Economic and Environmental Geology (자원환경지질)

The Korean Society of Economic and Environmental Geology (대한자원환경지질학회)
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Safety Assessment of Near Surface Disposal Facility for Low- and Intermediate-Level Radioactive Waste (LILW) through Multiphase-Fluid Simulations Based on Various Scenarios

다양한 시나리오 기반 유체거동 수치모사를 통한 중·저준위 방사성 폐기물 표층처분시설 안전성 평가

  • Jeong, Jina (Department of Geology, Kyungpook National University) ;
  • Kown, Mijin (Department of Geology, Kyungpook National University) ;
  • Park, Eungyu (Department of Geology, Kyungpook National University)
  • 정진아 (경북대학교 지구환경시스템과학부) ;
  • 권미진 (경북대학교 지구환경시스템과학부) ;
  • 박은규 (경북대학교 지구환경시스템과학부)
  • Received : 2018.03.26
  • Accepted : 2018.04.03
  • Published : 2018.04.28
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Abstract

In the present study, the safety of the near surface disposal facility for low- and intermediate-level radioactive waste (LILW) is examined based on the fluid-flow simulation model. The effects of the structural design and hydrological properties of the disposal system are quantitatively evaluated by estimating the flux of infiltrated water at the boundary of the structure. Additionally, the safety margins of the disposal system, especially for the cover layer and vault, are determined by applying the various scenarios with consideration of possible facility designs and precipitation conditions. The overall results suggest that the disposal system used in this study is sufficiently suitable for the safe operation of the facility. In addition, it is confirmed that the soundness of both the cover layer and the vault have great impact on the safety of the facility. Especially, as shown in the vault degradation scenario, capability of the concrete barrier of the vault make more positive contribution on the safe operation of the facility compared to that of the cover layer.

본 연구에서는 중 저준위 방사성 폐기물 표층처분시설의 방사성 핵종 누출에 대한 안전성을 검증하기 위해 덮개층 및 처분고의 구조적 특성 및 물성이 고려된 유체거동 수치모사를 실시하였다. 유체거동 수치모사를 통해 시설 내 침투수거동 양상을 모사한 후, 덮개층 및 처분고 구조물 경계면을 따라 침투수 흐름 선속을 정량적으로 산정함으로써 방사성 핵종 누출의 위험성이 평가되었다. 또한 발생 가능한 시설 설계조건 및 외부 환경 변화가 고려된 다양한 시나리오 기반 수치모사를 실시함으로써 구축된 표층처분시설의 안전여유도 평가 또한 실시되었다. 그 결과, 본 연구에서 이용된 설계 구조가 표층처분시설의 안전적 운영에 적합한 것을 확인하였으며, 다양한 시나리오 기반 다중 수치모사 결과를 통해 덮개층과 처분고 수리특성의 건전성 유지 여부가 시설 안전성에 지대한 영향을 미침을 확인하였다. 특히, 처분고 콘크리트 벽체의 열화상황에서 처분고 내부로의 침투수 흐름을 관찰함으로써 처분고의 차수기능이 처분시설 안전성에 중요한 영향을 미치는 것으로 판단된다.

Keywords

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