ML20137L291

Forwards for Comments 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

ML20137L291
Person / Time
Site:	Clinton
Issue date:	01/22/1986
From:	Siegel B Office of Nuclear Reactor Regulation
To:	Spangenberg F ILLINOIS POWER CO.
References
NUDOCS 8601270389
Download: ML20137L291 (3)

Text

_ _ _ - _ _ -. .

l l Jail 22 1 3 Docket No. 50-461 DISTRIBUTION l Docket File- BSiegel NRC PDR EHylton Local PDR ACRS (10)

Mr. Frank A. Spangenberg PD#4 Reading Manager - Licensing and Safety RBernero Clinton Power Station Goddard, OELD P.O. Box 306 EJordan Mail Code V920 BGrimes Clinton, Illinois 61727 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 it:elt 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 melt frequency and consequences of radioactive releases) from systems, components and events.

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

Sincerely, oriennt sienot r,y Byron Siegel, Project Manager BWR Project Directorate No. 4 Division of BUR Licensing

Enclosures:

As stated cc: See next page odee

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1. 4 UNITED STATES

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$ . ,E WASHINGTON, D. C. 20555

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/ JMi 2 21956 Docket I:o. 50-461 th.FrankA.Spangenberg lianager - Licensing and Safety Clinton Power Station P.O. Box 306 Mail Code V920 Clinton, Illinois 61727

SUBJECT:

REPORTS ON PRA INSIGHTS Enclosed are two draft reports concerning technical insights gained from Probabilistic Risk Assessments (PRAs). These reports are the outcone of an ongoing effort to make available and utilize in numerous technical and managerial activities the information in probabilistic risk assessrients regarding the factors which dominate the risk associated with nuclear powcr 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 addition, 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 PFAs; the contribution to core melt frequency from classes of sequences induced by various initiating events; modifications, both hardware and procedural, which have been iraplemented to address probices identified in the conduct or as a result of PRAs; insights into PRA methodologies; and the contribution to measures of risk (core raelt frequency and consequences of radioactive releases) f rom systems, compor.cr.ts and events.

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

Sincerely, ,

P f /

!Qjui Zlif Byron Siegel, Project Manager BWR Project Directorate lio. 4 Division of BWR Licensing

Enclosures:

As stated cc: See next page

Mr. Frank A. Spangenberg Clinton Power Station Illinois Power Company Unit I cc:

Mark Jason Jean Foy, Esquire Assistant Attorney General 511 W. Nevada Public Utilities Division Urbana, Illinois 61801 Office of the Attorney General State of Illinois Center Pichard B. Hubbard 100 West Randolph Street - 12th Floor Vice President

Chicago, Illinois 60601 Technical Associates 1723 Hanilton Avenue - Suite K Mr. D. P. Hall San Jose, California 95125 Vice President Clinton Power Station P. O. Box 678 Clinton, Illinois, 61727 Mr. D. C. Shelton Manager-Nuclear Station Engineering Dpt.

Clinton Power Station P. O. Box 678 Clinton, Illinois 61727 Sheldon Zabel, Esquire Schiff, Hardin & Waite 7200 Sears Tower

• 233 Macker Drive Chicago, Illinois 60606 Resident Inspector

(' U. S. Nuclear Regulatory Commission RR 3, Box 229 A Clinton, Illinois 61727 Mr. R. C. Heider

. Project Manager Sargent & Lundy Engineers '

. E5 East Monroe Street Chicago, Illinois 60603

,- Mr. L. Larson Project Manager General Electric Company 175 Curtner Avenue, h/C 305

, San Jose, California 95125 Regional Administrator, Region III 799 Roosevelt Road Glen Ellyn, Illinois 60137 i

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