• Journal of the Korean Society of Systems Engineering
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• v.17 no.1
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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.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.18 no.2_spc
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• pp.291-303
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• 2020

The Kori-Unit 1 nuclear power plant, which is scheduled to be decommissioned after permanent shutdown, is expected to generate large amounts of various types of radioactive waste during the decommissioning process. Among these, nuclear reactors and internal structures have high levels of radioactivity and the dismantled structure must have the proper size and weight on the primary side. During decommissioning, it is important to prepare an appropriate and efficient disposal method through analysis of the disposal status and the legal restrictions on wastes generated from the reactors and internal structures. Nuclear reactors and internal structures generate radioactive wastes of various levels, such as medium, very low, and clearance. A radiation evaluation indicates that wastes in the clearance level are generated in the reactor head and upper head insulation. In this study, a clearance waste safety evaluation was conducted using the RESRAD-RECYCLE code, which is a safety evaluation code, based on the activation evaluation results for the clearance level wastes. The clearance scenario for the target radioactive waste was selected and the maximum individual and collective exposure doses at the time of clearance were calculated to determine whether the clearance criteria limit prescribed by the Nuclear Safety Act was satisfied. The evaluation results indicated that the doses were significantly low, and the clearance criteria were satisfied. Based on the safety assessment results, an appropriate metal recycle and disposal method were suggested for clearance, which are the subject of the deregulation of internal structures of nuclear power plant.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.6
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• pp.694-700
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• 2018

Korea has disposed of medium and low level radioactive waste generated by operating nuclear power plants permanently through the radioactive waste repository located in Gyeongju. However, the maritime transport of radioactive waste is exposed to the risk of marine accidents, and it will be necessary to introduce a system to secure safety from the viewpoint of the function and role of the Korea Coast Guard. Especially, Korea is affected by large-scale marine accidents, such as the Hebei Spirit or Sewol accidents. From this point of view, we analyzed the current status of Korea radioactive waste shipping and examined the response systems of major foreign countries. As a result of examining major cases of accidents, we have operated an Emergency Towing Vessel (ETV) fleet centering on European countries in order to respond urgently to marine casualties that may have social, regional and international effects, such as accidents of similar nuclear material carriers and dangerous cargo ships. It proves a partial effect. Based on this, we propose the introduction of the Korean ETV System. In other words, it is necessary to respond to large-scale marine accidents that could lead to enormous environmental, property, and personal damage, such as marine accidents involving nuclear material ships, large oil tankers, and large passenger ships. For this, it seems necessary to introduce Korea ETV, which can carry out emergency towing, oil pollution control function, large - scale rescue equipment and manpower. This will lead to the enhancement of the Korea Coast Guard response to marine accidents, and will not miss the golden time of the initial response to the national disaster, which will help protect precious people, property and the environment.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.05b
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• pp.341-344
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• 1997

A vitrification process is under development in KEPRI for the treatment of low-and medium-level radioactive waste. Although the project is for developing and building Vitrification Pilot Plant in Korea, one of KEPRI's concerns is the quality control of the vitrified glass. This paper discusses a methodology for the estimation of glass composition by on-line measurement of molten glass properties, which could be applied to the plant for real-time quality control of the glass product. By remotely measuring viscosity and density of the molten glass, the glass characteristics such as composition can be estimated and eventually controlled. For this purpose, using the database of glass composition vs. physical properties in isothermal three-component system of SiO$_2$-Na$_2$O-B$_2$O$_3$, a software TERNARY has been developed which determines the glass composition by using two known physical properties(e.g. density and viscosity).

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.15 no.3
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• pp.231-237
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• 2017

The present study researched and analyzed decontamination technology for decommissioning a nuclear power plant. The decision-making technique (EXPERT-CHOICE) was used to evaluate and select the optimal decontamination technology. In principle, this evaluation method is generally performed by a group of experts in the relevant field. The results of the weights were calculated by multiplying the weights with regard to each criterion and evaluation score. The evaluation scores were categorized into 3 ranges (high, medium, and low), and each range was weighted for differentiation. The level of the technology analysis was improved by additionally quantifying the weights with regard to each criterion and subdividing criteria into subcriteria. The basic assumption of the evaluation was that the weight values would decided on in an expert survey and assigned to each criterion. The evaluation criteria followed high weight for the 'High' range. Accordingly, H, M, and L were assigned weights of 10:5:1, respectively. This was based on the EXPERT-CHOICE optimal analysis. The minimum and maximum values were excluded, and the average value was used as the evaluation value for each scenario.