ML16216A059

Proposed Priority Rankings of Generic Issues: Ninth Group

ML16216A059
Person / Time
Issue date:	07/20/1995
From:	Banks M Advisory Committee on Reactor Safeguards
To:	Taylor J NRC/EDO
References
D950720
Download: ML16216A059 (5)

Text

D950720 Mr. James M. Taylor Executive Director for Operations U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001

SUBJECT:

PROPOSED PRIORITY RANKINGS OF GENERIC ISSUES: NINTH GROUP During the 422nd meeting of the Advisory Committee on Reactor Safeguards, June 8-10, 1995, we reviewed the priority rankings proposed by the NRC staff for the generic issues listed in the attached Table A. During this meeting, we had the benefit of discussions with representatives of the NRC staff. We also discussed this matter during our 423rd meeting on July 13-14, 1995.

Our comments on various generic issues considered during this meeting are contained in the following attachments:

Attachment 1 lists those generic issues for which we agree with the proposed priority rankings.

Attachment 2 identifies the issues for which we agree with the proposed priority rankings, but have comments.

Attachment 3 identifies the issue for which we disagree with the proposed priority ranking.

In addition to our comments on the priority rankings of those issues considered at this time, we are concerned that the prioritization process is not timely for some generic safety issues. Currently, three identified issues still await assignment of priority. One was first identified for prioritization in February 1991. However, we note that for the issues scheduled for resolution, the timeliness of resolution appears to be improving.

We note that often the title of a generic issue is much broader than the scope of the issue actually being addressed in the determination of priority. Examples are GSI-149, "Adequacy of Fire Barriers," and GSI-160, "Spurious Actuations of Instrumentation Upon Restoration of Power." Although we may agree with the priority assigned to the narrow issue defined by the scope, we do not wish to imply that we would agree that such a priority is necessarily appropriate for the larger issue denoted by the title.

Sincerely,

/s/

T. S. Kress Chairman

Attachments:

As noted above TABLE A GENERIC ISSUES REVIEWED BY THE ACRS DURING THE 422ND MEETING, JUNE 8-10, 1995 Generic Priority Ranking Issue Proposed by Reference Number Title the NRC Staff Document 149 Adequacy of Fire Barriers LOW Memorandum from E. Beckjord to W. Minners, Oct 19, 1992 158 Performance of Safety-Related MEDIUM Memorandum from Power-Operated Valves Under E. Beckjord to Design-Basis Conditions J. Murphy, Jan 26, 1994 159 Qualification of Safety-DROP Memorandum from Related Pumps While Running E. Beckjord to on Minimum Flow W. Minners, Sep 22, 1993 160 Spurious Actuations of DROP Memorandum from Instrumentation Upon E. Beckjord to Restoration of Power W. Minners, Sep 30, 1993 161 Use of Non-Safety-Related DROP Memorandum from Power Supplies in Safety-E. Beckjord to Related Circuits (previously T. Murley, called "Associated Circuits") Mar 12, 1993 162 Inadequate Technical DROP Memorandum from Specifications for Shared E. Beckjord to Systems at Multiplant Sites W. Minners, When One Unit is Shut Down Jul 29, 1993

164 Neutron Fluence in Reactor DROP Memorandum from Vessel (Ongoing RES E. Beckjord to efforts T. Murley, adequately Nov 30, 1992 address this issue.)

165 Spring-Actuated Safety and HIGH Memorandum from Relief Valve Reliability E. Beckjord to W. Minners, Nov 26, 1993 166 Adequacy of Fatigue Life of NEARLY RESOLVED Memorandum from Metal Components E. Beckjord and T. Murley to J. Sniezek, Apr 1, 1993 167 Hydrogen Storage Facility LOW Memorandum from Separation E. Beckjord to J. Murphy, Sep 29, 1994 168 Environmental Qualification NEARLY RESOLVED Memorandum from of Electrical Equipment E. Beckjord and T. Murley to J. Sniezek, Apr 1, 1993 ATTACHMENT 1 LIST OF GENERIC ISSUES FOR WHICH THE ACRS AGREES WITH THE PRIORITY RANKINGS PROPOSED BY THE NRC STAFF Generic Issue No. Title 158 Performance of Safety-Related Power-Operated Valves Under Design-Basis Conditions 159 Qualification of Safety-Related Pumps While Running on Minimum Flow 161 Use of Non-Safety-Related Power Supplies in Safety-Related

Circuits 164 Neutron Fluence in Reactor Vessel 165 Spring-Actuated Safety and Relief Valve Reliability 166 Adequacy of Fatigue Life of Metal Components 167 Hydrogen Storage Facility Separation 168 Environmental Qualification of Electrical Equipment ATTACHMENT 2 GENERIC ISSUES FOR WHICH THE ACRS AGREES WITH THE PRIORITY RANKINGS PROPOSED BY THE NRC STAFF BUT WITH COMMENTS Generic Issue No.: 160

Title:

Spurious Actuations of Instrumentation Upon Restoration of Power Proposed Priority Ranking: DROP ACRS Comment: The scope of the prioritization analysis appears limited to the risk associated with (1) inadvertent actuation of low-temperature overpressure-protection relief valve and (2) inter-system LOCA due to inadvertent opening of a low-pressure safety-injection (LPSI) discharge valve, combined with check valve failure, resulting in over-pressurization of the LPSI system from reactor coolant system pressure. This scope seems overly narrow, particularly in view of the continuing digitization of instrumentation and control (I&C) systems in operating nuclear power plants. The digitization of I&C systems warrants careful recon-sideration of issues which originated with analog-based I&C systems, but which may become more risk significant due to the nature of digital technology. It may be appropriate to address this issue in the revision to the NRC Standard Review Plan.

Generic Issue No.: 162

Title:

Inadequate Technical Specifications for Shared Systems at Multiplant Sites When One Unit is Shut Down Proposed Priority Ranking: DROP ACRS Comment: We note that the prioritization analysis did not

encompass the Susquehanna spent fuel pool issue, which partly involved shared cooling systems at a multiplant site and upon which we commented in our letter of December 19, 1994. We believe that reconsideration of the scope of systems included in the prioritization analysis may be needed.

ATTACHMENT 3 GENERIC ISSUE FOR WHICH THE ACRS DISAGREES WITH THE PRIORITY RANKING PROPOSED BY THE NRC STAFF Generic Issue No.: 149

Title:

Adequacy of Fire Barriers Proposed Priority Ranking: LOW ACRS MEDIUM Recommendation:

Basis: The focus of this GSI is on overpressurization of fire barrier seals in room penetrations. Nuclear plant fire barrier qualification is usually based on meeting the ASTM-119 or NFPA-251/252 Standards. As noted in NUREG-0933, testing to these Standards does not always simulate realistic nuclear plant fire conditions.

Accounting for the difference between these Standards and realistic conditions is a necessary first step to be taken before assessing the safety significance of specific issues such as this one. Accordingly, we believe that additional work needs to be done on this generic issue. Alternatively, such penetration seal issues as overpressurization could be included in the scope of NRR's current task action plan on fire protection requirements.