• 방사성폐기물학회지
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• 제17권4호
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• pp.389-403
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• 2019

Large amounts of concrete waste are likely to arise from the decommissioning of a Kori-1 nuclear power plant. Several studies have been conducted on decommissioning concrete waste in recent decades, however, they have been limited to contaminated concrete issues or were small pilot-scale experiments. This study constructed two industrial-scale models of on-site concrete waste management for clean as well as contaminated concrete. To evaluate the performance of both the models, simulations were conducted using the Flexsim software. The concrete particle size distribution of Kori-1 and concrete processor properties based on widely used construction equipment were used as sources of input data for the simulations. It was observed that it may take over two years to complete the on-site concrete management processes owing to the performance of existing processors. In addition, it was demonstrated that it is essential to identify bottlenecks in the system and enhance the performance of the relevant processors to avoid delays of the decommissioning schedule. Our results suggest that this novel approach can contribute to developing schedules or expediting delayed activities in the Kori-1 decommissioning project.

• 방사성폐기물학회지
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• 제19권1호
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• pp.61-74
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• 2021

A paradigm shift in the government's energy policy was reflected in its declaration of early closure of old nuclear plants as well as cancellation of plans for the construction of new plants. To this end, unit 1 of Kori Nuclear Power Plant was permanently shut down and is set for decommission. Based on these changes, the off-site transport of spent fuels from nuclear power plants has become a critical issue. The purpose of this study is to develop an optimized method for transportation of spent fuels from Kori Nuclear Power Plant's units 1, 2, 3, and 4 to an assumed interim storage facility by simulating the scenarios using the Flexsim software, which is widely used in logistics and manufacturing applications. The results of the simulation suggest that the optimized transport methods may contribute to the development of delivery schedule of spent fuels in the near future. Furthermore, these methods can be applied to decommissioning plan of nuclear power plants.

• 시스템엔지니어링학술지
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• 제8권2호
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• pp.57-67
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• 2012

It is the sensitivity and confidentiality of nuclear power plant decommissioning cost that prevent detailed cost information to be released to the public, which causes some limitation to analyze and reuse the costs. This limitation to access cost information means that the lessons learned from preceding cost estimating may not systematically feed back into following cost estimates. As an alternative, decommissioning cost estimation framework is indispensable to reflecting available experience and knowledge for decommission costs. This study provides the cost estimation framework including data flow and structuralization based on engineering and bottom up approach to enhance decommissioning cost estimation.

• 방사성폐기물학회지
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• 제20권1호
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• pp.99-110
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• 2022

In decommissioning a nuclear power plant, numerous concrete structures need to be demolished and decontaminated. Although concrete decontamination technologies have been developed globally, concrete cutting remains problematic due to the secondary waste production and dispersion risk from concrete scabbling. To minimize workers' radiation exposure and secondary waste in dismantling and decontaminating concrete structures, the following conceptual designs were developed. A micro-blast type scabbling technology using explosive materials and a multi-dimensional contamination measurement and artificial intelligence (AI) mapping technology capable of identifying the contamination status of concrete surfaces. Trials revealed that this technology has several merits, including nuclide identification of more than 5 nuclides, radioactivity measurement capability of 0.1-10⁷ Bq·g^-1, 1.5 kg robot weight for easy handling, 10 cm robot self-running capability, 100% detonator performance, decontamination factor (DF) of 100 and 8,000 cm²·hr^-1 decontamination speed, better than that of TWI (7,500 cm²·hr^-1). Hence, the micro-blast type scabbling technology is a suitable method for concrete decontamination. As the Korean explosives industry is well developed and robot and mapping systems are supported by government research and development, this scabbling technology can efficiently aid the Korean decommissioning industry.

• 방사성폐기물학회지
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• 제20권1호
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• pp.13-22
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• 2022

The decommissioning of a nuclear power plant generates large amounts of radioactive waste, which is of several types. Radioactive concrete powder is classified as low-level waste, which can be disposed of in a landfill. However, its safe disposal in a landfill requires that it be immobilized by solidification using cement. Herein, a safety assessment on the disposal of solidified radioactive concrete powder waste in a conceptual landfill site is performed using RESRAD. Furthermore, sensitivity analyses of certain selected input parameters are conducted to investigate their impact on exposure doses. The exposure doses are estimated, and the relative impact of each pathway on them during the disposal of this waste is assessed. The results of this study can be used to obtain information for designing a landfill site for the safe disposal of low-level radioactive waste generated from the decommissioning of a nuclear power plant.

• 방사성폐기물학회지
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• 제19권1호
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• pp.141-160
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• 2021

Unit 1 of the Kori Nuclear Power Plant (NPP) and Unit 1 of the Wolsong NPP are being prepared for decommissioning; their decommissioning is expected to generate large amounts of intermediate-level, low-level, and very low level Waste. Mixed waste containing both radioactive and hazardous substances is expected to be produced. Nevertheless, laws and regulations, such as the Korean Nuclear Safety Act and Waste Management Act, do not define clear regulatory guidelines for mixed waste. However, the United States has strictly enforced regulations on mixed waste, focusing on the human health and environmental effects of its hazardous components. The U.S. Nuclear Regulatory Commission and the U.S. Department of Energy regulate the radioactive components of mixed waste under the Atomic Energy Act. The U.S. Environmental Protection Agency regulates the hazardous waste component of mixed waste under the Resource Conservation and Recovery Act. In this study, the laws, regulations, and authorities pertaining to mixed waste in the United States are reviewed. Through comparison and analysis with waste management laws and regulations in Korea, a treatment direction for mixed waste is suggested. Such a treatment for mixed waste will increase the efficiency of managing mixed waste when decommissioning NPPs in the near future.

• 한국방사선학회논문지
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• 제9권5호
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• pp.269-277
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• 2015

세계적으로 수명을 다한 원자력발전소들이 증가하면서 노후화 된 원전의 해체에 대한 관심도 커져가고 있다. 특히 국토가 좁고 자원이 부족한 국내의 경우 원전을 해체하는데 있어 부지 재이용 문제는 하나의 중요한 사안이지만, 아직까지 부지 재이용을 위한 구체적인 법적 부지해제기준이 마련되어 있지 않다. 따라서 본 연구에서는 부지해제를 위한 IAEA의 국제적 안전기준(Safety Guide No. WS-G-5.1) 및 국내 관련기준, 미국 유럽 등 선진국들의 부지해제 사례들을 분석하였으며, 이를 바탕으로 적절한 선량기준 및 국내 부지해제 기준 수립 시 고려해야하는 사항들을 제언하였다. 이는 원전 해체 후 부지 재이용을 위한 국내 부지해제 기준 수립을 위한 기초자료로 활용될 것으로 판단된다.

• 한국화재소방학회논문지
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• 제34권3호
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• pp.134-140
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• 2020

국내 원전은 심층화재방어 개념에 따라 화재 발생 시 원전 외부로 방사능의 누출을 억제하고 발전소의 안전정지기능이 유지되어야 한다. 또한 화재방호 설비가 노형별 화재방호 설계 요건에 맞게 설치되어 운전 중 요구하는 설계기능이 유지되고 있는지 관련 규정에 따라 정기적인 시험으로 건전성을 확인한다. 현재 국내 원전은 원자력안전법과 국내외 소방관계법을 동시에 적용하고 있으며 특히 이러한 법규 환경과 더불어 2017년 국내 최초 영구 정지된 고리1호기에도 유사한 규정이 적용될 것으로 사료된다. 하지만 향후 단계적인 해체원전의 증가를 고려하여 해체특성을 고려한 화재방호 세부 규제규정이 마련되어 체계적으로 해체원전의 화재방호프로그램이 정착되는 기반을 마련할 필요가 있다. 따라서 원전을 다수 운영 중인 미국, 일본, 캐나다 및 유럽 국가들의 원자력 법령체계를 검토하였고, 해외 해체 원전에 활용되고 있는 미국 영구정지 및 해체원전의 화재방호 규제지침인 Reg Guide 1.191의 규제 요건을 고려한 해체원전의 화재방호프로그램 법령체계 마련을 위한 방향을 제시하였다. 본 연구에서는 해체원전의 화재방호프로그램 최적화 및 화재분야의 원전 해체 기반기술 확보를 위해 화재방호 규정 마련을 위한 방향을 제시하고자 한다.

• 방사성폐기물학회지
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• 제21권2호
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• pp.255-269
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• 2023

Compared to operational wastes, nuclear power plant (NPP) decommissioning wastes are generated in larger quantities within a short time and include diverse types with a wider range of radiation characteristics. Currently used 200 L drums and IP-2 type transport containers are inefficient and restrictive in packaging and transporting decommissioning wastes. Therefore, new packaging and transport containers with greater size, loading weight, and shielding performance have been developed. When transporting radioactive materials, radiological safety should be assessed by reflecting parameters such as the type and quantity of the package, transport route, and transport environment. Thus far, safety evaluations of radioactive waste transport have mainly targeted operational wastes, that have less radioactivity and a smaller amount per transport than decommissioning wastes. Therefore, in this study, the possible radiation effects during the transport from NPP to disposal facilities were evaluated to reflect the characteristics of the newly developed containers and decommissioning wastes. According to the evaluation results, the exposure dose to transport workers, handling workers, and the public was lower than the domestic regulatory limit. In addition, all exposure dose results were confirmed, through sensitivity analysis, to satisfy the evaluation criteria even under circumstances when radioactive materials were released 100% from the container.

• 방사성폐기물학회지
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• 제20권4호
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• pp.541-550
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• 2022

When decommissioning nuclear power plant (NPP), the first task performed is cost estimation. This is an important task in terms of securing adequate decommissioning funds and managing the schedule. Therefore, many countries and institutions are conducting continuous research and also developing and using many programs for cost estimation. However, the cost estimated for decommissioning an NPP typically differs from the actual cost incurred in its decommissioning. This is caused by insufficient experience in decommissioning NPPs or lack of decommissioning cost data. This uncertainty in cost estimation can be in general compensated for by applying a contingency. However, reflecting an appropriate standard for the contingency is also difficult. Therefore, in this study, data analysis was conducted based on the contingency guideline suggested by each institution and the actual cost of decommissioning the NPP. Subsequently, TLG Service, Inc.'s process, which recently suggested specific decommissioning costs, was matched with ISDC (International Structure for Decommissioning Costing)'s work breakdown structure (WBS). Based on the matching result, the guideline for applying the contingency for ISDC's WBS Level 1 were presented. This study will be helpful in cost estimation by applying appropriate contingency guidelines in countries or institutions that have no experience in decommissioning NPPs.