ML16204A248
| ML16204A248 | |
| Person / Time | |
|---|---|
| Issue date: | 08/15/1996 |
| From: | Banks M Advisory Committee on Reactor Safeguards |
| To: | |
| References | |
| Download: ML16204A248 (3) | |
Text
August 15, 1996 The Honorable Shirley Ann Jackson Chairman U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001
Dear Chairman Jackson:
SUBJECT:
SECY-96-128, "POLICY AND KEY TECHNICAL ISSUES PERTAINING TO THE WESTINGHOUSE AP600 STANDARDIZED PASSIVE REACTOR DESIGN" During the 433rd meeting of the Advisory Committee on Reactor Safeguards, August 8-10, 1996, we reviewed the subject document. Our Subcommittee on Westinghouse Standard Plant Designs met on July 19, 1996 to review this matter.
During this review, we had the benefit of discussions with representatives of the staff and of the Westinghouse Electric Corporation. We also had the benefit of the documents referenced.
Conclusion We endorse the positions recommended by the staff in addressing the following three policy issues pertaining to the Westinghouse AP600 standardized passive reactor design.
Policy Issues Prevention and Mitigation of Severe Accidents The staff is seeking Commission approval to consider the use of non-safety systems in the AP600 design to address the uncertainties associated with the passive fission product removal mechanisms for design-basis analysis and for balance between prevention and mitigation of severe accidents.
Westinghouse has no objection to the staff's crediting of non-safety equipment that is already a part of the AP600 design, but objects to a requirement for adding a non-safety-grade containment spray system.
The applicant's submittals provide some support for demonstrating fission product removal using only passive removal mechanisms.
Nonetheless, we are persuaded by the staff position that systems beyond the passive removal mechanisms should be evaluated to provide greater confidence in the performance of the plant design in mitigating design-basis and severe accidents. We recommend Commission approval.
External Reactor Vessel Cooling The staff is seeking Commission approval for requiring that the applicant provide limited analytical evaluation of postulated ex-vessel phenomena, notwithstanding that the AP600 design is intended to prevent reactor vessel melt-through. We recommend Commission approval.
Post-72-hour Actions The staff is seeking Commission approval for requiring that the AP600 design be capable of sustaining all design-basis events with onsite equipment and supplies for the long term. We recommend Commission approval.
Technical Issues The staff added spent fuel pool cooling to its list of technical issues being tracked in the review. At present, the applicant will be required to provide additional onsite capability to remove decay heat from the spent fuel pool over an extended period of time. We believe this requirement may be found unnecessary after considering the low risk associated with the current design.
Dr. Dana A. Powers did not participate in the Committee's deliberations regarding the severe accident source term. Dr. T. S. Kress did not participate in the Committee's deliberations regarding external reactor vessel cooling.
Sincerely,
/s/
T. S. Kress Chairman
References:
- 1. U. S. Nuclear Regulatory Commission, SECY-96-128, dated June 12,
- 1996, from James M. Taylor, Executive Director for Operations, NRC, to the Commissioners,
Subject:
Policy and Key Technical Issues Pertaining to the Westinghouse AP600 Standardized Passive Reactor Design
- 2. Letter dated June 15, 1995, from T.S. Kress, Chairman, ACRS, to James M.
Taylor, Executive Director for Operations, NRC,
Subject:
Proposed Commission Paper on Staff Positions on Technical Issues Pertaining to the Westinghouse AP600 Standardized Passive Reactor Design
- 3. Letter dated August 8, 1995, from James M. Taylor, Executive Director for Operations, NRC, to T.S. Kress, Chairman, ACRS,
Subject:
Response
to ACRS Comments on Commission Paper on Technical Issues Pertaining to the Westinghouse AP600 Design