ML20137L277

Forwards,For Comment by 860224,two Draft Repts Re Pras. Insights Re Plant Strengths & Weaknesses,Core Melt Frequency,Procedural & Hardware Mods & PRA Methodologies Discussed.Repts to Be Published in 2 Months.W/O Encls

ML20137L277
Person / Time
Site:	River Bend
Issue date:	01/22/1986
From:	Stern S Office of Nuclear Reactor Regulation
To:	William Cahill GULF STATES UTILITIES CO.
References
NUDOCS 8601270379
Download: ML20137L277 (3)

Text

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JAN 2 21986 Docket No. 50-458 DISTRIBUTION

" Docket: File; SStern NRC PDR '~ EHylton Mr. William J. Cahill, Jr. Local PDR ACRS (10)

Senior Vice President PD#4 Reading River Bend Nuclear Group RBernero Gulf States Utilities Ccmpany Dewey, OELD Post Office Box 2951 EJordan Beaumont, Texas 77704 BGrines ATTN: Mr. J. E. Booker JPartlow

SUBJECT:

REPORTS ON PRA INSIGHTS Enclosed are two draft reports concerning technical insights gained from Probabilistic Risk Assessments (PRAs). These reports are the outcome of an ongoing effort to make available and utilize in numerous technical and managerial activities the information in probabilistic risk assessments regarding the factors which dominate the risk associated with nuclear power plants. This effort includes identification of the features of design or operational practices which have been found to be important to safety in the types of plants which have been subjected to risk assessments. In additicn, the section on insights into PRA method focuses on areas which are sensitive to the results and the overall perception of plant weaknesses and vulnera-bilities.

In particular, these reports contain discussions of: general insights on plant strengths and weaknesses gained from PRAs; the contribution to core melt frequency from classes of sequences induced by various initiating events; modifications, both hardware and procedural, which have been implemented to address problems identified in the conduct or as a result of PRAs; insights into PRA metnodologies; and the contribution to measures of risk (core melt frequency and consequences of radioactive releases) f rcm systems, components '

and events.

These reports will be published in their final fonns in approximately two months. These reports are being provided to you, as well as all other licensees, in advance of formal publication for your infornation. If, after reviewing these reports, you wish to provide consents to the staff, please provide them by February 24, 1986.

Sincerely, Original Signnt by Stephen Stern, Project Manager BWR Project Directorate No. 4 Division of BUR Licensing

Enclosures:

As stated U

cc' .See next page PD hPM Stern:1b 9601270379 e60122

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1. % UNITED STATES P "t, NUCLEAR REGULATORY COMMISSION y ,g wAsmNGTON, D. C. 20555 e

%.....* JAN 2 213S6 Docket No. 50-458 Mr. Willian J. Cahill, Jr.

Senior Vice President River Bend Nuclear Group Gulf States Utilities Company Post Office Box 2951 Beaumont, Texas 77704 ATTN: Mr. J. E. Booker

SUBJECT:

REPORTS ON PRA INSIGHTS Enclosed are two draft reports concerning techr.ical insights gained from Probabilistic Risk Assessments (PRAs). These reports are the outcome of an cngoing effort to make available and utilize in numerous technical and managerial activities the informaticn in probabilistic risk assessments regarding the factors which doninate the risk associated with nuclear power plants. T' 's effort includes identification of the features of design or operationai actices which havs been found to be important to safety in the types of pla ' which have been subjected to risk assessments. In addition, the section o. , sights into PRA method focuses on areas which are sensitive to the results i the overall perception of plant weaknesses and vulnera-bilities.

In particular, these reports contain discussions of: general insights en plant strengths and weaknesses gainea from PRAs; the contribution to core melt frequency from classes of sequences induced by various initiating events; modifications, both hardware and procedural, which have been implemented to address problems identified in the conduct or as a result of PRAs; insights into PRA methodologies; and the contribution to measures of risk (core celt frequency and consequences of radioactive releases) from systens, components and e ents.

These reports will be published in their final foms in approximately two mon th:, . These reports are being provided to you, as well as all other licensees, in udvance of formal publication for your information. If, after reviewing these reports, ycu wish to provide comments to the staff, please provide tFem by February 24, 1986. ,

Since e y,

'w dtyh #. Stern, Project Manager BWR Project Directorate No. 4 Division of Bkk Licensing Enc 1csures: As stated cc: See next page

t Mr. William J. Cahill, Jr.

Gulf States Utilities Company River Bend Nuclear Plant cc:

Troy B. Conner, Jr., Esq. Ms. Linda B. Watkins/Mr. Steven Irving Conner and Wetterhahn Attorney at Law 1747 Pennsylvania Averue, NW 355 Napoleon Street Washington, D.C. 20006 Baton Rouge, Louisiana 70602 Mr. William J. Reed, Jr. Mr. David Zaloudek Director - Nuclear Licensing Nuclear Energy Division i Gulf States Utilities Company Louisiana Department of

! P. O. Box 2951 Environmental Quality Beaumont, Texas 77704 P. O. Box 14690 Richard H. Troy, Jr. , Esq.

Assistant Attorney General in Charge Mr. J. David McNeill, III State of Louisiana Department of Justice William G. Davis, E:q.

234 Loyola Avenue Department of Justice New Orleans, Louisiana 70112 Attorney General's Office 7434 Perkins Road

, Resident Inspector Baton Rouge, Louisiana 70808 i P. O. Box 1051

St. Francisville, Louisiana 70775 H. Anne Plettinger 3456 Villa Rose Drive

, Gretchen R. Rothschild Baton Rouge, Louisiana 70806

Louisianians for Safe Energy, Inc. *

1659 Glenmore Avenue i baton Rouge, Louistano 70775 James W. Pierce, Jr., Esq.

P. O. Box 23571 Caton Rouge, Louisiana 70893 Regional Administrator, Region IV U.S. Nuclear Regulatory Commissicn Office of Executive Director for Operations 611 Ryan Plaza Drive, Suite 1000 Arlington, Texas 76011 t

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