• Proceedings of the Korean Radioactive Waste Society Conference
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• 2019.05a
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• pp.251-252
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• 2019

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.22 no.1
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• pp.81-89
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• 2024

Highly radioactive waste is solidified to restrict leaching, retain its shape, and maintain its structural stability to prevent it from affecting humans and the environment as much as possible. This operation should be performed consistently regardless of whether the waste is homogeneous or heterogeneous. However, currently, there are no specific performance requirements for heterogeneous waste in Korea. This study reviewed domestic research results and the status of overseas applications, and proposed immobilization requirements for heterogeneous waste to be applied in Korea. IAEA safety standards, domestic laws, and waste acceptance criteria were reviewed. The status of heterogeneous waste immobilization in countries such as the United States, France, and Spain was reviewed. Most countries treat heterogeneous waste by encasing it in concrete, and impose immobilization requirements on this concrete. Based on these data, safety standards for the thickness, compressive strength, and diffusion limit of this concrete material were proposed as immobilization requirements for heterogeneous waste disposal in Korea. Quantitative values for the above requirements need to be derived through quantitative assessments based on the characteristics of domestic heterogeneous waste and disposal facilities.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.9 no.2
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• pp.87-92
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• 2011

This paper introduces the policy and regulations on very low level waste (VLLW) management in China. Given the important decommissioning and site restoration program of the old facility, it is considered necessary to create a new disposal facility dedicated to VLLW. Many general design principles are in common with to the disposal facility for low and intermediate level waste (LILW), namely the isolation of the waste by means of a multibarrier system, but using bentonite and/or high density polyethylene membranes instead of the generalized use of concrete barriers. The design of the facility is consistent with the design of disposal facilities for hazardous waste. The engineering design of two VLLW disposal facilities is introduced.

• 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%.

• Nuclear Engineering and Technology
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• v.23 no.1
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• pp.81-94
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• 1991

In order to develop the acceptance criteria for the low and intermediate level radioactive wastes for the land disposal: the following items were reviewed : classifications of radioactive wastes is respect to disposal, basic requirements and criteria that have to be considered during waste management from the origin to disposal. From these studies, the standard test methods to evaluate radioactive waste forms（or packages) were shown.

• Journal of Soil and Groundwater Environment
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• v.20 no.7
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• pp.90-102
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• 2015

To understand the hyrogeochemical variation of bedrock aquifer during underground space construction, various graphical methods including multiple-component plots and chemical trends were used to estimate the mixing rate between seawater and freshwater and to investigate the evolution of water quality. The water chemistry and mixing rate between fresh and sea waters, which are generally localized in the construction area (MW-7, in land), shows typical characteristics of freshwater that doesn’t affect its validity as seawater intrusion. Especially, the water chemistry of a MW-4 (coastline) was classified as Na-Cl type, Na-HCO₃ type, and Ca-Cl type due to the influence of the seawater intrusion. And hydrogeochemical and isotopic data show that local freshwater is subjected to geochemical processes, such as reverse ion-exchange. Throughout the Chadha’s diagrams, four different case histories with the temporal and spatial variation of groundwaters in the study area were proposed, which is recommended to interpret the hydrogeochemical reactions effectively.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2009.11a
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• pp.498-499
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• 2009

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2018.11a
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• pp.341-342
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• 2018

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.12 no.4
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• pp.345-361
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• 2014

The systematic quality assurance activities on documents of the safety assessment are required for the safety case of the low- and intermediate-level radioactive waste disposal facility. In this paper, quality assurance system focused on the input data including the site characterization, groundwater flow, system design and monitoring are prepared and discussed. Rule for the input data selection is suggested and applied for the safety assessment which is based on the in-situ/experiment observations, final facility design and waste pileup plan, engineered barrier, field monitoring, recent biosphere, and radionuclide inventory. The reduction of data uncertainty will be expected to contribute to the safety of disposal facility further.

• Nuclear Engineering and Technology
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• v.53 no.5
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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.