april 17, 2008 attn: document control desk mail stop p1 ... · pressure test" described in...

AmerenUECallaway Plant

PO Box 620Fulton, MO 65251

April 17, 2008

U.S. Nuclear Regulatory CommissionAttn: Document Control DeskMail Stop P1-137Washington, DC 20555-0001

ULNRC-05490

WAmneren Ladies and Gentlemen:

I I/IDOCKET NUMBER 50-483

CALLAWAY PLANT UNIT 1UNION ELECTRIC COMPANY

FACILITY OPERATING LICENSE NPF-3010CFR50.55a REQUEST: PROPOSED ALTERNATIVE

TO ASME SECTION X1 REQUIREMENTS FORREPLACEMENT OF CLASS 3 BURIED PIPING (TAC NO. MD6792)

Reference: ULNRC-05434 dated August 30, 2007

In the reference cited above, Union Electric Company (AmerenUE) submittedRelief Request 13R- 10 regarding paragraph IWA-422 1(b) of the American Society ofMechanical Engineers (ASME) Boiler and Pressure Vessel Code, Section XI. TheCode Edition applicable to the current 10-year Inservice Inspection interval forCallaway Plant is the 1998 Edition (up to and including the 2000 Addenda).

The requested relief request is needed to support the planned replacement ofburied steel piping in Callaway's essential service water (ESW) system withpolyethylene (PE) piping. For this repair/replacement activity, IWA-422 1(b) wouldrequire the new/replacement piping to meet the original Construction Coderequirements for the ESW piping. The applicable Construction Code (ASME SectionIII), however, does not provide rules for the design, fabrication, installation,examination and testing of PE piping. ASME Code Case N-755 provides conditionsunder which PE material may be used for ASME Section III, Class 3 buried pipingsystems. AmerenUE therefore requested relief, in the reference cited above, from thenoted Code requirements in order to utilize the provision of Code Case N-755 withthe exceptions identified in the relief request.

AtLnUA(4

a subsidiary of Ameren Corporation

ULNRC-05490April 17, 2008

AmerenUE's relief request is currently under review by the NRC staff, andfrom that review the NRC staff has identified the need for additional information. Arequest(s) for additional information (RAI) has thus been received by AmerenUE,consisting of questions from the NRC staff reviewers.

Pursuant to the RAI(s), Enclosure 1 of this letter contains the responses to sixquestions from the NRC's Piping and NDE Branch (CPNB) that were received.electronically on February 29, 2008, as well as six questions from the Mechanical andCivil Engineering Branch (EMCB) that were provided during a meeting with NRCstaff on January 23, 2008. (The final EMCB question was received electronically onFebruary 29, 2008.)

Attachment 2 to Enclosure 1 provides a list of additional exceptions thatAmerenUE is taking to ASME Code Case N-755.

Given that procurement, construction, and fabrication activities associatedwith this request are currently proceeding, AmerenUE requests that NRC contactAmerenUE as soon as possible for any questions or concerns that the NRC may haveregarding the responses or information provided by this letter. For any questionsregarding this letter or its enclosures, please contact Scott Maglio at (573) 676-8719or Tom Elwood at (573) 676-6479.

Very truly yours,

uke H. GraessleManager - Regulatory Affairs

GGY/MDB/nls

* Enclosure: 1. Response to Relief Request QuestionsAttachments:1) Dow Chemical DGDA-2492 BK 100 Data Sheet2) Updated AmerenUE Exceptions to Code Case N-755

2. PPI Letter to Dow Chemical3. Preliminary Stress Calculation 2007-16760


cc: Mr. Elmo E. Collins, Jr.Regional AdministratorU.S. Nuclear Regulatory CommissionRegion IV611 Ryan Plaza Drive, Suite 400Arlington, TX 76011-4005

Senior Resident InspectorCallaway Resident OfficeU.S. Nuclear Regulatory Commission8201 NRC RoadSteedman, MO 65077

Mr. Mohan C. Thadani (2 copies)Licensing Project Manager, Callaway PlantOffice of Nuclear Reactor RegulationU. S. Nuclear Regulatory CommissionMail Stop O-8G14Washington, DC 20555-2738


Index and send hardcopy to QA File A160.0761

Hardcopy:Certrec Corporation4200 South Hulen, Suite 630Fort Worth, TX 76109(Certrec receives ALL attachments as long as they are non-safeguards and may be publiclydisclosed.)

Electronic distribution for the following can be made via Responses and ReportsULNRC Distribution:

C. D. NaslundA. C. HeflinT. E. HerrmannL. H. GraessleG. A. HughesS. M. MaglioT. B. ElwoodR. D. MyattC. R. KieferS. L. GallagherL. M. Belsky (NSRB)Mr. Ron Reynolds, Director (SEMA)Mr. Edward Gray, Senior REP Planner (SEMA)Mr. John Campbell, REP Planner (SEMA)Ms. Diane M. Hooper (WCNOC)Mr. Dennis Buschbaum (TXU)Mr. Scott Bauer (Palo Verde)Mr. Stan Ketelsen (PG&E)Mr. Scott Head (STP)Mr. John O'Neill (Pillsbury Winthrop Shaw Pittman LLP)Mr. Floyd Gilzow (DNR)

ULNRC-05490Enclosure 1

ENCLOSURE 1

RESPONSE TO RELIEF REQUEST QUESTIONS

Enclosure 1Page 1 of20

REQUEST FOR ADDITIONAL INFORMATION ON THE NRC STAFF REVIEW OFRELIEF FROM ASME CODE REQUIREMENTS TO INSTALL POLYETHYLENE

PIPINGUNION ELECTRIC COMPANY,

CALLAWAY PLANT UNIT 1 (TAC MD6792)DOCKET NO. 50-483

On August 30, 2007, Union Electric Company submitted a request to use polyethylenepiping to replace carbon steel piping in the essential service water (ESW) system atCallaway Plant. On January 23, 2008, the U.S. Nuclear Regulatory Commission (NRC)staff met with Callaway representatives to discuss the major issues with the proposedalternative. As discussed in the meeting, the NRC staff has developed the followingrequest for additional information. The following questions from the NRC's Piping andNDE Branch (CPNB) were transmitted electronically on February 29, 2008.

Due to the time interval between the ASME final approval of Code Case N-755 (March2007) and its publication (October 2007), AmerenUE Relief Request 13R-10 (submittedvia ULNRC-05434 dated August 30, 2007) used the final~revision accepted by the ASMECommittees (Rev. 9 Duke). The following Requests for Additional Information (RAIs)reference the ASME published version. The Quality Program developed by AmerenUEis based on the Rev. 9 Duke version of the Code Case. To aid the reviewer whenrequired, the paragraph identification from the Rev. 9 Duke version is included as aparenthetical aid below, where applicable.

1. Procedure Qualifications: Section 1-200 provides two processes for fused jointprocedure qualifications.

Question:

1.(a) The licensee should identify the procedure qualification process applicable to thisproposed alternative.

Response:

AmerenUE is using the Standard Fusion Procedure Specification (FPS) per paragraph1-221 (QF-221).

Question:

1.(b) Paragraph 1-222 lists the procedure essential variables. The procedure shouldidentify all essential variables that affect heat transfer in the fusion process. The essentialvariables must be controlled to ensure internal soundness, structural integrity, andfabrication repeatability. The essential variables listed in the procedure do not appear tobe all inclusive. Pipe wall thickness and ambient temperature also affect heat transfercharacteristics. Provide a basis fornot including pipe wall thickness and ambienttemperature as essential variables.

Enclosure 1Page 2 of 20

Response:

The list of essential variables in paragraph 1-222 (QF-222) is all inclusive with theexception of "(d) fusion pressure" which is fusion machine dependent. This item is beingremoved in Revision 1 of the Code Case.

Pipe wall thickness and ambient temperature are not essential variables because both aredirectly proportional to the amount of time it takes to have indication of melt entirelyaround the pipe (to relax heating pressure) and also how long it takes for the requiredbead size to form. These are the essential criteria (not a specified period of time) thatestablish when the heater is to be removed and the subsequent fusion accomplished.

Low ambient temperatures are not a concern since all fusing that is anticipated for thisproject will be done during the spring and summer months, with average ambienttemperatures greater than 50'F. Any fusing done below 50'F will require anenvironmental enclosure to be placed over the work area to control temperature.

Question:

1.(b)(1) Subparagraph 1-132.1 does not treat wall thickness as an essential variable forelevated temperature testing. Provide technical justification for not performing elevatedtemperature testing on the specific wall thicknesses being used on the essential servicewater system.

Response:

The quality program developed by AmerenUE incorporates standard industry practicesand established, approved codes and standards. As indicated above, the Standard FusionProcedure (FPS) identified in paragraph 1-221 (QF-221) will be used. The "SustainedPressure Test" of paragraph 1-132 (QF-132) is only required for the qualification of a newFPS, 1-223 (QF-223), and a new FPS is not required.

Note that paragraph 1- 132.1 (QF- 132.1) deals with the "Elevated Temperature SustainedPressure Test" described in ASTM D3035-03a. On review of the ASTM standardparagraph 6.4 the following sentence was found:

"Tests may be conducted on any pipe size, but tests conducted on 6 in. (168 mm)nominal size pipe shall be considered representative of all pipe sizes."

This indicates that the 8-inch pipe referenced in 1-132.1 is representative of all pipe sizes.The pipe wall thickness is compensated for by Table Tin ASTM D3035-03a.

Question:

1.(b)(2) Paragraph 1-221 has adopted testing criteria from the Plastics Pipe Institute, TR-33/2001, "Generic Butt Fusion Joining Procedure for Field Joining of PolyethylenePipe." The criteria do not address the variety of material and configurations applicable to


polyethylene pipe. Specify the specific material, cell classification, pipe diameter, wallthickness, and representative configurations that will be used for procedure performancedemonstration. Discuss the performance demonstrations process for ensuring theprocedure's effectiveness for the different essential variable ranges.

Response:

The material selected for the project is Dow Chemical, Continuum DGDA-2492 BK 100.The material is a two reactor "Bimodal" polyethylene. The cell classification is445574C, which is a stronger material than the 445474C material identified in the CodeCase, with similar fusion characteristics (400 - 4507F heater temperature and 60 - 90 psiinterfacial fusion pressure). Two pipe diameters will be used: 36-inch DR 9.5 and 4-inchDR 9. As stated above the Standard Fusion.Procedure Specification (FPS) will be usedand a performance demonstration is not required.

Question:

1.(b)(3) Paragraph 1-300.3(a) contains the statement that "qualified thickness ranges forbase material need not be identical, but these thicknesses shall be adequate to permitfusing of the test coupons." The term "adequate" is an undefined term. Explain if thethickness must be within the procedure's qualified range. If the thickness does not haveto be within the procedure qualified range, provide the technical justification forexpanding an essential variable without a performance demonstration.

Response:

AmerenUE does not intend to perform simultaneous performance qualifications withanother organization. All performance qualifications will be done using AmerenUEFusion Procedure Specifications.

Question:

1.(c) Section 1-220 discusses the process for procedure qualifications. The procedurequalification attests to its joining capabilities through performance demonstration testing.The demonstration is to establish the procedure effectiveness through and at the rangelimits of the essential variables. The joints produced by the demonstrations are evaluatedwith visual, tensile impact, and elevated temperature sustained pressure tests. Satisfyingthe testing acceptance criteria qualifies the procedure. The ability to trace thequalifications back to the test data is not clear. The licensee should address how a thirdparty, such as the NRC staff, would audit the procedure qualifications and traceabilityback to the test data.

Response:

Paragraph 1-220 (QF-220) provides two methods for the qualification of a FusionProcedure Specification (FPS):


a. Use the Standard FPS which uses criteria established by TR-33. NodemOnstration testing is required for this method.

b. Develop a new FPS when deviations to the Standard FPS are required. This isallowed by 1-221 (b) (QF-221 (b)) and requires demonstration testing specifiedin paragraph 1-223 (QF-223).

As discussed above AmerenUE is using the Standard Fusion Procedure Specification(FPS). Therefore no testing is required. If a fusion procedure outside the range of thestandard FPS is required, the testing required byi-223 (QF-223) will be performed anddocumented under the AmerenUE Quality Assurance Program.

Question:

1 .(d) The above questions also apply for fittings. The licensee should address auditing theprocedure qualifications and traceability back to the test data. The licensee should alsoaddress examinations of pipe-to-fitting joints.

Response:

See the response to question 1 .(c) above.

2. Design for Accessibility: Paragraph 1-121 requires visual examination of allaccessible surfaces.

Question:

2.(a) The use of high density polyethylene (PE) pipe in Code Class 3 applications is newto the nuclear power industry. The relief request requires visual testing (VT) examinationof the pipe and joint outside surfaces. The licensee should address accessibility for VTexaminations of PE pipe from the inside surface.

Response:

AmerenUE considers "accessible" as being within reach from an open end. The insidesurfaces of the 36-inch fittings are accessible during fabrication. The inside surfaces ofthe 4-inch pipe and fittings are not considered accessible since the nominal insidediameter is less than 3.5 inches.

Because of the distance between joints (often 50 feet), and the nominal inside diameter ofthe joints (less than 28 inches), the interior of the 36-inch pipe is considered inaccessibleto personnel. While remote video inspection could be performed, it has shown to beinconclusive with indeterminate results in similar industry applications.

An additional consideration with regard to interior inspection is the potential forpersonnel or equipment moving within the pipe to cause damage to the ID surface.


See the response to question 2.(b), as follows, for additional information regardingprovisions forfuture access to inside pipe and joint surfaces.

Question:

2.(b) The visual examinations are being used as an indicator of internal pipe and jointsoundness. In time, improvements in volumetric examination techniques may result inthe ability to detect potential, flaws or flaws may occur that require field examination aspart of the corrective action. Since volumetric examinations would provide increasedconfidence in system integrity, the NRC staff believes that the piping design shouldinclude provisions for future access to the inside pipe and joint surfaces. Provide adiscussion on the licensee's plans for designing access for future examinations of theinside surface.

Response:

Removable spools will be installed that would provide future access to the ID surfaces ineach replacement line should suitable remote equipment be developed. Althoughremovable spools will be installed, it is the intent of AmerenUE to install a permanentpiping system using a quality program where future examinations are not required. Thequality program includes the following:

1. All inspection personnel will be trained as fusing machine operators.2. Detailed Fusion Procedure Specifications (FPS) will be utilized.3. Detailed NDE procedures will be utilized:

a. Visual examination procedures will be utilized.b. Time-of-Flight Diffraction (TOFD) volumetric examination (ultrasonic

testing) procedure will be utilized.4. Detailed Work Control procedures will be utilized.5. The most advanced type of PE material currently available will be used.

When complete, the PE piping portion of the Essential Service Water system will betested and maintained in accordance with ASME Section XI.

3. NDE Qualifications: The NRC.staff is interested in NDE procedure and personnelqualifications for examinations of PE piping systems.

Question:

3.(a) Section -5500 provides qualification for nondestructive examination personnel. Theguidance in the relief request does not appear adequate for performance-baseddemonstrations of the VT examinations. The NRC staff is interested in reviewing aspecific proposal for VT personnel qualifications. The licensee should address the use ofrepresentative (wall thickness, cell classification, joint configuration) pipe and/or fittingsamples of acceptable and unacceptable joints (in conjunction with pictures) for trainingand performance-based VT personnel qualification.


Response:

Two different qualifications are required to support the Code Case. As AmerenUE haselected .to use the Owner option (-5530) of the Code Case, VT-1 and VT-2 examiners arebeing trained to support the project. "Performance-based Demonstrations" will not beused; this is not required by ASME Section V, Article 9, since it is not invoked by CodeCase N-755.

VT-1

Existing personnel with VT-1 qualifications will be trained as fusion machine operatorsin accordance with -5100(b). This training will follow Appendix A (Supplement 9,Appendix A) of the Code Case. VT-1 personnel will perform the receipt examinationsand fused joint examinations (-5200(a) & (b)).

VT-2

Existing personnel with VT-2 qualifications will be trained to perform the hydrostatic testinspections required by -6000 of the Code Case. This training requires a 4-hour trainingclass to educate the personnel on PE piping and fusion practices.

Ouestion:

3.(b) The relief request is silent on VT examinations performed from the inside surface ofthe piping system. Discuss inside surface VT examinations for piping, fused joints, andfittings. Provide the acceptance criteria for VT examinations performed on the insidesurface.

Response:

The Code Case does not require examinations on the interior surface of the pipe;therefore, ID examinations were not addressed in the Relief Request.

As discussed in the response to question #2 above, visual examinations of fused jointswill only be done on the OD fusion beads. The acceptance criteria will be:

a. uniform beads, andb. cleavage between the bead does not extend below the OD substrate.

The Code Case also requires a receipt examination when the PE material arrives on site.The personnel performing this examination will be. the trained VT-1 examiners discussedin the response to question 3(a) above. The acceptance criteria for this examination willcome from ASTM F714, paragraphs 5.0 to 5.2, in addition to the Code Caserequirements.

Enclosure 1Page 7 of 20.

Question:

3.(c) Paragraph -2310 does not address internal soundness. By not addressing internalsoundness, the industry is implying that PE piping is free of volumetric flaws. Paragraph-5200 does not address inspection of the pipe ends to ensure internal soundness.However, field failures indicate the presence of volumetric flaws in the vicinity of thefailed joint. Describe inspection responsibilities for examining pipe ends for volumetricflaws (e.g,, voids and inclusions) during the joining process. Provide a description of thetraining and qualification of individuals carrying out inspection for volumetric flaws inthe pipe ends prior to joining. Provide acceptance criteria for flaws detected during thejoining process.

Response:

Paragraph -5200 does not address in-process examination of the faced pipe ends, becausethis has not been identified as an industry issue. However, an inspection of the faced pipeends (both prior to and immediately after heating) is a good workmanship practice, isaddressed in the training of all fusion machine operators and inspectors, and is includedin the AmerenUE work procedures. The personnel performing the inspections will havereceived a minimum of 24 hours of fusion training as required by the Code Case.

Although volumetric examination will not be performed on the pipe ends prior to fusing,a volumetric examination (TOFD) will be performed on the completed fusion joint.

Question:

3.(d) Paragraph -4130 does not address sample expansion when flaws are detected in thepipe. The presence of volumetric flaws that are exposed by facing the pipe ends duringthe joining process may indicate a more extensive problem with volumetric flaws.Provide a specific proposal for disposition of unacceptable volumetric flaws. When avolumetric flaw is detected, describe the actions taken to determine the extent ofvolumetric flaws in the vicinity of the surfaces to be joined.

Response:

Unacceptable material flaws detected at any time during the manufacture, fabrication,and installation necessitates stopping work and generating a Corrective Action Programdocument in accordance with the AmerenUE Quality Assurance Program. TheCorrective Action Program requires an extent of condition evaluation for all suchconditions.


Question:

3.(e) An alternative to 3(c) and 3(d) is a volumetric examination of the fused joint.Paragraphs -5320, 1-120, and 1-300.3 are silent on volumetric examinations. Describe thevolumetric examination techniques, and describe the performance demonstration testingused for qualifying personnel and procedures. Provide the acceptance and flawdisposition criteria.

Response:

Code Case N-755 requires the following activities to provide assurance of piping andjoint integrity:

1. Data acquisition and review of essential variables during the fusion process2. 100% visual external inspection of all joints3. Hydrostatic testing

To provide added assurance of joint integrity beyond the requirements of Code CaseN-755, AmerenUE will perform ultrasonic Time-of-Flight Diffraction (TOFD)examination of all completed, fusion joints, with the exception of portions ofjoints wherethe geometry prohibits effective examination (i.e. intrados and extrados areas of miteredfitting joints). The UT examiners will be qualified in accordance with SNT-TC-1A.

Since the TOFD technique is a nonstandard ASME inspection method a certain amountof freedom to implement this technique is required. The potential contractor performingthe TOFD does not have a 10 CFR 50 Appendix B quality program. To address thisrequirement, the Contractor will be hired under a non-safety purchase order. The TOFDtechnique will be demonstrated to the Authorized Nuclear Inservice Inspector. TheContractor's examiners will be qualified in accordance with SNT-TC-1A.

AmerenUE is currently evaluating and refining acceptance criteria based on industrystandards (e.g. ASME B31 piping codes). The current acceptance criteria require thatany unbonded area in the joint, found as a result of the TOFD, is cause for rejection.

It should be noted that AmerenUE will retain copies of all TOFD joint examinations forfuture reference.

4. In-Process Testing: The use of PE piping is new to ASME applications which mayperform differently in nuclear power plant applications than other industry applications.

Ouestion:

4.(a) The NRC staff is concerned that cold fusion is not sufficiently understood by theindustry to develop effective nondestructive examination methods. The NRC staffbelieves that the licensee needs to develop a program for in-process destructiveexaminations of the fused joint to detect process weaknesses. The in-process

Enclosure 1Page 9 of 20examination should validate material and equipment effectiveness on a routine basis andmaterial, equipment, and operator effectiveness on a random basis. The in-processtesting should include sample selection criteria, testing frequency, testing methods, andacceptance criteria. The testing should be at various circumferential locations to addressnon-uniform flaw distribution in fused joints. Discuss the in-process verificationprogram that will be implemented.

Response:

AmerenUE does not currently plan to provide a program for in-process destructiveexaminations. As discussed above, AmerenUE will perform TOFD examinations in lieuof in-process examinations. The TOFD process will be performed on all installed joints;whereas in-process destructive examination would only be performed on a sampling ofuninstalled joints.

Ouestion:

5. Proposed Alternative: The requested alternative should identify the specific parts ofthe ASME Code Case referenced in the relief request which are being modified forCallaway's specific application, or request an alternative as a stand alone document thatdoes not mention the Code Case. The portion of the request identified as the alternativeshould avoid mentioning criteria that is not need for the specific application.

Response:

Specific sections of Code Case N-755, along with the exceptions requested, wereidentified in letter ULNRC-05434 dated August 30, 2007. As design, procurement, andinstallation details have been developed, additional exceptions have been identified. Theadditional exceptions requested are provided in Attachment 2 to this Enclosure.

6. Other

Question:

6.(a) Paragraph -4130 references paragraphs -2900. The referenced Code Case is missingparagraphs -2400 though -2900. You are requested to review the Code Case for missingparagraphs and provide them in your response to this RAI.

Response:

The reference to -2900 is a typographic error and is being corrected in Revision 1 of theCode Case. The reference should be -2300.

Enclosure .1Page 10 of 20

Question:

6.(b) Subparagraph 1-322.1(a) provides criteria on expiration of qualifications. Thesubparagraph uses the term process which indicates multiple processes exist. In the eventof multiple processes, the concern is on the effectiveness of an operator to apply a givenprocedure with acceptable results. Provide a discussion on the application of thesubparagraph and how it will apply to procedures.

Response:

Appendix 1 (Supplement 9) is written to accept other fusing processes as they becomeavailable. For example, the electro-fusion process could be included in a subsequentrevision to the Code Case. The only process AmerenUE has identified and will allow isthermal butt fusion.


The following questions are from the NRC's Mechanical and Civil Engineering Branch(EMCB). The first five questions below were distributed during the January 23, 2008meeting and were also attached to the NRC meeting minutes dated February 29, 2008(ADAMS Accession No. ML080380647). There were some minor revisions to thequestions as reflected in the meeting minutes. The last (sixth) question was receivedelectronically on February 29, 2008.

Question:

1. AmerenUE indicatedthat PE material with a cell classification of 445574C will beutilized. This PE material has a higher tensile strength than 445474C PE materialspecified in the code case. Provide the mechanical properties of the 445574C.PEmaterial.

Response:

AmerenUE selected the 445574C material, not only because of the higher tensilestrength, but because it is a bimodal material and is the most advanced type of PEmaterial currently available. The selected Dow Chemical material (ContinuumDGDA-2492 BK 100) has a high resistance to Slow Crack Growth. PENT testing (ASTMF1473) requires material to resist crack growth for 500 hours to achieve a rating of"7"(highest number) in the cell classification. The DGDA-2492 BK 100 material has beentested for over 10,000 hours and did not fail. A data sheet for DGDA-2492 BK 100 isattached (Attachment 1 to this Enclosure).

Enclosure 2 to this RAI response letter provides a letter from the Plastic Pipe Institute(PPI) Hydrostatic Test Board to Dow Chemical on the results of their review of test datato support inclusion into PPI document TR-4, "PPI Listing of Hydrostatic Design Basis(HDB), Hydrostatic Design Stress (HDS), Strength Design Basis (SDB), Pressure DesignBasis (PDB) and Minimum Required Strength (MRS) Ratings for Thermoplastic PipingMaterials or Pipe."

If the NRC would like to review the data associated with the testing of this material,arrangements can be made with Dow Chemical.

Question:

2. AmerenUE indicated that mitered elbows of less than 90 degrees (i.e., 45 and 22.5degree) and less than 3 [three] joints may be utilized, while the Code Case specifiesthree- or five-joint mitered elbows. Address if any test data is available and what stressintensification factor values will be used for mitered joints with less than three joints.


Response:

Code Case N-755 does not differentiate between 3- and 5-joint mitered elbows whenspecifying stress intensification factors. The stress intensification of 2.0 provided in theCode Case will be used for all mitered elbows, including those with less than 3 joints. Incases where mitered elbows with less than 3 joints are used, each segment is limited to22.50, as specified by the Code Case.

Question:

3. The relief request did not include the piping diameter (Do), wall thickness (t), anddimension ratio (DR) values. Provide this information for the PE pipe sizes proposed foruse at Callaway.

Response:

Two different sizes of pipe will be used in the project: 1) 36-inch DR 9.5 and 2) 4-inchDR 9.

Fittings will be fabricated from extruded rod stock of at least one DR lower in accordancewith the Code Case.

Question:

4. Provide a complete stress analysis calculation package of one buried ESW pipingsystem containing detailed evaluations showing structural integrity, stress margins, andfactors of safety.

Response:

A preliminary stress analysis calculation is provided as Enclosure 3 to this RAI responseletter. This is not a final, approved calculation.

5. AmerenUE stated that the PE piping will be subjected to pressures and temperaturesas high as 165 psig [pounds per square inch gauge], and 180'F [degrees Fahrenheit],which exceed the limitations provided in ASME Code Case N-755. The materialproperties will be determined by material testing.

Question:

5.a. Provide the material test data for the 445574C PE material for temperatures up to180 0F.


Response:

AmerenUE has revised the design conditions for the section of open-ended pipingbetween the Control Building and the Ultimate Heat Sink (UHS) Cooling Tower. Therevised design conditions are 45 psig at 1750 F.

The DGDA-2492 BK 100 material has been tested at over 500 psi @ 176' F for 2 yearswith no failures. This is documented in the letter from PPI to DOW Chemicaldocumented in Enclosure 2 to this RAI response letter. As indicated above, if the NRCwould like to review the data associated with the testing of this material, arrangementscan be made with Dow Chemical.

Question:

5.b. Provide structural integrity evaluations performed for the high pressure, hightemperature applications of the PE piping showing stress margins, and factors of safety.

Response:

The structural integrity evaluations performed are provided in the calculation provided asdiscussed in the response to question 4.

Question:

6. Flaw depths of 10 percent of the wall thickness, especially sharp cracks, may not beacceptable from slow crack growth and crack driving force standpoint. Provideadditional limitations or evaluations to show acceptable flaw depth based on pipedimension ratio (DR), pressure, and temperature.

Response:

In lieu of the discussion contained in Relief Request 13R-10 (ULNRC-05434), damage topolyethylene piping under the scope of this project will be addressed by:

(1) For 4-inch piping, any section with a flaw exceeding 10% of the wall thicknessshall be cut out and replaced.

(2) For 36-inch piping, any section with a flaw exceeding 7% of the wall thicknessshall be cut out and replaced.

(3) Any section of piping with a flaw not exceeding 5% of the wall thickness may beleft as-is.


(4) All other flaws shalibe removed by blending as follows:

(a) The depression after flaw elimination is blended uniformly into thesurrounding surface with a maximum taper not to exceed 3:1 (ratio ofwidth to height).

(b) After flaw elimination, the area will be examined by visual examination toensure that the flaw has been removed.

(c) If the elimination of the flaw reduces the thickness of the section belowthe minimum required design thickness, the section of piping containingthe flaw shall be cut out and replaced.


Attachment 1DOW CHEMICAL DGDA-2492 BK 100 Data Sheet

Enclosure 1Page 16 of.20

Technical Information - Resin for Pipe Extrusion and Pipe Fittings

CONTINUUM DGDA-2492 BKBimodal Polyethylene Resin

Industrial Standards Compliance:ASTM D 3350: cell dassification

Black- PE445576C" (MRS)Black- PE445574C" (HDB)

* Plastics Pipe Institute (PPI): TR-4Black Pipe - CONTINUUMT DGDA-2492 BK 100>"- ISO PE100 pipe grade - MRS 10 @ 20°0; CRS 6.3 @ 60°C,11 yr- ASTM PE4710 pipe grade- 1600psi HDil @ 73°F, 1000psi HDB @ 140'F

* National Sanitation Foundation (NSF): Standard 14 and 61. Black Pipe- DGDA-2492()

Consult the regulations for complete details.

CONTINUUMTM

DGDA-2492BK Bimodal PolyethyleneResin is produced usingUNIPOLTM II processtechnology. This productmay be utilized for pipe

applications where long-termhydrostatic strength combined withoutstanding resistance to slowcrack growth, rapid crackpropagation, and high meltstrength is desired. Suitable

applications include natural gasdistribution pipes, large diameterindustrial piping, mining, sewage,and municipal water service lines.

Resin PropertiesMelt Index (I,) @190'C/2.16 kg. 9/10 min ASTM D 1238 0.06Flow Index (I,) @190°C/21.60 kg, g/10 min ASTM D 1238 5.5Density (natural resin). q/cc ASTM D 1505 0.949Density", g/cc ASTM D 1505 0.959Thermal Stability, 'F (°C) ASTM D 3350 >428 (>220)

Mechanical Propertles'0

Tensile Strength at Yield, psi (MPa) ASTM D 638 3600 (24.8)Elongation at Break, % ASTM D 638 740Flexural Modulus, psi (MPa) ASTM D 790, method1, 150,000 (1034)

procedure BNotched Izod Impact @ 23'C, ftlbf/in. (J/m) ASTM D 256, method A 9.1 (488)Brittleness Temperature, °F (°Cl ASTM D 746, procedure A <-103 (<-75)Slow Crack Growth PENT, hours ASTM F 1473 '10,000

Pipe Propertieso'Hydrostatic Strength @ 20°C/ 1798 psi (12.4 Mpa), hr. ASTM 1598 >100Hydrostatic Strength fi 80°C/ 798 psi (5.5 Mpa), hr. ASTM 1598 >1000Resistance to Rapid Crack Propagation', Pc, psi (bar) ASTM F 1589 >174 (>12)Resistance to Rapid Crack Propagation", Tc, °F (°C) ISO 13477 <0 (<-IS)

Fabrication Conditions:* Screw Type: High quality HDPE (preferably barrier for complete

melting)* Melt Temperature Range: 380-440'F (193-225'C)

tI)

(2)

(3)

(4)

(5)

The first ri numbers of the cell classification are based on naturalresin. The last number and letter are based on bladk resin (naturalredn plus 6.5% oFNF-0092).Natural resin extruded under proper conditions with carbon blackmasterbhatun DFNF-0092 (6.5%).Typlcal values, not to be construed as specications. Users shouldconfirm results by their aw• tests.Compression molded pals prepared according to ASTM D 4703Procedure C unless otherv~se noted In the test method. Propertiesvll vary with changes In molding conditions and aging time.Pipe diameter of 10 inch IPS (25.4 on) and Standard Diameter Ratio(SOR) .1•.

Form No. 782-00101-1205Page 1 ol 2 "t'Trademark of The Dow Chemical Company C'Dow') or an atfliated company of Dew


ProductStewardship

CustomerNotice

Dow MedicalApplication Policy

Disclaimer

The Dow Chemical Company and its subsidiaries (Dow) has a fundamental concern for all who make, distribute,and use its products, and for the environment in which we live. This concern is the basis for our Product Stewardshipphilosophy by which we assess the safety, health and etvironrmental inormation on our products and then takeappropriate steps to protect employee and public health and our environment. The success of aur Product Stewardshipprogram rests wah each and every individual involved with Dow products - from the inital concept and research, tomanufacture, use, sale, disposal, and recycle of each product.

Dow strongly encourages its customers to review both their manufacturing processes and their applications of Dowproducts from the standpoint of human health and ensiroronental quality to ensure that Dow products are not used inways for which they are not intended or tested. Dow personnel are available to answer your questions and to providereasonable technical support. Dfw product literature, including safety data sheets, should be consulted prior to use ofDow products. Current safety data sheets are available from Dow.

Dow will not knowingly selt or sample any product or service CProduct3 into any commercial or developmentalapplication that is intended for:a. permanent (Long term) contact with internal body fluids or internal bodytissues. Long term is a use which exceeds

72 cantinuous hours (except 30 days for PE LLETHANE TM polyurethane elastomers);b. use in cardiac prosthetic devices regardless of the length of time involved; (Cardiac prosthetic devices include,.

but are not limited to, pacemaker leads and devices, artificial hearts, heart valves, intra-aortc balloons and controlsystems, and ventricalar bypass assisted devices);

c. use as a critical component in medical devices that support or sustain human life; ord , use specifically by pregnant women or in applications designed specifically to promote or interfere with human

reproduction.

Additionally, all Products intended for use in pharmaceutical applications, other than pharmaceutical packa Ong,must pass the current Pharmaceutical Liability Guidelines.

" For the products sold by the Plastics Portlolio, new business opportunities require a business assessment priorto sale or sampling of Dow products.

" Authorized distributors and resellers will adhere to this medical policy." The Dow Chemical Company does not endorse or claim suitability of their products for specific medical applications.

It is the responsibility oa the medical device or pharmaceutical manufacturer to determine that the Dow product issafe, lawful, and technically suitable for the intended use. DOW MAKES NO WARRANTIES, EXPRESS ORIMPLIED, CONCERNING THE SUITABILITY OF ANY DOW PRODUCT FOR USE IN MEDICAL APPLICATIONS.

NOTICE: No freedom from infringement oa any patent owned by Dow or others is to be inlerred. Because useconditions and applicable laws may differ Irom one location to another and may change with time, the Customer isresponsible foe determining whether products and the informabon in this document are appropriate for the Customer'suse and for ensuring that the Customer's workplace and disposal practices are in compliance with applicable lawsand other governmental enactments. Dow assumes no obligation or liability for the information in this document.NO WARRANTIES ARE GIVEN; ALL IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR APARTICULAR PURPOSE ARE EXPRESSLY EXCLUDED.

NOTICE: If products ire described as'experimental or developmentar: (1) product specifcations may not be tullydetermined; (2) analysis of hazards and caution in handling and use are required; and (3) there is greater potentialfor Dow to change specifications andlor discontinue production.

AdditionalInformation

www.dowplastics.com

North AmericaU.S. & Canada: 1-800-441-4369

1-9W89-32-1426Mexico: +1-800-441-4369

Latin AmericaArgentina: +54-11-4319-0100Brazil: +55-11-5188-9222Colombia: +57-1-319-2100Mexico: +52-55-5201-4700

Published September 2005

EuropelMiddle East +800-3694-6367+32-3-450-2240

South Africa

Asia Pacific

+800-99-5078

+800-7776-7776+60-3-7958-3392

-4ý.Form No. 782-00101-1205

Page 2 of 2 S2*'Trademark of The Dow Chemical Company V'fow') oras affiliated company ol Dow


Attachment 2 - Updated AmerenUE Exceptions to Code Case N-755

Supplemental Alternatives to ASME Section XI Requirements for Replacement ofClass 3 Buried Piping in Accordance with 10 CFR 50.55a(a)(3)(i)

Reference Code Case N-755(Version approved by BNCS March 22, 2007)

The following alternatives to Code Case N-755. supplement those identified inAmerenUE Relief Request 13R- 10 (ULNRC-05434).

Material

* Paragraph 2110 - PE material with a cell classification of 445574C will beutilized. The material may contain a color stripe with cell classification of445574E. (Note that there is no physicaldifference between C and E, other thanthe color.)

* Paragraph 2320 -In lieu of the discussion contained in Relief Request 13R-10(ULNRC-05434), damage to polyethylene piping under the scope of this projectwill be addressed as provided in the body of the response above.

Design

0 Paragraph 1100 - In lieu of the values contained Relief Request 13R-10 (ULNRC-05434), the design pressures and temperatures of the various lines to be replacedwill be 165 psig at 95°F, 160 psig at 95°F, or 45 psig at 175°F, as applicable tothe specific line.

* Paragraph 3016 - The design factor will be 0.56 or lower. This is currently beingaddressed in a revision to Code Case N-755.

e Paragraph 3016 - Miner's Rule (in accordance with ISO 13760) will be used toaccount for operation for 30 days at post-accident conditions and normaloperating conditions for the balance of the 40-year design life.

Fabrication and Installation

" Paragraph 4421 - Ends of larger outside diameter (OD) fittings that adjoin smallerOD pipe may be counterbored externally to match the OD of the pipe, usingtransitional dimensions similar to those provided in Figure -4421.3-1. Heavier-wall segments with larger outside diameter (i.e. "inverted" elbows) will be usedfor elbow fabrication to minimize flow restriction.

" Paragraph 4520 - Gaskets may or may not be used, depending on the application.Use of gaskets may not be appropriate in all sizes and thicknesses of HDPEpiping. This is currently being addressed in a revision to Code Case N-755.


" Paragraph 4520 - The required HDPE flange joint seating stress and bolt torquewill be determined in accordance with the guidance provided in PPI documentTechnical Note TN-38, "Bolt Torque for Polyethylene Flanged Joints".

* Paragraph 4520 = Following acceptable visual examination, the external fusion.joint beads may be removed to accommodate installation of the metallic back-upring.

* Paragraph QF-133.1 - For pipe coupons greater than 1" thick, alternative means-ofachieving similar cross-sectional stress at the joint with shorter test specimens(such as using fixed radius rollers) may be used. Bend Test requirements forperformance qualification testing are impractical for large diameter heavy-walledpiping. To provide added assurance ofjoint integrity beyond the requirements ofCode Case N-755, AmerenUE has elected to qualify fusion machine operators onpiping of sizes and thickness similar to that used in production.

* TABLE QF-221(a)-I Approximate Melt Bead Size (inches) for >24 to <36 shouldread: 7/16 to 9/16. This is currently being addressed in a revision to Code CaseN-755.

* The Heater Removal and Joint Closure Times provided for heavy-wall pipe areinadequate. The value provided in the Code Case for >1.18" wall thickness isinconsistent with the incremental increases provided for lesser pipe wallthicknesses. It is noted that heater removal time was not identified as an essentialvariable of TR-33/2001, it was added by ASME.

Table QF-221(a)-2 is revised in part to read:

Max. Heater Plate RemovalPipe Wall Thickness, in to Joint Closure Time

1.18"7to 2.00" 25 seconds>2.0" to 4.0" 45 seconds>4.0" to 6.0" 60 seconds

This is currently being addressed in a revision to Code Case N-755.

Paragraph QF-222(a)(4) - The list of essential variables contains redundancy.Fusion Pressure is the same as Interfacial Pressure, and is therefore not consideredan added essential variable for Fusion Procedure Specifications. This is currentlybeing addressed in a revision to Code Case N-755.


Examination

Paragraph 5321 - For mitered joints, the beads at the extrados may not roll backto the pipe surface, and beads at the intrados may exhibit multiple beads or heavybeads with no cleavage. The profiles of Figures -5321-1 (and QF-121-1 andSupplement 5) do apply to the outside beads along the centerline of such fittings.This is currently being addressed in a revision to Code Case N-755.

Nameplates, Stampin2 and Reports

Paragraph 8110 - Thermal indentation line printing is permitted during pipe manufacture.This is currently being addressed in a revision to Code Case N-755.

ULNRC-05490Enclosure 2

ENCLOSURE 2

PPI LETTER TO DOW CHEMICAL

PLASTICS.PIPE.INSTITUTE"

December 15, 2005

Mr. Dane ChangDow Chemical Company2301 N. Brazosport Blvd.Bldg. B-1607Freeport, TX 77541

Dear Dane:

The DGDA-2492 BK 100 material is currently listed as a PE 100 with an MRS of 10.0 MPa, anda PE 3408 with an experimental grade HDB of 1600 psi at 730F and 1000 psi at 1401F in TR-4.Based on the information and additional stress rupture data provided with your letter ofNovember 19, 2005 I have been authorized by the Hydrostatic .Stress Board to grantequivalency of this resin to the DGDA-2490 BK 100 material. This new listing will be publishedin the next revision to TR-4.

Material Temp. MRS/CRS HBD Grade Expiration PPI(MPa) psi Date Dataset

DGDA-2492 BK 100 200C 10.0 S 12/31/2010 3080DGDA-2492 BK 100 (60'C, 11yr) 6.3 S 12/31/2010 3080DGDA-2492 BK 100 (80'C, 2 yr) 4.0 S 12/31/2010 3080DGDA-2492 BK 100 73°F 1600 S* 12/31/2010 3080DGDA-2492 BK 100 140OF 1000 S 12/31/2010 3080

The hydrostatic data submitted meets the requirements to establish equivalency for a modifiedPE compound as per TR-3, Part F.6. The 230C and 600C data support the LTHS of 1600 psiand 1000 psi, respectively. The 900 C data validates the 600C HDB, and all lower temperatureHDBs. Analyzing the 23°C, 600C, and 800C data according to ISO 9080 using the 4 parametermodel supports the current MRS 10.0 MPa. As requested, the data also supports the CRSvalue (60 0C, 11 yrs) of 6.3 MPa, and (800C, 2 yrs) of 4.0 MPa. Since the 80'C data was thehighest temperature tested, the CRS (800C, 2 yr) is based on hours of actual testing with noextrapolation. These new ratings are effective this date.

By copy of this letter, NSF will be notified of these new listings for DGDA-2492 BK 100.

There is an initial TR-4 listing fee of $375.00 (PPI member fee) for each material at eachtemperature. These fees will be added to your 2006 invoice.

Please call me at 202-462-9607 ext. 11 if there are additional questions pertaining to this listing.

Sincerely,

Stephen BorosChairman, Hydrostatic Stress Board

CC: Nasrin Kashefi - NSF1825 Connecticut Ave. NW, Suite 680, Washington DC 20009 P: 202-462-9607 F: 202-462-9779 www.plasticpipe.org

april 17, 2008 attn: document control desk mail stop p1 ... · pressure test" described in...

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