ML24303A223

NRC Presentation on Industry Engagement in NRCs Ope Program for October 30, 2024 Public Meeting

ML24303A223
Person / Time
Issue date:	10/30/2024
From:	John Lane NRC/RES/DRA/PRB
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Download: ML24303A223 (1)

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PRA Parameter Estimates & OpE Data Program October 30, 2024, Public Meeting John C Lane, PE Sr Reliability & Risk Engineer Office of Nuclear Regulatory Research

NRCs OpE Data Program

• Nuclear industry involvement is welcomed and encouraged

• Search for inappropriate data getting into the evaluations

• NRC obtains the INPO IRIS data via muti-year commercial contract

• Inappropriate/inaccurate/incomplete data in IRIS makes the process more expensive to administer and may lead to less accurate/more uncertain results

• High-quality data is a top priority

• NRCs data collection and coding program follows well-established guidance

• Handbook of Parameter Estimation for PRA, NUREG/CR-6823 (HOPE, circa 2003)

• OpE results are public: https://nrcoe.inl.gov/

• Overview & Reference Document for OpE Results and Database Trending (2016)

• Skilled, trained analysts with plant experience and years of involvement

Does Excess Conservatism Exist in PRA Parameters?

• True values of risk parameters can only be estimated

• OpE-based parameters vary over time, sometimes increasing, sometimes decreasing

• If excess conservatism exists, it may best be eliminated via:

• Thorough and comprehensive reporting of all relevant OpE events to INPO/IRIS and to NRC via LERs

• Evolution of analytical approaches as new insights are gained

• More realistic CCF parameter estimations (discussed earlier)

• New generation techniques to gain insights, such as AI

• Data uncertainty should be accounted for (ASME/ANS RA-S-1.1-2024)

• HLR-DA-D

• SECY-97-101 (Data Rule)

• Staff should continue to work with industry to improve the content of the voluntary data

• Minimize the need for compensatory measures to derive needed parameter estimates

• Staff should periodically update the Commission on its efforts to work with industry

Nuclear Industry Safety Improves with Cooperation on OpE Data

• NRC and industry have a good track-record of working together to improve PRA parameters:

• Prior Activities

• PWROG OpE review, (2021, ML21242A029)

• Audit of FLEX-parameters, (2022, 22014A084)

• Updated LPSD study by EPRI (2022)

• EPRI revisions to LOOP recovery times (2020)

• Westinghouse peer review of CCF events (~2015)

• Current

• Review of BWR Component Reliability Data Issues

• Issues related to Turbine Driven Pump failures & Misclassified events