교육기관내 방사성동위원소 사용시설 사고시 주변 주민 방사선량 평가

Abstract

IAEA recommends a graded approach to emergency response based on the characteristics and potentialrisk of nuclear facilities. However, in Republic of Korea, regulations related to radiation emergency responseare primarily structured around NPP, and the same regulatory framework is applied uniformly to facilities withsignificantly different characteristics and risk profiles. To establish a graded emergency response system for nonnuclear power facilities, it is essential to comprehensively consider both the environmental impact of radioactivematerial releases during radiation emergency and the frequency of such accidents occurring. In this study, weassessed radiation doses to residents surrounding a radioisotope facility located within an educational institution,which is categorized as a non-nuclear power facility. A conservative accident scenario involving a fire was assumed,and the corresponding source term was defined. Exposure scenarios were set reflecting the characteristics of thesurrounding area, and exposure pathways were set based on the characteristics of the assumed accident. 16 directionsfrom the facility were set as assessment groups, and radiation doses were calculated for residents in each group. The source term was assumed to involve the release of gaseous radioactive materials due to the fire. Exposurescenarios were defined by age group 1-year, 10-year and adult. Exposure pathways considered in this study included1) external exposure from radioactive plumes, 2) internal exposure via inhalation. Radiation dose assessments wereconducted using models presented in Regulatory Guide 14.2 of the Korea Institute of Nuclear Safety. Radiation doseassessments were performed for each of the 16 directional sectors around the facility. Among all assessment groups,the highest dose was calculated for 1-year-old residents located to the south of the facility, with a value of 1.06 × 10−3mSv. This value was assessed to be significantly lower than the lowest emergency protective action decision levelof 10 mSv specified in the Enforcement Rules of the Act on Measures for the Protection of the Public in RadiationEmergencies The results of this study are expected to serve as foundational data for developing a graded emergencyresponse plan for non-nuclear power facilities in the future.