ML20058F175
| ML20058F175 | |
| Person / Time | |
|---|---|
| Issue date: | 11/10/1993 |
| From: | Wilkins J Advisory Committee on Reactor Safeguards |
| To: | Selin I, The Chairman NRC COMMISSION (OCM) |
| References | |
| ACRS-R-1540, NUDOCS 9312080022 | |
| Download: ML20058F175 (2) | |
Text
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NUCLEAR REGULATORY COMMISSION ACRSR-1540 n
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'E ADVISORY COMMITTEE ON REACTOR SAFEGUARDS o
WASHINGTON, D. C. 20555 5
p November 10, 1993 The Honorable Ivan Selin Chairman U.S.
Nuclear Regulatory Commission Washington, D.C.
20555
Dear Chairman Selin:
SUBJECT:
DRAFT FINAL REPORT OF THE PRA WORKING GROUP During the 403rd meeting of the Advisory Committee on Reactor Safeguards, November 4-6, 1993, we heard presentations by the NRC staff on the draft final report of the PRA Working Group and its recommendations to the Commission.
We also had the benefit of the documents referenced, of which we call special attention to the November 2,
1993 letter of the NRC Office Directors to the Executive Director for Operations.
In general, we were favorably impressed by the report, and of course gratified that the final version took account of many of the concerns expressed by the external reviewers and by us.
In some
- cases, the responses were aspirational (i.e.,
to the pivotal concern that there is as yet no NRC policy on how PRA should be used in regulation, the report acknowledges that that is important and needs to be addressed), but even aspirational responses are better than denials that there is a problem.
What really matters, of course, is the extent to which NRC will in fact enhance its capabilities, tune its regulatory activities to the risk posed by the objects of regulation, and adjust its life style to the new awareness of the implications of probabilistic analysis.
In this context we welcome the November 2, 1993 letter mentioned above, which records the intent of the Office Directors to develop a plan for the application of PRA throughout the agency, and to do so by December 30, 1993.
In such a short time span, especially at this time of year, it is not possible to do more than establish a program plan, and make the commitment of resources.
Given the magnitude of the job, the history of inconsistency and unevenness in the use of PRA, the frequent misunderstandings, etc.,
those resources will have to be substantial if the job is to be taken seriously.
We have to reserve judgment until we can see if the actions match the words.
9322080022 931310 PDR ACRS R-1540 pop gl / D
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The Honorable Ivan Selin 2
November 10, 1993 Still, we think that the PRA Working Group has done a creditable job, especially given the limited resources it had available, and we are heartened by the positive response accorded its report by the senior staff.
Some of the problems left for the future are, though acknowledged, extremely difficult and fundamental.
A central issue since the beginning is to find a mechanism for the incorporation of risk-based, and therefore probabilistic, considerations into a determin-istic regulatory struccure.
The Committee has only hinted at the existence of technigdes for doing this, and the question is left entirely open by the PRA Working Group. It will not be simple, especially in an agency whose staff has limited training and experience in such matters.
We are therefore pleased that the Working Group has produced a valuable report, and that the senior staff appears to be taking it seriously. After the battle at El Alamein in World War II, Winston Churchill said that it was not the end, nor even the beginning of the end, but that perhaps it was the end of the beginning.
We have the same cautious hope. We remain interested in this activity, and
+
would like to be kept aware of the progress.
)
Sincerely,
/A.Em J.
Ernest Wilk ns, Jr.
Chairman
References:
1.
Memorandum dated October 8, 1993, from Warren Minners, NRC, for John T. Larkins, ACRS,
Subject:
PRA Working Group Draft i
Final Report (Draft Predecisional) 2.
Memorandum dated November 2, 1993, from NRC Office Directors (NRR, RES, AEOD, NMSS) for James M.
Taylor, NRC Executive Director for Operations,
Subject:
Agency Directions for Current and Future Uses of Probabilistic Risk Assessment (PRA) 3.
Letter dated May 20, 1993, from Paul Shewmon, ACRS Chairman, to James M.
Taylor, NRC Executive Director for Operations,
Subject:
Draft Report of the PRA Working Group j
4.
Letter dated July 19, 1991, from David A. Ward, ACRS Chairman, to the Honorable Ivan Selin, NRC Chairman,
Subject:
The Consistent Use of Probabilistic Risk Assessment l
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