ML18087A373
| ML18087A373 | |
| Person / Time | |
|---|---|
| Issue date: | 03/14/2018 |
| From: | Stephen Dinsmore Office of Nuclear Reactor Regulation |
| To: | |
| References | |
| Download: ML18087A373 (11) | |
Text
Risk-Informed Licensing Applications Regulatory Information Conference Stephen Dinsmore, Senior Reliability and Risk Analyst Technical Session TH35 March 14, 2018
In-service Testing: RG 1.175 An Approach for Plant-Specific, Risk-Informed Decision making: In-service Testing. Partially subsumed into Risk-Informed Technical specifications Graded Quality Assurance: RG 1.176 An Approach for Plant-Specific, Risk-Informed Decisionmaking:
Graded Quality Assurance. Became 50.69 Technical Specifications: RG 1.177 An Approach for Plant-Specific, Risk-Informed Decisionmaking:
Technical Specifications.
In-service Inspection: RG 1.178 An Approach for Plant-Specific Risk-Informed Decisionmaking for Inservice Inspection of Piping
Generic, bounding, and low risk estimates can sometimes be used with, as applicable, Demonstration of applicability to a plant Use of 50.65(a)(4) program to manage risk.
Risk Informed Technical Specifications changes based generally on generic risk End state modification (Initiative 1 and 3)
Missed Surveillances (Initiative 2)
Limited modification for 3.0.3 Action and completion times for selected Technical Specifications (Initiative 6)
Use of detailed, plant specific PRA results that can approach RG 1.174 acceptance guidelines requires confidence in plant specific PRA model Integrated Leak Rate Test frequency extension Programs to change technical specifications based on detailed plant specific PRA results Relocation of Surveillance intervals to licensee controlled documents (Initiative 5b)
Flexible completion times based on real-time risk evaluation (Initiative 4b)
Risk-Informed In-service Inspection (RG 1.178)
Relocated and reduced the number of Class 1 and Class 2 weld inspections Additional changes to in-service inspections requested and accepted Extended RCP flywheel inspection interval from 10 to 20 years Extended Reactor Vessel weld and internals inspections from 10 to 20 year Extended Vessel nozzle weld inspections from 10 to 20 years
50.44 Combustible gas control for large dry containments 50.65 Requirements for monitoring the effective-ness of maintenance at nuclear power plants 50.69 Risk-Informed Categorization and Treatment of Structures, Systems and Components for Nuclear Power Reactors 50.61a Alternative Fracture Toughness Requirements for Protection Against Pressurized Thermal Shock 50.48(c) National Fire Protection Association Standard NFPA 805.
Goal is to have short review times Achieved for fixed-scope applications Expected for 50.69 and 4b LARs with improved PRA technical acceptability processes Using deviations extends the review External events screening/PRAs to support licensee programs vary by application types Screening risk evaluations have been successful when applicable and PRA models may sometimes be needed for less conservative decisions
45 LARs approved during 2017, most less than 11 months 40 LARs approved during 2016, many less than 12 months but including 14 NFPA-805 LARs Programmatic LAR and safety evaluation development have impacted industry and NRC workloads and schedules 4b program development has been complex External events need to be systematically considered in 50.69 and 4b programs
Risk-Informed Licensing Actions Received from FY16-FY18 120 100 TMRE NTTF R2.1 79 50.69 80 Number of Licensing Actions Misc AOT 60 TSTF-505, 4B GSI-191 41 TSTF-411 40 RI-ISI RS TS 20 TSTF-425, 5B 20 NFPA805 ILRT 0
FY16 FY17 FY18
Internal Events Only 50.69 Change in Approach New External Events PRA (Already has 50.69)
Limerick - 670 Vogtle1 - 650 Palo Verde2 - 875 Point Beach5 - 850 Brunswick3 - 1350 Duane Arnold - 650 Byron/Braidwood - 610 Peach Bottom - 694 Harris4 -
1 - Vogtle already has 50.69 and is adding an SPRA 2 - Palo Verde includes an SPRA 3 - Brunswick includes a Flooding and High Winds PRA 4 - Harris is currently undergoing acceptance review 5 - Point Beach was an early submittal and the original LAR included High Winds PRA
License risk-informed programs to use the PRA to make future changes without prior staff review are becoming more prevalent Some of these applications use risk results to make changes up to the RG 1.174 acceptance guidelines RG 1.174: The more emphasis put on the risk insights and on PRA results in the decision-making process, the more requirements have to be placed on the PRA in terms of both scope an how well the risk and the change in risk are assessed.
PRAs determined to be acceptable for past application may need to be improved, and the improvement demonstrated, for new applications