Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT) (방사성폐기물학회지)

Korean Radioactive Waste Society (한국방사성폐기물학회)
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Effects of Excavation Damaged Zone on Thermal Analysis of Multi-layer Geological Repository

다층 심지층처분장 열해석에 미치는 암반손상대의 영향

  • Received : 2018.11.13
  • Accepted : 2019.02.22
  • Published : 2019.03.31
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Abstract

As the present single-layer repository concept requires too large an area for the site of the repository, a multi-layer repository concept has been suggested to improve the disposal density. The effects of the excavation damaged zone around the multi-layer repository constructed in the deep host rock on the temperature distribution in the repository were analyzed. For the thermal analysis of the multi-layer repository, the hydrothermal model was used to consider the resaturation process occurring in the buffer, backfill and rock. The existence of an excavation damaged zone has a significant effect on the temperature distribution in the repository, and the maximum peak temperatures of double-layer and triple-layer repositories can rise to $7^{\circ}C$ and $12^{\circ}C$, respectively depending on the size of the excavation damaged zone and the degree of decrease of the thermal conductivity. The dominant factor affecting the peak temperature in the multi-layer repository is the decrease of thermal conductivity in the excavation damaged zone, and the excavation damaged zone formed around the deposition hole has more significant effects on the peak temperature than does the excavation damaged zone formed around the disposal tunnel.

현재 고려되고 있는 단층 심지층처분장 개념은 부지 소요면적이 지나치게 크기 때문에, 처분밀도를 향상시키기 위한 다층 심지층처분장 개념이 제안되고 있다. 심부암반에 건설된 다층 심지층처분장 주위에 형성된 암반손상대가 심지층처분장의 온도 분포에 미치는 영향이 분석되었다. 다층 심지층처분장의 열해석에는 완충재, 뒤채움재 및 암반에서 일어나는 재포화 현상을 고려한 열-수리 모델이 사용되었다. 암반손상대의 존재는 심지층처분장의 온도 분포에 큰 영향을 미치는 것으로 나타났으며, 손상대의 크기와 열전도도 저하 정도에 따라 복층 및 삼층 심지층처분장의 최고첨두온도를 각각 최대 $7^{\circ}C$와 $12^{\circ}C$까지 증가시킬 수 있다. 다층 심지층처분장의 첨두온도에 영향을 크게 미치는 인자는 암반손상대에서의 열전도도 저하이며, 처분공 주위에 형성된 암반손상대가 처분터널 주변에 형성된 암반손상대보다 첨두온도에 더 큰 영향을 미친다.

Keywords

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