An External Dose Assessment of Worker during RadWaste Treatment Facility Decommissioning

Abstract

Background: Kori unit #1 is permanently shut down after a 40-year lifetime. The Nuclear Safety and Security Commission recommends establishing initial decommissioning plans for all nuclear and radwaste treatment facilities. Therefore, the Korea Atomic Energy Research Institute (KAERI) must establish an initial and final decommissioning plan for radwaste-treatment facilities. Radiation safety assessment, which constitutes one chapter of the decommissioning plan, is important for establishing a decommissioning schedule, a strategy, and cost. It is also a critical issue for the government and public to understand. Materials and Methods: This study provides a method for assessing external radiation dose to workers during decommissioning. An external dose is calculated following each exposure scenario, decommissioning strategy, and working schedule. In this study, exposure dose is evaluated using the deterministic method. Physical characterization of the facility is obtained by both direct measurement and analysis of the drawings, and radiological characterization is analyzed using the annual report of KAERI, which measures the ambient dose every month. Results and Discussion: External doses are calculated at each stage of a decommissioning strategy and found to increase with each successive stage. The maximum external dose was evaluated to be 397.06 man-mSv when working in liquid-waste storage. To satisfy the regulations, working period and manpower must be managed. In this study, average and cumulative exposure doses were calculated for three cases, and the average exposure dose was found to be about 17 mSv/yr in all the cases. Conclusion: For the three cases presented, the average exposure dose is well below the annual maximum effective dose restriction imposed by the international and domestic regulations. Working period and manpower greatly affect the cost and entire decommissioning plan; hence, the chosen option must take account of these factors with due consideration of worker safety.

Analysis of the Work Time and the Collective Dose by Correcting the Learning-Forgetting Curve Model in Decommissioning of a Nuclear Facility

“…Various studies have simulated the complex changing environment in the D&D process [4][5][6][7]. Some studies have analyzed the radiation-dose rate change using neutron analysis codes, e.g., the Monte Carlo N-Particle Transport Code (MCNP), and three-dimensional (3D) computer-aided design (CAD) modeling.…”

A Simple and Effective Purification Method for Removal of U(VI) from Soil-Flushing Effluent Using Precipitation: Distillation Process for Clearance

“…In South Korea, a large amount of soil contaminated with U(VI) was generated during the decommissioning of the U(VI)-conversion plant operated by the Korea Atomic Energy Research Institute. This soil waste is being stored in a radioactive waste storage facility awaiting management and disposal [9][10][11]. Therefore, it is necessary to develop a technology for treating the soil contaminated with U(VI) to reduce the amount of https://doi.org/10.14407/jrpr.2022.00059 JRPR stored radioactive waste and economically dispose of it.…”

A Note on the Design of Waste Management System Using QR Code for Radioactive Waste

“…Due to the operation and dismantling of nuclear facilities by the Korea Atomic Energy Research Institute, mid-and low-level radioactive waste (MLW and LLW) generated by nuclear power plants is expected to steadily increase until the 2030s due to the gradual reduction in nuclear power plants [1,2]. In particular, unlike high-level radioactive waste, MLW and LLW of various forms and materials are generated in fields such as medical care and industry, and special management is required for their management and disposal.…”