LICENSING MODERNIZATION PROJECT FOR OPERATING REACTORS

As part of the Nuclear Regulatory Commission’s (NRC’s) effort to provide resources to longer-term, forward looking research projects with potential regulatory benefits, this future focused research (FFR) project was established to study the implementation of the Licensing Modernization Project (LMP) methodology for operating reactors. This research effort used the LMP methodology and applied the NRC’s Level 3 probabilistic risk assessment (PRA) model results to gain feasibility insights. The initial phase of this effort used results from a limited scope of the NRC’s level 3 PRA model to explore high-level risk-insights of the licensing basis for reactors licensed under Title 10 of the Code of Federal Regulations (10 CFR) Part 50. The results discussed in this paper are derived from the NRC developed level 1, level 2, and level 3 base case PRA for internal events and internal floods to identify implementation challenges and explore the feasibility of using these types of results. These PRA results are used in the context of the LMP frequency-consequence (F-C) curve to both gain experience with the overall LMP methodology’s risk-informed performance-based guidance and to identify risk-insights on operating reactor technology. Furthermore, these insights provide an example of a “safety case” for operating plants which include discussions on the relative rankings of risk-important release categories. These insights may be used to highlight the portions of Part 50 that are the best candidates for further risk-informed considerations.