enclosure 1 m170090 - nrc: home pagein accordance with asce 7-88, the design wind velocity used in...

Enclosure 1

M170090

GEH Supplemental Response #5 to RAI 02-1

IMPORTANT NOTICE REGARDING CONTENTS OF THIS DOCUMENT Please Read Carefully

The information contained in this document is furnished solely for the purpose(s) stated in the transmittal letter. The only undertakings of GEH with respect to information in this document are contained in the contracts between GEH and its customers or participating utilities, and nothing contained in this document shall be construed as changing that contract. The use of this information by anyone for any purpose other than that for which it is intended is not authorized ; and with respect to any unauthorized use, GEH makes no representation or warranty, and assumes no liability as to the completeness, accuracy, or usefulness of the information contained in this document.

M170090 Enclosure 1

PURPOSE OF SUPPLEMENTAL RESPONSE:

Page 1 of 5

This enclosure provides the updated response (Supplement 5) to NRC Request for Additional Information (RAI) 02-1. The original response and supplemental responses to RAI 02-1 were submitted in the references below.

PREVIOUS RESPONSE AND SUPPLEMENTAL RESPONSES:

1. Letter from Jerald G. Head, GEH, to USNRC, Subject: NRC Request for Additional Information Letter Number 2 Related to Chapters 1, 2, and 12 for GE-Hitachi Nuclear Energy Advanced Boiling Water Reactor Design Certification Rule Renewal Application -GEH Response to RAI 02-1 , November 19, 2014.

2. Letter from Jerald G. Head, GEH, to USNRC, Subject: NRC Request for Additional Information Letter Number 2 Related to Chapters 1, 2, and 12 for GE-Hitachi Nuclear Energy Advanced Boiling Water Reactor Design Certification Rule Renewal Application -GEH Supplemental Response to RAI 02-1 , June 30, 2015.

3. Letter from Jerald G. Head, GEH, to USNRC, Subject: NRC Request for Additional Information Letter Number 2 Related to Chapters 1, 2, and 12 forGE-Hitachi Nuclear Energy Advanced Boiling Water Reactor Design Certification Rule Renewal Application -GEH Supplemental Response #2 to RAI 02-1 , November 5, 2015.

4. Letter from Jerald G. Head, GEH, to USNRC, Subject: NRC Request for Additional Information Letter Number 2 Related to Chapters 1, 2, and 12 for GE-Hitachi Nuclear Energy Advanced Boiling Water Reactor Design Certification Rule Renewal ApplicationGEH Supplemental Response #3 to RAI 02-1 , January 12, 2016.

5. Letter from Jerald G. Head, GEH, to USNRC, Subject: NRC Request for Additional Information Letter Number 2 Related to Chapters 1, 2, and 12 for GE-Hitachi Nuclear Energy Advanced Boiling Water Reactor Design Certification Rule Renewal ApplicationGEH Supplemental Response #4 to RAI 02-1 , November 16, 2016.

During a public teleconference held on March 2, 2017, GE Hitachi (GEH) discussed slides (Agencywide Documents Access and Management System (ADAMS) Accession No. ML 17060A476) associated with proposed Advanced Boiling-Water Reactor (ABWR) design control document (DCD) changes made to Section 3.3.1.2 provided in the response to Request for Additional Information (RAI) 02-1 . GEH also discussed proposed clarifying changes to the RAI response. The NRC summarized the teleconference in NRC memorandum of March 23, 2017 (ML 17082A215). Based on the ABWR DCD and GEH's slides, the staff identified the following :

1. The velocity pressure equation provided in Tier 2, Section 3.3.1 .2, "Determination of Applied Forces," in GEH ABWR, Revision 6, is consistent with the velocity pressure equation provided in Tier 2, Section 3.3.1.2 in GEH ABWR, Revision 4 and Eq. 3 in Section 6.5 of American Society of Civil Engineers (ASCE) 7-88, "Minimum Design Loads for Buildings and Other Structures".

2. In accordance with ASCE 7-88, the design wind velocity used in the velocity pressure equation in DCD Tier 2, Section 3.3.1.2 is assumed to be the fastest-mile wind speed. However, the new maximum hurricane wind speed site parameter value added to DCD Tier 1, Table 5.0 and Tier 2, Table 2.0-1 is defined as the nominal 3-second gust wind speed measured at 10m above ground over open terrain , which is consistent with the wind speed values presented in Regulatory Guide (RG) 1.221 .

M170090 Enclosure 1

The NRC staff provided feedback to GEH as summarized below.

Page 2 of 5

1. The staff accepted the ASCE 7-88 equation in GEH ABWR, Revision 4 as part of the review of the ABWR design certification.

2. GEH should proceed with the proposal to delete the phrase "which is consistent with that of ASCE/SEI 7-05" from the first sentence in DCD Tier 2, Section 3.3.1 .2.

3. GEH should include, in addition to the reported values in DCD Tier 1, Table 5.0, and Tier 2, Table 2.0-1 , the 3-second gust site parameter values for the severe wind speed. These tables should identify each reported value as either a 3-second gust wind speed or fastest-mile wind speed . In addition, the DCD sections where the velocity pressure equations are discussed should clearly identify the appropriate site parameter values that have been used (i.e., 3-second gust wind speed or fastest-mile wind speed).

a. GEH should confirm that the current severe wind speed site parameter values are fastestmile values, which is what ASCE 7-88 is based on. Standard Review Plan 2.3.1 (Rev. 3, March 2007) states combined license (COL) applicants should derive their 1 00-year return period site characteristic values from ASCE 7-05 which reports these values as 3-second gust wind speed values. As an example, the South Texas Project COL applicant converted the ABWR fastest-mile severe wind speed site parameter value to a 3-second gust wind speed value for comparison with their severe wind speed site characteristic value which was derived from ASCE 7-05. GEH should also discuss how the fastest mile wind speed values compare to 3-second gust wind speed values for the speeds of concern (-110-120 mph).

4. GEH should include, in addition to the reported values in DCD Tier 1, Table 5.0, and Tier 2, Table 2.0-1, the 3-second gust site parameter value for the extreme wind maximum tornado wind speed. These tables should identify each reported value as either a 3-second gust wind speed or fastest % mile wind speed.

a. GEH should confirm that the current extreme wind maximum tornado wind speed site parameter value is a fastest % mile wind speed value (the original Fujita tornado damage scale was based on the fastest % mile wind speed value). Note that the wind speed values presented in Revision 1 to RG 1.76 are 3-second gust wind speed values. GEH should also discuss how the fastest % mile wind speed values compare to 3-second gust wind speed values for the speeds of concern (-300 mph).

UPDATED RESPONSE- SUPPLEMENT 5:

Below, GEH addresses the NRC feedback and provides information regarding the associated changes to the ABWR DCD.

GEH Updated Response to RAI 02-1 (Supplement #5):

During the ABWR certification renewal , the DCD was updated to meet new regulatory guidance that addresses extreme wind gusts during hurricanes and their relations to design-basis hurricane wind and missiles, in accordance with RG 1.221 , "Design-Basis Hurricane and Hurricane Missiles for Nuclear Power Plants, " (Reference 1). GEH provided DCD markups in response to RAI 02-1 , including Supplement 1 to 4, in which the site parameter tables (Tier 1 Table 5.0 and Tier 2 Table

M170090 Enclosure 1

Page 3 of 5

2.0) were updated to include the Extreme Hurricane Design Wind loading based on '3-second gust' in accordance with RG 1.221 . The staff noted that additional clarification of the reported DCD site parameter values is needed to identify each wind loading parameter in terms of either 'fastest-mile' or '3-second gust'. Additionally, clarification of the appropriate site parameter value is needed in the DCD sections where the procedures used to transform the design wind speed into velocity pressure are described.

American Society of Civil Engineers (ASCE-7), "Minimum Design Loads for Buildings and Other Structures," is the governing standard for determination of Severe Hurricane Wind speeds and the procedure by which the wind speeds are transformed into equivalent pressure and forces on a structure. The specific edition of this standard that is applicable to the ABWR design certification is ASCE 7-88 (Reference 2). This standard was developed using the 'fastest-mile' wind speed design basis methodology.

In 1995, the ASCE 7 standard changed the design-basis methodology from 'fastest-mile' to '3-second gust'. The change impacted the contour maps, the applicable equations and coefficients for determination of equivalent wind pressures and forces on the structure. Thus, wind speeds used in the designs prior to ASCE 7-95 are not directly applicable to wind speeds used in more current designs.

Design-Basis Wind Loading

The ABWR design certification design-basis wind speed for Severe Wind loads is defined in terms of 'fastest-mile', which is consistent with the methodology prescribed in ASCE 7-88 (see Section 6.2 and Figure 1 of Reference 2) . The velocity pressure equation provided in Tier 2, Section 3.3.1.2, "Determination of Applied Forces," in the ABWR DCD, Revision 6, is consistent with the velocity pressure equation provided in Section 6.5 of ASCE 7-88.

Revision 6 of the DCD was updated to address the design wind speeds for Extreme Wind condition, using the '3-second gust' design basis wind speed , following the guidance in NRC RG 1.221. This '3-second gust' wind speed is not equivalent to the wind speed defined in ASCE 7-88 using 'fastest-mile'. Per Reference 3, "International Code Council , 2006 International Building Code", Equation 16-34, the formula given that permits the designer to convert from '3-second gust' to 'fastest-mile' basic wind speed is as follows:

Vtm = (V3s -10.5) I 1.05 (Eq. 16-34 of Reference 3)

V3s = 1.05Vtm +1 0.5

where Vtm is the 'fastest-mile' basic wind speed (mph) and V3s is the '3-second gust' basic wind speed (mph).

See Table 1 (below) for the comparison of ABWR DCD Severe and Extreme design wind speeds for 'fastest-mile' and equivalent '3-second gust' .

M170090 Enclosure 1

T bl 1 ABWR DCD H a e urn cane w· dS In >~ee

ABWR DCD Hurricane Wind Loading

50-yr Mean Recurrence Interval

Severe Wind 1 00-yr Mean Recurrence Interval

Extreme Wind

dC ompansons (1)

Fastest-Mile

177 km/hr (110mph)

197 km/hr (122mph)

257 km/hr (159.5 mph)

(1) Conversion between 'fastest-mile' and '3-second' gust per Equation 16-34 of Reference 3.

Design-Basis Tornado Characteristics

Page 4 of 5

3-Second Gust

203 km/hr (126 mph)

224 km/hr (139 mph)

286.5 km/hr (178 mph)

The ABWR design certification design-basis tornado characteristics were originally based on Revision 0 of RG 1.76 (Reference 4) in which the tornado wind speeds are characterized in fastest %-mile. At the designated fastest %-mile wind speed the corresponding 3-second gust speed is equivalent.

The procedures used to transform the tornado loading into pressure distribution and effective loads across the structures are described in DCD Section 3.3.2.2 in accordance with Bechtel Topical Report BC-TOP-3-A (Reference 5).

T arisons <1J able 2. ABWR Tornado Wind Speed Camp;

Fastest %-mile 3-Second Gust Wind Speed Wind Speed

483 Km/hr 483 km/hr (300 mph) (300 mph)

1 (1) Convers1on between Fastest Y.. -m1le and 3-Second gust per Table 2-1 of Reference 6

For the ABWR certified design site-parameters, the bounding wind speed for the structural design for the safety-related buildings is the tornado wind speed of 483 km/hr 'fastest %-mile'. This also bounds the maximum hurricane wind speed of 257 km/hr 'fastest-mile' (286.5 km/hr '3-second gust') , as explained in DCD Sections 2.2, 2.3, and 3.3.3.

Per RG 1.221 , in areas where effects of design basis tornado missiles do not bound the effects of site-specific hurricane missiles, the site-specific hurricane missile loadings should replace tornado missile loadings. These areas are limited to certain coastal regions along Southwestern Atlantic and Gulf of Mexico.

M170090 Enclosure 1

References

Page 5 of 5

1. US NRC RG 1.221 , "Design-Basis Hurricane and Hurricane Missiles for Nuclear Power Plants", Rev. 0, October 2011.

2. ANSI/ASCE 7-88, "Minimum Design Loads for Buildings and Other Structures" (DCD Reference 3.3-1).

3. International Code Council, 2006 International Building Code. International Code Council , 2006 International Building Code.

4. USNRC RG 1.76, "Design-Basis Tornado for Nuclear Power Plants", Rev. 0, April1974.

5. Bechtel Topical Report BC-TOP-3-A, Revision 3, 'Tornado and Extreme Wind Design Criteria for Nuclear Power Plants" (DCD Reference 3.3-3).

6. NUREG/CR-4461 "Tornado Climatology of the Contiguous United States", Rev. 2, February 2007.

The information presented above and the associated DCD markups provided with this response address the NRC feedback. The basis for the values that are added to the DCD site parameter tables are explained above.

Impact on DCD:

The DCD is updated to indicate the Severe and Extreme Hurricane Design Wind Speed in terms of 'fastest-mile', consistent with the ASCE 7-88 methodology. The corresponding equivalent '3-second gust' is provided in the site-parameter table to facilitate comparison of design wind speeds with respect to the applicable ASCE 7 standard referenced by the future COL applicant consistent with RG 1.221 and RG 1.76 Revision 1.

Additionally, for Tornado Wind loading , the DCD is updated to confirm the Tornado Design Wind Speed in 'Fastest %-mile'. The corresponding equivalent 3-Second gust design wind speed is also provided in the site-parameter table for future COL applicant site-specific tornado wind speed comparison.

DCD Section 1.0. DCD Tier 1, Table 5.0, and Tier 2, Table 2.0-1 , Section 3.3 and Appendix 3H are changed as shown on the DCD markups in Enclosure 2.

Enclosure 2

M170090

ABWR Design Certification Renewal Design Control Document Markups

IMPORT ANT NOTICE REGARDING CONTENTS OF THIS DOCUMENT Please Read Carefully

The information contained in this document is furnished solely for the purpose(s) stated in the transmittal letter. The only undertakings of GEH with respect to information in this document are contained in the contracts between GEH and its customers or participating utilities, and nothing contained in this document shall be construed as changing that contract. The use of this information by anyone for any purpose other than that for which it is intended is not authorized; and with respect to any unauthorized use, GEH makes no representation or warranty, and assumes no liability as to the completeness, accuracy, or usefulness of the information contained in this document.

Draft Revision 7 Pages 25A5675AA Revision 7

ABWR Design Control Document/Tier 1

5.0 Site Parameters

This section provides a definition of the site parameters used as the basis for the Certified

Design.

Site Parameters 5.0-1



Table 5.0 ABWR Site Parameters

Maximum Ground Water Level: Severe Wind: Basic Wind Speed:

61 .0 em below grade 177 km/h(I)/197 km/h(2)

Maximum Flood (or Tsunami) Level : Extreme Wind

30.5 em below grade

Tornado ~ Precipitation (for Roof Design): • Maximum tornado wind speed: 483 km/h

• Maximum rainfall rate: • Maximum pressure drop:

• Maximum snow load:

49.3 cm/h(3)

2.394 kPa • Missile spectra: .-jd-el-et-e-(8-)-,h

Hurricane ' ~ • Maximum hurricane wind speed(8l:

13.827 kPaD Spectrum rC4l

~ • Missile spectra:

Ambient Design Temperature: Soil Properties:

I% Exceedance Values • Minimum static bearing

• Maximum: 37.8°C dry bulb capacity :

25°C wet bulb (coincident) • Minimum shear wave velocity:

26.7°C wet bulb (non-coincident) • Liquefaction potential:

• Minimum:

0% Exceedance Values (Historical Limit)

• Maximum: 46.1 °C dry bulb

26.7°C wet bulb (coincident) • Minimum Dynamic Bearing

27.2°C wet bulb (non-coincident) Capacity :

• Minimum:

Exclusion Area Boundary (EAB): An area whose

boundary has a Chi/Q less than or equal to 1.37x10-3s/m3.

- 40°C • Maximum Settlement(9l: • Maximum Foundation Angular

Distortion:

Seismology:

286.5 km/h Spectrum I(4J

718.20 kPa 305 m/s(6)

None at plant site resulting from site

specific SSE ground

motion

2700 kPa

75mm

1/750(IO)

• SSE response spectra: See Figures 5.0a and 5.0b(7)

Fastest-mile (203 km/h 3- .--..., second gust) ;

Meteorological Dispersion (Chi/Q):

• Maximum 2-hour 95% EAB

• Maximum 2-hour 95% LPZ

• Maximum annual average

(8760 hour) LPZ

1.37 x 10-3 s/m3

4.11 x 10-4 s/m3

1.17 x 10-6 s/m3

(1 )'-V 50-year recurrence interval ; value to be utilized for design of non-safety-related structures only.

(2) 1 00-year recurrence interval ; value to be utilized for design for safety-related structures only.

Fastest-mile (224 km/h 3-second gust);

5.0-2

(3) Maximum value for 1 hour over 2.6 km2 probable maximum precipitation (PMP) with ratio of 5 minutes to 1 hour PMP of0.32. Maximum short-term rate: 15.7cm/5 min .

Site Parameters



(4) Spectrum I missiles consist of a massive high kinetic energy missile which deforms on impact, a rigid missile to test penetration resistance, and a small rigid missile of a size sufficient to just pass through any openings in protective barriers. These missiles consists of an 1810 kg automobile, a 130 kg, 20 em diameter armor piercing artillery shell , and a 2.54 em diameter solid steel sphere , all iA'IpaetiR§ at :J§% sf the A'l alEiA'ItJA'I hsri;:sRtal wiR sspees efthe sesi§R easis terRass sr a §9% sf the A'IOJEiA'ItJA'I hsri;:sRtal "iRs spees sf the sesi§R easis hmrieaRe. sphere. These missiles have a horizontal tornado missile velocity of 35% of the maximum tornado wind speed and a horizontal hurricane missile velocity of 59% of the maximum hurricane wind speed These missiles have a vertical tornado missile velocity of 70% of the horizontal tornado missile velocity lwith the exception of the solid steel sphere\ and a vertical hurricane missile velocity of 26 m/s. The solid steel sphere has a vertical tornado missile velocity of 35% of the maximum tornado wind speed. The automobile missile is considered to impact at all altitudes less than 9.14 m 130 feet\ above all plant grade levels within 0.8 km 10 5 mile\ of the plant structures. The armor piercing artillery shell and solid steel sphere are considered to impact the full height of the structure. The first two missiles are assumed to impact at normal incidence, the last to impinge upon barrier openings in the most damaging directions.

(5) At foundation level of the reactor and control buildings.

(6) This is the minimum shear wave velocity at low strains after the soil property uncertainties have been

applied. !per RG 1.22 1 I (7) Free-field, at plant grade elevation. T (8) RSA'I iRa l 3-second gust wind speed\fheasured at 10m above

und over open terrain.

(9) Sett ent is long term (post construction) value.

(1 0) Angular istortion is defined as the slope between two adjacent columns. Angular distortion is long term (post cons ction) value.

Fastest-mile wind speed. This co rresponds to 286 .5 km/h

(11) Maximum tornado wind speed is in fastest 1 /4-mile. The corresponding 3-second gust wind speed is 483 km/h .

Site Parameters 5.0-3

ABWR

Draft Revision 7 Pages 25A5675AD Revision 7

Design Control Document/Tier 2

2.0 Site Characteristics

2.0.1 Summary

This section defines the envelope of site-related parameters which the AB WR Standard Plant

is designed to accommodate. These parameters envelope most potential sites in the U.S. A

summary of the site envelope design parameters is given in Table 2.0-1.

2.0.2 References

2.0-1 Electric Power Research Institute, "Advanced Light Water Reactor Utility

Requirements Document," Revision 8, March 1999

Site Characteristics 2.0-1

ABWR


Table 2.0-1


Envelope of ABWR Standard Plant Site Design Parameters

Maximum Ground Water Level:* 61 .0 em below grade

Severe Wind: Basic Wind Speed: 177 km/h./ 197 km/ht

Maximum Flood (or Tsunami) Level:* 30.5 em below grade

Extreme Wind:

Tornado:

!delete ·•••·

Hurricane:

Precipitation (for Roof Design):

Ambient Design Temperature:

Soil Properties:

2.0-2

- Maximum Tornado Wind Speed: - Maximum Rotational Speed:

483km/h~ 386 km/h

-Translational Velocity: -Radius: -Maximum Pressure Drop: - ate of Pressure Drop: - · sile Spectra:

- Maxi m Hurricane Wind Speed··:

- Missile Spectra:

- Maximum Rainfall Rate: - Maximum Snow Load:

1% Exceedance Values -Maximum: 37.8°C dry bulb

97 km/h 45.7m 13.827 kPaD 8.277 kPa/s Spectrum 1!

28€Hi km/h Spectrum Jl

49.3 em/h •• 2.394 kPa

25oC wet bulb (coincident) 26.7"C wet bulb (non-coincident)

- Minimum: -23.3°C 0% Exceedance Values (Historical limit)

-Maximum 46.1 oc dry bulb 26.7"C wet bulb (coincident) 27.2°C wet bulb (non-coincident)

- Minimum: -40°C

- Minimum Static Bearing Capacity:

-Minimum Shear Wave Velocity: 718.20 kPa tt 305 m/s:)::l:

257 km/h ••• I

- Liquification Potential: None at plant site resulting from site specific SSE ground motion

Site Characteristics



Table 2.0-1 Envelope of ABWR Standard Plant Site Design Parameters (Continued)

Seismology: -SSE Peak Ground Acceleration : o.3ogff - SSE Response Spectra: per RG 1.60 -SSE Time History: Envelope SSE

Response Spectra - MmEiR'll:lR'l Minimum Dynamic

Bearing Capacity: 2700kPa - Maximum Settlement: 75mmttt -Maximum Foundation Angular

Distortion: 1 /75o:t:tt

Hazards in Site Vicinity: - Site Proximity Missiles and Aircraft -Toxic Gases :51 o-7 per year -Volcanic Activity None -An area whose boundary has a None

Exclusion Area Boundary: (EAB) Chi/Q less than or equal to 1.37 x 1 o-3 s/m3

Meteorological Dispersion (Chi/Q): - Maximum 2-hour 95% EAB 1.37x1o-3 s/m3

- Maximum 2-hour 95% LPZ 4.11x1o-4 s/m3

Fastest-mile -Maximum annual average (8760 1.17x1 o-6 s/m3

(203 km/h 3- n hour) LPZ

second gust); * ~

Fastest-mile (224 km/h 3-second gust);

50-year recurrence Interval, value to be utilized for des1gn of non-safety-related structures only.

1 00-year recurrence interval ; value to be utilized for design for safety-related structures only.

As defined in Table 1.2-6 of Volume II of Reference 2.0-1.

Spectrum I missiles consist of a massive high kinetic energy missile which deforms on impact, a rigid missile to test penetration resistance, and a small rigid missile of a size sufficient to just pass through any openings in protective barriers. These missiles consists of an 1810 kg automobile, a 130 kg , 20 em diameter armor piercing artillery shell , and a 2.54 em diameter solid steel SFJ I=l ere , all iR'lFJaetiR§ at 3§% sf tl=le R'laHiR'l i::I R'l l=lsrizeRtal wiRSSFJees ef tl=le sesi§R sas is tsrRase sr at a §9% sf tl=le R'lSJEiR'li::IR'l l=lerizsRtal Si3ees ef tl=le sesi§R sas is l=ll::lrrieaRe .sphere. These missiles have a horizontal tornado missile velocity of 35% of the maximum tornado wind speed and a horizontal hurricane missile velocity of 59% of the maximum hurricane wind speed. These missiles have a vertical tornado missile velocity of 70% of the horizontal tornado missile velocity (with the exception of the solid steel sphere) and a vertical hurricane missile velocity of 26 m/s. The solid steel sphere has a vertical tornado missile velocity of 35% of the maximum tornado wind speed. The automobile missile is considered to impact at all altitudes less than 9.14 m (30 feetl above all plant grade levels within 0.8 km 10.5 mile) of the plant structures. The armor piercing artillerv shell and solid steel sphere are considered to impact the full height of the structure. The first two missiles are assumed to impact at normal incidence, the last to impinge upon openings in the most damaging directions.

Maximum value for 1 hour over 2.6 km2 probable maximum precipitation (PMP) with ratio of 5 minutes to 1 hour PMP of 0.32 as found in National Weather Source Publication HMR No. 52. Maximum short term rate: 15.7 cm/5 min.

tt At foundation level of the reactor and control buildings.

:t::t: This is the minimum shear wave velocity at low strains after the soil property uncertainties have been applied.

Site Characteristics 2.0-3

ABWR

f f Free-field, at plant grade elevation.

ground over open terr 1


tttsettlement are long erm (post-construction) values.


:l::l::t: Angular distortion s defined as the slope between two adjacent columns. Angular distortion is long term (post constructio value.

2.0-4

Fastest-mile wind speed. This corresponds to 286.5 km/h

****Maximum tornado wind speed is in fastest 1 /4-mile. The corresponding 3-second gust wind speed is 483 km/h .

Site Characteristics

ABWR

Draft Revision 7 Pages 25A5675AE Revision 7


3.3 Severe Wind and Extreme Wind (Tornado and Hurricane) Loadings

ABWR Standard Plant structures which are Seismic Category I are designed for severe and

extreme wind phenomena.

3.3.1 Severe Wind Loads (fastest-mile) 3.3.1.1 Design Wind Velocity

Seismic Category I structures are designed to withstand a design wind velocit of 177 km/h

with a recurrence interval of 50 years and 197 km/h with a recurrence interval of 1 00 years at

an elevation of lOrn above grade (see Subsection 3.3.3.1 and 3.3.3.3 for COL license

information requirements).

3.3.1.2 Determination of Applied Forces

The design wind velocity is converted to velocity pressure using the formula given in Reference

3.3.1 v.·hie!:t is eeAsisteAt witfi tfiat efASCB/SEI 7 05 :

qz 4.94x 10-5 Kz(IV)2 ~ where Kz

v

The velocity pressure exposure coefficient which depends upon the

type of exposure and height (z) above ground per Table 6 of Reference

3.3-1

The importance factor which depends on the type of structure;

appropriate values of I are listed in Table 3.3-1

Des;gn w;nd velodty ~h a recurrence ;nterval of 50 years, ;n km/h,

and (fastest-mile) I

Velocity pressure in kPa

The design wind pressures and forces for buildings, components and cladding, and other

structures at various heights above the ground are obtained, in accordance with Table 4 of

Reference 3.3-1 by multiplying the velocity pressure by the appropriate pressure coefficients

and gust factors. Gust factors are in accordance with Table 8 of Reference 3 .3-1 . Appropriate

pressure coefficients are in accordance with Figures 2, 3a, 3b, 4, and Tables 9 and 11 through

16 of Reference 3.3-1. Reference 3.3-2 is used to obtain the effective wind pressures for cases

which Reference 3.3-1 does not cover. Since the Seismic Category I structures are not slender

or flexible , vortex-shedding analysis is not required and the above wind loading is applied as a

static load.

Applied forces for the Reactor, Control and Radwaste Buildings are found in Appendices 3H.l ,

3H.2 and 3H.3, respectively.

Severe Wind and Extreme Wind (Tornado and Hurricane) Loadings 3.3-1

ABWR



3.3.2 Extreme Wind Loads (Hurricanes and Tornados) ~~~~~~------~~

257 km/h (fastest-mile) 3.3.2.1 Applicable Design Parameters

Extreme wind loads include loads from design basis hurricane and des·on basis tornado.

The design basis hurricane is described by the following par7 rs:

(I) A maximum hurricane wind speed of286.5 kmf.A.

(2) The spectrum of hurricane generated missile and their pertinent characteristics as

given in Table 2.0-1.

The design basis tornado is described by the following parameters:

(1) A maximum tornado wind speed of483 km/h at a radius of45.7m from the center of

the tornado.

(2) A maximum translational velocity of97 km/h.

(3) A maximum tangential velocity of 386 km/h, based on the translational velocity of

97 km/h.

( 4) A maximum atmospheric pressure drop of 13.8 kPa with a rate of the pressure change

of 8.3 kPals.

(5) The spectrum of tornado-generated missiles and their pertinent characteristics as

given in Table 2.0-1 .

See Subsection 3.3 .3.2 for COL license information.

3.3.2.2 Determination of Forces on Structures The procedures for transforming extreme hurricane wind loading into effective loads and distribution across the structures are in accordance with Reference 3.3-1.

3.3-2

he procedures of transforming the tornado loading into effective loads and the distribution

across the structures are in accordance with Reference 3.3-3. The procedure for transforming

the tornado-generated missile impact into an effective or equivalent static load on structures is

given in Subsection 3.5.3.1. The loading combinations of the individual tornado loading

components and the load factors are in accordance with Reference 3.3-3. Per RG I .221, in areas

where effects of design basis tornado missiles do not bound the effects of site-specific hurricane

missiles, the site-specific hurricane loadings should replace tornado loadings. These areas arc

limited to certain coastal regions along Southwestern Atlantic and Gulf of Mexico.

The reactor building and control building are not vented structures. The exposed exterior roofs

and walls of these structures are designed for the 13.8 kPa pressure drop. Tornado dampers are

provided on all air intake and exhaust openings. These dampers are designed to withstand a

negative I 3.8 kPa pressure.

Severe Wind and Extreme Wind (Tornado and Hurricane) Loadings

ABWR



3.3.2.3 Effect of Failure of Structures, Systems or Components Not Designed for Tornado and Hurricane Loads

All safety-related systems and components are protected within tornado-resistant or hurricane

resistant structures.

See Subsection 3.3 .3.4 for COL license information requirements .

3.3.3 COL License Information

3.3.3.1 Site-Specific Design Basis Wind

The site-specific design basis wind shall not exceed the design basis wind given in Table 2.0-1

(Subsection 2.2.1 ).

3.3.3.2 Site-Specific Design Basis Tornado and Hurricane

The site-specific design basis tornado and hurricane shall not exceed the design basis tornado

and hurricane given in Table 2.0-1 (Subsection 2.2 .1 ).

3.3.3.3 Effect of Remainder of Plant Structures, Systems and Components Not Designed for Wind Loads

All remainder of plant structures, systems and components not designed for wind loads shall be

analyzed using the 1.11 importance factor or shall be checked that their mode of failure will not

effect the ability of safety-related structures, systems or components performing their intended

safety functions.

3.3.3.4 Effect of Remainder of Plant Structures, Systems, and Components Not Designed for Tornado and Hurricane Loads

All remainder of plant structures, systems, and components not designed for tornado loads _and

hurricane loads shall be analyzed for the site-specific loadings to ensure that their mode of

failure will not effect the ability of the Seismic Category I ABWR Standard Plant structures,

systems, and components to perform their intended safety functions. (See Subsection 3.3.2.3)

t-f?-881 3.3.4 References 1/ -3.3-1 ANSI/ASCE 9-, "Minimum Design Loads for Buildings and Other Structures",

}levemeer 27, 1990.

3.3-2 ASCE Paper No. 3269, "Wind Forces on Structures", Transactions of the American

Society of Civil Engineers, Vol. 126, Part II , 1961.

3.3-3 Bechtel Topical Report BC-TOP-3-A, Revision 3, "Tornado and Extreme Wind

Design Criteria for Nuclear Power Plants. "

Severe Wind and Extreme Wind (Tornado and Hurricane) Loadings 3.3-3

ABWR


Design Control DocumenVTier 2

I3H.1.4.2

Reactor Building

Radius: 45.7m

Maximum Pressure Drop: 13.83 kPa

Maximum Rate of Pressure Drop: 8.28 kPa/s

Missile Spectrum: See Table 2.0-1.

(9) Hurricane: ~ Maximum Hurricane Wind Speed*** : 286.5 km/h ~ (* **see Chapter 2, Table 2.0-1 for Notes)

Missile Spectra: Spectrum I

(10) Maximum Rainfall :

Design rainfall is 493 mm/h. Roof parapets are furnished with scuppers to

supplement roof drains, or are designed without parapets so that excessive

ponding of water cannot occur. Such roof design meets the provisions of

ASCE 7, Section 8.0.

3H.1-5