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Technical Paper

Study on the performance inspection and evaluation framework for buffer block inspection in deep geological disposal tunnel construction

처분시스템 준실규모 성능 실증을 위한 완충재 블록 제작 및 품질검사 공정 연구

Yonghyeon Lee1
,
Jae-Deuk Kim1
,
Jin-Seop Kim2*
이 용현1
,
김 재득1
,
김 진섭2*
1Post-Doctoral Researcher, Disposal Performance Demonstration R&D Division, Korea Atomic Energy Research Institute
2Principal Researcher, Disposal Performance Demonstration R&D Division, Korea Atomic Energy Research Institute
1비회원, 한국원자력연구원 처분성능실증연구부 박사후연구원
2정회원, 한국원자력연구원 처분성능실증연구부 책임연구원
*Corresponding Author
31 March 2026. pp. 185-204
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Abstract

In this study, a preliminary investigation was conducted to design the block manufacturing and performance inspection processes for the semi-field scale demonstration (K-COIN) planned at the KURT in 2027. A disk-type bentonite block (approximately 900 kg) was fabricated using a 10,000-ton uniaxial compaction press, and the effects of loading speed, maximum pressure holding time, confinement time, bentonite source, and water content on block quality were examined. The results indicated that the maximum pressure holding time and confinement time were critical parameters for increasing dry density and suppressing surface defects. In addition, a water content of 16% was required for ensuring block integrity. For performance inspection, ultrasonic wave velocity, gamma-ray attenuation, and electrical resistivity measurements were performed to evaluate the applicability of non-destructive testing methods. The results showed that gamma-ray attenuation exhibited the clearest correlation with dry density, while electrical resistivity showed the strongest correlation with water content. In addition, unconfined compressive strength and image-based defect area fraction were examined as indicators for evaluating block integrity and surface quality. This study provides basic data for developing a Korean life-cycle process for bentonite buffer blocks.

Keywords
Deep geological disposal system
Semi-field scale demonstration
Buffer block manufacturing process
Buffer block performance inspection

본 연구에서는 2027년 수행 예정인 KURT 기반 준실규모 처분실증연구(KURT THMC COupled and INteraction test, K-COIN)에 적용하기 위한 완충재 전주기 공정 중 블록 제작 및 성능검사 공정 설계를 목표로 예비 연구를 수행하였다. 준실규모(실규모 대비 1/1.3 축소, 약 900 kg급) 디스크형 벤토나이트 블록을 10,000 ton급 일축 압축 프레스를 이용하여 제작하였으며, 재하 속도, 최대 압력 유지 시간, 하중 제거 후 구속 시간, 벤토나이트 원료 종류 및 함수비가 블록 품질에 미치는 영향을 검토하였다. 그 결과 재하 속도는 블록 품질에 영향이 거의 없었으며, 최대 압력 유지 시간과 구속 시간이 건조밀도 증가와 표면 결함 억제에 더 중요한 변수로 나타났다. 또한 함수비 16% 조건이 블록의 무결성 확보에 가장 유리한 조건으로 확인되었다. 품질검사 후보기술로서 탄성파, 감마선 감쇠, 전기비저항 측정을 수행하여 비파괴검사 기술의 적용 가능성을 검토한 결과, 감마선 감쇠는 건조밀도와, 전기비저항은 함수비와 가장 뚜렷한 상관관계를 보였다. 추가적으로 일축압축강도와 이미지 기반 결함비를 이용하여 블록의 건전성과 표면 품질 평가 방법을 검토하였다. 본 연구는 대형 완충재 블록의 제작 및 성능검사 공정에 대한 국내 초기 실증 결과를 제시한 것으로, 향후 실제 처분장 적용을 위한 한국형 완충재 블록 설계 및 제작 그리고 품질관리를 위한 기초 자료로 활용될 수 있을 것이다.

키워드
처분시스템
준실규모 실증프로젝트
블록 제작 공정
블록 성능검사 기술
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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 : 28
  • No :2
  • Pages :185-204
  • Received Date : 2026-03-11
  • Revised Date : 2026-03-25
  • Accepted Date : 2026-03-25
  • DOI :https://doi.org/10.9711/KTAJ.2026.28.2.185
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