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2025 Vol.35, Issue 3 Preview Page

Original Article

Measurements of Fundamental Thermal Properties Using a Single Rock Specimen around KURT

단일 시험편을 사용한 KURT 주변 암석의 주요 열물성 측정

Seungbeom Choi1*
,
Saeha Kwon1
,
Taehyun Kim1
,
Seong-Jun Ha1
,
Jin-Seop Kim2
최 승범1*
,
권 새하1
,
김 태현1
,
하 성준1
,
김 진섭2
1Senior Researcher, Korea Atomic Energy Research Institute (KAERI)
2Principal Researcher, Korea Atomic Energy Research Institute (KAERI)
1한국원자력연구원 선임연구원
2한국원자력연구원 책임연구원
*Corresponding Author
30 June 2025. pp. 287-303
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Abstract

High-level radioactive waste disposed of in rock mass continuously emits decay heat, leading to a rise in the temperature of the surrounding near field rock mass. Depending on the disposal concept, the temperature may reach up to 120℃. Therefore, such high temperature conditions must be considered in the design and operation of the engineered barrier system, and accurate measurements of the thermal properties of rock are essential. Among the various test methods proposed for measuring the thermal properties, some require the use of very small specimens. However, considering the inherent heterogeneity of rock, such small specimens may compromise practicality and/or representativeness. Thus, it is thought more appropriate to use single specimen of typical core size. In this study, thermal conductivity, specific heat, thermal diffusivity, and thermal expansion coefficient were measured using granite core specimens of standard NX size collected from the vincinity of the KURT. The DBM, TDBM, and strain gage method were employed. The results showed an average thermal conductivity of 2.79 W/m·K, specific heat of 0.78 J/g·K, thermal diffusivity of 1.35 mm2/s, and expansion coefficient of 6.59×10-6 1/K. Compared to previous studies conducted on similar location and rock type, the present results exhibited reduced dispersion, which was possibly attributed to the use of larger rock specimen so that the effect of heterogeneity was somewhat mitigated.

Keywords
Rock thermal properties
Single specimen
DBM
TDBM
Strain gage method

암반에 처분된 고준위방사성폐기물은 지속적으로 방사성 붕괴열을 발산하여 근계 암반의 온도를 상승시킨다. 이는 처분 개념에 따라 120℃에 달할 수 있기 때문에 이러한 고온 조건은 공학적방벽의 설계 및 운영에 반드시 반영되어야 한다. 또한 근계암반 매질의 열물성을 정확히 측정하는 것 역시 이 과정에서 요구되는 매우 중요한 사항이다. 암석의 열물성을 측정하기 위해 제안된 여러 시험법 중 일부는 매우 작은 시험편을 요구한다. 이는 암석 고유의 불균질성을 감안하면 편의성 및 대표성 문제가 있으므로 일반적인 크기의 단일 암석 시험편을 사용하는 것이 바람직한 것으로 판단하였다. 본 연구에서는 NX 표준 크기이며 KURT 주변에서 취득된 화강암 시험편을 사용하여 열전도도, 비열, 열확산도, 열팽창계수를 측정하였다. 이를 위해 DBM, TDBM, 스트레인게이지법을 적용했으며 그 결과, 열전도도는 평균 2.79 W/m·K, 비열 0.78 J/g·K, 열확산도 1.35 mm2/s, 열팽창계수 6.59×10-6 1/K가 측정되었다. 유사한 지역과 암종에 대해 수행된 선행연구 결과와 비교하면 본 연구의 결과는 산포도 면에서 개선된 결과를 도출했으며, 이는 보다 큰 시험편을 사용함으로써 불균질성이 일정 부분 완화된 것도 원인 중 하나로 판단되었다.

키워드
암석 열물성
단일 시험편
DBM
TDBM
스트레인게이지법
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Information
  • Publisher :Korean Society for Rock Mechanics and Rock Engineering
  • Publisher(Ko) :한국암반공학회
  • Journal Title :Tunnel and Underground Space
  • Journal Title(Ko) :터널과 지하공간
  • Volume : 35
  • No :3
  • Pages :287-303
  • Received Date : 2025-06-05
  • Revised Date : 2025-06-16
  • Accepted Date : 2025-06-17
  • DOI :https://doi.org/10.7474/TUS.2025.35.3.287
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