Regulatory Direction for Physical Protection Systems in the Standard Design Approval Stage of Light-Water Small Modular Reactors

As the deployment of small modular reactors (SMRs) and advanced reactors expands, physical protection system regulatory frameworks are shifting from prescriptive, compliance-driven approaches to risk-informed and performance-based methodologies. In Korea, the amendment to the Act on Physical Protection and Radiological Emergency, promulgated on March 31, 2026, establishes a legal basis for the institutionalization of Security by Design (SbD) by requiring physical protection regulations to be reviewed from the Standard Design Approval (SDA) stage onward. This study examines the applicable regulatory direction for the SDA stage of Light-Water SMRs based on an analysis of regulatory trends in major countries. It investigates alternative requirements reflecting SMR-specific characteristics and performance-based regulatory approaches and proposes a preliminary regulatory framework incorporating performance assessment feedback into design improvement. The findings serve as a technical foundation for developing review guidance at the SDA stage to advance SbD institutionalization in Korea.