Study on Regulatory Gap Analysis of LOCA in the RCPB SMR in South Korea = 한국 RCPB SMR의 LOCA 규제 격차 분석 연구

다국어 초록 (Multilingual Abstract)

This study evaluates South Korea’s preparedness to regulate Small Modular Reactors (SMRs) that incorporate integrated Reactor Coolant Pressure Boundary (RCPB) designs and passive safety systems, using the NuScale Power SMR, which has received approval from the U.S. Nuclear Regulatory Commission, as a benchmark. A comparative assessment was conducted between the regulatory frameworks of South Korea’s Nuclear Safety and Security Commission, U.S. NRC requirements, and International Atomic Energy Agency safety standards to identify regulatory gaps related to Loss- of-Coolant Accident (LOCA) management, Emergency Core Cooling System (ECCS) requirements, and the classification of components in integral SMR (i-SMR) designs. Haque SK Nazmul Supervised by Prof. Daeho Lee Dept. of Mechanical Engineering Graduate School of Gachon University The analysis reveals that South Korea’s existing regulatory approach, which is largely based on active ECCS operation and conventional assumptions regarding core uncover during accident conditions, does not fully align with the safety philosophy of advanced SMRs that rely on passive safety mechanisms. Furthermore, the absence of dedicated SMR-specific regulations and clearly defined exemption procedures restricts the adaptability of the current licensing framework. To address these challenges, the study proposes the adoption of risk-informed and performance-based regulatory approaches, the development of specialized guidelines for SMR technologies, and the implementation of structured exemption mechanisms. These measures would facilitate the safe deployment of SMRs in South Korea while enhancing the country’s competitiveness in the evolving field of advanced nuclear energy technology.

목차 (Table of Contents)

• Chapter 1: Introduction 10
• 1.1 Background of the Study 10
• 1.2 Research Motivation and Problem Statement 14
• 1.3 Research Questions and Objectives 16
• 1.4 Significance of the Research 19
• 1.4.1 Updating Regulatory Framework for Advanced Reactors 19
• 1.4.2 Enhancing Safety Assurance for Passive Systems 20
• 1.4.3 Enhancing National Energy Strategy for Global Competitiveness 21
• 1.4.4 Unifying Research and Regulations for Maximum Impact 21
• 1.5 Thesis Structure 21
• Chapter 2: Literature Review 23
• 2.1 Small Modular Reactors (SMRs) and Their Reactor Coolant Pressure Boundary (RCPB) Systems 23
• 2.1.1 Types of SMR 25
• 2.1.2 Working Principle of SMR Reactor 28
• 2.2 NuScale SMRs 32
• 2.3 System-Integrated Modular Advanced Reactor Technology (SMART) 33
• 2.4 Innovative Small Modular Reactor (i-SMR) 33
• 2.5 Integral Design and Thermal-Hydraulic Performance of RCPB Systems in SMRs 35
• 2.6 Passive Safety Systems and Their Regulatory Implications for SMRs 42
• 2.7 LOCA and RCPB Related Accidental Scenario 52
• 2.7.1 Recent LOCA Incident 54
• 2.7.2 Earlier LOCA Incident 56
• Chapter 3: Methodology 59
• 3.1 Technical Design Analysis of NuScale SMR and i-SMR 59
• 3.2 Passive Safety System Evaluation for Design Basis Accident 60
• 3.3 Regulatory Benchmarking and Gap Analysis 62
• Chapter 4: Results and Discussion 64
• 4.1 Comparative Assessment of RCPB-Related Regulatory Frameworks 64
• 4.2 Identified Gaps and Benchmark Exemptions 71
• 4.3 Importance of Exemptions for i-SMR Design Components 78
• 4.4 Risk-informed and Performance-based Regulations 80
• Chapter 5: Proposed Regulatory Reform Roadmap 95
• Chapter 6: Conclusion 99
• 6.1 Contribution of the Study 99
• 6.2 Future Research Directions 99
• Appendixes 102
• A1 Appendix Table 102
• A2. Appendix Table 108
• References 111
• Acknowledgement 134
• Achievements 137