NORM 폐기물 매립 시 NDD 분석을 활용한 부지 내 주요 피폭인자 도출

Abstract

As part of the social response to the radon bed incident in 2018, the Nuclear Safety and Security Com mission took measures to collect and dispose of all radon beds. The Waste Management Act provides landfill dispos al as one of the disposal methods for natural radioactive product waste, which is one of the NORM wastes. WhenNORM wastes are landfilled, workers and the public at the landfill site are exposed to radiation through variouspathways, such as leaching of radionuclides through soil and groundwater, and multiple exposure factors are involvedsimultaneously. In order to improve the reliability of radiological impact assessment, the values of main exposurefactors should be selected more accurately. Therefore, before developing the main exposure factors for site character istics, it is necessary to prioritize main exposure factors reflecting domestic characteristics of NORM waste landfills. Therefore, in this study, the main exposure factors for NORM waste landfill were derived using NDD analysis. Toderive the main exposure factors, the analysis tool was first selected as RESRAD-ONSITE computer code, and theexposure scenarios were mainly selected as a resident farmer and suburban resident scenario, recreation scenario, andindustrial worker scenario. Then, the priority 1 and 2 factors were selected for sensitivity analysis, and a Korean stan dard model was established to reflect Korean characteristics. Finally, the sensitivity analysis was conducted throughNDD, and the main exposure factors were derived based on this. In the resident farmer scenario, the contaminatedzone distribution coefficients of 226Ra, 210Pb, 232Th, 228Ra, 234U, and 238U, as well as precipitation and evapotranspirationfactors, were derived as the main exposure factors. In the suburban resident scenario, the contaminated zone distribu tion coefficients of 226Ra, 210Pb, 232Th, 228Ra, 234U, and 238U, as well as precipitation and evapotranspiration coefficients,were derived as the main exposure factors. In the recreation scenario, the contaminated zone distribution coefficientof 232Th was derived as the main exposure factor. For the industrial worker scenario, the erosion rate was derived asthe main exposure factor. The main exposure factors for each scenario were analyzed to be different depending onthe scenario characteristics. The results of this study can be utilized as a basis for radiological environmental impactassessment of NORM waste landfill in Korea.