ML20137J786

Forwards Draft Repts Re Technical Insights Gained from PRAs for Review by 860210.Repts Discuss General Insights on Plant Strengths & Weaknesses & Contribution to Core Melt Frequency from Sequences Induced by Initiating Events.W/O Encls

ML20137J786
Person / Time
Site:	Fort Calhoun
Issue date:	01/09/1986
From:	Thadani A Office of Nuclear Reactor Regulation
To:	Andrews R OMAHA PUBLIC POWER DISTRICT
References
NUDOCS 8601230208
Download: ML20137J786 (2)

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. January 9, 1986 i

Docket No. 50-285 NRC & Local PDR ACRS (10) FMiraglia FTC File JPartlow PKreutzer BGrimes ETourigny AThadani PWR8 Reading EJordan Docket File Mr. R. L. Andrews Division Manager - Nuclear Production Omaha Public Power District 1623 Harney Street Omaha, Nebraska 6810?

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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 addition, the section on insights into PPA methodologies focuses on areas which are sensitive to the results and the overall perception of plant weaknesses and l vulnerabilities.

in particular, these reports contain discussions of: general insights on plant j

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 methodologies; and the contribution to measures of risk (core melt frecuency and consequences of radioactive releases) from systems, components and events.

These reports will be published in their final forms in approximately two months.

l These reports are being provided to you, as well as all other ifcensees, in

advance of formal publication for your information. If, af ter reviewing these '

l reports, you wish to provide comments to the staff, please provide then by February 10, 1986 l

i Sincerely.

/S/

0601230200 960109 Ashok Thadani. Director PDH ADOCM 05000205 PWR Pro. ject Directorate #8 P PDN Division of PWR Licensing - B

Enclosures:

As Stated cc w/o enclosures:

See next page l' PBDd8 PBD@l*/I PRD#

ETourigny;ef AThe ani PKp{jutzer

['/ /86 / / ') /86 // /86 i

Mr. R. L. Andrews Fort Calhoun Station Omaha Public Power District tinit No, I cc:

Harry H. Voigt, Esq.

LeBoeuf, Lamb, Leiby & MacRae 1333 New Hampshire Avenue, NW Washington, D.C. 20036 Mr. Jack Jensen, Chairman Washington County Roard of Supervisors Blair, Nebraska 68023 Metropolitan Planning Agency ATTN: Dagnia Prieditis 7000 West Center Road Omaha, Nebraska 68107 Mr. Phillip Harrell, Resident Inspector U.S. Nuclear Regulatory Commission P. O. Box 309 Fort Calhoun, Nebraska 68023 Mr. Charles B. Brinkman, Manager Washington Nuclear Operatins C-E Power Systems 7910 Woodmont Avenue Bethesda, Maryland 20814 Regional Administrator, Region IV U.S. Nuclear Regulatory Commission Office of Executive Director for Operations 611 Ryan Plaza Drive, Suite 1000 Arlington, Texas 76011 1

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