• Nuclear Engineering and Technology
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• v.54 no.8
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• pp.2819-2827
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• 2022

The disposal area of a deep geological repository (DGR) for the disposal of spent nuclear fuels (SNFs) is estimated considering the spacing between deposition holes and between disposal tunnels, as determined by a thermal analysis using the decay heat of a reference SNF. Given the relatively large amount of decay heat of the reference SNF, the disposal area of the DGR is found to be overestimated. Therefore, we develop a computer program using MATLAB, termed ACom (Assembly Combination), to combine SNFs when stored in canisters such that the decay heat per canister is evenly distributed. The stability of ACom was checked and the overall distribution of the decay heat per canister was analyzed. Finally, ACom was applied to disposal scenarios suggested in the conceptual design of a DGR for SNFs, and it was confirmed that the decay heat per canister could be evenly distributed and that the maximum decay heat of the canister could be much lower than that of a canister estimated using a reference SNF. ACom can be used to improve the disposal efficiency by reducing the disposal area of a DGR for SNFs by ensuringg a relatively even distribution of decay heat per canister.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.20 no.4
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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.

• Nuclear Engineering and Technology
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• v.55 no.4
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• pp.1540-1554
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• 2023

To use nuclear energy sustainably, spent nuclear fuel, classified as high-level radioactive waste and inevitably discharged after electricity generation by nuclear power plants, must be managed safely and isolated from the human environment. In Korea, the land area is limited and the amount of high-level radioactive waste, including spent nuclear fuels to be disposed, is relatively large. Thus, it is particularly necessary to maximize disposal efficiency. In this study, a high-efficiency deep geological repository concept was developed to enhance disposal efficiency. To this end, design strategies and requirements for a high-efficiency deep geological repository system were established, and engineered barrier modules with a disposal canister for pressurized water reactor (PWR)-type and pressurized heavy water reactor type Canada deuterium uranium (CANDU) plants were developed. Thermal and structural stability assessments were conducted for the repository system; it was confirmed that the system was suitable for the established strategies and requirements. In addition, the results of the nuclear safety assessment showed that the radiological safety of the new system met the Korean safety standards for disposal of high-level radioactive waste in terms of radiological dose. To evaluate disposal efficiency in terms of the disposal area, the layout of the developed disposal areas was assessed in terms of thermal limits. The estimated disposal areas were 2.51 km² and 1.82 km² (existing repository system: 4.57 km²) and the excavated host rock volumes were 2.7 Mm³ and 2.0 Mm³ (existing repository system: 4.5 Mm³) for thermal limits of 100 ℃ and 130 ℃, respectively. These results indicated that the area and the excavated volume of the new repository system were reduced by 40-60% compared to the existing repository system. In addition, methods to further improve the efficiency were derived for the disposal area for deep geological disposal of spent nuclear fuel. The results of this study are expected to be useful in establishing a national high-level radioactive waste management policy, and for the design of a commercial deep geological repository system for spent nuclear fuels.

• Architectural research
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• v.13 no.2
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• pp.31-40
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• 2011

Asbestos have been used around the world by physical and chemical characteristics that are a reliable and cost-effective. But asbestos, once called the miracle of mineral, is now a quiet time bomb. Asbestos hazards have been studied and the government has pursued 'Comprehensive Measures for Asbestos Management' jointly with related departments. As a part of plan, Ministry of Environment is to introduce legislation 'Asbestos Safety Management Act' through Environment Announcement No. 2010-108. The same Act. 24 shows as follows. Minister of Environment or governor should do survey on the actual condition targeting rural buildings with slates and partly or fully fund to dissolve, remove asbestos slate which was used in each building. However, the local survey was only conducted by each municipality regionally. And there is no actual condition data by area, application and year, and there was no data on disposal costs concerning asbestos slate buildings In this study, discharge of asbestos slate was calculated per unit area and formula was developed with regression analysis. In addition, Demolition, dismantling, disposal costs were computed via a phone survey to disposal companies and then this study proposed standards for this.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.15 no.2
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• pp.151-159
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• 2017

A deep geological disposal at a depth of 500 m in stable host rock is considered to be the safest method with current technologies for disposal of spent fuels classified as high-level radioactive waste. The most important requirement is that the temperature of the bentonite buffer, which is a component of the engineered barrier, should not exceed $100^{\circ}C$. In Korea, the amount of spent fuel generated by nuclear power generation, which accounts for about 30% of the total electricity, is continuously increasing and accumulating. Accordingly, the area required to dispose of it is also increasing. In this study, various duplex disposal concepts were derived for the purpose of improving the disposal efficiency by reducing the disposal area. Based on these concepts, thermal analyses were carried out to confirm whether the critical disposal system requirements were met, and the thermal stability of the disposal system was evaluated by analyzing the results. The results showed that upward 75 m or downward 75 m apart from the reference disposal system location of 500 m depth would qualify for the double layered disposal concept. The results of this study can be applied to the establishment of spent fuel management policy and the design of practical commercial disposal system. Detailed analyses with data of a real disposal site are necessary.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.11 no.4
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• pp.303-309
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• 2013

As an alternative of the spent fuel disposal in a geologic repository, a deep borehole disposal concept for disposal at the section of 3 - 5km deep in a borehole has been proposed in several countries. In this paper, the latest reports of Sandia National Laboratories on the borehole disposal researches are analyzed. For implementation of this disposal concept in Korea, a conceptual design of spent fuel disposal canister and a modified deep borehole concept are suggested along with a required disposal area.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.18 no.spc
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• pp.1-19
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• 2020

Based on the current high-level radioactive waste management basic plan and the analysis results of spent nuclear fuel characteristics, such as dimensions and decay heat, an improved geological disposal concept for spent nuclear fuel from domestic nuclear power plants was proposed in this study. To this end, disposal container concepts for spent nuclear fuel from two types of reactors, pressurized water reactor (PWR) and Canada deuterium uranium (CANDU), considering the dimensions and interim storage method, were derived. In addition, considering the cooling time of the spent nuclear fuel at the time of disposal, according to the current basic plan-based scenarios, the amount of decay heat capacity for a disposal container was determined. Furthermore, improved disposal concepts for each disposal container were proposed, and analyses were conducted to determine whether the design requirements for the temperature limit were satisfied. Then, the disposal efficiencies of these disposal concepts were compared with those of the existing disposal concepts. The results indicated that the disposal area was reduced by approximately 20%, and the disposal density was increased by more than 20%.

• Journal of the Korean Home Economics Association
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• v.38 no.9
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• pp.107-118
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• 2000

This study was carried out to obtain the information concerning the behavior and underlying consciousness of housewives about the disposal of foods waste and to find out relationships among environmental variables. Data were obtained through questionnaires and interviews from 350 housewives in Ulsan area. Foods waste can be produced at every stage of cooking. It was found that the most amount of foods waste was produced at the preparation stage of cooking. The type of dishes which produces the most waste was chigas. About 49.4% of foods waste consisted of vegetables and fruits and 18.5% of that was fishes. The environmental concern related to foods waste disposal was relatively high among subjects and they were willing to accept foods waste reducing system if it is not too complicated to use and not too expensive. These results have demonstrated that menu planning before food preparation and buying cleaned and trimmed materials in the market should be highly recommended to reduce the foods waste. To improve the disposal behavior of foods waste, it is required that well programmed education for environmental conservation and the public facility for foods waste disposal.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.10a
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• pp.259-260
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• 2005

• Journal of Soil and Groundwater Environment
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• v.22 no.6
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• pp.104-111
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• 2017

As carcass disposal is increasing widely in Republic of Korea, there is a need to comprehensively analyze the impacts and subsequent damages of carcass disposal. Especially, since environmental policy aims to not only reduce environmental damages, but also enhance overall sustainability, we apply the concept of environmental welfare to assess the comprehensive impact of carcass disposal, especially focusing on the rural area. In specific, assessment criteria were suggested based on the four categories related to environmental welfare, which were 'environmental quality', 'level of environmental service', 'environmental safety', and 'participation, openness to public, and communication'. The results showed negative impacts of carcass disposal in environmental, social and economical elements. Overall decrease in environmental quality negatively impacts the other elements of environmental welfare. Furthermore, there were discrepancies of level of impacts and damages among stakeholder. In the end, we suggest critical elements that need to be applied in relevant policies and regulation to promote effective carcass disposal management.