ML22140A335
| ML22140A335 | |
| Person / Time | |
|---|---|
| Issue date: | 03/08/2022 |
| From: | Matthew Humberstone NRC/RES/DRA |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| Download: ML22140A335 (15) | |
Text
Licensing Modernization Project for Operating Reactors Matthew Humberstone, PhD US NRC
Project Overview
- The Licensing Modernization Project (LMP) for operating reactors leverages the NRCs Level 3 probabilistic risk assessment (PRA) (L3PRA) model to test the feasibility of the LMP methodology for use beyond the original intent.
- LMP methodology
- Licensing approach for nonlight-water reactors
- Described in Nuclear Energy Institute (NEI) 18-04 and endorsed by the NRC in Regulatory Guide 1.233
- Uses L3PRA results
- NRC L3PRA model
- Pressurized-water reactors
- Initially had only internal events results available
- Has expanded to include external hazards and other enhancements
Phase 1 Future Focused Research Feasibility Limited Scope Project Scope Phase 2 Expanded Insights L3PRA Model Enhancements NRC Regulatory Needs Support Proposals
Objectives The LMP methodology is feasible for light-water Study LMP Feasibility reactors (LWRs)
Pilot LMP Used the L3PRA model results to pilot the LMP Identify Issues/Challenges Identified insights on implementation of the LMP Use L3PRA Results Used L3PRA results for Phase 1 and Phase 2 Glean LWR Risk Insights LWR safety profile consistent with NRC expectations Communication Shared progress/results
Technical Approach NRC L3PRA Model LMP Methodology
- Severe Accident - Risk-Informed, Research Performance-Based
- LWR Experience - Non-LWR licensing
L3PRA Process 1
6 L3PRA Plant Damage Release Cutsets ~50,000 States (PDS): 368 Categories: 16
Release Category Release Category Contributions LMP Frequency-Consequence Curve Phase 1 Results Initial Phase 2 Insights
- Changes to the NRCs L3PRA model results vary
- External events
- FLEX credit, etc.
- No impact 8
- Different impacts on release categories/accidents
- Loss-of-coolant accidents
- Loss of offsite power
- Station blackout 2 6
Phase 2 Results Conclusions
- LMP methodology is useful beyond the original intent
- Insights gained to support future non-LWR licensing
- Operating reactors safety profile is consistent with current NRC expectations
- Several opportunities are being explored to leverage LMP methods and tools
Next Steps
- Continue Phase 2 research
- Enhanced model results
- Accident sequence evaluations
- Uncertainty impacts
- Engagement with NRC technical staff on future needs
- Supporting future regulatory work
- Continue communication effort