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,.j j BROOKHAVEN NATIONAL LABORATORY a _,
ASSOCIATED UNIVERSITIES, INC.
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u Od Upton. Long istcnd. New York 11973 (516) 282N FTS 666' 2444 Deportrnent of Nuclect Energys s
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October 17, 1983
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Dr. Themis P. Speis, Director Division of Safety Technology t
Office of Nuclear Reactor Regulation i
U. S. Nuclear Regulatory Commission i
Washington, D. C.
20555 I
Dear Dr. Speis:
A proposal (Form 189) entitled " Review of Probabilistic Risk Assessment for the Shoreham Nuclear Power Plant" has been sent to NRC under separate cover.
As per discussion between R. A. Bari and A. Tnadani, the work described in the 189, at the stated level of effort, is consistent with BNL's assessment of the resource re More specifically, BNL re-quires that (1)quirements for a PRA of this scope.
the initial PRA submittal and supporting documentation be essen-1 t
tially complete at the initiation of the review, (2) BNL participation in i
requests for clarifying information (including BNL participation in formal Q's to an applicant) during the course of the review will be cbtained only if it is determined that it is needed by BNL, (3) a quantitative evaluation of the core melt frequency will be performed, and (4) a qualitative evaluation of uncertain-ties will be performed.
i However, a comprehensive review of the PRA, that is, one that will include j
a quantitative uncertainty assessment and an importance/ sensitivity analysis, will require an additional 10 staff-months of effort. We believe that a quan-titative uncertainty analysis that provides the range of possible values of the j
core damage frequency (and of accident sequences) along with the corresponding likelihood of each value and an importance analysis that enables the performance of various sensitivity studies, are essential parts of the PRA review and will greatly facilitate and rationalize the associated regulatory decision making.
We expect that the total level of effort for a comprehensive PRA review will decrease from the presently estimated three staff years (for a Level 1 PRA without external events) to a lower level, as the PRA methodology and documenta-tion matures and stabilizes. At the present time, however, the novelty, diversity and differences of the various PRAs require the aforementioned level of effort for review.
8507150097 850426 PDR FOIA BELAIRB5-199 PDR
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Dr. Themis P. Speis October 17, 1983 3
2 We are awaiting further guidance from you.
If you desire any additional j
information in this respect, please feel free to call Dr. R. A. Bari (FTS 666-2629) or me.
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Sincerely yours, l
W
.l Walter / airman Kato Depu h
s WYK/dt cc:
R. A. Bari I. A. Papazoglou A.- C. Thadani 1
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