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The Assessment of Exposure Dose of Radiation Workers for Decommissioning Waste in the Radioactive Waste Inspection Building of Low and Intermediate-Level Radioactive Waste Disposal Facility

경주 중·저준위방사성폐기물 처분시설의 방폐물검사건물에서 해체 방사성폐기물 대상 방사선작업종사자의 피폭선량 평가 및 작업조건 도출

  • Received : 2020.05.29
  • Accepted : 2020.08.11
  • Published : 2020.08.30

Abstract

The Korea Radioactive Waste Agency plans to expand the storage capacity of radioactive waste by constructing a radioactive waste inspecting building to solve the problem of the lack of inspection space and drum-handling space in the radioactive waste receipt and storage building for the first-stage disposal facility. In this study, the exposure doses of radiation workers that handle new disposal containers for decommissioning waste in the storage areas of the radioactive waste inspecting building were calculated using the Monte Carlo N-particle transport code. The annual collective dose was calculated as a total of 84.8 man-mSv for 304 new disposal containers and an estimated annual 306 working hours for the radiation work. When the 304 new disposal containers (small/medium type) were stored in the storage areas, it was found that 25 radiation workers should be involved in acceptance/disposal inspection, and the estimated exposure dose per worker was calculated as an average annual value of 3.39 mSv. When the radiation workers handle the small containers in high-radiation dose areas, the small containers should be shielded further by increasing the concrete liner thickness to improve the work efficiency and radiation safety of the radiation workers. The results of this study will be useful in establishing the optimal radiation working conditions for radiation workers using the source term and characteristics of decommissioning waste based on actual measurements.

한국원자력환경공단은 처분시설 내 1단계 인수·저장구역의 인수검사 공간 및 드럼 취급 공간 부족에 대한 문제를 해결하기 위하여 방폐물검사건물을 건설하여 저장·처리능력을 확충할 예정이다. 본 연구에서는 MCNP 코드를 이용하여 방폐물검사건물 내 저장구역에서 취급하는 해체 방사성폐기물 대상 신형처분용기를 대상으로 작업종사자의 피폭선량을 평가하였다. 평가결과, 시설 내 저장 가능한 최대 용기 개수(304개)와 방사선작업에 대한 연간 예상 작업시간(약 306시간)에 대하여 연간 집단선량은 총 84.8 man-mSv로 계산되었다. 시설 내 총 304개의 신형처분용기(소형/중형 타입)가 저장 완료된 시점에서 인수검사, 처분검사를 위한 작업종사자의 투입인력은 총 25명, 작업종사자 당 예상피폭선량은 연평균 3.39 mSv로 산출되었다. 소형용기 취급 시 작업종사자의 고방사선량 작업에 따른 작업효율과 방사선적 안전성 확보를 위해서는 콘크리트 라이너의 두께를 증가시키는 추가적인 차폐가 필요할 것으로 평가되었다. 향후 본 연구를 바탕으로 실측기반의 해체폐기물의 선원항과 특성을 활용하여 방사선작업 당 작업시간 및 투입인력을 산출함으로써 작업종사자의 최적의 방사선작업조건을 도출할 수 있을 것으로 사료된다.

Keywords

Acknowledgement

This research was supported by the Korea Institute of Energy Technology Evaluation and Planning (KETEP), (No. 20181510300870).

References

  1. Korea Radioactive Waste Agency, General Design Criteria for the radwaste inspecting building, 92-101, KORAD-TR-2016-11 (2016).
  2. Nuclear Safety and Security Commission, Guidelines for the Operation of Low and Intermediate-Level Radioactive Waste Disposal Facilities, NSSC Notice No. 2016-26 (2016).
  3. Korea Radioactive Waste Agency, Safety Analysis Report for Low and Intermediate Level Radioactive Waste Disposal Facility, 8559-8560 (2016).
  4. Korea Radioactive Waste Agency, the Operating Procedure of Low and Intermediate Level Radioactive Waste Disposal Facilities - Management of Radiation Exposure Dose, Notice No. LILW-Operation-Radiation-041 (2010).
  5. Korea Radioactive Waste Agency, the Operating Procedure of Low and Intermediate Level Radioactive Waste Disposal Facilities - Operating of As Low As Reasonably Achievable (ALARA), No. LILW-Operation-Radiation-075 (2019).
  6. Nuclear Safety and Security Commission, Standards for Radiation Protection, etc., NSSC Notice No.2019-10 (2019).
  7. Korea Radioactive Waste Agency, the Operating Procedure of Low and Intermediate Level Radioactive Waste Disposal Facilities - Acceptance of Radioactive Waste, Notice No. LILW-Operation-Radiation-027 (2020).
  8. Korea Radioactive Waste Agency, the Operating Procedure of Low and Intermediate Level Radioactive Waste Disposal Facilities - Acceptance Inspection of Radioactive Waste, Notice No. LILW-Operation-Radiation-028 (2018).
  9. Korea Radioactive Waste Agency, Safety Analysis Report for 2st Phase Low and Intermediate-Level Waste Disposal Facility on the Construction Phase, 4969-4971 (2016).
  10. Korea Radioactive Waste Agency, Annual report of Development of Waste Package, Transportation and Disposal Containers for Decommissioning Wastes of Nuclear Power Plant (2019).
  11. Los Alamos National Laboratory, MCNP6 Users Manual - Code Version 1.0, 15-40, LA-CP-13-00634 (2013).
  12. OAK Ridge National Laboratory, SCALE Code System, 1561-1562, ORNL/TM-2005-39 (2016).
  13. Los Alamos National Laboratory, RSICC Computer Code Collection MCNP6.1/MCNP5, MCNPX, 97-99, CCC-810 (2013).