Development of Effective-Dose-Based Risk Profiles for Exhaustive Scenarios in Nuclear Power Plants

Conventional probabilistic safety assessment (PSA) has primarily focused on frequency-based quantitative goals (e.g., CDF, LERF) and relied on a limited number of representative scenarios for consequence assessment. However, recent decision-making processes based on the Risk-Informed Performance-Based (RIPB) regulation, including design, licensing, and emergency planning zone (EPZ) determination, require comprehensive risk quantification that integrates both the frequency and consequences of all identifiable severe accident scenarios. Therefore, this study presents a methodology for developing a quantitative risk profile based on effective dose, comprehensively considering both frequency and consequences for exhaustive severe accident scenarios. In this study, risk profiles were constructed by combining the accident frequency and total effective dose equivalent (TEDE) of each scenario, thereby visualizing the risk distribution of the nuclear power plant. Furthermore, this study analyzed a risk contribution by source term categories (STCs) to quantitatively identify the dominant STCs driving the total risk. Moreover, the derived total risk was compared against quantitative health objectives (QHO). By comprehensively evaluating both accident frequency and consequences, the exhaustive scenario-based risk profiling framework proposed in this study can be utilized not only for the safety assessment of SMRs and advanced reactors but also for the implementation of RIPB regulations.

Keywords: Risk profile, exhaustive scenario, source term, total effective dose equivalent, frequency-consequence, OPR1000.