• 터널과지하공간
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• 제1권
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• pp.32-38
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• 1991

9 nuclear power plants are presently in operation in Korea. They produce radioactive waste of which the most long-lived radioactive elements need to be safely stored for hundreds of thousands of years, isolated from humanity and the environment. The safe disposal of high level radioactive waste in mined cavities requires knowledge of the mechanical. thermal and fluid flow characteristics of rock as perturbed by a thermal pulse The literature review was performed to assemble data on the following properties: modulus tensile strength compressive strength thermal expansion specific heat, thermal conductivity thermal diffusivity and permeability.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2009년도 학술논문요약집
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• pp.179-181
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• 2009

This presentation is a short summary of the Finnish process for selection and characterisation of potential sites for geological deep disposal of spent nuclear fuel. The process lasted nearly two decades from 1983 to 2000, and was concluded by the Government's Decision in Principle (DiP) on the construction of a repository in Olkiluoto. This presentation gives an outline of the early site selection criteria and a description of this process.

• 방사성폐기물학회지
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• 제5권3호
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• pp.239-255
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• 2007

고준위폐기물 기준처분시스템의 건전성과 처분안전성의 실험적 검증에 필수적 시설인 지하처분연구시설이 한국원자력연구원 부지 내에 건설되었다. 지하처분연구시설의 부지조사 결과에 대해 기술하고, 이 부지에 건설될 지하처분연구시설의 설계, 인허가, 건설 과정과 건설된 시설의 개요에 대해 하였다. 또 지하처분연구시설에서 수행 중인 현장실험에 대해 소개하였다.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2005년도 추계 학술대회 논문집
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• pp.153-162
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• 2005

본 연구에서는 사전연구로부터 사용후 핵연료의 처분용기 원형모델로 제안된 처분용기의 전체 크기와 배열을 평가하기 위하여 일련의 공학적 분석을 수행하였다. 그러한 노력의 결과 용기 내부 저장통의 배열형태와 외곽쉘과 상하부뚜껑의 두께와 같은 새로운 설계변수를 도출하였다. 공학적 분석 작업에는 처분용기의 기계구조 해석 결과를 근거로 도출된 용기의 규격자료에 대한 방사선 안전성 측면에서의 타당성을 검토하기 위하여 방사선차폐 해석과 핵임계 해석 등이 수행되었다. 처분용기 내부 삽입체의 직경변화에 따른 구조안정성 해석 결과에 따르면, 직경 102cm일 때 극한 외압조건은 물론 정상적인 외압조건 하에서도 최대 Von Mises 응력이 안전계수 2.0을 만족하는 것으로 나타났다. 이 경우에도 핵임계 및 방사선차폐 해석 결과 안전기준치를 만족시키며, 무게는 20톤 가량 줄어드는 효과가 있는 것으로 나타났다.

• 터널과지하공간
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• 제32권6호
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• pp.411-434
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• 2022

사용후핵연료의 심층처분 개념에서 근계영역 암반은 열-수리-역학적 복합거동을 하게 되는 것으로 잘 알려져있다. 이러한 복합거동 과정에서 암석의 여러 물성들은 변화하는데, 이러한 물성변화를 합리적으로 반영하는 경우 고준위방사성폐기물 처분장의 장기안정성의 평가를 위해 활용되는 해석 및 현장시험의 신뢰도를 향상시킬 수 있다. 이를 위해 본 기술보고에서는 암석의 열-수리-역학적 간접복합거동에 관한 국내외 연구사례를 조사하고 분석하였다. 특히, 간접복합거동의 대표적인 사례 중 지하수에 의한 포화 및 온도 증가에 따른 암석의 여러 물성 변화, 응력 변화에 의한 투수계수 변화를 중점적으로 조사·요약하였다.

• Nuclear Engineering and Technology
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• 제45권1호
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• pp.53-60
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• 2013

Bentonite is generally used as a buffer material in high-level radioactive waste disposal facilities and consists of 50% quartz by weight. Quartz strongly affects the behavior of bentonite over very long periods. For this reason, quartz dissolution experiment was performed under high-pressure and high-alkalinity conditions based on the conditions found in a high-level radioactive waste disposal facility located deep underground. In this study, two quartz dissolution experiments were conducted on 1) quartz beads under low-pressure and high-alkalinity conditions and 2) a single quartz crystal under high-pressure and high-alkalinity conditions. Following the experiments, a confocal laser scanning microscope (CLSM) was used to observe the surfaces of experimental samples. Numerical analyses using the finite element method (FEM) were also performed to quantify the deformation of contact area. Quartz dissolution was observed in both experiments. This deformation was due to a concentrated compressive stress field, as indicated by the quartz deformation of the contact area through the FEM analysis. According to the numerical results, a high compressive stress field acted upon the neighboring contact area, which showed a rapid dissolution rate compared to other areas of the sample.

• Geomechanics and Engineering
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• 제22권5호
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• pp.375-384
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• 2020

In this study, the application of conventional cubic law to a deep depth condition was experimentally evaluated. Moreover, a modified equation for estimating the rock permeability at a deep depth was suggested using precise hydraulic tests and an effect analysis according to the vertical stress, pore water pressure and fracture roughness. The experimental apparatus which enabled the generation of high pore water pressure (< 10 MPa) and vertical stress (< 20 MPa) was manufactured, and the surface roughness of a cylindrical rock sample was quantitatively analyzed by means of 3D (three-dimensional) laser scanning. Experimental data of the injected pore water pressure and outflow rate obtained through the hydraulic test were applied to the cubic law equation, which was used to estimate the permeability of rock fracture. The rock permeability was estimated under various pressure (vertical stress and pore water pressure) and geometry (roughness) conditions. Finally, an empirical formula was proposed by considering nonlinear flow behavior; the formula can be applied to evaluations of changes of rock permeability levels in deep underground facility such as nuclear waste disposal repository with high vertical stress and pore water pressure levels.

• 방사성폐기물학회지
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• 제19권4호
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• pp.517-532
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• 2021

Safe geological disposal of spent nuclear fuel (SNF) requires knowledge of the deep hydrochemical characteristics of the repository site. Here, we conducted a set of deep hydrochemical investigations using a 750-m borehole drilled in a model granite system in Wonju, South Korea. A closed investigation system consisting of a double-packer, Waterra pump, flow cell, and water-quality measurement unit was used for in situ water quality measurements and subsequent groundwater sampling. We managed the drilling water labeled with a fluorescein dye using a recycling system that reuses the water discharged from the borehole. We selected the test depths based on the dye concentrations, outflow water quality parameters, borehole logging, and visual inspection of the rock cores. The groundwater pumped up to the surface flowed into the flow cell, where the in situ water quality parameters were measured, and it was then collected for further laboratory measurements. Atmospheric contact was minimized during the entire process. Before hydrochemical measurements and sample collection, pumping was performed to purge the remnant drilling water. This study on a model borehole can serve as a reference for the future development of deep hydrochemical investigation procedures and techniques for siting processes of SNF repositories.

• Nuclear Engineering and Technology
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• 제54권6호
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• pp.2062-2066
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• 2022

Nuclear energy sources are indispensable in cost effectively achieving carbon neutral economy, where public opinion is critical to adoption as the consequences of nuclear accident can be catastrophic. In this context, discussion on spent nuclear fuel is a prerequisite to expanding nuclear energy, as it leads to the issue of radioactive waste disposal. Given the dearth of study on spent nuclear fuel public acceptance, we use text mining and big data analysis on the news article and public comments data on Naver news portal to identify the Korean public opinion on spent nuclear fuel. We identify that the Korean public is more interested in the nuclear energy policy than spent nuclear fuel itself and that the alternative energy sources affect the position towards spent nuclear fuel. We recommend relating spent nuclear fuel issue with nuclear energy policy and environmental issues of alternative energy sources to further promote spent nuclear fuel.

• 터널과지하공간
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• 제30권2호
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• pp.136-148
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• 2020

우리나라는 1978년부터 원자력발전소를 운영해왔으며 그에 따른 고준위방사성폐기물 발생이 누적되고 있다. 이를 안전하게 처분하기 위한 영구 처분시설이 시급한 실정이나 처분 부지를 선정하는 과정에서 광범위하고 정밀한 부지조사가 요구되기 때문에 장기간에 걸친 조사가 선행되어야한다. 이러한 부지조사는 단계별로 진행되는 것이 일반적이며 이 과정에서 다학제적 평가가 이루어진다. 본 논문에서는 부지조사 과정에서 요구되는 암반공학적 요소를 중점으로 사례조사를 수행하였다. 단계별로 고려되는 암반공학적 평가요소와 그 적용 사례를 정리하였으며 이 과정에서 수행된 해외 연구 사례를 조사하였다. 동시에 국내 연구현황을 정리하였고 부지조사와 관련된 향후 연구 계획을 간략히 보고하였다. 향후 연구를 통해 부지조사 시 참고할 수 있는 기반자료를 생산하고자 하며 본 논문에서 수집된 사례 역시 활용할 예정이다.