Evaluation of thermal-hydro-mechanical behavior of bentonite buffer under heating-hydration condition at disposal hole

Yohan Cha; Changsoo Lee; Jin-Seop Kim; Minhyeong Lee

doi:10.9711/KTAJ.2023.25.2.175

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2023 Vol.25, Issue 2 Preview Page

Technical Paper

Evaluation of thermal-hydro-mechanical behavior of bentonite buffer under heating-hydration condition at disposal hole 처분공 가열-수화 조건에서 벤토나이트 완충재의 열-수리-역학적 거동 특성 평가

31 March 2023. pp. 175-186

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Abstract

The buffer materials in disposal hole are exposed to the decay heat from spent nuclear fuels and groundwater inflow through adjacent rockmass. Since understanding of thermal-hydro-mechanical-chemical (T-H-M-C) interaction in buffer material is crucial for predicting their long-term performance and safety of disposal repository, it is necessary to investigate the heating-hydration characteristics and consequent T-H-M-C behavior of the buffer materials under disposal conditions considering geochemical factors. In response, the Korea Atomic Energy Research Institute developed a laboratory-scale ‘Lab.THMC’ experiment system, which characterizes the T-H-M behavior of buffer materials under different geochemical conditions by analyzing heating-hydration process and stress changes. This technical report introduces the detail design of the Lab.THMC system, summarizes preliminary experimental results, and outlines future research plans.

Keywords

Disposal hole

Engineered barrier

Buffer

Heating-hydration

Test-setup

처분공 내에 위치한 완충재는 사용후핵연료로부터 발산된 고온의 붕괴열과 지하수에 노출되며, 이와 같은 가열-수화를 포함한 처분환경 하의 완충재의 열-수리-역학-화학적 상호작용은 완충재의 장기적 성능과 건전성에 핵심적으로 작용하는 것으로 알려져 있다. 따라서 본 연구에서는 처분환경 조건에서 완충재의 가열-수화 특성 및 지하수 지화학 조건을 고려한 벤토나이트의 열-수리-역학-화학적(Thermal-Hydraulic-Mechanical-Chemical, 이하 THMC) 복합거동 특성 규명을 위한 실험실 규모의 Lab.THMC 실험시스템을 개발하였다. 본 실험시스템은 스페인 CIEMAT의 열-수리-역학 복합거동 실험장치를 토대로 개발되었으며, 화학적 특성을 달리한 지하수 주입 조건에서 벤토나이트 완충재의 가열-수화 특성을 파악하고 응력 변화를 계측함으로써 열-수리-화학적 변화에 따른 역학적 성능 변화 특성을 규명하는 것을 목표로 한다. 본 기술논문에서는 개발된 Lab.THMC 실험시스템의 설계 및 구성을 간략하게 소개하고, 장치 검토 및 주요 변수설정을 위해 수행된 예비실험 결과와 차후 연구계획에 대해 정리하였다.

키워드

처분공

공학적방벽

완충재

가열수화

실험장치

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Information

Publisher :Korean Tunneling and Underground Space Association
Publisher(Ko) :한국터널지하공간학회
Journal Title :Journal of Korean Tunnelling and Underground Space Association
Journal Title(Ko) :한국터널지하공간학회 논문집
Volume : 25
No :2
Pages :175-186
Received Date : 2023-03-10
Revised Date : 2023-03-17
Accepted Date : 2023-03-22
DOI :https://doi.org/10.9711/KTAJ.2023.25.2.175

Journal of Korean Tunnelling and Underground Space Association ISSN:2233-8292(Print) 2287-4747(Online) 한국터널지하공간학회 논문집

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