• 방사성폐기물학회지
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• 제20권4호
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• pp.501-510
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• 2022

The nuclear criticality analyses considering burnup credit were performed for a spent nuclear fuel (SNF) disposal cell consisting of bentonite buffer and two different types of SNF disposal canister: the KBS-3 canister and small standardized transportation, aging and disposal (STAD) canister. Firstly, the KBS-3 & STAD canister containing four SNFs of the initial enrichment of 4.0wt% ²³⁵U and discharge burnup of 45,000 MWD/MTU were modelled. The k_eff values for the cooling times of 40, 50, and 60 years of SNFs were calculated to be 0.79108, 0.78803, and 0.78484 & 0.76149, 0.75683, and 0.75444, respectively. Secondly, the KBS-3 & STAD canister with four SNFs of 4.5wt% and 55,000 MWD/MTU were modelled. The k_eff values for the cooling times of 40, 50, and 60 years were 0.78067, 0.77581, and 0.77335 & 0.75024, 0.74647, and 0.74420, respectively. Therefore, all cases met the performance criterion with respect to the k_eff value, 0.95. The STAD canister had the lower k_eff values than KBS-3. The neutron absorber plates in the STAD canister significantly affected the reduction in k_eff values although the distance among the SNFs in the STAD canister was considerably shorter than that in the KBS-3 canister.

• 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.290-299
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• 2005

Two decommissioning projects are carried out at the KAERI (Korean Atomic Energy Research Institute), one for the Korea research reactors, KRR-1 and KRR-2, and another for the uranium conversion plant (UCP). The concept of the management of the wastes from the decommissioning sites was reviewed with a relation of the decommissioning strategies, technologies for the treatment and the decontamination, and the characteristics of waste. All the liquid waste generated from KRR-1 and KRR-2 decommissioning site is evaporated by a solar evaporation facility and all the liquid waste from the UCP is treated together with lagoon sludge waste. The solid wastes from the decommissioning sites are categorized into three groups; not contaminated, restricted releasable and radioactive waste. The not-contaminated waste will be reused and/or disposed at an industrial disposal site, and the releasable waste is stored for the future disposal at the KAERI. The radioactive waste is packed in containers, and will be stored at the decommissioning sites till they are sent to a national repository site. The reduction of the radioactive solid waste is one of the strategies for the decommissioning projects and could be achieved by the repeated decontamination. By the achievement of the minimization strategy, the amount of radioactive waste was reduced and the disposal cost will be reduced, but the cost for manpower, for direct materials and for administration was increased.

• Nuclear Engineering and Technology
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• 제39권6호
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• pp.697-702
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• 2007

Radioactive waste has been produced in the UK for many decades. Since the 1950' s much of this has been associated with civil nuclear power production and the nuclear weapons programme. There have been a number of unsuccessful attempts in the UK since the 1980s to deal with the waste and find suitable sites for its disposal. However, the UK Government has addressed this and in 2001 introduced the "Managing Radioactive Waste Safely" programme. The aim of this was to make decisions on the long-term radioactive waste management policy through stakeholder engagement. In 2006, it adopted a policy of geological disposal for higher activity wastes and following further consultations, is now at the stage of choosing how that policy should be implemented.

• Nuclear Engineering and Technology
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• 제45권1호
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• pp.29-40
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• 2013

Two different kinds of nuclear power plants produce a substantial amount of spent fuel annually in Korea. According to the current projection, it is expected that around 60,000 MtU of spent fuel will be produced from 36 PWR and APR reactors and 4 CANDU reactors by the end of 2089. In 2006, KAERI proposed a conceptual design of a geological disposal system (called KRS, Korean Reference disposal System for spent fuel) for PWR and CANDU spent fuel, as a product of a 4-year research project from 2003 to 2006. The major result of the research was that it was feasible to construct a direct disposal system for 20,000 MtU of PWR spent fuels and 16,000 MtU of CANDU spent fuel in the Korean peninsula. Recently, KAERI and MEST launched a project to develop an advanced fuel cycle based on the pyroprocessing of PWR spent fuel to reduce the amount of HLW and reuse the valuable fissile material in PWR spent fuel. Thus, KAERI has developed a geological disposal system for high-level waste from the pyroprocessing of PWR spent fuel since 2007. However, since no decision was made for the CANDU spent fuel, KAERI improved the disposal density of KRS by introducing several improved concepts for the disposal canister. In this paper, the geological disposal systems developed so far are briefly outlined. The amount and characteristics of spent fuel and HLW, 4 kinds of disposal canisters, the characteristics of a buffer with domestic Ca-bentonite, and the results of a thermal design of deposition holes and disposal tunnels are described. The different disposal systems are compared in terms of their disposal density.

• 방사성폐기물학회지
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• 제14권3호
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• pp.279-287
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• 2016

경주 중 저준위 방사성폐기물 처분시설의 운영에 따라, 한국원자력연구원(대전)에 임시보관 중인 방사성동위원소폐기물을 처분시설로 육상운반하였다. 본 연구에서는 방사성동위원소폐기물의 국내육상운반에 따른 작업자 및 일반인에 대한 방사선 피폭선량을 평가하고 그 결과를 국내 방사선피폭 법적제한치와 비교하였다. 또한 방사성폐기물의 상하차 작업 시 작업자와 드럼 간 거리 및 방사성핵종 누출율의 변화에 따른 예상피폭선량의 민감도를 분석하였다. 정상 및 사고조건에서의 예상피폭선량은 국내 법적제한치를 충분히 만족하였음을 확인하였다.

• 방사성폐기물학회지
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• 제17권4호
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• pp.447-457
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• 2019

일본에서는 2000년 고준위방사성폐기물의 심층처분을 위한 「특정방사성폐기물의 최종 처분에 관한 법률」을 제정하고 부지선정을 착수하였으나, 부지선정 절차에 참여를 원하는 지자체가 존재하지 않았다. 따라서, 일본 정부는 2015년 문헌조사 단계에 새로운 부지선정을 절차를 개발하고, 지자체의 공모를 촉진하고자 2017년 6월 28일 심층처분을 위한 전국규모 과학적 특성 지도를 발간하였다. 이 지도는 심층처분장 초기 혹은 개념단계에 고려되는 요건 및 기준 등을 제공하고 심층처분을 위한 적합성을 분석함으로써, 공공의 이해도 증진과 지자체와의 의견교환 등을 위해서 유용하게 활용되고 있다.

• 방사성폐기물학회지
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• 제20권4호
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• pp.469-488
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• 2022

Technology for high-level-waste disposal employing a multibarrier concept using engineered and natural barrier in stable bedrock at 300-1,000 m depth is being commercialized as a safe, long-term isolation method for high-level waste, including spent nuclear fuel. Managing heat generated from waste is important for improving disposal efficiency; thus, research on efficient heat management is required. In this study, thermal management methods to maximize disposal efficiency in terms of the disposal area required were developed. They efficiently use the land in an environment, such as Korea, where the land area is small and the amount of waste is large. The thermal effects of engineered barriers and natural barriers in a high-level waste disposal repository were analyzed. The research status of thermal management for the main bedrocks of the repository, such as crystalline, clay, salt, and other rocks, were reviewed. Based on a characteristics analysis of various heat management approaches, the spent nuclear fuel cooling time, buffer bentonite thermal conductivity, and disposal container size were chosen as efficient heat management methods applicable in Korea. For each method, thermal analyses of the disposal repository were performed. Based on the results, the disposal efficiency was evaluated preliminarily. Necessary future research is suggested.

• Journal of Radiation Protection and Research
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• 제35권1호
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• pp.6-11
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• 2010

Embodying the safety of radioactive waste disposal requires the relevant safety criteria and the corresponding stylized methods to demonstrate its compliance with the criteria. This paper proposes a conceptual model of risk-based safety evaluation for integrating complex potential radiation exposure situations in radioactive waste disposal. For demonstrating compliance with a risk constraint, the approach deals with important exposure scenarios from the viewpoint of the receptor to estimate the resulting risk. For respective exposure situations, it considers the occurrence probabilities of the relevant exposure scenarios as their probability of giving rise to doses to estimate the total risk to a representative person by aggregating the respective risks. In this model, an exposure scenario is simply constructed with three components:radionuclide release, radionuclide migration and environment contamination, and interaction between the contaminated media and the receptor. A set of exposure scenarios and the representative person are established from reasonable combinations of the components, based on a balance of their occurrence probabilities and the consequences. In addition, the probability of an exposure scenario is estimated on the assumption that the initiating external factors influence release mechanisms and transport pathways, and its effect on the interaction between the environment and the receptor may be covered in terms of the representative person. This integrated approach enables a systematic risk assessment for complex exposure situations of radioactive waste disposal and facilitates the evaluation of compliance with risk constraints.

• 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.

• 방사선산업학회지
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• 제18권1호
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• pp.95-100
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• 2024

To establish a radioactive waste life cycle history management system, a series of processes including waste generation, classification, packaging, storage, transportation, and disposal were reflected in the information management system. A preliminary review process was introduced to reduce the amount of radioactive waste generated and manage it efficiently. Through this, the amount of radioactive waste generated must be checked from the beginning of the research, and the generated radioactive waste must be thoroughly managed from the stage of generation to final disposal. In particular, in the case of radioactive waste data generated during nuclear facility operation and each experiment, a radioactive waste information management system must be operated to receive information from the waste generator and integrate it with processing information at the management stage. The application process for small-package containers was reflected so that information such as the generation facility of radioactive waste, generation facility, project information, types of radioactive waste, major radionuclides, etc. In the radioactive waste management process, the preceding steps are to receive waste history from the waste generators. This includes an application for a specified container with a QR label, pre-inspection, and management request. Next, the succeeding steps consist of repackaging, treatment, characterization, and evaluating the suitability of disposal, for a process to transparently manage radioactive wastes.