ML20216D687

Forwards Request for Addl Questions for Site Audit for Resolution of Pilgrim Nuclear Power Station Individual Plant Exam of External Events Submittal

ML20216D687
Person / Time
Site:	Pilgrim
Issue date:	04/14/1998
From:	Wang A NRC (Affiliation Not Assigned)
To:	Olivier L BOSTON EDISON CO.
References
GL-88-20, TAC-M83660, NUDOCS 9804150398
Download: ML20216D687 (4)

Text

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April 14, 1998 Mr. Leon J. Olivier

- Vice President - Nuclear / Station Director Boston Edison Company Pilgrim Nuclear Power Station RFD #1 Rocky Hill Road Plymouth, MA 02360

SUBJECT:

REQUEST FOR SITE AUDIT FOR THE RESOLUTION OF THE PILGRIM NUCLEAR POWER STATION (PILGRIM) INDIVIDUAL PLANT EXAMINATION e OF EXTERNAL EVENTS (IPEEE) SUBMITTAL, (TAC NO. M83660)

Dear Mr. Olivier:

Based on the NRC's ongoing review of the Pilgrim IPEEE submittal and the Boston Edison Company's responses to the'NRC requests for additional information (RAls), the NRC has been unable to conclude that the Pilgrim IPEEE meets the intent of Supplement 4 to Generic Letter 88-20. The NRC proposes a site audit be conducted to evaluate the Pilgrim seismic analyses in more detail. The attached questions related to the seismic analyses of the IPEEE were developed to provide BECo specific detail concoming the areas of our concems.

' The NRC would propose a 3-5 day audit some time in June 1998. This is not a formal request for additional information and no written response is necessary.

Questions regarding this request should be sent to my attention at the above address; or, you a contact me at (301) 415-1445.

Sincerely, (Original signed by)

Alan B. Wang, Project Manager Project Directorate I-3 Division of Reactor Projects - 1/11 Office of Nuclear Reactor Regulation Docket No. 50-293

Enclosure:

Request for Additional Information cc w/ encl: See next page DISTRIBUTION Docket File T. Clark J. Zwolinski ACRS PUBLIC . A. Wang - C. Cowgill, Rt R. Heman PDI-3 R/F - OGC J. Chen DOCUMENT NAME: G:\ PILGRIM \A46.RAI T@ receive a copy of this document, indicate in the box: "C" = Copy without attachment / enclosure "E" = Copy with attachment / enclosure "N" = No copy OFFICE LA:PDI-3 ._ , l E PM:PDI l JA7DiPQi>3--- [N l l NAME TLClark ')n( b AWang fd W (CTE6n(as DATE 04//2/98 - 04/)498 04#998 OFFICIAL RECORD COPY ,

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Mr. Leon J. Olivier Boston Edison Company Pilgrim Nuclear Power Station oc:

Mr. Ron Ledgett' Ms. Nancy Desmond Executive Vice President Manager, Reg. Affairs Dept.

800 Boyleston Street . Pilgrim Nuclear Power Station Boston, MA 02199 RFD #1 Rocky Hill Road Plymouth, MA 02360 Resident inspector j

U. S. Nuclear Regulatory Commission Mr. David F. Tarantino Pilgrim Nuclear Power Station NuclearInformation Manager Post Office Box 867 Pilgrim Nuclear Power Station Plymouth, MA 02360 RFD #1, Rocky Hill Road Plymouth, MA 02360 _. _

Chairman, Board of Selectmen 11 Lincoln Street Ms. Kathleen M. OToole Plymouth, MA 02360 Secretary of Public Safety Executive Office of Public Safety Chairman, Duxbury Board of Selectmen One Ashburton Place Town Hall Boston, MA 02108 878 Tremont Street Duxbury, MA 02332 Mr. Peter LaPorte, Director Attn: James Mucke heide Office of the Commissioner Massachusetts Emergency Management Massachusetts Department of Agency Environmental Protection 400 Worcester Road One Winter Street P.O. Box 1496 Boston, MA 02108 Framingham, MA 01701-0317

. Office of the AMomey General Chairman, Citizcres Urging One Ashburton Place - Responsible Energy ,

20th Floor P.O. Box 2621  !

Boston, MA 02108 Duxbury, MA 02331 Mr. Robert M. Hallisey, Director Citizens at Risk i Radiation Control Program P.O. Box 3803 Massachusetts Department of Plymouth. MA 02361 1 Public Health '

305 South Street W.S. Stowe, ti4 quire  !

Boston, MA 02130 Boston Edison Company ,

800 Boyleston St.,36th Floor '

Regional Administrator, Region i Boston, MA 02199 U. S. Nuclear Regulatory Commission i 475 Allendale Road Chairman King of Prussia, PA 19406 Nuclear Matters Committee Town Hall Ms. Jane Fleming - 11 Uncoln Street 8 Oceanwood Drive Plymouth, MA 02360 Duxbury, MA 0233 '

Mr. William D. Meinert Mr. Jeffery Keene Nuclear Engineer Licensing Division Manager Massachusetts MunicipalWholesale Boston Edison Company Electric Company 4 600 Rocky Hill Road P.O. Box 426 Plymouth, MA 02360 5599 Ludlow, MA 01056-0426

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ADDITIONAL QUESTIONS FOR SITE AUDIT PILGRIM NUCLEAR PCWER STATION. UNIT 1 INQN.lDUAL PLANT EXAMINATION OF EXTERNAL EVENTS (IPEE)

Bs. sed on Boston Edison Company's (BECo/ licensee) submittal and responses to Requests for Additional Information (RAls) received to date, the NRC has been unable to conclude at this time that BECo has met the intent of Supplement 4 to Generic Letter (GL) 88-20.' The following seismic issues (additional or follow-up to previous RAls) are to be the subject of the proposed site audit. While no formal written response is necessary, BECo should be prepared 'o address the following: - - - ~

1. In NUREG-1407, Table 3.1, Pilgrim was not assigned to a seismic margin Din based upon

. BECo's commitment to perform a seismic PRA. However, it was recognized that the site had a comparatively high seismic hazard (relative to other nuclear power plant sites east of the Rocky Mountains) based on both the 1989 Electric Power Research Institute (EPRI) and 1993 Lawrence Livermore National Laboratory (LLNL) seismic hazard results.

Appendix A of NUREG-1407 specifically identified the NRC staff's conclusion that Pilgrim belonged to the 0.5g bin for seismic margin purposes. Nonetheless, the Pilgrim seismic IPEEE submittal screened components at a level of 0.3g, rather than 0.5g.

2. Be prepared to describe (with reference to NUREG-1407) the bases for employing the 0.3g screening tables for seismic capacity evaluation rather than the 0.5g screening tables. In addition, identify the structures and components which screened at 0.3g but which would not have screened using the 0.5g tables, and provide fragility estimates for those components. Also, be able to describe how the seismic core damage frequency (CDF) estimate, the identification of dominant contributing accident scenarios to the seismic CDF, and the identification of dominant seismic failures would be affected by incorporation of the additional components into the seismic PRA model.

In the seismic IPEEE submittal, the 1993 LLNL seismic hazard analysis was used as the basis for defining the spectrel shape; however, the 1989 EPRI seismic hazard analysis was used for the baseline seismic PRA calculations. This introduces an anomaly into the seismic CDF and other results of the seismic PRA.'

Provide the seismic PRA result details for calculations employing tae 1993 LLNL seismic hazard curve (e.g., seismic CDF calculations, identification of dominant contributing sequences and seismic failures) or describe how the seismic PRA results would have been affected by employing a spectral shape based on the 1989 EPRI seismic hazard estimates or the NUREG/CR-0098 spectrum (as recommended in NUREG-1407).

3. BECos IPEEE submittal and responses to previous seismic RAls 7-9 indicated that all but one of the seismic capacity estimates in the Pilgrim seismic IPEEE submittal were identified as having identical uncertainty parameters associated with their median capacity (p, = 0.46, pu = 0). This approach is not consistent with any of the guidance rited in NUP.EG-1407 (Section 3.1.1.3) for seismic PRA fragility estimation. Moreover, it is not reasonable that the uncertainty in median capacity would be the same for all components and structures.

Enclosure

1

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1 2

Be prepared to describe the technical bases for estimating the uncertainty in median i fragility employed in the seismic IPEEE submittal, with specific reference to each of the structures and components identified contributing significantly to seismic CDF. In =A.Mn.

provide revised fragility parameters (estimated in accordance with the methods identified in i Section 3.1.1.3 of NUREG-1407) for all structures and components surviving screening, and provide revised seismic PRA results based on these fragility parameters.

In addition, provide the seismic capacity evaluation and seismic fragility evaluation .

packages, including copies of any photographs taken, for the following components: (a)

- condensate storage tank, T105 NB, and nitrogen tank (interaction); (b) residual heat '

removal (RHR) loop A area cooling;-(c) RHR loop B area cooling; (d) block' wall 45.1; (e) block wall 64.50; (f) emergency diesel generator (EDG) building; (g) block wall 20g.0; (h),

480 voit emergency bus B2; and (i) AC bus AB.

4. The seismic IPEEE submittal notes the limited capacity of the north wall of the EDG building and improvements made to improve the capacity of the non-safety station blackout (SBO) diesel (responses to previous seismic RAls 3-6). No improvements to the EDG building were identified.

Be prepared to describe the rationale for making improvements to the SBO diesel versus improving the capacity of the EDG building. Identify and describe ainy improvements to the EDG building capacity that were considered (e.g., structural bracing). In addition, provide a discussion of the impact on the seismic PRA results of removing the SBO diesel from the model, identifying the estimated increase in seismic CDF which would result. Similarly, provide a discussion of the impact on the seismic PRA results of not crediting the SBO diesel improvements, identifying the estimated increase in seismic CDF which would ,

result. Finally, provide copies of any photographs taken of the SBO diesel as part of the seismic walkdown process.

5 In response to a previous request for additional information concoming resolution of  !

USl A-45 for Pilgrim for seismic events, it was identified that loss of decay heat removal scenarios are responsible for about one-third of the estimated seismic CDF. It was indiened that a substantial period of time is available for repair and recovery. l Identify the time period available for repair and recovery of loss of decay heat removal scenarios resulting from seismic events, and relate this time period to the identified seismic failure modes contributing to loss of decay heat removal (i.e., given the identified failure modes, is there sufficient time available to effect repairs and recover system l operability before containment failure and/or core damage?).' '

j l

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April 14. 1998 Mr. Leon J. Olivier -

Vice President - Nuclear / Station Director Boston Edison Company- -

Pilgrim Nuclear Power Station RFD #1 Rocky Hill Road Plymouth, MA 02360

SUBJECT:

REQUEST FOR SITE AUDIT FOR THE RESOLUTION OF THE PILGRIM -

NUCLEAR POWER STATION (PILGRIM) INDIVIDUAL PLANT EXAMINATION OF EXTERNAL EVENTS (IPEEE) SUBMITTAL, (TAC NO. M83660)

Dear Mr. Olivier:

~

Based on the NRC's ongoing . vuof the P!! grim IPEEE submittal and the Boston Edison Company's responses to the NRC requests for additional information (RAls), the NRC has been unable to conclude that the Pilgrim IPEEE meets the intent of Supplement 4 to Generic Letter 88-20.' The NRC proposes a site audit be conducted to evaluate the Pilgrim seismic analyses in more detail. The attached questions related to the seismic analyses of the IPEEE were developed to provide BEco specific detail concoming the areas of our concems.

The NRC would propose a 3-5 day audit some time in June 1998. This is not a formal request for additional information and no written response is necessary.

)

Questions regarding this request should be sent to my attention at the above address; or, you can contact me at (301) 415-1445.

i Sincerely, (Original signed by)_

Alan B. Wang, Project Manager Project Directorate 1-3 Division of Reactor Projects - t/II Office of Nuclear Reactor Regulation Docket No. 50-293 I

Enclosure:

Request for Additional Information  ;

cc w/ encl: See next page DISTRIBUTION-Docket File ~ T. Clark J. Zwolinski ACRS PUBLIC - . A. Wang C. Cowgill, RI R. Heman PDl-3 R/F . OGC J. Chen DOCUMENT NAME: G:\PILGRIMW46.RAI To receive a copy of this document, indicate in the box: "C" = Copy without attachment / enclosure "E" = Copj with attachment / enclosure "N" = No copy  !

OFFICE LA PDl ,.,,lE PM:PDI l JAJD1 PQl 3--- N l l NAME TLClark M('s AWang TLd t> dOWi6 twas DATE 04//2/98- 04/)498 ~ 04# 9 98-OFFICIAL RECORD COPY

&{fDYid1T398 9q.

Mr. Leon J. Olivier Boston Edison Company Pilgrim Nuclear Power Station cc:

Mr. Ron Ledgett Ms. Nancy Desmond Executive Vice President Manager, Reg. Affairs Dept.

800 Boyleston Street Pilgrim Nuclear Power Station Boston, MA 02199 RFD #1 Rocky Hill Road Plymouth, MA 02360 Resident inspector U. S. Nuclear Regulatory Commission Mr. David F. Tarantino

' Pilgrim Nuclear Power Station Nuclear information Manager Post Office Box 867 Pilgrim Nuclear Power Station Plymouth, MA 02360 RFD #1, Rocky Hill Road Plymouth, MA 02360 Chairman, Board of Selectmen 11 Lincoln Street Ms. Kathleen M. OToole Plymouth, MA 02360 Secretary of Public Safety Executive Office of Public Safety Chairman, Duxbury Board of Selectmen One Ashburton Place Town Hall Boston, MA 02108 878 Tremont Street Duxbury, MA 02332 Mr. Peter LaPorte, Director Attn: James Muckerheide Office of the Commissioner Massachusetts Emergency Management Massachusetts Department of Agency Environmental Protection 400 Worcester Road One Winter Street P.O. Box 1496 Boston, MA 02108 Framingham, MA 01701-0317 Office of the Attomey General Chairman, Citizens Urging One Ashburton Place Responsible Energy 20th Floor P.O. Box 2621 Boston, MA 02108 Duxbury, MA 02331 Mr. Robert M. Hallisey, Director Citizens at Risk Radiation Control Program P.O. Box 3803 Massachusetts Department of Plymouth, MA 02361 Public Health 305 South Street W.S. Stowe, Esquire Boston, MA 02130 Boston Edison Company 800 Boyleston St.,36th Floor Regional Administrator, Region i Bos'on, MA 02199 U. S. Nuclear Regulatory Commission 475 Allendale Road Chairman King of Prussia, PA 19406 Nuclear Matters Committee Town Hall Ms. Jane Fleming 11 Lincoln Street 8 Oceanwood Drive Plymouth, MA 02360 Duxbury, MA 0'!33 Mr. William D. Meinert Mr. Jeffery Keene Nuclear Engineer

' Licensing Division Manager Massachusetts Municipal Wholesale Boston Edison Company Electric Company 600 Rocky Hill Road P.O. Box 426 Plymouth, MA 02360-5599 Ludlow, MA 01056-0426

ADDITIONAL QUESTIONS FOR SITE AUDIT PILGRIM NUCLEAR POWER STATION. UNIT 1 INDIVIDUAL PL. ANT EXAMINATION OF EXTERNAL EVENTS (IPEE)

Based on Boston Edison Company's (BECo/ licensee) submittal and responses to Requests for Additional Information (RAls) received to date, the NRC has been unable to conclude at this time

- that BECo has met the intent of Supplement 4 to Generic Letter (GL) 88-20. The following seismic issues (additional or follow-up to previous RAls) are to be the subject of the proposed site audit. While no formal written response is necessary, BECo should be prepared to address the following: - - -

1. .1 NUREG-1407, Table 3.1, Pilgrim was not assigned to a seismic margin bin based upon BECo's cornmitment to perform a seismic PRA. However, it was recognized that the site had a comparatively high seismic hazard (relative to other nuclear power plant sites east of the Rocky Mountains) based on both the 1989 Electric Power Research Institute (EPRI) and 1993 Lawrence Livermore National Laboratory (LLNL) seismic hazard results.

Appendix A of NUREG-1407 specifically identified the NRC staff's conclusion that Pilgrim belonged to the 0.5g bin for seismic margin purposes. Nonetheless, the Pilgrim seismic IPEEE submittal screened components at a level of 0.3g, rather than 0.5g.

2. Be prepared to describe (with reference to NUREG-1407) the bases for employing the 0.3g screening tables for seismic capacity evaluation rather than the 0.5g screening tables. In addition, identify the structures and components which screened at 0.3g but which would not have screened using the 0.5g tables, and provide fragility estimates for those components. Also, be able to describe how the seismic core damage frequency (CDF) estimate, the identification of dominant contributing accident scenarios to the seismic CDF, and the identification of dominant seismic failures would be affected by incorporation of the additional components into the seismic PRA model.

In the seismic IPEEE submittal, the 1993 LLNL seismic hazard analysis was used as the basis for defining the spectral shape; however, the 1989 EPRI seismic hazard analysis was used for the baseline seismic PRA calculations. This introduces an anomaly into the seismic CDF and other results of the seismic PRA.

Provide the seismic PRA result details for calculations employing the 1993 LLNL seismic hazard curve (e.g., seismic CDF calculations, identification of dominan' contributing sequences and seismic failures) or describe how the seismic PRA results would have been affected by empicying a spectral shape based on the 1989 EPRI seismic hazard estimates or the NUREG/CR-0098 spectrum (as recommended in NUREG-1407).

3. BECos IPEEE submittal and responses to previous seismic RAls 7-9 indicated that all but one of the seismic capacity estimates in the Pilgrim seismic IPEEE submittal were identified as having identical uncertainty parameters associated with their median capacity (p, = 0.46. Eu = 0).' This approach is not consistent with any of the guidance cited in NUREG-1407 (Section 3.1.1.3) for seismic PRA fragility estimation. Moreover, it is not j reasonable that the uncertainty in median capacity would be the same for all components and structures.

Enclosure 4

~

E Be prepared to desenbe the technical bases for estimating the uncertainty in median fragility employed in the seismic IPEEE submittal, with specific reference to each of the structures and components identified contributing significantly to seismic CDF. In addition, provide revised fragility parameters (estimated in accordance with the methods identified in Section 3.1.1.3 of NUREG-1407) for all structures and components surviving screening, and provide revised seismic PRA results based on these fragility parameters.

In addition, provide the seismic cepecity evaluation and seismic fragility evaluation ,

packages, including copies of any photographs taken, for the following components: (a) condensate storage tank,.T105 NB, and nitrogen tank (interaction); (b) residual heat removal (RHR) loop A area cooling; (c) RHR loop B area cooling; (d) block wall 45.1; (e) block wall 64.50; (f) emergency diesel generator (EDG) building; (g) block wall 209.0; (h),

480 volt emergency bus B2; and (i) AC bus A8.

4. The seismic IPEEE submittal notes the limited cepacity of the north wall of the EDG building and improvements made to improve the capacity of the non-safety station blackout (SBO) diesel (responses to previous seismic RAls 3-6). No improvements to the EDG .

building were identified.

Be prepared to describe the rationale for making improvements to the SBO diesel versus improving the capacity of the EDG building. Identify and describe ainy improvements to the EDG building capacity that were considered (e.g., structural bracing). In addition,' provide a discussion of the impact on the seismic PRA results of removing the SBO diesel from the model, identifying the estimated increase in seismic CDF which would result. Similarty, provide a discussion of the impact on the seismic PRA results of not crediting the SBO diesel improvernents, identifying the estimated increase in seismic CDF which would result. Finally, provide copies of any photographs taken of the SBO diesel as part of the seismic walkdown process.

5. In response to a previous request for additional information concoming resolution of USl A-45 for Pilgrim for seismic events, it was identified that loss of decay heat removal scenarios are responsible for about one-third of the estimated seismic CDF. It was indicated that a substantial period of time is available for repair and recovery.

Identify the time period available for repair and recovery of loss of decay heat removal scenarios resulting from seismic events, and relate this time period to the identified seismic failure modes contributing to loss of decay heat removal (i.e., given the identified failure modes, is there sufficient time available to effect repairs and recover system operability before containment failure and/or core damage?).

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