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{{#Wiki_filter:NRC Public Meeting Fukushima Near-Term Task Force Recommendation 2.1SeismicRe
{{#Wiki_filter:NRC Public Meeting Fukushima Near-Term Task Force Recommendation 2.1 Seismic Re-evaluation and Screening Results Surry Power Station - Units 1 and 2 Mill t Millstone Unit U it 2 Dominion June 25, 2014
-evaluationandScreeningResults Seismic Re-evaluation and Screening ResultsSurry Power Station -Units 1 and 2 MilltUit2 Millstone Unit 2DominionJune25,2014 June 25, 2014 AgendaAgenda *SurryGMRSDifferences Surry GMRS Differences*Introduction
*NRCandEPRIGMRS NRC and EPRI GMRSand Surry SSE Comparison*Velocity Profiles*Basis for Kappa
*Basis for Depth to Hard Rock S*Summary *ConclusionMilltUit2DftRAI2*Millstone Unit 2 -Draft RAIs Introduction Introduction*Dominion followed the NRC-endorsed industry guidance (EPRI1025287SPID)todeveloptheSurryground (EPRI 1025287 -SPID) to develop the Surry ground motion response spectrum (GMRS) in response to the NRC 10CFR 50.54(f) request for information letter*Dominion submitted the GMRS/hazard curves and screening results for Surry Power Station Units 1 and 2 onMarch312014 on March 31, 2014*The objective of this meeting is to discuss the identified differences between the Surry submittal and NRC confirmatory results, i.e., shear wave velocity profiles,


total effective kappa and depth to hard rock
Agenda
*Dominionwillpresentthebasisforthe information 3*Dominion will present the basis for the information provided in the submittal related to these differences Surry GMRS and SSE CiComparison*Surry is a low seismic hazard site (SSE spectral peak < 0.23g at 5% damping)*GMRS (Dominion) enveloped by SSE*GMRS (NRC) <0.29g (est.) spectral peak*NRC GMRS confirmatory analysis differences-Shear Wave Velocity (Vs) Profiles-Total Kappa Value (0.027s [NRC] vs. 0.034s [Dominion])-Depth to Hard Rock (1460' [NRC] vs. 1700' [Dominion])
* Surry GMRS Differences
4 GMRS and SSE CiComparison5 VsProfiles Vs Profiles*Basis for Shear Wave Velocity (Vs) Profiles
* Introduction
-Site-specific geotechnical profile data from Report Table 2.3.2-1SSEcontrolpointatsurface(26
* NRC and EPRI GMRS and Surry SSE Comparison
'6El)-SSE control point at surface (266 El.)-Vs values
* Velocity Profiles
*Compactedfill
* Basis for Kappa
-16'-1000fpsCompacted fill 16 1000 fps*Upper 140' -based on sampler penetration tests (hammer blows)*Uncertaintyfactorof157appliedbasedonlimiteddata
* Basis for Depth to Hard Rock
*Uncertainty factor of 1.57 applied based on limited data-Profiles reflect site-specific estimated Vs values
* Summary S
-Nogradientappliedsincesoftsoilsite(consistent 6No gradient applied since soft soil site (consistent with SPID)
* Conclusion
VsProfiles Vs Profiles7 VsProfiles Vs Profiles8 CalculationofKappa Calculation of Kappa*Basis For Estimate of Total Effective Kappa-Kappa = 0.034s based on SPID Appendix B.5.1.3.1 guidancefor soil site with <3,000 ft depth to hard rock
* Millstone Mill t      U Unit it 2 - Draft D ft RAIs RAI 2
-Contributions from soil ( 1,600 ft) plus underlying hard rock
-Soil contribution from empirical relation based


on soil depth 9-Hard rock contribution 0.006s DepthtoHardRock Depth to Hard Rock*Surry Screening Report:  'Hard rock' (i.e., shear wave litV9200ft/)ltitd 1700'velocity, Vs, >9200 ft/sec) elevation reported as -1700'*Based on review of USGS Professional Paper No. 1612 (Feb22,2000) 1(Feb 22, 2000)*Extrapolation of borehole 60 (Hog Island) [Plate 4] -
Introduction
indicates 'crystalline basement rocks' reached at
* Dominion followed the NRC-endorsed industry guidance (EPRI 1025287 - SPID) to develop the Surry ground motion response spectrum (GMRS) in response to the NRC 10CFR 50.54(f) request for information letter
'approximately -1600
* Dominion submitted the GMRS/hazard curves and screening results for Surry Power Station Units 1 and 2 on March 3131, 2014
'*Additional 100' depth to Vs=9200 ft/sec was assumed in ordertoaccountforlikelyweatheringeffectsduringthe order to account for likely weathering effects during the period the Potomac formation was being deposited 1USGS Professional Paper No. 1612, The Effects of the Chesapeake Bay Impact Crater on the Geological Framework and Correlation of H ydrogeologicUnits of the Lower York-James Peninsula
* The objective of this meeting is to discuss the identified differences between the Surry submittal and NRC confirmatory results, i.e., shear wave velocity profiles, total effective kappa and depth to hard rock
, Virginia.10ygg,g DepthtoHardRock Depth to Hard Rock11 DepthtoHardRock Depth to Hard Rock12 SummarySummary*SurryGMRSandscreeningresultsdeveloped Surry GMRS and screening results developed based on the NRC-endorsed EPRI SPID
* Dominion will present the basis for the information provided in the submittal related to these differences 3


Guidance*Surry Vs profiles are based on site-specific data and develo ped consistent with SPID p*Surry site kappa value consistent with SPID Appendix B methodolo gyppgy*Surry site depth to hard rock is based on a reasonable inter pretation of available data 13p Conclusion Conclusion
Surry GMRS and SSE C
*SurryGMRSandscreeningresultsare Surry GMRS and screening results are consistent with industry guidance
Comparison    i
*Surryscreensoutfromperformanceoffurther Surry screens out from performance of further seismic risk assessment, high frequency confirmation, and s pent fuel pool evaluation pp*Expedited Seismic Evaluation Process (ESEP) is not re quired per the Au gmented Approach qpgppguidance (EPRI 3002000704) 14 MillstoneUnit2 Millstone Unit 2*TheMillstoneUnit2GMRSandscreening The Millstone Unit 2 GMRS and screening submittal provided the screening results based
* Surry is a low seismic hazard site (SSE spectral peak < 0.23g at 5% damping)
* GMRS (Dominion) enveloped by SSE
* GMRS (NRC) <0.29g (est.) spectral peak
* NRC GMRS confirmatory analysis differences
  - Shear Wave Velocity (Vs) Profiles
  - Total Kappa Value (0.027s [NRC] vs. 0.034s [Dominion])
  - Depth to Hard Rock (1460 [NRC] vs. 1700 [Dominion])
4


on comparison of the GMRS to the IPEEE HCLPF spectrum (IHS) per the SPID guidance*NRC has drafted two re quests for additional qinformation related to the Millstone Unit 2 submittal*Dominion has reviewed these requests and is providing information for discussion 15 MillstoneUnit2 Millstone Unit 2*Request 1q-In the IPEEE adequacy review supporting IHS screening, HCLPF capacity calculations could not be located for resolution of two items:
GMRS and SSE C
(1) Battery Racks DB1 and DB2
Comparison i
, and (2) Chilled ()y,()Water Surge Tank. The submittal indicates that calculations were subsequently reconstituted for these components with
5


acceptable results.-Provide a detailed description of the methods and inputs for the evaluation of the battery racks and chilled water surge tank performed for the submittal p-Provide a detailed description of any modifications to these components performed to support the reconstitution of the
Vs Profiles
* Basis for Shear Wave Velocity (Vs) Profiles
  - Site-specific geotechnical profile data from Report Table 2.3.2-1
  - SSE control point at surface (266 (26 6 El El.))
  - Vs values
* Compacted fill - 16 16 - 1000 fps
* Upper 140 - based on sampler penetration tests (hammer blows)
* Uncertainty factor of 1 1.57 57 applied based on limited data
  - Profiles reflect site-specific estimated Vs values
  - No gradient applied since soft soil site (consistent with SPID) 6


calculations 16 MillstoneUnit2 Millstone Unit 2*Request 1 Discussion q-The calculations were reconstituted for these components to resolve comments from the IPEEE adequacy review.Themethodsusedinthesetworecentcalculationsare
Vs Profiles 7
-The methods used in these two recent calculations are consistent with the Seismic Margin Assessment (SMA) methodology in EPRI NP-6041 SL, Rev. 1 and were independentlyreviewedThecapacitiesofbothitemsare independently reviewed. The capacities of both items are >0.25g, therefore plant HCLPF remains unchanged.-There were no new modifications to improve the HCLPF of the batteryracksorthechilledwatersurgetankcomponentsafter battery racks or the chilled water surge tank components after the IPEEE submittal and closure of IPEEE open issues.
17 MillstoneUnit2 Millstone Unit 2*Request2Request 2-The Millstone Unit 2 IPEEE submittal included "Opportunities for Safety Enhancements" and identified valve 2-CHW-11 as an item to be resolved.
This air operated valve has a heavy yoke that is


independently braced.py-Provide a detailed description of how this item was resolved and its safety significance related to the lHCLPFf02 plant HCLPF of 0.25g18 MillstoneUnit2 Millstone Unit 2*Request 2 Discussion
Vs Profiles 8
-The vital chilled water s ystem (CHW) provides chilled water for y()pthe DC Switchgear Room HVAC system, which is a support system. Valve 2-CHW-11 provides isolation from the non-seismic portion of the system.-The CHW system is a two-train system and failure of 2-CHW-11 only affects one train. The room cooling support function is


maintained b y the redundant train. Therefore, valve 2-CHW-11 yhas low safety significance.-Valve 2-CHW-11 is top-braced at the valve actuator. The top bracing, and pipe supports in the vicinit y of the valve
Calculation of Kappa
, are g,ppppy,anchored to the same structure and stresses due to differential
* Basis For Estimate of Total Effective Kappa
  - Kappa = 0.034s based on SPID Appendix B.5.1.3.1 guidance for soil site with <3,000 ft depth to hard rock
  - Contributions from soil ( 1,600 ft) plus underlying hard rock
  - Soil contribution from empirical relation based on soil depth
  - Hard rock contribution 0.006s 9


displacement are minimal.
Depth to Hard Rock
-Thevalvewasanalyzedinthisconfigurationandconfirmedto 19The valve was analyzed in this configuration and confirmed to meet the design basis requirements as part of the USI A-46
* Surry Screening Report: Hard rock (i.e., shear wave velocity, l it V      Vs, >9200 9200 ft/sec) ft/        ) elevation l      ti reported        t d as -17001700
* Based on review of USGS Professional Paper No. 1612 (Feb 22, 2000)1
* Extrapolation of borehole 60 (Hog Island) [Plate 4] -
indicates crystalline basement rocks reached at approximately -1600
* Additional 100 depth to Vs=9200 ft/sec was assumed in order to account for likely weathering effects during the period the Potomac formation was being deposited 1 USGS Professional Paper No. 1612, The Effects of the Chesapeake Bay Impact Crater on the Geological Framework and Correlation of Hydrogeologic y g      g Units of the Lower York-James Peninsula,, Virginia.
g 10


program.}}
Depth to Hard Rock 11
 
Depth to Hard Rock 12
 
Summary
* Surry GMRS and screening results developed based on the NRC-endorsed EPRI SPID Guidance
* Surry Vs profiles are based on site-specific data and developed p consistent with SPID
* Surry site kappa value consistent with SPID Appendix pp      B methodology gy
* Surry site depth to hard rock is based on a reasonable interpretation p        of available data 13
 
Conclusion
* Surry GMRS and screening results are consistent with industry guidance
* Surry screens out from performance of further seismic risk assessment, high frequency confirmation, and spent p    fuel p pool evaluation
* Expedited Seismic Evaluation Process (ESEP) is not required q      p per the Augmented g        Approach pp guidance (EPRI 3002000704) 14
 
Millstone Unit 2
* The Millstone Unit 2 GMRS and screening submittal provided the screening results based on comparison of the GMRS to the IPEEE HCLPF spectrum (IHS) per the SPID guidance
* NRC has drafted two requests q      for additional information related to the Millstone Unit 2 submittal
* Dominion has reviewed these requests and is providing information for discussion 15
 
Millstone Unit 2
* Request q      1
  - In the IPEEE adequacy review supporting IHS screening, HCLPF capacity calculations could not be located for resolution of two items: ((1)) Batteryy Racks DB1 and DB2,, and (2)
( ) Chilled Water Surge Tank. The submittal indicates that calculations were subsequently reconstituted for these components with acceptable results.
  - Provide a detailed description of the methods and inputs for the evaluation of the battery racks and chilled water surge tank performed for the submittal p
  - Provide a detailed description of any modifications to these components performed to support the reconstitution of the calculations 16
 
Millstone Unit 2
* Request q      1 Discussion
  - The calculations were reconstituted for these components to resolve comments from the IPEEE adequacy review.
  - The methods used in these two recent calculations are consistent with the Seismic Margin Assessment (SMA) methodology in EPRI NP-6041 SL, Rev. 1 and were independently reviewed reviewed. The capacities of both items are
    >0.25g, therefore plant HCLPF remains unchanged.
  - There were no new modifications to improve the HCLPF of the battery racks or the chilled water surge tank components after the IPEEE submittal and closure of IPEEE open issues.
17
 
Millstone Unit 2
* Request 2
  - The Millstone Unit 2 IPEEE submittal included Opportunities for Safety Enhancements and identified valve 2-CHW-11 as an item to be resolved.
This air operated valve has a heavy yoke that is independently p        y braced.
  - Provide a detailed description of how this item was resolved and its safety significance related to the plant l  HCLPF off 0.25g 02 18
 
Millstone Unit 2
* Request 2 Discussion
  - The vital chilled water system y      ((CHW)) p provides chilled water for the DC Switchgear Room HVAC system, which is a support system. Valve 2-CHW-11 provides isolation from the non-seismic portion of the system.
  - The CHW system is a two-train system and failure of 2-CHW-11 only affects one train. The room cooling support function is maintained by  y the redundant train. Therefore, valve 2-CHW-11 has low safety significance.
  - Valve 2-CHW-11 is top-braced at the valve actuator. The top g, and pipe bracing,      p p supports pp    in the vicinity y of the valve,, are anchored to the same structure and stresses due to differential displacement are minimal.
  - The valve was analyzed in this configuration and confirmed to meet the design basis requirements as part of the USI A-46 program.                                                           19}}

Latest revision as of 03:07, 4 November 2019

6/25/2014, Dominion Public Meeting Presentation for Surry GMRS Profile
ML14176A092
Person / Time
Site: Millstone, Surry  Dominion icon.png
Issue date: 06/25/2014
From:
Dominion, Nuclear Management Co, Virginia Electric & Power Co (VEPCO)
To:
Division of Inspection and Regional Support
References
Download: ML14176A092 (19)


Text

NRC Public Meeting Fukushima Near-Term Task Force Recommendation 2.1 Seismic Re-evaluation and Screening Results Surry Power Station - Units 1 and 2 Mill t Millstone Unit U it 2 Dominion June 25, 2014

Agenda

  • Surry GMRS Differences
  • Introduction
  • Velocity Profiles
  • Basis for Kappa
  • Basis for Depth to Hard Rock
  • Summary S
  • Conclusion
  • Millstone Mill t U Unit it 2 - Draft D ft RAIs RAI 2

Introduction

  • Dominion followed the NRC-endorsed industry guidance (EPRI 1025287 - SPID) to develop the Surry ground motion response spectrum (GMRS) in response to the NRC 10CFR 50.54(f) request for information letter
  • Dominion submitted the GMRS/hazard curves and screening results for Surry Power Station Units 1 and 2 on March 3131, 2014
  • The objective of this meeting is to discuss the identified differences between the Surry submittal and NRC confirmatory results, i.e., shear wave velocity profiles, total effective kappa and depth to hard rock
  • Dominion will present the basis for the information provided in the submittal related to these differences 3

Surry GMRS and SSE C

Comparison i

  • Surry is a low seismic hazard site (SSE spectral peak < 0.23g at 5% damping)
  • GMRS (NRC) <0.29g (est.) spectral peak
  • NRC GMRS confirmatory analysis differences

- Shear Wave Velocity (Vs) Profiles

- Total Kappa Value (0.027s [NRC] vs. 0.034s [Dominion])

- Depth to Hard Rock (1460 [NRC] vs. 1700 [Dominion])

4

GMRS and SSE C

Comparison i

5

Vs Profiles

  • Basis for Shear Wave Velocity (Vs) Profiles

- Site-specific geotechnical profile data from Report Table 2.3.2-1

- SSE control point at surface (266 (26 6 El El.))

- Vs values

  • Compacted fill - 16 16 - 1000 fps
  • Upper 140 - based on sampler penetration tests (hammer blows)
  • Uncertainty factor of 1 1.57 57 applied based on limited data

- Profiles reflect site-specific estimated Vs values

- No gradient applied since soft soil site (consistent with SPID) 6

Vs Profiles 7

Vs Profiles 8

Calculation of Kappa

  • Basis For Estimate of Total Effective Kappa

- Kappa = 0.034s based on SPID Appendix B.5.1.3.1 guidance for soil site with <3,000 ft depth to hard rock

- Contributions from soil ( 1,600 ft) plus underlying hard rock

- Soil contribution from empirical relation based on soil depth

- Hard rock contribution 0.006s 9

Depth to Hard Rock

  • Surry Screening Report: Hard rock (i.e., shear wave velocity, l it V Vs, >9200 9200 ft/sec) ft/ ) elevation l ti reported t d as -17001700
  • Based on review of USGS Professional Paper No. 1612 (Feb 22, 2000)1
  • Extrapolation of borehole 60 (Hog Island) [Plate 4] -

indicates crystalline basement rocks reached at approximately -1600

  • Additional 100 depth to Vs=9200 ft/sec was assumed in order to account for likely weathering effects during the period the Potomac formation was being deposited 1 USGS Professional Paper No. 1612, The Effects of the Chesapeake Bay Impact Crater on the Geological Framework and Correlation of Hydrogeologic y g g Units of the Lower York-James Peninsula,, Virginia.

g 10

Depth to Hard Rock 11

Depth to Hard Rock 12

Summary

  • Surry GMRS and screening results developed based on the NRC-endorsed EPRI SPID Guidance
  • Surry Vs profiles are based on site-specific data and developed p consistent with SPID
  • Surry site kappa value consistent with SPID Appendix pp B methodology gy
  • Surry site depth to hard rock is based on a reasonable interpretation p of available data 13

Conclusion

  • Surry GMRS and screening results are consistent with industry guidance
  • Surry screens out from performance of further seismic risk assessment, high frequency confirmation, and spent p fuel p pool evaluation
  • Expedited Seismic Evaluation Process (ESEP) is not required q p per the Augmented g Approach pp guidance (EPRI 3002000704) 14

Millstone Unit 2

  • The Millstone Unit 2 GMRS and screening submittal provided the screening results based on comparison of the GMRS to the IPEEE HCLPF spectrum (IHS) per the SPID guidance
  • NRC has drafted two requests q for additional information related to the Millstone Unit 2 submittal
  • Dominion has reviewed these requests and is providing information for discussion 15

Millstone Unit 2

  • Request q 1

- In the IPEEE adequacy review supporting IHS screening, HCLPF capacity calculations could not be located for resolution of two items: ((1)) Batteryy Racks DB1 and DB2,, and (2)

( ) Chilled Water Surge Tank. The submittal indicates that calculations were subsequently reconstituted for these components with acceptable results.

- Provide a detailed description of the methods and inputs for the evaluation of the battery racks and chilled water surge tank performed for the submittal p

- Provide a detailed description of any modifications to these components performed to support the reconstitution of the calculations 16

Millstone Unit 2

  • Request q 1 Discussion

- The calculations were reconstituted for these components to resolve comments from the IPEEE adequacy review.

- The methods used in these two recent calculations are consistent with the Seismic Margin Assessment (SMA) methodology in EPRI NP-6041 SL, Rev. 1 and were independently reviewed reviewed. The capacities of both items are

>0.25g, therefore plant HCLPF remains unchanged.

- There were no new modifications to improve the HCLPF of the battery racks or the chilled water surge tank components after the IPEEE submittal and closure of IPEEE open issues.

17

Millstone Unit 2

  • Request 2

- The Millstone Unit 2 IPEEE submittal included Opportunities for Safety Enhancements and identified valve 2-CHW-11 as an item to be resolved.

This air operated valve has a heavy yoke that is independently p y braced.

- Provide a detailed description of how this item was resolved and its safety significance related to the plant l HCLPF off 0.25g 02 18

Millstone Unit 2

  • Request 2 Discussion

- The vital chilled water system y ((CHW)) p provides chilled water for the DC Switchgear Room HVAC system, which is a support system. Valve 2-CHW-11 provides isolation from the non-seismic portion of the system.

- The CHW system is a two-train system and failure of 2-CHW-11 only affects one train. The room cooling support function is maintained by y the redundant train. Therefore, valve 2-CHW-11 has low safety significance.

- Valve 2-CHW-11 is top-braced at the valve actuator. The top g, and pipe bracing, p p supports pp in the vicinity y of the valve,, are anchored to the same structure and stresses due to differential displacement are minimal.

- The valve was analyzed in this configuration and confirmed to meet the design basis requirements as part of the USI A-46 program. 19