ML20059H619
| ML20059H619 | |
| Person / Time | |
|---|---|
| Issue date: | 11/02/1993 |
| From: | Beckjord E, Jordan E, Murley T NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD), Office of Nuclear Reactor Regulation, NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES) |
| To: | Taylor J NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO) |
| References | |
| NUDOCS 9311100145 | |
| Download: ML20059H619 (5) | |
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tbvember 2,1993 MEMORANDUM FOR:
Jamce F. Taylor Executive Director for Operations FROM:
Thomas E. Murley, Director Office of Nuclear Reactor Regulation Eric 5. Beckjord, Director j
Office of Nuclear Regulatory Research l
Edward L. Jordan, Director Office for Analysis & Evaluation of Operational Data Robert M. Bernero, Director Office of Nuclear Material Safety and Safeguards l
AGENCY DIRECTIONS FOR CURRENT AND FUTURE USES
SUBJECT:
OF PROBABILISTIC RISK ASSESSMENT (PRA)
To develop a plan for PRA applications within PURPOSE:
the NRC BACKGROUND:
The NRC has expended significant resources in risk assessment This has encompassed tne ground breaking technology development.
followed by the more extensive NUREG-1150 risk work of WASH-1400, Extensive research has been directed toward baseline studies.
assessing and quantifying severe accident phenomena to enable the suff to reduce levels of uncertainty regarding these complex The staff has encouraged the industry to develop risk issues.
assessment expertise and to support plant-specific risk studies as part of the Individual Plant Examination (IPE) program.
The NRC has been making use of pRA technology to varying degrees To some extent, in its regulatory activities since WASH-1400.
this has been an ad hoc application, depending on the av.11-Nonstheless, ability of expertise in various technical groups.
risk assessment technology has been successfully applied to numerous NRC px > grams, proving itself to bei a valuable adjunct to This was our previous deterministic engineering approaches.
shown in the early 1980's when the methodology provided useful y ll f 5 3..,9 ) c h ND 9 yr o (7c y 007. :7Y '
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James M. Taylor Ncved>er 2,1993 risk importance input for assassing deviations from current licensing critaria during the Systamatic Evaluation Program (SEP).
The technology was valuable to NRC staff assessing and prioritizing generic issues and assassing the relativa value/ impact of backfit proposals.
More recently, detailed PRAs have been required of all applicants of advanced standard plant designs, and the staff has used the methodology to identify severe accident vulnerabilities with the nau designs.
Additional benefits include the use of risk-based ins; action guidas in focusing inspector resourcas.
NRC also has applied these techniques in assassing the importance of operational events and in planning for some major team inspections (e.g., inspections focusing on shutdown risk).
Risk-based insights, including avant precursor evaluations, have provided significant impact to sanior Management Meeting deliberations on potential problem plants.
An increasing number of requests for licensing actions are using as their basis plant-specit.c riak analyses.
And finally, a data base of IPE findings is being developed to support plant-specific and generic queries.
Recently there have been a number of high-level studies within NRC that have focused on the status of PRA use and its role in the regulatory process.
The studies have been carried out by three specific groups:
The PRA Working Group was established in October 1991 to assess the status of and develop guidance for consistent and approprieta current uses of PRA, to idvatify necessary PRA knowledge and skills, and to identify needed improvaments in PRA methods and data.
The Regulatory iteview Group was established in January 1993 to review processes, programs, and practices associated with nuclear reactor regulation with focus on the feasibility of substituting performance-based requirements and guidance founded on risk insights for prescriptive requirements and guidance.
The Regulatory Analysis Steering Group is charged with ensuring that adequata guidance is available to support and justify proposed regulatory actions, including necessary updates to " Regulatory Analysis Guidelines,"
NUREG/BR-0058, and the " Handbook for Value/ Impact Assessment," NUREG/BR-3568.
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t Novecter 2,1993 James M. Taylor '
The Commission has also addressed the use of PRA within the agency.
For example, in his September 7, 1993, memorandum, Dr. Selin recognized the promise from developing performance oriented and risk-based regulations for containment leakage testing and fire protection requirements.
Additionally, he expressed a desire that the Commission evaluate the Regulatory Review Group report and develop an implementation plan.
DISCUSSION:
Collectively, the findings and recommendations of these groups l
support the view that there is a need for increased emphasis on PRA technology applications.
For the full value of our invest-ment in risk assessment methodology to be achieved, it is important that consistent high-level agency guidance be provided on the appropriate uses of PRA.
It is also important that the findings and recommendations from these groups be appropriately For example, considered in providing unified agency guidance.
risk insights flowing from the IPE program should. provide a source of information suitable for improving the regulation of Results from the IPE program indicate that operating reactors.
it cay be appropriate to reexamine the adequacy of the ATWS and SBO rules.
At the same time, it is important that the agency avoid undue emphasis on bottom-line PRA numbers because of the considerable uncertainties present.
It is also important that we address criticisms of PRA use raised by the ACRS and others involving a coherent use of these methods throughout the Agency, as well as the recommendations of the Regulatory Review Group.
The commitment of the Agency to have senior management also consider the broader question of where else PRA should be used was identified in the July 6, 1993, Taylor to Wilkins meno (attached).
To this end, we propose that the Office Directors of NRR, AEOD, and RES take the initiative in providing guidance on
Specifically, we propose to address the recommended actions of the PRA Working J
Group.
The major recommendations include Develocuent of an intecrated clan for the staff's risk assessment and risk manacement cractices.
We endorse this-initiative and propose to define the present structure of-the agency's risk assessment and risk management practices-and to define plans for improving and expanding PRA uses This plan will include a proposed within the agency.
revision to the 5-year plan reflecting increased e=phasis on PRA applications.
Mechanisms I=provine interactions with industry PRA croups, will be proposed to improve interactions between industry l
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James M. Taylor Ncvedxr 2,1993 PRA users and those in the e".aff.
Candidata nuclear reactor industry participants include the NUMARC " Regulatory Threshold" Working Group, EPRI, and specific licensees with f
active risk assessment and risk management programs.
We propose to work within the existing line management in each of our offices to address these recommendations of the PRA Working Group and other PRA issues that are outside the scope of the Working Group.
These other issues include those criticisms of PRA use raised by the ACRS, as well as the recommendations of the Regulatory Review, Group.
In the process of developing an implementation plan specific to each office's areas of regulatory responsibility, activities which support the appropriate agency-wide use of PRA must be addressed.
Our preliminary assignments of lead responsibility in this regard are as follows-ggg:
Develop, coordinate and publish NRC staff guidance on PRA use in nuclear reactor regulation.
AEOD:
Implement a training program consistant with current and anticipated PRA needs; compile operating experience (both equipment and human performance) for use in PRAs; evaluate operating experience.
i EII:
Develop and extend PRA methods; develop and atintain PRA-related software; evaluate IPE i
information and identify risk insights on the adequacy, completeness, and effectiveness of regulations and guidance with respect to reactor safety; develop, coordinate, and publish guidance on the use of PRA in regulatory analyses.
NMSS:
Develop, coordinate, and publish NRC staff guidance on PRA use in materials and safeguards applications To ensure coherence among the offices in the use of PRA and to support sanior management oversight and guidance, we will retain the PRA Working Group on an as-tasked basis to respond to technical issues associated with the conduct and use of PRA.
the Office Directors will meet on a periodic basis Furthermore, to ensure coordination of efforts among the offices and to provide the necessary management oversight.
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i Ibvember 2,1993 James M. Taylor.
We propose to develop an implamentation plan, including resourca need and commitments, by Decanbar 30, 1993, and to present our fin ngs at the next Senior Management Meeting.
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h'.Ro rt M. Bernero, Director Eric S. Beckjon, Director Offi of Nuclear Material Office of Nucle Regulatory Safety and Safeguards Research
, Director' Thomas E. Murley, Director or offi e or Analysis &
office of Nuclear Reactor Eva a
on of operational Regulation Dt
Enclosure:
As stated l
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