ML23072A084
| ML23072A084 | |
| Person / Time | |
|---|---|
| Issue date: | 03/14/2023 |
| From: | Jay Robinson NRC/NRR/DRA/APLB |
| To: | |
| References | |
| Download: ML23072A084 (1) | |
Text
Impacts of Risk-Informed Licensing Actions at Nuclear Power Plants In 1995, the Commission formalized its commitment Since issuing the PRA Policy Statement, the NRC has to risk-informed regulation through the expanded developed and implemented risk-informed initiatives in several areas, allowing licensees to increase the use of PRA use of probabilistic risk assessment (PRA) by issuing technology in regulatory matters:
its PRA Policy Statement. The PRA Policy Statement states, in part, that the use of PRA Containment Leakage Rate Testing technology should be increased in all regulatory Surveillance Frequency Control Program, TSTF-425 matters to the extent supported by the state of the Risk-Informed, Performance-Based Fire Protection Program, 10 CFR 50.48(c) (NFPA 805) art in PRA methods and data, and in a manner that Risk-Informed Categorization of Structures, Systems, and complements the NRC's deterministic approach Components, 10 CFR 50.69 and supports the NRC's traditional defense-in-depth Risk-Informed Completion Times, TSTF-505 philosophy.
Containment Leakage Rate Testing Number of Nuclear Power Plant Units Type A ILRT Frequency Allows the Type A test or integrated leak rate test (ILRT) to be Extension to 15 Years extended permanently to a 15-year interval using a risk-informed process.
The ILRT measures the primary reactor containment overall integrated 1 12 leakage rate after completion of the containment and at periodic intervals thereafter. It is initially conducted after 48 months of operation, with extension to 10 years after two successful tests.
BENEFITS STATUS
- Safety benefit to shutdown risk
- First amendment issued in 2014
- Reduced planned outage time
- 79 unit amendments issued, 86%
79
- Reduced costs
- 12 units not yet submitted, 13%
- 1 unit currently under review, 1%
Approved In Progress Not Submitted
Surveillance Frequency Control Program, TSTF-425 Allows for the relocation of surveillance test intervals of various Number of Nuclear Power Plant Units technical specification (TS) surveillance requirements to a new Surveillance Frequency Control surveillance frequency control program.
Program, TSTF-425 Provides for a risk-informed method to change surveillance frequencies in which PRA methods are used, in combination with plant performance data and other considerations, to identify and justify modifications to the surveillance frequencies of equipment.
BENEFITS STATUS
- Lower chance of initiating event
- First amendment issued in 2006 92
- Greater equipment availability
- 92 unit amendments issued, 100%
- Optimal alignment of test intervals
- Last amendment issued in 2022
- Lower burden on licensee Approved
Risk-Informed, Performance-Based Fire Protection Program, 10 CFR 50.48(c) (NFPA 805)
Number of Nuclear Power Plant Units Allows transition of existing deterministic fire protection program to a Risk-Informed, Performance-Based risk-informed, performance-based program based on National Fire Fire Protection Program, Protection Association Standard (NFPA) 805, Performance-Based 10 CFR 50.48(c)
Standard for Fire Protection for Light Water Reactor Electric Generating Plants, 2001 Edition.
Allows the use of performance-based methods, such as fire modeling, in conjunction with risk information to demonstrate 43 compliance with the nuclear safety performance criteria.
49 BENEFITS STATUS
- Plant changes result in safety
- First amendment issued in 2010 improvements
- 43 unit amendments issued, 47%
- Reduction in fire risk
- 49 units not submitted, 53%
Approved Not Submitted
- Improvement in fire risk methods
- No units currently under review
- Eliminates compensatory
- Last amendment issued 2020 measures
Risk-Informed Categorization of Structures, Systems, and Components, 10 CFR 50.69 Number of Nuclear Power Plant Units Determine safety significance of structures, systems, and Risk-Informed, Categorization of SSCs, components (SSCs) based on an NRC-approved, risk-informed 10 CFR 50.69 categorization process.
Modify special treatment requirements for safety-related SSCs of low safety significance.
39 BENEFITS STATUS
- Improved focus on SSCs of high
- First amendment issued in 2018 50 safety significance
- 50 unit amendments issued, 54%
- Accelerated completion of
- 39 units not submitted, 43%
deferred maintenance
- 3 units currently under review, 3% 3
- Increased operational flexibility
- Most recent amendment issued in
- Reduction in regulatory burden 2022 Approved In Progress Not Submitted without adversely affecting public safety
Risk-Informed Completion Times, TSTF-505 Adds new program in TS Administrative Controls, entitled the Number of Nuclear Power Plant Units Risk-Informed Completion Time Program, that allows TS TSTF-505 completion times to be extended using a risk-informed approach. Risk-Informed Completion Times BENEFITS STATUS
- Averted shutdowns
- First amendment issued in 2007 39
- Reduced outage complexity
- 44 unit amendments issued, 48%
44
- Reduction in notices of
- 39 units not submitted, 42%
- 9 units currently under review, 10%
- Reduction in one-time allowed
- Most recent amendment issued in outage time/completion time 2022 9 extension requests Approved In Progress Not Submitted
Overall Benefits of Risk-Informed Licensing Actions at Nuclear Power Plants
- Reduced personnel dose
- Plant modifications result in safety improvements
- Reduced plant shutdowns
- Reduced outage duration, complexity, and risk
- Enables work to be completed while plant is online, reducing outage risk
- Completion of deferred maintenance without additional license amendments or exemptions
- Extended surveillance frequencies
- NRC staff become familiar with plant PRAs Current Status of Risk-Informed Licensing Actions
- Over 300 risk-informed unit amendments issued since 2006 for major program initiatives (ILRT, TSTF-425, 10 CFR 50.48, 10 CFR 50.69, and TSTF-505). Major risk-informed program initiatives either complete or 50% or more complete/in progress
- Over 250 risk-informed unit amendments issued since 2001 for other programs, such as risk-informed inservice inspection, technical specification allowed outage time/completion time extensions, other TSTFs, Tornado Missile Risk Evaluator (TMRE), seismic PRA, risk insights, and Risk-Informed Process for Evaluations (RIPE)
Contact Information Jay Robinson, Acting Chief PRA Licensing Branch B Division of Risk Assessment Office of Nuclear Reactor Regulation Jay.Robinson@nrc.gov Information used in this exhibit is current as of January 25, 2023, and does not necessarily represent the views of the NRC.