ML20206S762
| ML20206S762 | |
| Person / Time | |
|---|---|
| Issue date: | 11/12/1998 |
| From: | Advisory Committee on Reactor Safeguards |
| To: | Advisory Committee on Reactor Safeguards |
| References | |
| ACRS-3127, NUDOCS 9905210211 | |
| Download: ML20206S762 (6) | |
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CERTIFIED BY:
Date issued: 11/12/98 George Apostolakis - 11/20/98 ADVISORY COMMITTEE ON REACTOR SAFEGUARDS MEETING OF THE SUBCOMMITTEE ON RELIABILITY AND PROBABILISTIC RISK ASSESSMENT MEETING MINUTES - SEPTEMBER 24,1998 ROCKVILLE, MARYLAND INTRODUCTION The ACRS Subcommittee on Reliability and Probabilistic Risk Assessment (RPRA) met on September 24,1998, at 11545 Rockville Pike, Rockville, MD, in Room T-2B3. The purpose of this meeting was to discuss proposed options for developing a risk-informed i
approach to revising 10 CFR 50.59 (Changes, tests and experiments), options for broader changes to 10 CFR Part 50, and industry initiatives to certify probabilistic risk assessments (PRAs).
The entire meeting was open to public attendance. Mr. Michael T. Markley was the cognizant ACRS staff engineer for this meeting. The meeting was convened at 8:30 a.m. and adjoumed at 3:10 p.m.
ATTENDEES ACRS Members G. Apostolakis, Chairman D. Miller, Member M. Fontana, Member G. Wallis, Member T. Kress, Member M. Markley, ACRS Staff Princloal NRC Soeakers R. Barrett, NRR*
G. Holahan, NRR M. Cunningham, RES*
T. King, RES M. Drouin, RES E. McKenna, NRR J. Guttmann, RES PrincioalIndustry Soeakers B. Bradley, NEl*
NRR Office of Nuclear Reactor Regulation 7
RES Office of Nuclear Regulatory Research gcgM
,i NEl Nuclear Energy Institute g.L P ~
F'CYO 9905210211 981112 A
PDR ACRS DESICTATD ORIGillAL 3127 N
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Minutes There were approximately 7 members of the public in attendance at this meeting. A complete list of attendees is in the ACRS Office File, and will be made available upon request. The presentation slides and handouts used during the meeting are attached to the office copy of these minutes.
OPENING REMARKS BY THE SUBCOMMITTEE CHAIRMAN Dr. Apostolakis convened the meeting at 8:30 a.m. He stated that purpose of this I
meeting was to discuss proposed options for developing a risk-informed approach to revising 10 CFR 50.59 (Changes, tests and experiments), options for broader changes to 10 CFR Part 50, and industry initiatives to certify probabilistic risk assessments (PRAs).
Dr. Apostolakis stated that the Subcommittee had received no written comments or requests for time to make oral statements from members of the public.
DISCUSSION OF AGENDA ITEMS ACRS Presentation Dr. Thomas Kress provided a brief presentation of his views on making 10 CFR 50.59 risk-informed. He discussed the need to establish ground rules and assumptions regarding licensee participation in a risk-informed process, expectations for quantitative evaluation of risk, and a definition of what is considered risk-insignificant. He also offered a proposal for the staff and industry representatives to consider. Significant points made during the discussion include:
All licensees should be allowed to participate regardless of current risk status.
e The risk impact of proposed changes should be evaluated quantitatively, when e
possible. However, most changes under 10 CFR 50.59 are likely to be so small that PRAs will be insensitive to quantifying risk.
e The major difficulty lies in defining what is risk insignificant and criterion for allowing changes that are risk insignificant.
Core damage frequency (CDF) and risk achievement worth (RAW) should be used as acceptance criterion. Dr. Kress proposed that CDF-RAW of 1E-7 or IE-8 per reactor-year would be acceptable and 1E-6 per reactor-year would be unacceptable under his proposed approach to 10 CFR 50.59.
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Minutes NRC Presentation Messrs. Thomas King, RES, and Gary Holahan, NRR, led the discussions for the NRC staff regarding options to make 10 CFR Part 50 risk-informed. Messrs. Mark Cunningham, RES, and Richard Barrett, NRR, provided supporting discussion. Ms.
Mary Drouin and Mr. Jack Guttman, RES, and Eileen McKenna, NRR, discussed options for making 10 CFR 50.59 risk-informed. Messrs. Thomas King, Gary Holahan, and Ms. Mary Drouin discussed the planned staff review of industry initiatives to certify PRAs. Significant points made during the discussion include:
Agency requirements for reactors are based on the concepts of design-basis e
accidents and safety systems using traditional engineering approaches.
Proposed changes would allow use of risk information to provide flexibility in e
plant designMicensing basis.
Potential elements for constructing options to make Part 50 risk-informed include:
Redefine scope of requirements including the definition of " safety-related,"
Maintenance Rule, and 10 CFR Part 50, Appendix B (QA)
Make the change process per 10 CFR 50.59 risk-informed Allow alternatives to current operations and designMicensing requirements Add specific regulations to address license amendments, enforcement, and plant performance assessment Policy issues include: mandatory versus voluntary considerations, plant e
operation under exemptions, consideration of scope (i.e., design, operational, equipment pedigree, and process requirements), and relationship to ongoing rulemaking activities (e.g., Maintenance Rule, event reporting, etc.).
implementation issues include: selection of systems, structures, and components e
(SSCs), PRA quality, inclusion of risk significant equipment into a new safety-related category, inspection, enforcement, and plant performance assessment.
Key areas under consideration for revising 10 CFR 50.59 are the scope (related e
to FSAR and Technical Specifications) and parameters (related to determination of unreviewed safety questions). Options for modification include: no change, scope change only, parameter change only, and scope and parameter changes.
The probabilistic safety assessment (PSA) certification process is an industry-e sponsored initiative intended to identify levels of excellence in PSAs by verifying
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Minutes accuracy, realism, completeness, and documentation. The peer review process focuses on maintenance and updating of PSAs. The results of the certification process may integrated into the ASME/ANS effort to develop a Standard for PRA quality.
NEl Presentation Messrs. Tony Pietrangelo and Russell Bell of the Nuclear Energy Institute (NEI) provided a brief discussion of industry perspectives regarding possible changes to
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make 10 CFR Part 50 and 10 CFR 50.59 risk-informed. Mr. Biff Bradley discussed i
industry initiatives to certify PSAs. Significant points made during the discussion include:
The industry desires to bring stability and clarity to the 10 CFR 50.59 process.
e However, the industry does not want to pursue risk-informed 10 CFR 50.59 except to allow " minimal" increases in risk.
e NEl believes that the major impediment to making Part 50 risk-informed is the definition of " safety-related." NEl contends that many SSCs that are considered safety-related are not important to risk and that some which are important to risk are not safety-related. - NEl proposes to revise the Maintenance Rule as a trial application for making 10 CFR Part 50 risk-informed.
SUBCOMMITTEE COMMENTS. CONCERNS. AND RECOMMENDATIONS Dr. Wallis questioned how licensees decide that a change is acceptable when the risk is small and the criteria is fuzzy. Dr. Apostolakis stated that the expert panel will make Judgements using available qualitative information and frequency-consequence curves.
Dr. Kress added that some actual changes will be in the " noise" in which case measures such as CDF are useless. Dr. Kress suggested that risk achievement worth (RAW) be used in combination with CDF. Dr. Apostolakis stated that the analyst should evaluate the relevant event sequences to consider the context of the proposed change.
Dr. Wallis questioned the goals and objectives for revising 10 CFR Part 50. The staff stated that it was considering a number of options which would look at the strengths and limitations of the existing regulations. The staff stated that risk-informed licensing changes per Regulatory Guide 1.174 are voluntary, but noted that the NEl Whole Plant Study proposes to make some issues mandatory. The staff reiterated the importance of resolving a new definition of" safety-related" to consider risk information. The staff noted that there may bb some basis for developing separate criteria for design versus plant operations.
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n(linutes, Dr. Apostolakis questioned why the industry objects to using risk information for making changes to the plant per 10 CFR 50.59. NEl representatives stated that the 10 CFR l
50.59 process was relatively stable using NSAC-125 prior to the issues at the Millstone Nuclear Station. NEl stated that the industry seeks to achieve stability in the process and suggested that a risk-informed 10 CFR 50.59 process may make the process less certain rather than more stable. NEl reiterated its desire to allow for small increases in risk.
Dr. Apostolakis questioned what controls would be implemented to assure the qualifications of the Peer Review Team members for PSA certifications. The staff stated that licensees would establish the guidelines and that the NRC would verify adherence to the licensee's criteria.
STAFF AND INDUSTRY COMMITMENTS None.
SUBCOMMITTEE DECISIONS At the conclusion of the meeting, Dr. Apostolakis requested representatives of the NRC staff and NEl to summarize the key points regarding PSA certification to the full Committee on September 30-October 2,1998. Dr. Apostolakis noted that a joint Subcommittee meeting was scheduled for October 29-30,1998, to continue the Subcommittee's discussion of options to make 10 CFR Part 50 and 10 CFR 50.59 risk-informed.
FOLLOW-UP ACTIONS None.
BACKGROUND MATERIALS PROVIDED TO THE SUBCOMMITTEE PRIOR TO THIS MEETING 1.
Subcommittee agenda.
2.
Subcommittee status report.
3.
Note dated September 11,1998, from T.S. Kress, ACRS, to George Apostolakis, ACRS,
Subject:
Comments on 10 CFR 50.59 4.
Note dated September 10,1998, from George Apostolakis, ACRS, to ACRS Members and Staff,
Subject:
50.59 revisited.
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A RPRA Subcommittee 9/24/98
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Minutes 5.
Note dated August 10,1998, from Dana Powers, ACRS, to ACRS Members and Staff,
Subject:
Risk-Informed 50.59 6.
Note dated July 24,1998, from George Apostolakis, ACRS, to Mike Markley, ACRS Staff,
Subject:
Prcposal on 10 CFR 50.59, and attachments.
7.
Response dated July 29,1998, from Chairman Jackson, Chairman, NRC, to John C. Hoyle, Secretary,
Subject:
SECY-98-171 (pre-decisional, for ACRS use only) 8.
Response dated September 2,1998, from Commissioner Diaz, to John C.
Hoyle, Secretary,
Subject:
SECY-98-171 (pre-decisional, for intemal ACRS use only).
9.
Report dated July 16,1998, from R. L. Seale, Chairman, ACRS, to Shirley Ann Jackson, Chairman, NRC,
Subject:
Proposed Revisions to 10 CFR 50.59 (Changes, Tests and Experiments).
10.
Briefing handout dated September 15,1998, by South Texas Project to the NRC staff,
Subject:
South Texas Project Review of the Graded Quality Assurance implementation and Challenges.
11.
Meeting summary dated September 17,1998, from Noel Dudley, ACRS Staff, to ACRS Members,
Subject:
Meeting with NEl regarding Whole Plant Study and proposed schedule for Part 50 Rulemaking.
12.
Briefing handout dated October 21,1998, by Boiling Water Reactor Owners Group, to ACRS Subcommittee on Reliability and PRA,
Subject:
PSA Peer Review Certification Process.
Note: Additional details of this meeting can be obtained from a transcript of this meeting available in the NRC Public Document Room,2120 L Street, N.W.
Washington, D.C. 20006, (202) 634-3274, or can be purchased from Ann Riley &
Associates, Ltd., (Court Reporters and Transcribers) 1250 l Street, NW, Suite 300, Washington, D.C. Rhode Island Avenue, N.W. Washington, D.C. 20005 (202) 842-0034.
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