = Si
2
Equation 6Ti
where i = tally component index Ri = relative error of the i component S2
i = variance of the i component Ti = tally i component
For a result (ie dose rate) computed as a sum of different tallies the statistical relative error of the computed value is o btained from the variance of the result - S2
total which is th e sum of the estimated variances of the individual tallies S2
i n
2 2STotal = sum Si Equation 7 i=1
where S2Total = total estimated variance
n = total number of components Therefore the total tally value (dose rate) and the associated relative error are derived according to Equations 8 and 9
n TTotal = sumTi Equation 8
i=1
n n
sum (Ri timesTi )2
2 sum Si 2
STotal = i=1 = i=1 Equation 9RTotal = TTotal TTotal TTotal
where RTotal = total estimated relative error TTotal = total estimated tally
Equations 8 and 9 are utilized in Attachm ent II to ev aluate to tal dos e ra tes and their r elative errors
37
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
7 RESULTS AND CONCLUSIONS
71 RESULTS
The following sections summarize the results of this calculation Section 711 presents results for Conceptual Cask A while Section 712 for Conceptual Cask B Section 713 provides comparisons of the dose-rate reduction factors du e to the two conceptual casks and the axial source distributions in the active fuel region Do se rates and relative errors can be found in Attachment II within the output files and Excel files
711 Dose Rates of Conceptual Cask A
This section presents dose-rate results of the calculation sets 1 and 2 as described in Section 61 for Cask A Set 1 has axial p rofile sources in the active fuel region a nd consist of six runs resulting from the three PWR SNF source term s (maximum design basis and average) and the two radiation sources (gammas and neutrons) Set 2 has uniform axial sources in the active fuel region and consists of six run s r esulting f rom the th ree P WR SNF source term s and th e tw o radiation sources
As described in Section 61 dose ra tes are calculated at the three exterior surfaces (radial top and bottom) and at distances 1 m and 2 m from the exterior surfaces The total dose rates for set 1 are presented in Tables 13 14 and 15 for the ra dial top and bottom dire ctions respectively However the com ponents (primary gamma neutr on and secondary gamma) contributing to the total dose rates as well as the re lative error calculations can be found in Attachment II Excel file MCNP-Results1xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 2 are shown in Tables 16 17 and 18 The dose-rate components and the relative errors can be found in A ttachment II Excel file MCNP-Results2xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 13 and 16 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 14 and 17 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 15 and 18 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carrying th e maximum PWR SNF Based on the results in Tables 13 through 18 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask A indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these 6 tables the d ose-rate red uction f actors between the m aximum and the design basis fuels the maxim um and the averag e fuels and th e design basis and the average fuels are a lso presented
38
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 320E-02 00237 116E-02 00222 262E-03 00219 275 1223 445
1 m 133E-02 00164 494E-03 00171 106E-03 00162 269 1261 468 2 m 749E-03 00198 285E-03 00225 584E-04 00162 263 1282 488
Ring Detectors 1 m 133E-02 00116 492E-03 00115 108E-03 00124 271 1229 454 2 m 756E-03 00118 279E-03 00110 605E-04 00128 271 1250 462
Source Attachment II MCNP-Results1xls worksheet Summary
Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 142E-02 00368 628E-03 00446 934E-04 00483 226 1520 672
1 m 570E-03 00289 263E-03 00426 375E-04 00381 217 1520 701 2 m 265E-03 00364 123E-03 00547 169E-04 00374 216 1575 730
Point Detectors 1 m 598E-03 00238 274E-03 00271 402E-04 00354 219 1489 681 2 m 273E-03 00218 123E-03 00245 180E-04 00336 221 1515 684
Source Attachment II MCNP-Results1xls worksheet Summary
Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 653E-03 00298 265E-03 00276 510E-04 00341 247 1278 518
1 m 276E-03 00238 112E-03 00208 207E-04 00249 248 1334 539 2 m 125E-03 00185 508E-04 00199 933E-05 00246 246 1336 544
Point Detectors 1 m 291E-03 00227 118E-03 00203 218E-04 00242 247 1335 540 2 m 130E-03 00209 524E-04 00187 955E-05 00233 247 1357 549
Source Attachment II MCNP-Results1xls worksheet Summary
Tables 13 14 and 15 are results of calculation set 1 for conceptual Cask A with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
39
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 265E-02 00247 990E-03 00222 215E-03 00278 268 1234 461
1 m 116E-02 00178 468E-03 00549 960E-04 00189 248 1208 488 2 m 713E-03 00273 265E-03 00161 602E-04 00360 269 1184 439
Ring Detectors 1 m 117E-02 00120 454E-03 00132 979E-04 00141 259 1199 463 2 m 722E-03 00130 276E-03 00141 589E-04 00153 261 1226 469
Source Attachment II MCNP-Results2xls worksheet Summary
Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 199E-02 00461 827E-03 00455 147E-03 00536 241 1359 564
1 m 849E-03 00564 323E-03 00314 563E-04 00418 263 1507 574 2 m 415E-03 00832 158E-03 00603 253E-04 00501 263 1641 623
Point Detectors 1 m 877E-03 00348 353E-03 00275 615E-04 00391 248 1426 574 2 m 393E-03 00341 160E-03 00278 270E-04 00378 246 1454 590
Source Attachment II MCNP-Results2xls worksheet Summary
Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 879E-03 00374 356E-03 00333 669E-04 00406 247 1315 533
1 m 365E-03 00223 147E-03 00209 269E-04 00253 248 1358 548 2 m 164E-03 00229 674E-04 00205 120E-04 00248 243 1364 560
Point Detectors 1 m 383E-03 00217 155E-03 00204 285E-04 00248 247 1347 546 2 m 172E-03 00197 689E-04 00186 124E-04 00225 249 1391 558
Source Attachment II MCNP-Results2xls worksheet Summary
Tables 16 17 and 18 ar e results of calculation set 2 for conceptual Cask A with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
40
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
63 MCNP SPECIFIC INPUT
631 Source Probability
A linear radial distribution is used for all gamma and neutron sources The linear radial distribution is sam pled usi ng the built-in power function p(x) = xc a with a = 1 for the radial direction This sampling method results in a uniform source distribution over the area bounded by the outer radius of the source
The source axial distributions are unifor m for all four source regions The a xial uni form xp(x) = c distribution is sampled using the built-in power function a with a = 0 for extent
The energy distribu tions of the gamma and neutron sour ce term s are treated as energ y probabilities and are applied in MCNP5 using SISP cards
632 Dose Rate and Flux Tallies
MCNP5 dose rate calculations feature separate runs for the following calculation types
bull a photon transport calculation for prim ary ga mma contribution to the dose rates fr om photon fluxes
bull a coupled neutronphoton transport calculat ion for neutrons a nd secondary gamma (photons generated by neutron be ing captured) contributions to dose rates from neutron and gamma fluxes
The tally type F2 is us ed in th is d esign ca lculation as f lux estim ators The type F2 tally evaluates the flux averaged over a surface in particlescm2s
To generate dose ra tes in te rms of remhr the FM (tally multiplier ) and DEDF (dose energydose conversion factors) cards are used to en ter the tally multiplier f actor (source intensity in particless) energy boundaries in MeV and corresponding dose conversion factors in (remhr)(particlescm2s) respectively These factors were used in the input files
In order for the F2 tally to accum ulate flux ov er a surface a specific s urface area is requ ired The SD cards are used to enter a surface area in cm2 over which the flux will be tallied for an F2 tally
633 Variance Reduction Techniques
Variance reduction technique is usually em ployed in order to increase the efficiency of a calculation and obtain statistically m eaningful results within re asonable com puter tim e In Monte Carlo calculations when variance reduction scheme is employed the weights of particles are adjusted in order to account for the biasing and to preserve a fair game
Geometry splitting and Russian roulette techniques described in Reference 2224 (pp 2-140 ndash 2-142) are useful in shielding calculations and therefore deployed in all the MCNP5 runs
35
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
As particles migrate in an important direction (toward the detector) they are increased in number to provide better sampling by means of geometry splitting across geometric boundaries Russian roulette (the reverse process) is played when particles travel in an unimportant direction to allow termination of unim portant histories The IMP card required for every cel l ca rd is us ed to implement this technique
The other variance reduction technique deployed in the MC NP5 runs is source intensity biasing for the gamma sources from the four source regions (active fuel bottom end-fitting plenum and top end-fitting) The natural total gamma source intensity of comm ercial SNF is dom inated by the gamma source in the active fuel region This active fuel gamma source usually accounts for over 95 o f the total g amma source intens ity In order to im prove the efficiency of the axial dose rate calculations a biased source probability distribution is employed for the prim ary gamma dose rate calculations The biased gamma source probability distribution is chosen to be 005 080 010 and 005 for the bottom end-fitting the active fuel the plenum and the top end-fitting regions respectively
64 DOSE CONVERSION FACTORS
Project Design Criteria Document (Reference 2211 Se ction 41015) requires the use of flux-to-dose rate conversion fact ors from ANSIANS-611-1977 (Reference 221) for dose rate evaluations Table 16 lists the neutron and ga mma dose conversion factors used in the MCNP5 calculations
Table 12 Gamma and Neutron Flux to Dose Conversion Factors
Gamma Neutron Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
001 396E-06 140 251E-06 250E-08 367E-06 003 582E-07 180 299E-06 100E-07 367E-06 005 290E-07 220 342E-06 100E-06 446E-06 007 258E-07 260 382E-06 100E-05 454E-06 010 283E-07 280 401E-06 100E-04 418E-06 015 379E-07 325 441E-06 100E-03 376E-06 020 501E-07 375 483E-06 100E-02 356E-06 025 631E-07 425 523E-06 100E-01 217E-05 030 759E-07 475 560E-06 500E-01 926E-05 035 878E-07 500 580E-06 100E+00 132E-04 040 985E-07 525 601E-06 250E+00 125E-04 045 108E-06 575 637E-06 500E+00 156E-04 050 117E-06 625 674E-06 700E+00 147E-04 055 127E-06 675 711E-06 100E+01 147E-04 060 136E-06 750 766E-06 140E+01 208E-04 065 144E-06 900 877E-06 200E+01 227E-04 070 152E-06 1100 103E-05 080 168E-06 1300 118E-05 100 198E-06 1500 133E-05
Source Reference 221 Tables 1 and 3
36
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION
By def inition (Ref erence 2224 Equation 219) the estimated st atistic relative error of the i component is
Ri = Si
2
Equation 6Ti
where i = tally component index Ri = relative error of the i component S2
i = variance of the i component Ti = tally i component
For a result (ie dose rate) computed as a sum of different tallies the statistical relative error of the computed value is o btained from the variance of the result - S2
total which is th e sum of the estimated variances of the individual tallies S2
i n
2 2STotal = sum Si Equation 7 i=1
where S2Total = total estimated variance
n = total number of components Therefore the total tally value (dose rate) and the associated relative error are derived according to Equations 8 and 9
n TTotal = sumTi Equation 8
i=1
n n
sum (Ri timesTi )2
2 sum Si 2
STotal = i=1 = i=1 Equation 9RTotal = TTotal TTotal TTotal
where RTotal = total estimated relative error TTotal = total estimated tally
Equations 8 and 9 are utilized in Attachm ent II to ev aluate to tal dos e ra tes and their r elative errors
37
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
7 RESULTS AND CONCLUSIONS
71 RESULTS
The following sections summarize the results of this calculation Section 711 presents results for Conceptual Cask A while Section 712 for Conceptual Cask B Section 713 provides comparisons of the dose-rate reduction factors du e to the two conceptual casks and the axial source distributions in the active fuel region Do se rates and relative errors can be found in Attachment II within the output files and Excel files
711 Dose Rates of Conceptual Cask A
This section presents dose-rate results of the calculation sets 1 and 2 as described in Section 61 for Cask A Set 1 has axial p rofile sources in the active fuel region a nd consist of six runs resulting from the three PWR SNF source term s (maximum design basis and average) and the two radiation sources (gammas and neutrons) Set 2 has uniform axial sources in the active fuel region and consists of six run s r esulting f rom the th ree P WR SNF source term s and th e tw o radiation sources
As described in Section 61 dose ra tes are calculated at the three exterior surfaces (radial top and bottom) and at distances 1 m and 2 m from the exterior surfaces The total dose rates for set 1 are presented in Tables 13 14 and 15 for the ra dial top and bottom dire ctions respectively However the com ponents (primary gamma neutr on and secondary gamma) contributing to the total dose rates as well as the re lative error calculations can be found in Attachment II Excel file MCNP-Results1xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 2 are shown in Tables 16 17 and 18 The dose-rate components and the relative errors can be found in A ttachment II Excel file MCNP-Results2xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 13 and 16 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 14 and 17 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 15 and 18 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carrying th e maximum PWR SNF Based on the results in Tables 13 through 18 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask A indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these 6 tables the d ose-rate red uction f actors between the m aximum and the design basis fuels the maxim um and the averag e fuels and th e design basis and the average fuels are a lso presented
38
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 320E-02 00237 116E-02 00222 262E-03 00219 275 1223 445
1 m 133E-02 00164 494E-03 00171 106E-03 00162 269 1261 468 2 m 749E-03 00198 285E-03 00225 584E-04 00162 263 1282 488
Ring Detectors 1 m 133E-02 00116 492E-03 00115 108E-03 00124 271 1229 454 2 m 756E-03 00118 279E-03 00110 605E-04 00128 271 1250 462
Source Attachment II MCNP-Results1xls worksheet Summary
Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 142E-02 00368 628E-03 00446 934E-04 00483 226 1520 672
1 m 570E-03 00289 263E-03 00426 375E-04 00381 217 1520 701 2 m 265E-03 00364 123E-03 00547 169E-04 00374 216 1575 730
Point Detectors 1 m 598E-03 00238 274E-03 00271 402E-04 00354 219 1489 681 2 m 273E-03 00218 123E-03 00245 180E-04 00336 221 1515 684
Source Attachment II MCNP-Results1xls worksheet Summary
Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 653E-03 00298 265E-03 00276 510E-04 00341 247 1278 518
1 m 276E-03 00238 112E-03 00208 207E-04 00249 248 1334 539 2 m 125E-03 00185 508E-04 00199 933E-05 00246 246 1336 544
Point Detectors 1 m 291E-03 00227 118E-03 00203 218E-04 00242 247 1335 540 2 m 130E-03 00209 524E-04 00187 955E-05 00233 247 1357 549
Source Attachment II MCNP-Results1xls worksheet Summary
Tables 13 14 and 15 are results of calculation set 1 for conceptual Cask A with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
39
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 265E-02 00247 990E-03 00222 215E-03 00278 268 1234 461
1 m 116E-02 00178 468E-03 00549 960E-04 00189 248 1208 488 2 m 713E-03 00273 265E-03 00161 602E-04 00360 269 1184 439
Ring Detectors 1 m 117E-02 00120 454E-03 00132 979E-04 00141 259 1199 463 2 m 722E-03 00130 276E-03 00141 589E-04 00153 261 1226 469
Source Attachment II MCNP-Results2xls worksheet Summary
Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 199E-02 00461 827E-03 00455 147E-03 00536 241 1359 564
1 m 849E-03 00564 323E-03 00314 563E-04 00418 263 1507 574 2 m 415E-03 00832 158E-03 00603 253E-04 00501 263 1641 623
Point Detectors 1 m 877E-03 00348 353E-03 00275 615E-04 00391 248 1426 574 2 m 393E-03 00341 160E-03 00278 270E-04 00378 246 1454 590
Source Attachment II MCNP-Results2xls worksheet Summary
Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 879E-03 00374 356E-03 00333 669E-04 00406 247 1315 533
1 m 365E-03 00223 147E-03 00209 269E-04 00253 248 1358 548 2 m 164E-03 00229 674E-04 00205 120E-04 00248 243 1364 560
Point Detectors 1 m 383E-03 00217 155E-03 00204 285E-04 00248 247 1347 546 2 m 172E-03 00197 689E-04 00186 124E-04 00225 249 1391 558
Source Attachment II MCNP-Results2xls worksheet Summary
Tables 16 17 and 18 ar e results of calculation set 2 for conceptual Cask A with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
40
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
As particles migrate in an important direction (toward the detector) they are increased in number to provide better sampling by means of geometry splitting across geometric boundaries Russian roulette (the reverse process) is played when particles travel in an unimportant direction to allow termination of unim portant histories The IMP card required for every cel l ca rd is us ed to implement this technique
The other variance reduction technique deployed in the MC NP5 runs is source intensity biasing for the gamma sources from the four source regions (active fuel bottom end-fitting plenum and top end-fitting) The natural total gamma source intensity of comm ercial SNF is dom inated by the gamma source in the active fuel region This active fuel gamma source usually accounts for over 95 o f the total g amma source intens ity In order to im prove the efficiency of the axial dose rate calculations a biased source probability distribution is employed for the prim ary gamma dose rate calculations The biased gamma source probability distribution is chosen to be 005 080 010 and 005 for the bottom end-fitting the active fuel the plenum and the top end-fitting regions respectively
64 DOSE CONVERSION FACTORS
Project Design Criteria Document (Reference 2211 Se ction 41015) requires the use of flux-to-dose rate conversion fact ors from ANSIANS-611-1977 (Reference 221) for dose rate evaluations Table 16 lists the neutron and ga mma dose conversion factors used in the MCNP5 calculations
Table 12 Gamma and Neutron Flux to Dose Conversion Factors
Gamma Neutron Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
Energy (MeV)
Conversion Factors (remhr)(photoncm2s)
001 396E-06 140 251E-06 250E-08 367E-06 003 582E-07 180 299E-06 100E-07 367E-06 005 290E-07 220 342E-06 100E-06 446E-06 007 258E-07 260 382E-06 100E-05 454E-06 010 283E-07 280 401E-06 100E-04 418E-06 015 379E-07 325 441E-06 100E-03 376E-06 020 501E-07 375 483E-06 100E-02 356E-06 025 631E-07 425 523E-06 100E-01 217E-05 030 759E-07 475 560E-06 500E-01 926E-05 035 878E-07 500 580E-06 100E+00 132E-04 040 985E-07 525 601E-06 250E+00 125E-04 045 108E-06 575 637E-06 500E+00 156E-04 050 117E-06 625 674E-06 700E+00 147E-04 055 127E-06 675 711E-06 100E+01 147E-04 060 136E-06 750 766E-06 140E+01 208E-04 065 144E-06 900 877E-06 200E+01 227E-04 070 152E-06 1100 103E-05 080 168E-06 1300 118E-05 100 198E-06 1500 133E-05
Source Reference 221 Tables 1 and 3
36
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION
By def inition (Ref erence 2224 Equation 219) the estimated st atistic relative error of the i component is
Ri = Si
2
Equation 6Ti
where i = tally component index Ri = relative error of the i component S2
i = variance of the i component Ti = tally i component
For a result (ie dose rate) computed as a sum of different tallies the statistical relative error of the computed value is o btained from the variance of the result - S2
total which is th e sum of the estimated variances of the individual tallies S2
i n
2 2STotal = sum Si Equation 7 i=1
where S2Total = total estimated variance
n = total number of components Therefore the total tally value (dose rate) and the associated relative error are derived according to Equations 8 and 9
n TTotal = sumTi Equation 8
i=1
n n
sum (Ri timesTi )2
2 sum Si 2
STotal = i=1 = i=1 Equation 9RTotal = TTotal TTotal TTotal
where RTotal = total estimated relative error TTotal = total estimated tally
Equations 8 and 9 are utilized in Attachm ent II to ev aluate to tal dos e ra tes and their r elative errors
37
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
7 RESULTS AND CONCLUSIONS
71 RESULTS
The following sections summarize the results of this calculation Section 711 presents results for Conceptual Cask A while Section 712 for Conceptual Cask B Section 713 provides comparisons of the dose-rate reduction factors du e to the two conceptual casks and the axial source distributions in the active fuel region Do se rates and relative errors can be found in Attachment II within the output files and Excel files
711 Dose Rates of Conceptual Cask A
This section presents dose-rate results of the calculation sets 1 and 2 as described in Section 61 for Cask A Set 1 has axial p rofile sources in the active fuel region a nd consist of six runs resulting from the three PWR SNF source term s (maximum design basis and average) and the two radiation sources (gammas and neutrons) Set 2 has uniform axial sources in the active fuel region and consists of six run s r esulting f rom the th ree P WR SNF source term s and th e tw o radiation sources
As described in Section 61 dose ra tes are calculated at the three exterior surfaces (radial top and bottom) and at distances 1 m and 2 m from the exterior surfaces The total dose rates for set 1 are presented in Tables 13 14 and 15 for the ra dial top and bottom dire ctions respectively However the com ponents (primary gamma neutr on and secondary gamma) contributing to the total dose rates as well as the re lative error calculations can be found in Attachment II Excel file MCNP-Results1xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 2 are shown in Tables 16 17 and 18 The dose-rate components and the relative errors can be found in A ttachment II Excel file MCNP-Results2xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 13 and 16 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 14 and 17 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 15 and 18 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carrying th e maximum PWR SNF Based on the results in Tables 13 through 18 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask A indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these 6 tables the d ose-rate red uction f actors between the m aximum and the design basis fuels the maxim um and the averag e fuels and th e design basis and the average fuels are a lso presented
38
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 320E-02 00237 116E-02 00222 262E-03 00219 275 1223 445
1 m 133E-02 00164 494E-03 00171 106E-03 00162 269 1261 468 2 m 749E-03 00198 285E-03 00225 584E-04 00162 263 1282 488
Ring Detectors 1 m 133E-02 00116 492E-03 00115 108E-03 00124 271 1229 454 2 m 756E-03 00118 279E-03 00110 605E-04 00128 271 1250 462
Source Attachment II MCNP-Results1xls worksheet Summary
Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 142E-02 00368 628E-03 00446 934E-04 00483 226 1520 672
1 m 570E-03 00289 263E-03 00426 375E-04 00381 217 1520 701 2 m 265E-03 00364 123E-03 00547 169E-04 00374 216 1575 730
Point Detectors 1 m 598E-03 00238 274E-03 00271 402E-04 00354 219 1489 681 2 m 273E-03 00218 123E-03 00245 180E-04 00336 221 1515 684
Source Attachment II MCNP-Results1xls worksheet Summary
Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 653E-03 00298 265E-03 00276 510E-04 00341 247 1278 518
1 m 276E-03 00238 112E-03 00208 207E-04 00249 248 1334 539 2 m 125E-03 00185 508E-04 00199 933E-05 00246 246 1336 544
Point Detectors 1 m 291E-03 00227 118E-03 00203 218E-04 00242 247 1335 540 2 m 130E-03 00209 524E-04 00187 955E-05 00233 247 1357 549
Source Attachment II MCNP-Results1xls worksheet Summary
Tables 13 14 and 15 are results of calculation set 1 for conceptual Cask A with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
39
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 265E-02 00247 990E-03 00222 215E-03 00278 268 1234 461
1 m 116E-02 00178 468E-03 00549 960E-04 00189 248 1208 488 2 m 713E-03 00273 265E-03 00161 602E-04 00360 269 1184 439
Ring Detectors 1 m 117E-02 00120 454E-03 00132 979E-04 00141 259 1199 463 2 m 722E-03 00130 276E-03 00141 589E-04 00153 261 1226 469
Source Attachment II MCNP-Results2xls worksheet Summary
Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 199E-02 00461 827E-03 00455 147E-03 00536 241 1359 564
1 m 849E-03 00564 323E-03 00314 563E-04 00418 263 1507 574 2 m 415E-03 00832 158E-03 00603 253E-04 00501 263 1641 623
Point Detectors 1 m 877E-03 00348 353E-03 00275 615E-04 00391 248 1426 574 2 m 393E-03 00341 160E-03 00278 270E-04 00378 246 1454 590
Source Attachment II MCNP-Results2xls worksheet Summary
Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 879E-03 00374 356E-03 00333 669E-04 00406 247 1315 533
1 m 365E-03 00223 147E-03 00209 269E-04 00253 248 1358 548 2 m 164E-03 00229 674E-04 00205 120E-04 00248 243 1364 560
Point Detectors 1 m 383E-03 00217 155E-03 00204 285E-04 00248 247 1347 546 2 m 172E-03 00197 689E-04 00186 124E-04 00225 249 1391 558
Source Attachment II MCNP-Results2xls worksheet Summary
Tables 16 17 and 18 ar e results of calculation set 2 for conceptual Cask A with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
40
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
65 RELATIVE ERROR CALCULATION
By def inition (Ref erence 2224 Equation 219) the estimated st atistic relative error of the i component is
Ri = Si
2
Equation 6Ti
where i = tally component index Ri = relative error of the i component S2
i = variance of the i component Ti = tally i component
For a result (ie dose rate) computed as a sum of different tallies the statistical relative error of the computed value is o btained from the variance of the result - S2
total which is th e sum of the estimated variances of the individual tallies S2
i n
2 2STotal = sum Si Equation 7 i=1
where S2Total = total estimated variance
n = total number of components Therefore the total tally value (dose rate) and the associated relative error are derived according to Equations 8 and 9
n TTotal = sumTi Equation 8
i=1
n n
sum (Ri timesTi )2
2 sum Si 2
STotal = i=1 = i=1 Equation 9RTotal = TTotal TTotal TTotal
where RTotal = total estimated relative error TTotal = total estimated tally
Equations 8 and 9 are utilized in Attachm ent II to ev aluate to tal dos e ra tes and their r elative errors
37
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
7 RESULTS AND CONCLUSIONS
71 RESULTS
The following sections summarize the results of this calculation Section 711 presents results for Conceptual Cask A while Section 712 for Conceptual Cask B Section 713 provides comparisons of the dose-rate reduction factors du e to the two conceptual casks and the axial source distributions in the active fuel region Do se rates and relative errors can be found in Attachment II within the output files and Excel files
711 Dose Rates of Conceptual Cask A
This section presents dose-rate results of the calculation sets 1 and 2 as described in Section 61 for Cask A Set 1 has axial p rofile sources in the active fuel region a nd consist of six runs resulting from the three PWR SNF source term s (maximum design basis and average) and the two radiation sources (gammas and neutrons) Set 2 has uniform axial sources in the active fuel region and consists of six run s r esulting f rom the th ree P WR SNF source term s and th e tw o radiation sources
As described in Section 61 dose ra tes are calculated at the three exterior surfaces (radial top and bottom) and at distances 1 m and 2 m from the exterior surfaces The total dose rates for set 1 are presented in Tables 13 14 and 15 for the ra dial top and bottom dire ctions respectively However the com ponents (primary gamma neutr on and secondary gamma) contributing to the total dose rates as well as the re lative error calculations can be found in Attachment II Excel file MCNP-Results1xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 2 are shown in Tables 16 17 and 18 The dose-rate components and the relative errors can be found in A ttachment II Excel file MCNP-Results2xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 13 and 16 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 14 and 17 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 15 and 18 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carrying th e maximum PWR SNF Based on the results in Tables 13 through 18 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask A indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these 6 tables the d ose-rate red uction f actors between the m aximum and the design basis fuels the maxim um and the averag e fuels and th e design basis and the average fuels are a lso presented
38
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 320E-02 00237 116E-02 00222 262E-03 00219 275 1223 445
1 m 133E-02 00164 494E-03 00171 106E-03 00162 269 1261 468 2 m 749E-03 00198 285E-03 00225 584E-04 00162 263 1282 488
Ring Detectors 1 m 133E-02 00116 492E-03 00115 108E-03 00124 271 1229 454 2 m 756E-03 00118 279E-03 00110 605E-04 00128 271 1250 462
Source Attachment II MCNP-Results1xls worksheet Summary
Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 142E-02 00368 628E-03 00446 934E-04 00483 226 1520 672
1 m 570E-03 00289 263E-03 00426 375E-04 00381 217 1520 701 2 m 265E-03 00364 123E-03 00547 169E-04 00374 216 1575 730
Point Detectors 1 m 598E-03 00238 274E-03 00271 402E-04 00354 219 1489 681 2 m 273E-03 00218 123E-03 00245 180E-04 00336 221 1515 684
Source Attachment II MCNP-Results1xls worksheet Summary
Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 653E-03 00298 265E-03 00276 510E-04 00341 247 1278 518
1 m 276E-03 00238 112E-03 00208 207E-04 00249 248 1334 539 2 m 125E-03 00185 508E-04 00199 933E-05 00246 246 1336 544
Point Detectors 1 m 291E-03 00227 118E-03 00203 218E-04 00242 247 1335 540 2 m 130E-03 00209 524E-04 00187 955E-05 00233 247 1357 549
Source Attachment II MCNP-Results1xls worksheet Summary
Tables 13 14 and 15 are results of calculation set 1 for conceptual Cask A with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
39
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 265E-02 00247 990E-03 00222 215E-03 00278 268 1234 461
1 m 116E-02 00178 468E-03 00549 960E-04 00189 248 1208 488 2 m 713E-03 00273 265E-03 00161 602E-04 00360 269 1184 439
Ring Detectors 1 m 117E-02 00120 454E-03 00132 979E-04 00141 259 1199 463 2 m 722E-03 00130 276E-03 00141 589E-04 00153 261 1226 469
Source Attachment II MCNP-Results2xls worksheet Summary
Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 199E-02 00461 827E-03 00455 147E-03 00536 241 1359 564
1 m 849E-03 00564 323E-03 00314 563E-04 00418 263 1507 574 2 m 415E-03 00832 158E-03 00603 253E-04 00501 263 1641 623
Point Detectors 1 m 877E-03 00348 353E-03 00275 615E-04 00391 248 1426 574 2 m 393E-03 00341 160E-03 00278 270E-04 00378 246 1454 590
Source Attachment II MCNP-Results2xls worksheet Summary
Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 879E-03 00374 356E-03 00333 669E-04 00406 247 1315 533
1 m 365E-03 00223 147E-03 00209 269E-04 00253 248 1358 548 2 m 164E-03 00229 674E-04 00205 120E-04 00248 243 1364 560
Point Detectors 1 m 383E-03 00217 155E-03 00204 285E-04 00248 247 1347 546 2 m 172E-03 00197 689E-04 00186 124E-04 00225 249 1391 558
Source Attachment II MCNP-Results2xls worksheet Summary
Tables 16 17 and 18 ar e results of calculation set 2 for conceptual Cask A with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
40
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
7 RESULTS AND CONCLUSIONS
71 RESULTS
The following sections summarize the results of this calculation Section 711 presents results for Conceptual Cask A while Section 712 for Conceptual Cask B Section 713 provides comparisons of the dose-rate reduction factors du e to the two conceptual casks and the axial source distributions in the active fuel region Do se rates and relative errors can be found in Attachment II within the output files and Excel files
711 Dose Rates of Conceptual Cask A
This section presents dose-rate results of the calculation sets 1 and 2 as described in Section 61 for Cask A Set 1 has axial p rofile sources in the active fuel region a nd consist of six runs resulting from the three PWR SNF source term s (maximum design basis and average) and the two radiation sources (gammas and neutrons) Set 2 has uniform axial sources in the active fuel region and consists of six run s r esulting f rom the th ree P WR SNF source term s and th e tw o radiation sources
As described in Section 61 dose ra tes are calculated at the three exterior surfaces (radial top and bottom) and at distances 1 m and 2 m from the exterior surfaces The total dose rates for set 1 are presented in Tables 13 14 and 15 for the ra dial top and bottom dire ctions respectively However the com ponents (primary gamma neutr on and secondary gamma) contributing to the total dose rates as well as the re lative error calculations can be found in Attachment II Excel file MCNP-Results1xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 2 are shown in Tables 16 17 and 18 The dose-rate components and the relative errors can be found in A ttachment II Excel file MCNP-Results2xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 13 and 16 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 14 and 17 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 15 and 18 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carrying th e maximum PWR SNF Based on the results in Tables 13 through 18 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask A indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these 6 tables the d ose-rate red uction f actors between the m aximum and the design basis fuels the maxim um and the averag e fuels and th e design basis and the average fuels are a lso presented
38
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 320E-02 00237 116E-02 00222 262E-03 00219 275 1223 445
1 m 133E-02 00164 494E-03 00171 106E-03 00162 269 1261 468 2 m 749E-03 00198 285E-03 00225 584E-04 00162 263 1282 488
Ring Detectors 1 m 133E-02 00116 492E-03 00115 108E-03 00124 271 1229 454 2 m 756E-03 00118 279E-03 00110 605E-04 00128 271 1250 462
Source Attachment II MCNP-Results1xls worksheet Summary
Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 142E-02 00368 628E-03 00446 934E-04 00483 226 1520 672
1 m 570E-03 00289 263E-03 00426 375E-04 00381 217 1520 701 2 m 265E-03 00364 123E-03 00547 169E-04 00374 216 1575 730
Point Detectors 1 m 598E-03 00238 274E-03 00271 402E-04 00354 219 1489 681 2 m 273E-03 00218 123E-03 00245 180E-04 00336 221 1515 684
Source Attachment II MCNP-Results1xls worksheet Summary
Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 653E-03 00298 265E-03 00276 510E-04 00341 247 1278 518
1 m 276E-03 00238 112E-03 00208 207E-04 00249 248 1334 539 2 m 125E-03 00185 508E-04 00199 933E-05 00246 246 1336 544
Point Detectors 1 m 291E-03 00227 118E-03 00203 218E-04 00242 247 1335 540 2 m 130E-03 00209 524E-04 00187 955E-05 00233 247 1357 549
Source Attachment II MCNP-Results1xls worksheet Summary
Tables 13 14 and 15 are results of calculation set 1 for conceptual Cask A with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
39
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 265E-02 00247 990E-03 00222 215E-03 00278 268 1234 461
1 m 116E-02 00178 468E-03 00549 960E-04 00189 248 1208 488 2 m 713E-03 00273 265E-03 00161 602E-04 00360 269 1184 439
Ring Detectors 1 m 117E-02 00120 454E-03 00132 979E-04 00141 259 1199 463 2 m 722E-03 00130 276E-03 00141 589E-04 00153 261 1226 469
Source Attachment II MCNP-Results2xls worksheet Summary
Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 199E-02 00461 827E-03 00455 147E-03 00536 241 1359 564
1 m 849E-03 00564 323E-03 00314 563E-04 00418 263 1507 574 2 m 415E-03 00832 158E-03 00603 253E-04 00501 263 1641 623
Point Detectors 1 m 877E-03 00348 353E-03 00275 615E-04 00391 248 1426 574 2 m 393E-03 00341 160E-03 00278 270E-04 00378 246 1454 590
Source Attachment II MCNP-Results2xls worksheet Summary
Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 879E-03 00374 356E-03 00333 669E-04 00406 247 1315 533
1 m 365E-03 00223 147E-03 00209 269E-04 00253 248 1358 548 2 m 164E-03 00229 674E-04 00205 120E-04 00248 243 1364 560
Point Detectors 1 m 383E-03 00217 155E-03 00204 285E-04 00248 247 1347 546 2 m 172E-03 00197 689E-04 00186 124E-04 00225 249 1391 558
Source Attachment II MCNP-Results2xls worksheet Summary
Tables 16 17 and 18 ar e results of calculation set 2 for conceptual Cask A with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
40
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 13 Radial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 320E-02 00237 116E-02 00222 262E-03 00219 275 1223 445
1 m 133E-02 00164 494E-03 00171 106E-03 00162 269 1261 468 2 m 749E-03 00198 285E-03 00225 584E-04 00162 263 1282 488
Ring Detectors 1 m 133E-02 00116 492E-03 00115 108E-03 00124 271 1229 454 2 m 756E-03 00118 279E-03 00110 605E-04 00128 271 1250 462
Source Attachment II MCNP-Results1xls worksheet Summary
Table 14 Top Axial Dose Rates from Conceptual Cask A Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 142E-02 00368 628E-03 00446 934E-04 00483 226 1520 672
1 m 570E-03 00289 263E-03 00426 375E-04 00381 217 1520 701 2 m 265E-03 00364 123E-03 00547 169E-04 00374 216 1575 730
Point Detectors 1 m 598E-03 00238 274E-03 00271 402E-04 00354 219 1489 681 2 m 273E-03 00218 123E-03 00245 180E-04 00336 221 1515 684
Source Attachment II MCNP-Results1xls worksheet Summary
Table 15 Bottom Axial Dose Rates from Conceptual Cask A Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 653E-03 00298 265E-03 00276 510E-04 00341 247 1278 518
1 m 276E-03 00238 112E-03 00208 207E-04 00249 248 1334 539 2 m 125E-03 00185 508E-04 00199 933E-05 00246 246 1336 544
Point Detectors 1 m 291E-03 00227 118E-03 00203 218E-04 00242 247 1335 540 2 m 130E-03 00209 524E-04 00187 955E-05 00233 247 1357 549
Source Attachment II MCNP-Results1xls worksheet Summary
Tables 13 14 and 15 are results of calculation set 1 for conceptual Cask A with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
39
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 265E-02 00247 990E-03 00222 215E-03 00278 268 1234 461
1 m 116E-02 00178 468E-03 00549 960E-04 00189 248 1208 488 2 m 713E-03 00273 265E-03 00161 602E-04 00360 269 1184 439
Ring Detectors 1 m 117E-02 00120 454E-03 00132 979E-04 00141 259 1199 463 2 m 722E-03 00130 276E-03 00141 589E-04 00153 261 1226 469
Source Attachment II MCNP-Results2xls worksheet Summary
Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 199E-02 00461 827E-03 00455 147E-03 00536 241 1359 564
1 m 849E-03 00564 323E-03 00314 563E-04 00418 263 1507 574 2 m 415E-03 00832 158E-03 00603 253E-04 00501 263 1641 623
Point Detectors 1 m 877E-03 00348 353E-03 00275 615E-04 00391 248 1426 574 2 m 393E-03 00341 160E-03 00278 270E-04 00378 246 1454 590
Source Attachment II MCNP-Results2xls worksheet Summary
Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 879E-03 00374 356E-03 00333 669E-04 00406 247 1315 533
1 m 365E-03 00223 147E-03 00209 269E-04 00253 248 1358 548 2 m 164E-03 00229 674E-04 00205 120E-04 00248 243 1364 560
Point Detectors 1 m 383E-03 00217 155E-03 00204 285E-04 00248 247 1347 546 2 m 172E-03 00197 689E-04 00186 124E-04 00225 249 1391 558
Source Attachment II MCNP-Results2xls worksheet Summary
Tables 16 17 and 18 ar e results of calculation set 2 for conceptual Cask A with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
40
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 16 Radial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 265E-02 00247 990E-03 00222 215E-03 00278 268 1234 461
1 m 116E-02 00178 468E-03 00549 960E-04 00189 248 1208 488 2 m 713E-03 00273 265E-03 00161 602E-04 00360 269 1184 439
Ring Detectors 1 m 117E-02 00120 454E-03 00132 979E-04 00141 259 1199 463 2 m 722E-03 00130 276E-03 00141 589E-04 00153 261 1226 469
Source Attachment II MCNP-Results2xls worksheet Summary
Table 17 Top Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 199E-02 00461 827E-03 00455 147E-03 00536 241 1359 564
1 m 849E-03 00564 323E-03 00314 563E-04 00418 263 1507 574 2 m 415E-03 00832 158E-03 00603 253E-04 00501 263 1641 623
Point Detectors 1 m 877E-03 00348 353E-03 00275 615E-04 00391 248 1426 574 2 m 393E-03 00341 160E-03 00278 270E-04 00378 246 1454 590
Source Attachment II MCNP-Results2xls worksheet Summary
Table 18 Bottom Axial Dose Rates from Conceptual Cask A Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 879E-03 00374 356E-03 00333 669E-04 00406 247 1315 533
1 m 365E-03 00223 147E-03 00209 269E-04 00253 248 1358 548 2 m 164E-03 00229 674E-04 00205 120E-04 00248 243 1364 560
Point Detectors 1 m 383E-03 00217 155E-03 00204 285E-04 00248 247 1347 546 2 m 172E-03 00197 689E-04 00186 124E-04 00225 249 1391 558
Source Attachment II MCNP-Results2xls worksheet Summary
Tables 16 17 and 18 ar e results of calculation set 2 for conceptual Cask A with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask A
40
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
712 Dose Rates of Conceptual Cask B
This section presents dose-rate results of the calculation sets 3 and 4 for conceptual Cask B Set 3 has axia l prof ile sou rces in the a ctive fuel region and consist of six r uns resu lting f rom the three PW R SNF source term s ( maximum des ign ba sis and average) and the two radiatio n sources (gammas and neutrons) Set 4 has unifor m axial s ources in th e active fuel region and consists of six runs resulting from the thr ee PWR SNF source terms and the two radiation sources
Similar to c onceptual C ask A dose rates are c alculated at the three exterior surfaces and at distances 1 m and 2 m from the exterior su rfaces The total dose rates for set 3 are presented in Tables 19 20 and 21 for the radial top and bo ttom directions respectively However the components (primary gamma neutron and secondary gamma) contributing to the total dose rates as well as the relative erro r calculations can be found in Attachm ent II Excel file MCNPshyResults3xls worksheets Maximum DesignBasis and Average Similarly the total dose rates for set 4 are shown in Tables 22 23 and 24 The dose-rate components and the relative errors can be found in Attachm ent II Excel file MCNP-Results4xls worksheets Maximum DesignBasis and Average
The surface tallies in Tables 19 and 22 are the radial total dose rates for the middle segment (at Z between 175 and 205 c m in Figure 1) at contact 1 m and 2 m from the radial surface The surface tallies in Tab les 20 and 23 are th e top axial dose rates for the cen tral segment within a 40-cm radius at contact and 1 m and 2 m from the top surface Similarly the surf ace tallies in Tables 21 and 24 are the bottom axial dose rates within a 40-cm radius
This cask is expected to m eet exterior radiation standards of 10 CF R 7147(b) (Reference 231) when loaded with a TAD canister carry ing th e average P WR SNF Based on the results in Tables 19 through 24 it is clear that all cask surface contact dose rates are less than 200 mremhr and that all 2-m dose rates are less than 10 mremhr Therefore conceptual Cask B indeed meets the 10 CFR 7147(b) dosendashrate requirements
In these s ix tables th e dose-ra te reduction factors between th e maximum and the design basi s fuels the maxim um and the averag e fuels and th e design basis and the average fuels are also presented
41
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 19 Radial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 237E-01 00321 869E-02 00319 167E-02 00437 273 1424 522
1 m 104E-01 00228 372E-02 00224 759E-03 00339 279 1369 490 2 m 626E-02 00230 230E-02 00226 430E-03 00346 273 1455 534
Ring Detectors 1 m 105E-01 00103 379E-02 00102 717E-03 00148 277 1466 529 2 m 640E-02 00086 230E-02 00082 430E-03 00275 278 1488 535
Source Attachment II MCNP-Results3xls worksheet Summary
Table 20 Top Axial Dose Rates from Conceptual Cask B Axial Profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 341E-01 00276 135E-01 00267 307E-02 00281 251 1111 442
1 m 964E-02 00241 390E-02 00242 864E-03 00248 247 1116 451 2 m 371E-02 00272 155E-02 00279 334E-03 00299 240 1111 464
Point Detectors 1 m 101E-01 00225 405E-02 00219 910E-03 00229 251 1115 445 2 m 382E-02 00220 154E-02 00216 341E-03 00225 248 1120 451
Source Attachment II MCNP-Results3xls worksheet Summary
Table 21 Bottom Axial Dose Rates from Conceptual Cask B Axial profile Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 213E-01 00178 842E-02 00177 201E-02 00180 253 1059 419
1 m 703E-02 00132 279E-02 00132 666E-03 00136 252 1056 419 2 m 286E-02 00131 113E-02 00132 270E-03 00135 253 1059 419
Point Detectors 1 m 744E-02 00130 294E-02 00130 705E-03 00134 253 1056 417 2 m 295E-02 00126 117E-02 00125 279E-03 00130 252 1056 419
Source Attachment II MCNP-Results3xls worksheet Summary
Tables 19 20 and 21 are results of calculation set 3 for conceptu al Cask B with axial profile sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
42
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 22 Radial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 208E-01 00355 731E-02 00349 135E-02 00461 285 1538 540
1 m 944E-02 00235 336E-02 00240 628E-03 00316 281 1504 536 2 m 609E-02 00238 217E-02 00228 408E-03 00342 280 1494 533
Ring Detectors 1 m 970E-02 00119 345E-02 00179 643E-03 00182 281 1509 537 2 m 607E-02 00089 218E-02 00097 403E-03 00143 278 1506 542
Source Attachment II MCNP-Results4xls worksheet Summary
Table 23 Top Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 612E-01 00219 250E-01 00219 627E-02 00219 244 976 399
1 m 174E-01 00191 696E-02 00196 174E-02 00198 250 1002 401 2 m 665E-02 00214 271E-02 00233 665E-03 00216 245 1000 408
Point Detectors 1 m 182E-01 00174 734E-02 00181 182E-02 00179 248 999 402 2 m 687E-02 00172 273E-02 00173 681E-03 00178 251 1008 401
Source Attachment II MCNP-Results4xls worksheet Summary
Table 24 Bottom Axial Dose Rates from Conceptual Cask B Uniform Axial Sources
Maximum Fuel Design Basis Fuel Average Fuel Dose-Rate Reduction Factor Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error Dose Rate
(remhr) Relative
Error MaxDB MaxAve DBAve Surface Tallies Contact 310E-01 00156 124E-01 00156 290E-02 00155 251 1070 427
1 m 105E-01 00114 417E-02 00113 976E-03 00113 250 1071 428 2 m 427E-02 00116 171E-02 00115 400E-03 00113 249 1067 428
Point Detectors 1 m 111E-01 00112 441E-02 00112 104E-02 00113 251 1070 426 2 m 441E-02 00108 176E-02 00108 411E-03 00109 251 1073 428
Source Attachment II MCNP-Results4xls worksheet Summary
Tables 22 23 and 24 are results of calculation se t 4 for conceptual Cask B with uniform axial sources in the active fuel region The results in clude dose rates and dose-rate reduction factors between different PWR SNFs for the radial and axial directions of conceptual Cask B
43
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
713 Comparison of Dose-Rate Reduction Factors
This section examines the effects of the source axial distributions and the configurations of the conceptual casks on th e dose-rate reduction factors in the radial top and bottom directions outside the two conceptual casks The dose-rate reduction fact ors in Tables 13 through 24 are rearranged for clarity
Tables 25 and 26 com pare the dose -rate reduction factors in the ra dial direction for conceptu al Casks A and B with axial source profiles and w ith uniform axial sources respectively In these two tables the dose-rate reducti on factors from averaging Casks A and B are als o com puted Furthermore for each dose-rate reduction factor the average value f rom all five tallies are provided Similarly Tables 27 and 28 present the dose-rate reduction factors in the top direction and Tables 29 and 30 give the dose-rate reduction factors in the bottom direction
Starting with the radial direction in Tables 25 and 26 it is noted that the effect of the axial source distributions on the reduction factors is sm all but the effect of the conceptual cask co nfiguration is more pronounced For example the averag e dose-rate reduction fa ctors MaxDB MaxAve and DBAve for conceptual Cask A in Table 25 (bottom row) are 270 1249 and 463 respectively The same factors for conceptual Cask B in Tabl e 26 (bottom row) are 261 1210 and 464 Generally speaking these tw o sets of reduction factors are quite clos e On the other hand a comparison of the first set of factors fo r conceptual Cask A in Table 25 (270 1249 and 463) with the set for conceptual Cask B in Table 25 (276 1440 and 522) indicates that the difference between the two sets is larger Si milarly same conclusion can be reached between conceptual Casks A and B in Table 26
The small effect of the axial sour ce distributions to the reduction f actors can be attrib uted to the fact that the same axial distr ibutions whether uniform or axial pr ofiles are applied to all th ree PWR SNF source terms The influence of the axial distributions on the dose rates from different PWR SNF source term s is nearly lin ear and ther efore cancels out becaus e the reduction factors are th e ratio of dose rates from di fferent sou rce terms In contrast the configurations of the conceptual casks affect the dose rates from different PWR SNF source term s in a non-linear manner since radiation attenuation in the materials of the casks has a non-linear behavior either exponential or otherwise
Table 25 Radial Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 275 1223 445 273 1424 522 274 1323 483 1 m (Surface) 269 1261 468 279 1369 490 274 1315 479 2 m (Surface) 263 1282 488 273 1455 534 268 1368 511 1 m (Ring) 271 1229 454 277 1466 529 274 1347 492 2 m (Ring) 271 1250 462 278 1488 535 274 1369 498 Average 270 1249 463 276 1440 522 273 1345 493
Source Attachment II DR-Ratiosxls worksheet Radial
44
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 26 Radial Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 268 1234 461 285 1538 540 276 1386 500 1 m (Surface) 248 1208 488 281 1504 536 264 1356 512 2 m (Surface) 269 1184 439 280 1494 533 275 1339 486 1 m (Ring) 259 1199 463 281 1509 537 270 1354 500 2 m (Ring) 261 1226 469 278 1506 542 270 1366 505 Average 261 1210 464 281 1510 537 271 1360 501
Source Attachment II DR-Ratiosxls worksheet Radial
Table 27 Top Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 226 1520 672 251 1111 442 239 1315 557 1 m (Surface) 217 1520 701 247 1116 451 232 1318 576 2 m (Surface) 216 1575 730 240 1111 464 228 1343 597 1 m (Point) 219 1489 681 251 1115 445 235 1302 563 2 m (Point) 221 1515 684 248 1120 451 235 1318 568 Average 220 1524 694 247 1115 451 234 1319 572
Source Attachment II DR-Ratiosxls worksheet Top
Table 28 Top Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 241 1359 564 244 976 399 243 1167 482 1 m (Surface) 263 1507 574 250 1002 401 256 1255 487 2 m (Surface) 263 1641 623 245 1000 408 254 1320 515 1 m (Point) 248 1426 574 248 999 402 248 1213 488 2 m (Point) 246 1454 590 251 1008 401 249 1231 496 Average 252 1477 585 248 997 402 250 1237 494
Source Attachment II DR-Ratiosxls worksheet Top
Table 29 Bottom Dose-Rate Reduction Factors for Casks with Axial Profile Sources
Cask A (Set 1) Cask B (Set 3) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1278 518 253 1059 419 250 1169 469 1 m (Surface) 248 1334 539 252 1056 419 250 1195 479 2 m (Surface) 246 1336 544 253 1059 419 249 1198 481 1 m (Point) 247 1335 540 253 1056 417 250 1196 479 2 m (Point) 247 1357 549 252 1056 419 250 1207 484 Average 247 1328 538 253 1057 419 250 1193 478
Source Attachment II DR-Ratiosxls worksheet Bottom
45
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
Table 30 Bottom Dose-Rate Reduction Factors for Casks with Uniform Axial Sources
Cask A (Set 2) Cask B (Set 4) Average of Casks A amp B Tally Type MaxDB MaxAve DBAve MaxDB MaxAve DB Ave MaxDB MaxAve DBAve Contact (Surface) 247 1315 533 251 1070 427 249 1192 480 1 m (Surface) 248 1358 548 250 1071 428 249 1214 488 2 m (Surface) 243 1364 560 249 1067 428 246 1216 494 1 m (Point) 247 1347 546 251 1070 426 249 1208 486 2 m (Point) 249 1391 558 251 1073 428 250 1232 493 Average 247 1355 549 250 1070 427 249 1213 488
Source Attachment II DR-Ratiosxls worksheet Bottom
The recom mended average dos e-rate reduction f actors of Casks A an d B are su mmarized in Tables 31 32 and 33 for the radial top and bottom directions respectively
Table 31 Recommended Average Radial Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 27 135 49
Uniform Axial Sources 27 136 50
Table 32 Recommended Average Top Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 23 132 57
Uniform Axial Sources 25 124 49
Table 33 Recommended Average Bottom Dose-Rate Reduction Factors
MaxDB MaxAve DBAve Axial Profile Sources 25 119 48
Uniform Axial Sources 25 121 49
72 CONCLUSIONS
This calculation has been performed with the assumed configurations for a TAD canister and two conceptual transportation casks Cask A de signed to m eet the 10 CFR 7147( b) radiation standards with the m aximum CSNF PWR assemb lies and Cask B with the averag e CSNF PWR assemblies The dose rate reduction factors betw een different source term s with and without axial profiles have been com puted for the radi al top and bottom directions of the conceptual TAD transportation cas ks The av erage dos e-rate reduction factors f or the rad ial and ax ial directions of the conceptual casks are summ arized in Tables 31 32 and 33 Generally the average radial reduction factor between the m aximum and the design basis fuels is 27 The average top reduction factor between the m aximum and the design basi s fuels is 24 and the average bottom reduction factor between the maxim um and the design basis fuels is 25 The
46
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
average dos e-rate redu ction fact ors for other com binations of source term s are substantially higher and are shown in Tables 31 32 and 33
47
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask 000-00C-MGR0-05400-000-00A
ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
This attachment contains a description of electronic files for this calculation The electronic files are stored in a CD that is Attachment II of this calculation
In Table I-1 the Excel files MCNP-Resultsxls are summ aries of MCNP5 results w here ldquordquo is the calculation set num ber described in Section 61 The Excel file DR-Ratiosxls calculates the dose-rate ratios between different source terms The Excel file Geometryxls prepares an d calculates tally areas for MCNP5 input The Excel file PWR_fuel compxls calculates the atomic densities of m aterials for MCNP5 input Also the files in the folders max dsb and ave are MCNP5 input and outp ut files for runs with eith er neutron source or gamma source The files with an ldquoordquo at the end are the M CNP5 output f iles Again the nu mber in eac h f ile nam e corresponds to the calculation set number described in Section 61
Table I-1 Listing of Electronic Files on Compact Disc
Volume in drive D is DR-RECUCTIONFACT Volume Serial Number is AEA2-ACF5
Directory of DCD
11192008 0230 PM ltDIRgt 11202008 0345 PM ltDIRgt 11132008 0749 AM ltDIRgt ave 11192008 0230 PM 37376 DR-Ratiosxls 11132008 0751 AM ltDIRgt dsb 11132008 0429 PM 23552 Geometryxls 11192008 0345 PM ltDIRgt max 11142008 0824 AM 54272 MCNP-Results1xls 11172008 0521 PM 55808 MCNP-Results2xls 11142008 0831 AM 57344 MCNP-Results3xls 11172008 0532 PM 55296 MCNP-Results4xls 09282008 1118 AM 73728 PWR_fuel compxls
7 File(s) 357376 bytes 5 Dir(s) 0 bytes free
Directory of DCDmax
11192008 0345 PM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 1256 PM 20049 neut1 11012008 1007 AM 1373477 neut1o 09282008 1056 AM 19865 neut2 10012008 0558 AM 1352463 neut2o 11072008 0322 PM 18700 neut3
I- 1
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0218 AM 1360249 neut3o 11072008 0350 PM 18442 neut4 11102008 0220 AM 1366121 neut4o 10292008 1228 PM 15502 pgam1 10312008 1247 AM 1020042 pgam1o 09282008 1056 AM 15288 pgam2 09292008 0838 PM 994975 pgam2o 11072008 0322 PM 14247 pgam3 11082008 0457 PM 964365 pgam3o 11072008 0333 PM 13993 pgam4 11082008 0459 PM 953276 pgam4o
16 File(s) 9521054 bytes 2 Dir(s) 0 bytes free
Directory of DCDdsb
11132008 0751 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0310 PM 20082 neut1 11012008 1009 AM 1396700 neut1o 09282008 1056 AM 19897 neut2 10012008 0557 AM 1370656 neut2o 11072008 0344 PM 18736 neut3 11102008 0222 AM 1383127 neut3o 11072008 0353 PM 18476 neut4 11102008 0223 AM 1372810 neut4o 10292008 0318 PM 15466 pgam1 10312008 1248 AM 1012478 pgam1o 09282008 1056 AM 15252 pgam2 09292008 0837 PM 990329 pgam2o 11072008 0327 PM 14214 pgam3 11082008 0502 PM 956299 pgam3o 11072008 0336 PM 13957 pgam4 11082008 0503 PM 953725 pgam4o
16 File(s) 9572204 bytes 2 Dir(s) 0 bytes free
Directory of DCDave
11132008 0749 AM ltDIRgt 11192008 0230 PM ltDIRgt 10292008 0311 PM 20086 neut1 11062008 1102 AM 1358810 neut1o 09282008 1054 AM 19900 neut2 10012008 0556 AM 1376788 neut2o 11072008 0348 PM 18739 neut3
I- 2
000-00C-MGR0-05400-000-00A
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
-
- 4 METHODOLOGY
-
- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
-
- 421 Baseline Software
- 422 Commercial off the Shelf Software
-
- 43 CALCULATION APPROACH
-
- 431 MCNP5 Program
-
- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
-
- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
-
- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
-
- 63 MCNP SPECIFIC INPUT
-
- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
-
- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
-
- 7 RESULTS AND CONCLUSIONS
-
- 71 RESULTS
-
- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
-
- 72 CONCLUSIONS
-
- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
-
Dose Reduction Factors between Different Source Terms in a Cask
11102008 0225 AM 1357396 neut3o 11072008 0354 PM 18484 neut4 11102008 0225 AM 1352112 neut4o 10292008 0317 PM 15454 pgam1 11052008 0141 AM 1002114 pgam1o 09282008 1054 AM 15240 pgam2 09292008 0835 PM 1008401 pgam2o 11072008 0330 PM 14202 pgam3 11082008 0504 PM 961904 pgam3o 11072008 0338 PM 13950 pgam4 11082008 0505 PM 964756 pgam4o
16 File(s) 9518336 bytes 2 Dir(s) 0 bytes free
000-00C-MGR0-05400-000-00A
I- 3
- 1 PURPOSE
- 2 REFERENCES
-
- 21 PROJECT PROCEDURESDIRECTIVES
- 22 DESIGN INPUTS
- 23 DESIGN CONSTRAINTS
- 24 DESIGN OUTPUTS
-
- 3 ASSUMPTIONS
-
- 31 ASSUMPTIONS REQUIRING VERIFICATION
- 32 ASSUMPTIONS NOT REQUIRING VERIFICATION
-
- 321 Material and Wall Thickness of TAD Canister
- 322 Material and Thickness of TAD Shield Plug
- 323 Geometry and Materials of Conceptual TAD Transportation Casks
- 324 Usage of Unirradiated Fuel for Commercial SNF
- 325 Homogenization of Radiation Source Regions
- 326 Ignoring Internal Fuel Basket Materials
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- 4 METHODOLOGY
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- 41 QUALITY ASSURANCE
- 42 USE OF COMPUTER SOFTWARE
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- 421 Baseline Software
- 422 Commercial off the Shelf Software
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- 43 CALCULATION APPROACH
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- 431 MCNP5 Program
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- 5 LIST OF ATTACHMENTS
- 6 CALCULATIONS
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- 61 DESCRIPTION OF CALCULATIONS
- 62 CALCULATION INPUT
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- 621 TAD Canister
- 622 Conceptual TAD Transportation Casks
- 623 Fuel Assembly Selection
- 624 BampW 15x15 Mark B PWR Fuel Assembly
- 625 Material Compositions
- 626 Homogenization Assembly Materials
- 627 PWR Source Terms
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- 63 MCNP SPECIFIC INPUT
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- 631 Source Probability
- 632 Dose Rate and Flux Tallies
- 633 Variance Reduction Techniques
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- 64 DOSE CONVERSION FACTORS
- 65 RELATIVE ERROR CALCULATION
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- 7 RESULTS AND CONCLUSIONS
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- 71 RESULTS
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- 711 Dose Rates of Conceptual Cask A
- 712 Dose Rates of Conceptual Cask B
- 713 Comparison of Dose-Rate Reduction Factors
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- 72 CONCLUSIONS
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- ATTACHMENT I ELECTRONIC FILES ON COMPACT DISC
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