Journal of the Korean Geotechnical Society (한국지반공학회논문집)

Korean Geotechnical Society (한국지반공학회)
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Evaluation of Mechanical Properties for the Compacted Bentonite Buffer Materials

압축 벤토나이트 완충재의 역학 물성 평가

  • Yoon, Seok (Disposal Safety Evaluation Research Division, KAERI) ;
  • Hong, Chang-Ho (Disposal Performance Demonstration Research Division, KAERI) ;
  • Kim, Taehyun (Disposal Performance Demonstration Research Division, KAERI) ;
  • Kim, Jin-Seop (Disposal Performance Demonstration Research Division, KAERI)
  • 윤석 (한국원자력연구원 저장처분기술관리부) ;
  • 홍창호 (한국원자력연구원 처분성능실증연구부) ;
  • 김태현 (한국원자력연구원 처분성능실증연구부) ;
  • 김진섭 (한국원자력연구원 처분성능실증연구부)
  • Received : 2021.07.27
  • Accepted : 2021.09.30
  • Published : 2021.10.31
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Abstract

The compacted bentonite buffer is one of the most important components in an engineered barrier system (EBS) to dispose of high-level radioactive waste (HLW) produced by nuclear power generation. The compacted bentonite buffer has a crucial role in protecting the disposal canister against the external impact and penetration of groundwater, so it has to satisfy the thermal-hydraulic-mechanical requirements. Even though there have been various researches on the investigation of thermal-hydraulic properties, few studies have been conducted to evaluate mechanical properties for the compacted bentonite buffer. For this reason, this paper conducted a series of unconfined compression tests and obtained mechanical properties such as unconfined compressive strength, elastic modulus, and void ratio of Korean compacted bentonite specimens with different water content and dry density values. The unconfined compressive strength and elastic modulus increased, and the Poisson's ratio decreased a little with increasing dry density. It showed that unconfined compressive strength and elastic modulus were proportional to dry density. However, there was not a remarkable correlation between mechanical properties and water content.

압축 벤토나이트 완충재는 원자력발전소에서 발생하는 고준위폐기물을 처리하기 위한 공학적방벽시스템의 가장 중요한 요소 중 하나이다. 압축 벤토나이트 완충재는 외부 하중이나 지하수 침투로부터 처분 용기를 보호하기에, 열-수리-역학적인 요구 조건을 충족하여야 한다. 이러한 완충재의 열-수리 물성에 관한 연구는 많이 진행되어 왔지만, 역학 물성 규명에 관한 연구는 많이 부족한 실정이다. 이러한 이유로, 본 연구에서는 건조밀도와 함수비에 따른 다양한 국내 압축 벤토나이트 시료를 조성하여 이에 대한 일축압축강도시험을 실시하였으며, 일축압축강도, 탄성계수, 그리고 포아송비를 도출하였다. 압축 벤토나이트의 일축압축강도와 탄성계수는 건조밀도에 따라 증가하였으며, 포아송비는 건조밀도가 증가할수록 약간 감소하는 것으로 나타났다. 일축압축강도, 탄성계수 및 포아송비는 건조밀도와 큰 상관 관계를 보였으나, 함수비와는 특별한 상관성을 나타내지는 않았다.

Keywords

Acknowledgement

본 연구는 과학기술정보통신부의 재원으로 사용후 핵연료관리핵심기술개발사업단 및 한국연구재단(2021M2E1A1085193)과, 한국연구재단 원자력연구개발사업(2021M2E3A2041351)의 지원을 받아 수행되었습니다.

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