ML19325E525

Responds to Generic Ltr 88-20,Suppl 1,describing Plan for Completing Individual Plant Exam for Severe Accident Vulnerabilities.Performance of Level 1 PRA Based on Current Plant Design & Operation Intended

ML19325E525
Person / Time
Site:	Pilgrim
Issue date:	10/27/1989
From:	Bird R BOSTON EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
RTR-NUREG-CR-2300, RTR-NUREG-CR-2815 BECO-89-159, GL-88-20, NUDOCS 8911070344
Download: ML19325E525 (2)

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,' ,e j e aosnwansaw I

, hignm Nuclear Ftwer statiori l

Rot 6 y Hill Road i Plymouth, Masuchusetts 02360 1

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naiph c. s6te  !

Senior Vice President - Nuclear i BECo 89 159 l U.S. Nuclear Regul0 tory Commission October M,1989 Document Control Desk i Washington, DC .20555 }

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License DPR-35 i Docket 50-293 '

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RESPONSE TO GENERIC LETTER 88-20. SU_PPLEMENT 1  !

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i This letter describes Boston Edison's program plan for completing an Individual  !

Plant Examination (IPE) for severe accident vulnerabilities for the Pilgrim i Nuclear Power Station (PNPS). t i

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Boston Edison intends to perform a Level 1 Probabilistic Risk Assessitent (PRA) i based on current plant design and operation. The method will be consistent  ;

with NUREG/CR-2300 "PRA Procedures Guide", and accepted PRA guidance i documents. Fault tree linking methodology will be used for the front-end j systems analysis. The current plan is to use EPRI's CAFTA code for fault tree i analysis and the MAAP code for the determination of system success criteria i where appropriate. Previous effortt conducted on the performance of a i preliminary PNPS Probabilistic Safety Assessment, based on NUREG/CR-2815,  !

"Probabilistic Safety Analysis Procedures Guide", and an Individual Plant l Evaluation, based on the IDCOR methodology, will be incorporated into the PRA. '

I The IDCOR IPE methodology will be used in those areas where the NRC has found  ;

the methodology useful and acceptable. ,

t The back-end containment analysis will be performed in accordance with the  ;

guidai!:e provided in Appendix 1 to Generic Letter 88-20. " Guidance on the >

Examination of Containment System Performance", and Appendix A to NUREG-1335, i i, " Approach to Back-end Portion of IPE". MAAP will be used to simulate severe >

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accident progression and better define the phenomena occurring during the [

L postulated severe accidents.

L The schedule for ccmpletion of the IPE is tieing developed in conjunction with  !

,, our Long Term Program (LTP) integrated work management process and will be j i reported in the 1990 semi-annual LTP update. ,

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l G911070344 091027 PDR '

P ADOCK 05000293 PNV pq [

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DOSTON EDISON COMPANY

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O.i.1[uclea'r Yegulatory Commission Page Two l

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! Implementation of containment performance improvements began at PNPS as part of l r

our self-initiated Safety Enhancement Program (SEP). Regarding the potential '

Mark 1 enhancements discussed in Generic 1.etter 88-20 Supplement 1, we have i

already installed a hardened vent path, modified existing structures to provide

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an alternate source of water injection into the vessel, < mplemented Revision 4  ;

of the EPGs, and installed a backup nitrogen supply system to provide longer i term pneumatic control capability to the Automatic Depressurization System. i

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I u(_ - -

R. G. Bird j JDKlamm/3786 ) t Commonwealth of Massachusetts)  !

Ccunty of Plymouth ) I

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Then personally appeared before me, Ralph G. Bird, who being duly sworn, did state that he is Senior Vice President - Nuclear of Boston Edison Company and i that he is duly authorized to execute and file the submittal contained herein '

in the name and on behalf of Boston Edison Company and that the statements in ,

said submittal are true to the best of his knowledge and belief.

My commission expires: ddL;g /#g ght  !

DATE ' f NOTARY'PUBLIC

cc: Mr. D. Mcdonald, Project Manager .

Division of Reactor Projects - I/II i Office of Nuclear Reactor Regulation -

Mail Stop: 14D1  ;

U. S. Nuclear Regulatory Commission i 1 White Flint North  :

11555 Rockville Pike Rockville, MD 02852 -

U. S. Nuclear Regulatory Commission l Region I l 475 Allendale Road King of Prussia, PA 19406

, Senior NRC Resident Inspector [

Pilgrim Nuclear Power Station  :

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