Study on regulatory gap analysis of LOCA for the RCPB in SMR in South Korea

This study assesses South Korea's regulatory readiness for licensing Small Modular Reactors (SMRs) with integrated Reactor Coolant Pressure Boundary (RCPB) systems and passive safety features, benchmarked against the NuScale SMR, approved by the U.S. Nuclear Regulatory Commission (NRC). Through a comparative analysis of South Korea's Nuclear Safety and Security Commission (NSSC) regulations (e.g., Articles 21, 30, 41, 42 ), U.S. NRC standards (e.g., 10 CFR Part 50, Appendix K , GDC 35 ), and IAEA benchmarks (e.g., SSR-2/1 Req. 54, 69), the research identifies gaps in addressing Loss-of-Coolant Accident (LOCA) scenarios, Emergency Core Cooling System (ECCS) requirements, and in-vessel component classification for integral SMRs like i-SMR. The methodology integrates qualitative regulatory review, system-level safety analysis, and NuScale's exemption pathways (e.g., no forced reflooding, no post-CHF heat transfer). Findings reveal that NSSC assumptions, such as core uncovering ( Article 42 ) and active ECCS reliance ( Article 30 ), are misaligned with SMRs' passive, integral designs, while the absence of SMR-specific standards and exemption processes hinders innovation. The study recommends adopting risk-informed, performance-based criteria, developing SMR-specific guidelines, and establishing formal exemption pathways to ensure regulatory clarity and safety. These reforms are critical for enabling South Korea to lead in safe, efficient SMR deployment, advancing energy security, and nuclear innovation.