Tunnel and Underground Space (터널과지하공간)

Korean Society for Rock Mechanics and Rock Engineering (한국암반공학회)
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A Review of In-Situ Characterization and Quality Control of EDZ During Construction of Final Disposal Facility for Spent Nuclear Fuel

사용후핵연료 최종처분장 건설과정에서의 굴착손상영역(EDZ)의 현장평가 방법 및 시공품질관리 체계에 관한 사례검토

  • Kim, Hyung-Mok (Department of Energy Resources and Geosystems Engineering, Sejong University) ;
  • Nam, Myung Jin (Department of Energy Resources and Geosystems Engineering, Sejong University) ;
  • Park, Eui-Seob (Deep Subsurface Storage and Disposal Research Center, Korea Institute of Geoscience and Mineral Resources)
  • 김형목 (세종대학교 지구자원시스템공학과) ;
  • 남명진 (세종대학교 지구자원시스템공학과) ;
  • 박의섭 (한국지질자원연구원 국토지질연구본부 심층처분환경연구센터)
  • Received : 2022.04.06
  • Accepted : 2022.04.22
  • Published : 2022.04.30
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Abstract

Excavation-Disturbed Zone (EDZ) is an important design factor in constructing final disposal facilities for spent nuclear fuel, since EDZ affects mechanical stability including a spacing between disposal holes, and the hydraulic properties within EDZ plays a significant role in estimating in-flow rate of groundwater as well as a subsequent corrosion rate of a canister. Thus, it is highly required to characterize in-situ EDZ with precision and control the EDZ occurrence while excavating disposal facilities and constructing relevant underground research facilities. In this report, we not only reviewed EDZ-related researches carried out in the ONKALO facility of Finland but also examined appropriate methods for field inspection and quality control of EDZ occurrence. From the review, GPR can be the most efficient method for in-situ characterization of EDZ since it does not demand drilling a borehole that may disturb a surrounding environment of caverns. And the EDZ occurrence was dominant at a cavern floor and it ranged from 0 to 70 cm. These can provide useful information in developing necessary EDZ-related regulations for domestic disposal facilities.

사용후핵연료 최종처분장 건설 과정에서 발생하는 굴착손상영역(EDZ)은 처분시설의 역학적 안정성 및 처분공 간격 설정 등의 설계요소로서 고려해야 할 뿐만 아니라 영역 내 투수특성은 폐쇄 후 지하수 유입량 변화에 따른 처분용기 부식 속도 및 핵종유출 등에도 막대한 영향을 미치게 된다. 따라서, 처분시설 및 관련 지하연구시설(URL)의 건설과정에서는 EDZ의 발생양상을 현장에서 정확하게 파악하고 미리 규정된 요건을 만족할 수 있도록 철저하게 관리할 수 있어야 한다. 이 논문에서는 핀란드 온칼로 시설에서의 EDZ 관련 연구사례를 검토하고 처분시설 굴착과정에서의 EDZ의 현장평가방법 및 시공품질관리 체계에 대해 검토하였다. EDZ 현장 평가를 위해서는 굴찰 갱도 주변의 교란을 유발하는 시추공 굴착이 불필요한 GPR 탐사가 가장 적합함과 온칼로 처분시설의 EDZ는 바닥부에서 두드러지게 발생하여 0~70 cm의 두께로 발생함을 확인하였다. 이들 결과는 국내 처분환경에 적합한 EDZ 관련 규제요건 개발에 유용한 정보를 제공할 수 있을 것으로 기대된다.

Keywords

Acknowledgement

이 논문은 2022년도 원자력안전위원회의 재원으로 사용후핵연료관리핵심기술개발사업단 및 한국원자력안전재단의 지원(2109092-0121-WT112)을 받았습니다. 또한, 제1저자는 과학기술정보통신부 재원 한국연구재단의 지원(2022R1A2C1009524)을 받았습니다. 지원에 감사드립니다.

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