ML20151D284

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Summary of ACRS Subcommittee on Safety Philosophy,Technology & Criteria Meeting on 880209 in Washington,Dc Re Proposed Implementation Plan for Safety Goal Policy Statement.Agenda & Slides from Presentation Encl
ML20151D284
Person / Time
Issue date: 02/17/1988
From:
Advisory Committee on Reactor Safeguards
To:
Advisory Committee on Reactor Safeguards
References
ACRS-2554, NUDOCS 8804140100
Download: ML20151D284 (12)


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JATE ISSUED: 2/17/88 m ts-a?ssy ACRS SUBCOMMITTEE MEETING

SUMMARY

/ MINUTES FOR THE SAFETY PHILOSOPHY, TECHNOLOGY, AND CRITERIA FEBRUARY 9, 1988 WASHINGTON, D.C.

PURPOSE:

The ACRS Subcommittee on Safety Philosophy, Technology, and Criteria met on February 9, 1988, in Washington, D.C. The purpose of this meeting was to continue the discussion of the NRC Staff's proposed implementa-ticn plan for the Safety Goal Policy Statement. Copies of the agenda l and slides from the presentations are attached. The meeting began at 1:00 p.m. and adjourned at 5:00 p.m. and was held entirely in open j session. The principal attendees were as follows: '

l ATTENDEES:

ACRS NRC/RES D. Ward, Chairman W. Houston I J. Ebersole, Member l W. Kerr, Member I H. Lewis, Member C. Michelson, Member C. Wylie, Member l

. D. Houston, Staff l DISCUSSION:

On December 2, 1987, the Safety Philosophy, Technology and Criteria Subcomittee held a meeting with the RES Staff to discuss a draft of the proposed implementation plan for the Safety Goal Policy Statement. The Staff had intended to provide a revised draft of the implementation plan for this meeting but could not. Instead, they provided a draft option paper which described large release guidelines and plant perfonnance 8904140100 800217 4 PDR

j SPT&C Meeting Minutes February 9, 1988 objectives, level Three and Level Four of the five level safety goal hierarchy, respectively.

W. Houston (RES) discussed the current philosophy and status for the proposed implementation plan. He indicated that the next draft of the plan would be developed in a couple of months. In his presentation to the Subcomittee, he discussed the following details: (1) the overall purpose of safety goal policy implementation, (2) the concept of adapt-ing safety goals to the regulatory process, (3) an overview of the Staff's proposed plans, and (4) the quantitative safety goal objectives with details of the proposed large release guidelines and plant perfor-mance objectives. He emphasized that safety goals should be targets to strive for and should not be regulatory requirements or the definition of an adequate level of safety.

During the presentation, Subcomittee members extensively discussed the proposed Staff's plans and the quantitative safety goal objectives. The following topics were pursued during the discussion:

(1) PRAs - It was indicated that the Staff needs a definition of a full scope PRA as well as guidance on internal and external events.

NUREG-1150 was characterized as falling far short of state-of-the art PRA methodology. Thus, the initiative for defining the elements of a PRA might better come from the industry rather than the Staff. l (2) Large Release Guidelines - The Staff's concept for large release guidelines is based only on early containment failure. This limitation was considered to be a radical departure from past practices and the Subcommittee questioned whether this limitation

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would stand up under scrutiny or if the limitation was truly necessary. With this concept, it was indicated that one might conclude that filtered venting of containment and/or long tenn decay heat removal processes are not very important.

l SPT&C Meeting Minutes February 9, 1988 (3) Plant Performance Objectives - It was suggested that for the accident mitigation objective (containment failure), the probabil-ity of early containment failure ce designated as a conditional probability.

(4) Operational Performance Objective - The Staff proposed to reject the ACRS recommendation on grounds that this objective cannot be quantified probabilistically. The Subcommittee indicated that the Staff should give more emphasis to developing a suitable objective frr plant operation.

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NOTE: Additional meeting details can be obtained from a transcript of this meeting available in the NRC Public Document Room, 1717 H Street, N.W., Washington, D.C., or can be purchased from ACE-Federal Reporters, 444 North Capitol Street. Suite 402 Washington, D.C. 20001, (202) 347-3700.

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ACRS SUBCOMMITTEE MEETING ON SAFETY PHILOSOPHY, TECHNOLOGY, AND CRITERIA FEBRUARY 9, 19E8

- WASHINGTON, D.C.

- PROPOSED AGENDA -

SPEAKER APPROX. TIME A. Subcommittee Chairman's Remarks D. Ward 1:00 p.m.

B. Staff's Implementation Plan for R. W. Housten 1:15 p.m.

Safety Goal Policy Statement (RES)

- Hierarchy of Safety Goal Objecti.es

  • Definition of a large Release
  • Plant Ptrformance Objectives

- Use of Safety Goal and Sarpling Plan

      • BREAK *** 3:00-3:15 p.m.

C. Summary, Conclusions and Actions D. Ward 4:30 p.m.

For Future Comr.ittee Meeting D. Adjourn 5:00 p.m.

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SAFETY G0AL POLICY IMPLEMENTATION OVERALL PURPOSE o PROVIDE INTEGRATING FRAMEWORK FOR USE OF PRA IN REGULATORY PROCESS o RISK PERSPECTIVE COMPLEMENT TO BUT NOT SUBSTITUTE FOR DETERMINISTIC APPROACH TO REGULATORY DECISIGNS VIA SAFETY MARGINS

. O PRA AND SAFETY GOAL OBJECTIVES TOGETHER SHOULD PROVIDE PRIMARY BASIS FOR RESOLUTION OF MOST SEVERE ACCIDENT ISSUES SINCE PRAs DISPLAY RESIDUAL RISK DUE TO SEVERE ACCIDENTS 1

4 ADAPTING SAFETY G0ALS ,'

TO THE REGULATORY PROCESS PROBABILISTIC i RISK i ANALYSIS QUANTITATIVE SAFETY G0ALS COMPARISONS GENERIC LICENSIt!G

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N0 UNDUE y REGULATORY Y AND RISK REQUIREMENTS INSPECTION DECISIONS SAFETY MARGIN JUDGMEllTS DETERMINISTIC ANALYSIS FEEDBACK FROM 4 --- - OPERATING 4 EXPERIENCE

- RESEARCH

s OVERVIEW 0F PROPOSED _ STAFF PLANS o AD0 PTS ACRS RECOMMENDA710NS o BASED UPON CLOSE CORRELATION WITH STATE-OF-THE-AhT OF PRA MET liOD0 LOGY (NUREG-3150) o SAFETY G0AL OBJECTIVES DIRECTED TOWARD:

ACCIDENT PREVENTION (0F CORE DAMAGE): LEVEL I rRA ACCIDENT MITIGATION (OF F.P. RELEASE): LEVEL II PRA CONSEQUENCE MITIGATION (OF PUBLIC HEALTH EFFECTS: LEVEL III PRA o SHOULD NOT INHIB'T OR BIAS INDEPENDENT USE OF PRA METHODOLOGY BY INDUSTRY o SAMPLING PROGRAM INCLUDES:

CURRENT AND FUTURE PRAs: NilREG-1150 FOCUSED REVIEW ON PRESENT OR PROPOSED REQUIREMENTS IN RELATION TO SAFETY GOAL OBJECTIVES

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OUANTITATIVE SAFETY GOALS SHOULD BE o TARGETS TO STRIVE FOR:

IN Tile REGULATORY PROCESS BY INDUSTRY QUANTITATIVE SAFETY GOALS SHOULD NOT BE o REGULATORY REQUIREMENTS o DEFINITIONS OF WHAT IS (MINIMALLY) ADE00 ATE FOR SAFETY MANY IMPORTANT SAFETY ATTRIBUTES ARE NOT WITHIN KEN OF PRA METHODOLOGY UNCERTAINTIES IN PRA BOTTOM LINE RESULTS o

_ _ _ _ . _ _ _ _ _ . _ _ _ _ _ _ _ . _ _ _ _ _ _ . _ . _ _ _ _ _ . _ _ _ _ _ _ _ _ _ _ _ _ . _ _ _ _ _ _ _ _ _ _ . _ _ -- __ , _ u _ _ . _

QUANTITATIVE SAFETY GOAL OBJECTIVES o THESE ARE TO BE REGARDED AS OBJECTIVES FOR REGULATORY REQUIREMENTS o LEVEL TWO OF HIERARCHY (SPECIFIED IN SAFETY GOAL POLICY STATEMENT)

PROMPT MORTALITY RISK (5 x 10E-7/R-Y)

LATENT CANCER MORTALITY RISK (2 x 10E-6/R-Y) o LEVEL THREE OF HIERARCHY (LARGE RELEASE GUIDELINE IN POLICY STATEMENT)

(PROPOSED)

, THE OVERALL MEAN FREQUENCY OF ANY RELEASE OF RADI0 ACTIVE MATERIALS INTO THE ENVIRONMENT FROM EARLY CONTAINMENT FUNCTION FAILURE THAT HAS THE POTENTIAL FOR CREATING A PROMPT MORTALITY RISK, SHOULD BE LESS THAN 10E-6 PER YEAR OF REACTOR OPERATION N.B. THIS OBJECTIVE IS INTENDED TO BE COMPATIBLE WITH PRA METHODOLOGY, STAFF GUIDANCE ON INTERPRETATION IS IN PROCESS.

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CUANTITATIVE SAFETY GOAL OBJECTIVES (CONT'D.)

PROPOSED PLANT PERFORMANCE OBJECTIVES (LEVEL FOUR OF HIERARCHY) o ACCIDENT PREVENTION OBJECTIVE THE OVERAll MEAN CORE DAMAGE FREQUENCY SHOULD NOT EXCEED 10E-4 PER REACTOR YEAR o ACCIDENT MITIGATION OBJECTIVE THE WEIGHTED MEAN VALUE OF THE PROBABILITY OF EARLY CONTAINMENT FAILURE GIVEN PRIMARY SYSTEM BARRIER FAILURE SHOULD NOT EXCEED 0.1 l

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l ISSUES l

l l 0 ACRS RECOMMENDED AN CPERATIONAL PERFORMANCE OBJECTIVE. STAFF PROPOSES TO REJECT ON GROUNDS THAT IT CANNOT BE QUANTIFIED PROBABILISTICALLY o COST-BENEFIT NOT ADDRESSED BY ACRS. STAFF RECOMMENDATION TO INCORPORATE THIS IN BACKFIT POLICY (REVISED VALUE-IMPACT MANUAL) RATHER THAN IN SAFETY G0AL POLICY o TREATMENT OF DOMINANT SE00ENCES - BALANCING OBJECTIVE o USE OF LESS THAN FULL SCOPE PRAs l

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ISSUES (CONT'D.)

o APPLICABILITY OF SAFETY G0AL OBJECTIVES TO CLOSURE OF SEVERE ACCIDENT ISSUES

- REGULATORY REQUIREMENTS FOR CURRENT PLANTS (IPE, CONTAINMENT PERFCRMANCE)

REGULATORY REQUIREMENTS FOR ALWRs. (REVIEW OF EPRI ALWR REQUIREMENTS DOCUMENT IS A UNIQUE OPPORTUNITY)

REGULATORY REQUIREMENTS FOR ADVANCED REACTORS m

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