ML20042D171

Informs Commission of Status of Implementation of Integration Plan for Closure of Severe Accident Issues

ML20042D171
Person / Time
Issue date:	10/03/1989
From:	Taylor J NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO)
To:
References
TASK-PII, TASK-SE SECY-89-308, NUDOCS 8910120090
Download: ML20042D171 (9)

Text

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l October 3. 1989 SECY-89-308 The Commissione{Information)

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From:

James M. Taylor 1

Acting Executive Director for Operations

Subject:

STATUS OF IMPLEMENTATION OF INTEGRAT10F PLAN FOR CLCSURE OF SEVERE ACCIDENT ISSUES

Purpose:

To inform the Commission of the status of the implementation i

of the integration plan for closure nf severe accident issues.

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Background:

On May 25, 1986 the staff presented to the Conatssian j

the " Integration Plan for Closure of Severe Accident issun,"

i SECY-88-147. The objectives of this plan are:

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To describe the main and supporting eitments of the closure plan including the use of safety gu !s and backfit polic,y in the closure process.

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To provide an understanding of the Staff activities that I

are undarway to implement the Commission's Severe Accident Policy.

3.

To assure that these activities are consistent with the Commission's policy and strategic goals.

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To assure that the staff activities are consistent asong themselves, have a cosmon goal of ultimately leading to improved plant safety, and are properly coordinated among the responsible NRC organizations.

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To inform the Commission of the key technical activities and policy issues that need to be addressed in the near future.

There are six main elements of this plan which include:

l Individual Plant Examinations. Containment Performance Improvements, Severe Accident Research, Exterral Events.

Improved Plant Operations, and Accident Management. Closure of severe accident issues for existing plants will require the following:

Contact:

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Completion of the IPEst including external event examinations, identification of potential improvements, and implementation Sf improvements; as appropriate.

Development and implementation of a framework for accident management that can accomodate new information as it is developed.

Implementation of any Counission-approved generic requirements resulting from the Containment Performance Improvement Program.

While programs for improved plant operations and research in the area of severe accidents will continue completion of the aboveitemsbylicenseeswillconstituteclosureofsevere creident issues. Specific issues that may arise in the future due to ongoing research will be trea ud on c case-by-case basis and will not affect the closure process.

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The Commission was last briefed on the status of these efforts in April 1989. The purpose of this paper is to provide the commission with an update of the status of the implementation of this plan on a periodic b6 sis as requested in a Staff Requirements Memorandum dated April 20,1980.

Discussion:

Significant pre;ress has been u.ade on several elements of the integration plan. This paper provides an update on the status and schedules for each of the six main elements, with emphasis on major milestones accomplished since implementation of the plan. Projected schedules for each of the elements are shown in the enclosed Severe Accident Program - Master Plan, and l

each element is discussed below.

IndividualPlantExaminations(IPIs)

The IPEs were formally requested in Generic Letter 88-20 issued on Noveaber 23,1988. However the process did not start until completion by the staff of submittal guidance to licensees which were developed following issuance of the generic letter. The staff issued " Individual Plant Examination:

Submittal Guidance," MUREG-1335 as a Draft for Cement in l

January 1989 and conducted a workshop in February 1989 to l

solicit comments and questions on the IPE process. NUREG-1335 l

was revised to reflect the comments and questions raised at l

the workshop or later in writing and issued in final form in late August 1989. This issuance of the guidance document i

formally started the IPE process. Licensees are required to submit their plans and schedules for performing the IPE by late October 1989 and must complete their IPEs by August 1992.

Current staff activities in the area of the IPE involve t

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developing detailed plans and procedures for receipt and l

review of the IPE submittals.

As part of the generic letter transmitting NUREG-1335 to all licensees, the staff included a description of its findings under the Mark 1 Containment Performance Improvement Program i

for consideration by licensees during their IPE (see discussion below).

Containment Performance Improvements The staff presented recommended containment performance improvements for BWRs with Mark I containments to the Commission in January 1989 (SECY-89-017). These recommen-dations included: (1)animprovedhardenedventcapability, (2) improved reactor pressure vessel depressurization system reliability, (3) an alternate water supply to the reactor i

vessel and drywell sprays, (4) extended emergency procedures and training,lackout rule.and(5)acceleratedstaffactionstoimplement i

the station b By Staff Requirements Memorandum dated July 11, 1989, the Cosmission directed the staff to implement the recommended hardened vent and associated j

procedures and training via plant specific backfits. The Cosnission also directed the staff to expedite its actions in i

implementing the station blackout rule for Mark I plants. The staff was directed to forward to each Mark I owner the information regarding the other Mark I containment performance improvements identified by the staff for consideration while l

conducting their IPEs.

I The staff is currently implementing the Commission's direction concerning the Mark I improvements. Plant-specific backfits i

are being performed for the hardened vent on a schedule which calls for issuance of any backfit packages before the end of CY 1989. The staff has accelerated its actions with regard to implementation of the station blackout rule for Mark I plants.

Completion of all staff station blackout actions for Mark I i

plants is projected to be completed by April 1990.

Implementation of station blackout modifications would be completed by Mark I licensees within two years of this date.

Infor1 nation regarding the other Mark I improvements has been forwarded to Mark I owners via the letter forwarding the IPC guidance document to all licensees.

The staff is currently evaluating potential containment performance improvements for containments other than Mark Is.

While the focus of the Containment Performance Improvement (CPI)Programisoncontainmentperformanceandaccident mitigation as with the Mark 1 CPI Program, insights are also beingobtaInedintheareasofaccidentpreventionand accideat management.

In addition, the recommendations from this effort on other containment types will be broader than

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l those for Mark I plants. At this time, tbt staff has not identified any recomended generic improvements that would be l-applicable to all containments of a given type, but plans to make a number of recomendations for improvements to be considered further on e plant-specific basis at part of the IPE Program. This approach is consistent M Comission i

direction concerning the Mark I improvements. Recomendations will also likely be made for improvements to be included in the accident management program, and areas requiring additional research will be identified. The staff plans to provide these recomendations to the Comission in early 1990 so that consideration of the staff findings and recomendations can be factored in the IPEs, improved Plant Operations Improved plar t operations includes a number of ongcing efforts, as discussed in SECY-88 147. Major changes in this element include progress on efforts to factor accident management and IPE insights into plant operation as discussed 1

below,

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Severe Accident Research l

With respect to severe accident research being e M ucted in support of the other elements of the severe accident integration plan, in July of 1988 the Office of Nuclear Regulatcry Research set about reviewing and revising its Severe Accident Research Program to assure that the obligations of SECY-88-147 were unt.

In May 1989, the research staff presented to the Cosmission a Revised Severe Accident Research Program Plan (SECY-89-123) which detailed the tasks and schedules proposed by the staff to refocus and redirect the NRC's severe accident research to address those issues highlighted in SECY-88-147. Specifically, the staff proposed to emphasize over the next few years research on issues related to early containment failure, while maintaining a continuing program of phenomenological research on severe accidents. Tie Cosmission approved the staff's proposed plan 1

1 and the staff is now implementing it. The staff intends to meet again with the Commission this coming spring to report on progress made and provide for Cosmission review any revisions that may be proposed as a result of attempting to implement the revised plan. The revised Severe Accident Research Program Plan has been published as NUREG-1365.

External Events ThestaffestablishedanExternalEventsSteeringGroup(EESG) in December 1987 to make recomendations concerning the extent to which external events need to be considered as part of the

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'IPEs, and acceptable methods for analyzing external events in j

the context of the IPEs.

In April 1988, three subcomunittets were formed to assist the EESG in the areas of (1) Seismic.

o (2) Fires,and(3)HighWinds, Flood,andOthers(HF05). The subcosmiittees have essentially completed their work and have 1

made preliminary recommendetions. Recent activities involve j

working with industry, he examinations.through NUMARC and EPRI, to de i

methods of perfoming t Preliminary findings in the area of examinations for seismic vulnerabilities to severe accidents indicate that either a seismic PRA or a margins approach, such as that developed by either NRC or EPRI, would be acceptable methods of performing the IPEEE for seismic vulnerabilities. A fire PRA, using insights from the Fire Risk Scoping Study, would be an r

acceptable method of examination for velnerabilities due to fire. Other simplified methods to perform the IPEEE in the area of fire are also being developed by NUMARC.

In the areas ofHighWinds, Flood,andOthers(transportationandother man-made events), the HFOS subcossnittee has concluded that, in most cases, the design basis of the plant is likely to provide sufficient protection from severe accidents due to these initiators.

Isolated vulnerabilities due to these initiatots have been found 6t plants in the past, however. Thus the subcomunittee has recomunended a screening type approach to the IPEEE to quickly eliminate concerns about potential vulnerabilities in these areas.

The staff plans to make specific reconenendations to the Comunission concerning the IPEEE early in 1990.

Accident Managesent A comprehensive description of the Accident Management Program was provided in SECY-89-012. The program was discussed with the Comunission in January 1989 and further clarified in a response to the Staff Requirements Memorandum regarding SECY 89-012. The program includes both regulatory and research elements. These elements continue to be focused on two major NRC actions; specifically, issuance of " lessons-learned" from the conduct and review of PRAs and issuance of guidance on the scope and content of a utility accident management plan or framework.

" Lessons-learned" from past PRAs, in the fem of generic 1

accident management strategies, will be provided to utilities in late CY 1989 via a supplement to the IPE Generic Letter 88-20. The supplement will provide licensees a set of accident management strategies, and will request that licensees evaluate the strategies for applicability and effectiveness at their plants as part of the IPE. The letter

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will include, as a NURE6/CR attachment, a technical assessment of each of the accident management strategies, as well as evaluation guidance and cautions for each strategy to provide added assurance that use of the strategy will not detract from safety.

Considerable progress has also been made towards the longer I

term goal of developing guidance on the scope and content of a i

utility accident management framework, for issuance as a generic letter in late 1990. Industry through MUMARC, will play a key role in the process by deveIoping guidelines for use by utilities in evaluating their accident management capabilities for important sequences identified through the IPE. A draft version of the NUMARC " Guidelines for Evaluating i

Accident-Management Capabilitics' was provided to NRC and utilities and participating organizations in August 1989. NRC and industry consents on the guideline document are expected i

by October 1989. Present plans include application of the guidelines on a trial basis at several reference plants (to be determined)beginninginearly1990,andcompletionofafinal version of the guidelines by summer 1990. The NRC generic letter on accident management will address the role of these guidelines in the development of utility accident management capabilities.

In parallel with NUMARC's activities, NRC is developing information and guidance on the accident management framework as part of the Accident Management Research Program. This activity will provide a technical basis and perspective for i

evaluating the NUMARC accident management guidelines, and is expected to culminate in supplementary insights and guidance for inclusion in either the NUMARC guidelines or the NRC generic letter on accident management. Long-term work on more complex accident management strategies is also unde may.

Information from the severe Accident Research Program on severe accident phenomena and uncertainties, as well as the results of NUREG-1150, the CPI Program and research in the Human Factors Program, is being used to evaluate potential strategies.

The staff plans to inform the Connission periodically of progress in implementing the Integration Plan for Closure of severe Accident Issues. The staff intends to provide an overall update semi-annually (April 1 and October 1).

A K

I s M. T or cting Ex utive Director for Operations l

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Enclosure:

l Severe Accident Program - Master Plan l

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