ML16223A299

Draft Report of the PRA Working Group

ML16223A299
Person / Time
Issue date:	05/20/1993
From:	Shewmon P Advisory Committee on Reactor Safeguards
To:	Taylor J NRC/EDO
References
D930520
Download: ML16223A299 (2)

Text

D930520 Mr. James M. Taylor Executive Director for Operations U. S. Nuclear Regulatory Commission Washington, D.C. 20555

SUBJECT:

DRAFT REPORT OF THE PRA WORKING GROUP During the 397th meeting of the Advisory Committee on Reactor Safeguards, May 13-15, 1993, we discussed the draft report prepared by the NRC staff's PRA Working Group to document its activities during the past year and to provide recommendations on the use of PRA by the staff. Our Subcommittee on Probabilistic Risk Assessment held a meeting on May 11, 1993, to discuss this matter.

During these meetings, we had the benefit of discussions with representatives of the staff.

The PRA Working Group provided us with a copy of the April 1993 draft of its proposed report to you, and the comments of its External Review Group on an earlier draft that we have not seen.

We believe that the PRA Working Group is carrying out its mission within the defined scope of the Program Plan. Also, much of the Working Group's effort and material will be useful. However, judging from the questions raised during our briefings, we think that the report is currently inadequate. It has taken nearly two years to reach this point, and the investment of further and expanded effort could be cost-effective. In retrospect, it may well be that the problems derive from the limited scope of the Program Plan.

The PRA Working Group was made aware of our concerns during the meetings. We would like, therefore, to defer our detailed recommendations until another round of external review has occurred. If the effect is to be substantial and positive, the report should have a minimum of rough edges.

The PRA Working Group is relatively small, composed of part-time players, few of whom have any direct and substantial experience participating in a real PRA. The group of four external reviewers, though uniformly of high quality, includes only one with substantial direct PRA experience. And we have seen little evidence that the vast industry experience in living with PRA has been tapped in any substantial way by the PRA Working Group.

We are further concerned that resources are being expended on efforts to define what PRA is, rather than on how it should be used within the agency. Substantial literature exists which defines what PRA is, and identifies the availability of appropriate data and models.

One of the external reviewers said of the earlier draft, "The

fundamental questions of why and how NRC should use PRA have not been answered." The PRA Working Group considers these strategic questions outside the scope of the Program Plan. Yet, without attention to that overriding issue, this effort remains misdirected.

We believe that this issue can only be addressed by a collaboration between the PRA Working Group and high-level NRC management. The issue is of sufficiently high policy significance that it should not be delegated to middle management.

Sincerely, Paul Shewmon Chairman

Reference:

Memorandum dated April 22, 1993, from Eric S. Beckjord, Director, Office of Nuclear Regulatory Research, for James M. Taylor, EDO,

Subject:

Draft Report of the PRA Working Group (Includes External Reviewers' Comments on Previous Draft)