ML16211A204

Proposed Final Policy Statement on the Use of Probabilistic Risk Assessment Methods in Nuclear Regulatory Activities

ML16211A204
Person / Time
Issue date:	06/16/1995
From:	Kress T Advisory Committee on Reactor Safeguards
To:	Selin I NRC/Chairman
References
D950616
Download: ML16211A204 (2)

Text

D950616 The Honorable Ivan Selin Chairman U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001

SUBJECT:

PROPOSED FINAL POLICY STATEMENT ON THE USE OF PROBABILISTIC RISK ASSESSMENT METHODS IN NUCLEAR REGULATORY ACTIVITIES During the 422nd meeting of the Advisory Committee on Reactor Safeguards, June 8-10, 1995, we reviewed the proposed final Policy Statement on the Use of Probabilistic Risk Assessment Methods in Nuclear Regulatory Activities. We had the benefit of presentations by the NRC staff concerning the resolution of public comments as well as comments we made on a draft version of the Policy Statement. We also had the benefit of presentations by representatives of the Nuclear Energy Institute concerning a draft PSA Applications Guide. Finally, we had the benefit of the referenced documents.

We support a policy statement that encourages the use of probabilistic risk assessment (PRA) methods in nuclear regulatory activities. A policy statement that extends the use of such methods beyond the regulation of nuclear power reactors into other areas within the jurisdiction of the NRC provides a welcome opportunity to improve both the efficiency and the effectiveness of the body of the NRC regulations. Revisions made to the Policy Statement accommodate comments we made on an earlier draft. We feel it useful to issue a policy statement to update positions adopted in the past by the NRC concerning the use of PRA.

We are interested in the challenges that will have to be met to implement the Policy Statement. Technically defensible, risk-based regulatory activities will require the availability of PRAs that are adequately complete and of acceptable quality.

Uncertainties in the results of these risk assessments will have to be characterized adequately. The staff indicated that it is aware of these needs. We look forward to hearing more about staff efforts to define standards for PRAs and strategies that will be adopted to audit and to review PRAs submitted by licensees.

The staff is now considering the decision criteria that will be used in conjunction with the application of PRAs. The staff has stated that it feels inhibited from using the NRC safety goals in decisions concerning specific plants. We encourage the use of technically defensible PRA methods for risk management of individual plants consistent with the NRC safety goals. We note that, in such applications, these goals should not be treated as safety criteria. We believe that plant-specific risk management

is an important subject which we plan to pursue. We will report on our findings in the future.

The widespread use of PRA methods within the NRC will necessitate a cultural change within the agency. The staff will have to be receptive to different approaches to given issues by different licensees. Training for the staff may need to be on more than PRA applications and methods. For instance, training in formal decision analysis methods may also assist the needed change in culture at the NRC. We are interested in the full scope of the training program in PRA being developed for the NRC staff. We plan to review this training program and the PRA research program that NRC supports.

The Policy Statement calls for the consideration of the use of PRA methods in areas where these methods have not heretofore been extensively used. Consequently, the methods for these new applications are not as well developed as they are for application to nuclear power plants. The NRC may need to support an expanded research effort in the development of PRA methods for application in these new areas.

Sincerely, T. S. Kress Chairman

References:

1. SECY-95-126 dated May 18, 1995, from James M. Taylor, Executive Director for Operations, NRC, for the Commissioners,

Subject:

Final Policy Statement on the Use of Probabilistic Risk Assessment Methods in Nuclear Regulatory Activities (Draft Predecisional)

2. ACRS Report dated May 11, 1994, from T. S. Kress, Chairman, ACRS, to James M. Taylor, Executive Director for Operations, NRC,

Subject:

Draft Policy Statement on the Use of Probabilistic Risk Assessment Methods in Reactor Regulatory Activities

3. Letter dated January 17, 1995, from William H. Rasin, Nu-clear Energy Institute, to Ashok C. Thadani, Office of Nu-clear Reactor Regulation, NRC, transmitting final draft of PSA Applications Guide

4. ACRS Report dated May 13, 1987, from William Kerr, Chairman, ACRS, to The Honorable Lando W. Zech, Chairman, NRC,

Subject:

ACRS Comments On An Implementation Plan For The Safety Goal Policy