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

  • 제16권1호
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  • Pages.123-136
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  • 2018
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  • 1738-1894(pISSN)
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  • 2288-5471(eISSN)
한국방사성폐기물학회 (Korean Radioactive Waste Society)
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고준위폐기물처분장 내 공학규모의 균질 완충재 블록 성형특성 및 현장적용성 분석

A Study on the Manufacturing Characteristics and Field Applicability of Engineering-scale Bentonite Buffer Block in a High-level Nuclear Waste Repository

  • 투고 : 2017.11.22
  • 심사 : 2018.01.12
  • 발행 : 2018.03.30
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초록

본 연구의 목적은 고준위폐기물 처분기술 개발과 관련하여 현장실증 연구를 위해 사용될 공학규모 이상의 균질 완충재 블록을 제작하기 위한 새로운 방법론을 제시하는 것이다. 이와 관련하여 플롯팅 다이(floating die) 방식의 프레스 재하 및 냉간등방압프레스(CIP; Cold Isostatic Press) 기법을 국내 최초로 완충재 제작에 적용하였다. 또한 소요 밀도기준을 충족하는 완충재 블록을 생산하기 위한 최적의 제작조건(프레스 및 CIP의 소요 압력)과 현장 적용성을 분석하였다. 상기 기법의 적용을 통해 완충재 블록 내 밀도분포 편차가 현저히 감소하였으며, 이와 동시에 평균 건조밀도가 소폭 상승하고 약 5%의 크기가 감소하였다. 또한 CIP 적용을 통해 응력이완(stress release) 현상이 감소하고, 이로 인해 시간 경과에 따른 표면균열 발생이 현저히 저감됨을 시험제작을 통해 확인하였다. 본 연구에서 제시된 방법론은 공학규모 이상의 균질한 완충재 블럭을 성형할 수 있으며, 또한 이는 선진핵주기 고준위폐기물처분시스템(AKRS; Advanced Korea Reference Disposal System of HLW)의 완충재 소요 밀도기준을 충족하는 것으로 분석되었다.

The objective of this study is to propose a new methodology to fabricate a reliable engineering-scale buffer block, which shows homogeneous and uniform distribution in buffer block density, for in-situ experiments. In this study, for the first time in Korea, floating die press and CIP (Cold Isostatic Press) are applied for the manufacture of an engineering-scale bentonite buffer. The optimized condition and field applicability are also evaluated with respect to the method of manufacturing the buffer blocks. It is found that the standard deviation of the densities obtained decreases noticeably and that the average dry density increases slightly. In addition, buffer size is reduced by about 5% at the same time. Through the test production, it is indicated that the stress release phenomenon decreases after the application of the CIP method, which leads to a reduction in crack generation on the surface of the buffer blocks over time. Therefore, it is confirmed that the production of homogeneous buffer blocks on industrial scale is possible using the method suggested in this study, and that the produced blocks also meet the design conditions for dry density of buffer blocks in the AKRS (Advanced Korea Reference Disposal System of HLW).

키워드

참고문헌

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피인용 문헌

  1. 국내 벤토나이트 완충재의 함수특성곡선 평가 vol.17, pp.1, 2019, https://doi.org/10.7733/jnfcwt.2019.17.1.29
  2. In-situ Demonstration of Engineered Barrier System (In-DEBS) for Characterization of Coupled THM Behavior in KURT vol.17, pp.suppl, 2018, https://doi.org/10.7733/jnfcwt.2019.17.s.1
  3. Design of In-DEBS (In-situ Demonstration of Engineered Barrier System) and Analysis on Optimized Manufacturing Conditions for EBS vol.17, pp.suppl, 2018, https://doi.org/10.7733/jnfcwt.2019.17.s.25
  4. 온도 변화를 고려한 압축 벤토나이트 완충재의 수분흡입력 평가 vol.35, pp.11, 2018, https://doi.org/10.7843/kgs.2019.35.11.7
  5. 고준위방사성폐기물 처분시스템의 압축 벤토나이트 완충재의 포화 수리전도도 추정 vol.18, pp.2, 2018, https://doi.org/10.7733/jnfcwt.2020.18.2.133
  6. Experimental Investigation on Small-Strain Dynamic Properties and Unconfined Compressive Strength of Gyeongju Compacted Bentonite for Nuclear Waste Repository vol.24, pp.9, 2018, https://doi.org/10.1007/s12205-020-0372-z