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 ApplicationsRegulatory Information ConferenceStephen Dinsmore, Senior Reliability and Risk AnalystTechnical 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 specificationsGraded Quality Assurance: RG 1.176 An Approach for Plant-Specific, Risk-Informed Decisionmaking: Graded Quality Assurance. Became 50.69Technical 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 Decisionmakingfor InserviceInspection of Piping Generic, bounding, and low risk estimates can sometimes be used with, as applicable,Demonstration of applicability to a plantUse of 50.65(a)(4) program to manage risk.Risk Informed Technical Specifications changes based generally on generic riskEnd 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 extensionPrograms to change technical specifications based on detailed plant specific PRA resultsRelocation 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 inspectionsAdditional changes to in-service inspections requested and acceptedExtended RCP flywheel inspection interval from 10 to 20 yearsExtended Reactor Vessel weld and internals inspections from 10 to 20 yearExtended Vessel nozzle weld inspections from 10 to 20 years 50.44 Combustible gas control for large dry containments50.65 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 Reactors50.61a Alternative Fracture Toughness Requirements for Protection Against Pressurized
Thermal Shock50.48(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 processesUsing deviations extends the review External events screening/PRAs to support licensee programs vary by application typesScreening 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 LARsProgrammatic LAR and safety evaluation development have impacted industry and NRC workloads and
schedules4b program development has been complexExternal events need to be systematically considered in 50.69 and 4b programs 41 79 20 0 20 40 60 80 100 120FY16FY17FY18Number of Licensing ActionsRisk-Informed Licensing Actions Received from FY16-FY18TMRE NTTF R2.1 50.69 Misc AOTTSTF-505, 4B GSI-191TSTF-411 RI-ISI RS TSTSTF-425, 5B NFPA805ILRT InternalEvents Only 50.69Change in Approach (Already has 50.69)New ExternalEvents PRALimerick -670Vogtle 1-650Palo Verde 2-875Point Beach 5-850Brunswick 3-1350Duane Arnold -650 Byron/Braidwood -610 Peach Bottom -694 Harris 4-1 -Vogtlealready has 50.69 and is adding an SPRA2 -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 prevalentSome of these applications use risk results to make changes up to the RG 1.174 acceptance guidelinesRG 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