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Effect of Thermal Properties of Bentonite Buffer on Temperature Variation

벤토나이트 완충재의 열물성이 온도 변화에 미치는 영향

Min-Jun Kim1
,
Seung-Rae Lee2*
,
Seok Yoon3
,
Jun-Seo Jeon4
,
Min-Seop Kim4
김 민준1
,
이 승래2*
,
윤 석3
,
전 준서4
,
김 민섭4
1Graduate Student, Dept. of Civil and Environmental Eng., KAIST
2Prof., Dept. of Civil and Environmental Eng.
3Senior Researcher, Radioactive Waste Disposal Research Division, KAERI
4Graduate Student, Dept. of Civil and Environmental Eng., KAIST
1KAIST 건설 및 환경공학과 박사과정
2KAIST 건설 및 환경공학과 교수
3한국원자력연구원 방사성폐기물처분연구부 선임연구원
4KAIST 건설 및 환경공학과 박사과정
*교신저자. *Corresponding Author. 
31 January 2018. pp. 17-24
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Abstract

A buffer in a geological disposal system minimizes groundwater inflow from the surrounding rock and protects the disposed high-level waste (HLW) against any mechanical impact. As decay heat of a spent fuel causes temperature variation in the buffer that affects the mechanical performance of the system, an accurate estimation of the temperature variation is substantial. The temperature variation is affected by thermal and material properties of the system such as thermal conductivity, density and specific heat capacity of the buffer, and thus these factors should be properly included in the design of the system. In particular, as the thermal properties are variable depending on the density and water content of the buffer, consideration of the effects should be included in the analysis. Hence, in this study, a numerical model based on finite element method (FEM) which is able to consider the change of density and water content of the buffer was established. In addition, using the numerical model, a parametric study was conducted to investigate the effect of each thermal property on the temperature variation of the buffer.

Keywords
Deep geological disposal
Compacted bentonite buffer
Thermal conductivity
Density
Specific heat capacity

심층 처분시설에서 완충재는 지하수의 유입을 최소화하며, 역학적인 충격을 흡수하는 중요한 역할을 한다. 사용후핵연료로부터 발생하는 붕괴열은 완충재의 온도를 변화시켜 역학적 성능에 큰 영향을 미치기 때문에 완충재 온도 변화에 대한 정확한 예측이 필요하다. 이러한 온도 변화는 완충재의 열물성인 열전도도, 밀도, 비열에 영향을 받으며, 이에 대한 영향이 심층 처분시설의 열 해석에 고려되어야 한다. 특히 이들 열물성은 벤토나이트 완충재의 밀도와 함수비에 따라 변화하기 때문에 이에 대한 영향이 해석에 포함되어야한다. 따라서 본 연구에서는 완충재의 밀도와 함수비 변화 영향을 고려할 수 있는 유한요소법 기반의 열 해석 수치모델을 설정하였다. 또한 수치모델을 바탕으로 매개 변수 연구를 수행하여 각각의 열물성이 완충재의 온도 변화에 미치는 영향에 대해 살펴보았다.

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Information
  • Publisher :The Korean Geotechnical Society
  • Publisher(Ko) :한국지반공학회
  • Journal Title :Journal of the Korean Geotechnical Society
  • Journal Title(Ko) :한국지반공학회 논문집
  • Volume : 34
  • No :1
  • Pages :17-24
  • Received Date : 2017-11-01
  • Revised Date : 2017-12-06
  • Accepted Date : 2017-12-07
  • DOI :https://doi.org/10.7843/kgs.2018.34.1.17
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