• 방사성폐기물학회지
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• 제13권1호
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• pp.73-86
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• 2015

방사성폐기물 처분시설을 보유하고 있는 국가들은 방사성폐기물 처분시설 시스템의 이해도 제고 및 신뢰성 증진을 위해서는 다양한 보조지표를 선정하여 평가하고 있다. 본 논문에서는 처분시설에 적용되는 국외 처분시설의 보조지표들을 조사하고, 우리나라 월성 중·저준위 방사성폐기물 처분시설에서 근계지역의 공학적 방벽과 원계지역의 자연방벽 성능평가를 위해 연속적인 방벽에서의 방사성 핵종 이동을 보여줄 수 있는 방벽 간의 방사성 핵종 플럭스를 보조안전지표로 선정하여 적용하였다. 처분시설의 정상시나리오를 콘크리트 사일로의 건전조건과 열화조건으로 나누어 방벽별 성능평가를 수행하였으며, 방사성 핵종에서 방벽별 지연성능 기여도를 확인하였다. 콘크리트가 건전한 경우에서 공학적 방벽의 방벽별 상세성능을 파악하였으며, 열화콘크리트의 경우, 공학적 방벽의 성능저하도 및 자연암반과의 상대적 중요도를 정량적으로 확인하였다. 향후본 연구 결과는 2단계 표층처분시설 설계 최적화 및 방벽성능의 검증방법으로 활용할 수 있다. 아울러, 향후에는 처분시설의 Safety Case 구축과 안전성의 이해 제고 및 신뢰성 증진을 위하여 지속적으로 보조지표를 추가 선정하여 평가하고자 한다.

• 방사성폐기물학회지
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• 제18권spc호
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• pp.21-36
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• 2020

With respect to spent nuclear fuels, disposal containers and bentonite buffer blocks in deep geological disposal systems are the primary engineered barrier elements that are required to isolate radioactive toxicity for a long period of time and delay the leakage of radio nuclides such that they do not affect human and natural environments. Therefore, the thermal stability of the bentonite buffer and structural integrity of the disposal container are essential factors for maintaining the safety of a deep geological disposal system. The most important requirement in the design of such a system involves ensuring that the temperature of the buffer does not exceed 100℃ because of the decay heat emitted from high-level wastes loaded in the disposal container. In addition, the disposal containers should maintain structural integrity under loads, such as hydraulic pressure, at an underground depth of 500 m and swelling pressure of the bentonite buffer. In this study, we analyzed the thermal stability and structural integrity in a deep geological disposal environment of the improved deep geological disposal systems for domestic light-water and heavy-water reactor types of spent nuclear fuels, which were considered to be subject to direct disposal. The results of the thermal stability and structural integrity assessments indicated that the improved disposal systems for each type of spent nuclear fuel satisfied the temperature limit requirement (< 100℃) of the disposal system, and the disposal containers were observed to maintain their integrity with a safety ratio of 2.0 or higher in the environment of deep disposal.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2018년도 추계학술논문요약집
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• pp.265-266
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• 2018

• 동력기계공학회지
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• 제18권6호
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• pp.153-158
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• 2014

The food waste that occurs in one year is very high in our country and disposal is expensive. However, disposers for food waste are not used wisely at real life. This is because most of them some kind of problem, for example big volume, complicated construction, high cost, lots of troubles, low energy efficiency and so on. In this study, we propose the new dryer system to decrease drying times by injecting hot air in down the side of the drying bucket. The designed drying bucket has inclined inlet holes down both sides. The inlet holes have variable gradients, we adjust the inlet velocity of the hot air to find a suitable vortex in the drying bucket. We verify the properties of the proposed system though simulation. The results show the proposed dryer system can improve the drying time and save energy for food waste disposal.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2004년도 Proceedings of the 4th Korea-China Joint Workshop on Nuclear Waste Management
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• pp.51-59
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• 2004

The geological research as a part of HLW disposal program in Korea is carried out to provide necessary data for the establishment of the reference repository system in term of design and safety assessment in the crystalline rock terrains. Six deep boreholes were drilled to obtain hydrogeological and hydrochemical data from Jurassic granites in the Yuseong area, Korea. The core observation, televiewer logging and hydraulic testing were carried out during and after drilling and multi-packer system were installed in the boreholes of 500m depth for hydraulic and hydrochemical monitoring including environmental isotopes. The integration of hydrogeochemical and hydrodynamic data would be built greater confidence for the understanding of groundwater system in fractured rock mass. This geoscientific program could be possible to suggest a general guideline to develop the reference disposal concept of high-level radioactive waste in Korea.

• 방사성폐기물학회지
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• 제15권2호
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• pp.151-159
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• 2017

고준위 방사성폐기물로 분류되는 사용후핵연료를 현재 기술로 가장 안전한 격리 방법으로는 500 m 심도의 안정한 암반에 심지층 처분하는 방법으로, 가장 중요한 요건은 공학적방벽인 완충재의 온도가 $100^{\circ}C$를 초과하지 않도록 시스템을 설계하는 것이다. 국내의 경우 전체 전력 소요량의 약 30% 정도를 차지하고 있는 원자력발전으로 발생되는 사용후핵연료의 양은 지속적으로 증가하여 누적되고 있어, 이들을 처분하기 위한 소요면적도 증가하고 있다. 따라서, 본 연구에서는 처분면적을 감소시킴으로써 처분효율을 향상시키기 위한 목적으로 다양한 복층처분 개념을 도출하였다. 이를 바탕으로 중요한 처분시스템 요건 만족여부를 확인하기 위하여 열해석을 수행하고 그 결과를 분석하여 처분시스템 열적 안정성을 평가하였다. 평가결과, 기준시스템 위치인 500 m 심도로부터 상부 또는 하부로 75 m를 이격한 심도에 복층으로 처분시스템 구축이 가능하였으며, 실제 부지특성자료에 따른 상세 분석이 요구된다. 본 연구결과는 사용후핵연료 관리정책 수립 및 실제 처분시스템 설계에 활용될 것으로 사료된다.

• 시스템엔지니어링학술지
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• 제17권1호
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• pp.65-75
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• 2021

When the decommissioning of South Korea nuclear power plants is promoted in earnest with the permanent shutdown of Kori Unit 1 in 2017, a large amount of various types of radioactive waste will be generated. For minimal generation and safe management of decommissioning waste, the waste should be made by appropriate classification of the dismantling waste characteristics in accordance with physical, chemical and radiological characteristics to meet the acceptance criteria of disposal facilities. Replacing the preliminary inspection at the site for the compliance of the waste acceptance criteria (WAC) of medium and low-level radioactive waste with the generator's own radioactive waste certification program (WCP), from the perspective of disposal, the optimization of waste management at the national level contributes to the efficient availability of disposal, such as the processing of non-conforming radioactive wastes at the site. To this end, it is important to evaluate radioactivity in each system and area such as nuclear reactors before decommissioning is carried out in earnest, and the prior removal of harmful wastes is important. From waste collection to waste disposal, decommissioning waste should be managed at each stage in consideration of the acceptance criteria of disposal facilities to minimize the generation of non-conforming waste.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2005년도 Proceedings of The 6th korea-china joint workshop on nuclear waste management
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• pp.225-235
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• 2005

This paper outlined the status of the development of Korean Reference Disposal (KRS­1) system for high-level radioactive wastes. The repository concept was based on the engineering barrier system which KAERI has developed through a long-term research and development program. The design requirements were prepared for the conceptual design of the repository. The amount of PWR and CANDU spent fuels were projected with the current nuclear power plan. The disposal rates of PWR and CANDU spent fuels were analyzed. The reference geologic characteristics including classification of fracture zones were set for the KRS. The disposal concepts and the layout of the repository were described.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2005년도 Proceedings of The 6th korea-china joint workshop on nuclear waste management
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• pp.236-244
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• 2005

Radioactive wastes arising from a wide range of human activities are in many different physical and chemical forms, contaminated with varying radioactivity. Their common feature is the potential hazard associated with their radioactivity and the need to manage them in such a way as to protect the human environment. The geological disposal is regarded as the most reasonable and effective way to safely disposal high-level radioactive wastes in the world. The conceptual model of geological disposal in China is based on a multi-barrier system that combines an isolating geological environment with an engineered barrier system. The buffer is one of the main engineered barriers for HLW repository. The buffer material is expected to maintain its low water permeability, self-sealing property, radio nuclides adsorption and retardation property, thermal conductivity, chemical buffering property, overpack supporting property, stress buffering property over a long period of time. Benotite is selected as the main content of buffer material that can satisfy above. GMZ deposit is selected as the candidate supplier for Chinese buffer material of High Level Radioactive waste repository. This paper presents geological features of GMZ deposit and basic property of GMZ Na bentonite. GMZ bentonite deposit is a super large scale deposits with high content of Montmorillonite (about $75\%$) and GMZ-l, which is Na-bentonite produced from GMZ deposit is selected as reference material for Chinese buffer material study.

• Nuclear Engineering and Technology
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• 제53권5호
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• pp.1524-1533
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• 2021

The structural stability of a waste package is essential for containing radioactive waste for the long term in a repository. A silo-type disposal facility would require more severe verification for the structural integrity, because of radioactive waste packages staked with several tens of meters and overburdens of crushed rocks and shotcretes. In this study, structural safety was analyzed for a silo-type repository, located approximately 100 m below sea level in Gyeongju, Korea. Finite element simulation was performed to investigate the influence of the loads from the backfilling materials and waste package stacks on the mechanical stress of the disposed of wastes and containers. It was identified that the current design of the waste package and the compressive strength criterion for the solidified waste would not be enough to maintain structural stability. Therefore, an enhanced criterion for the compressive strength of the solidified waste and several reinforced structural designs for the disposal concrete container were proposed to prevent failure of the waste package based on the results of parametric studies.