• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.21 no.3
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• pp.329-345
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• 2023

This paper described a method for analyzing the structural performance of a metal container used for disposing radioactive waste generated during the decommissioning of a nuclear power plant, and numerical analysis results of a method for reinforcing the container. The containers to be analyzed were those that can be used in near-surface and landfill disposal facilities scheduled to be operated at the Gyeongju radioactive waste disposal facility. Structural reinforcement of the container was performed by lattice reinforcement, column reinforcement, and bottom plate reinforcement. Accordingly, a total of 14 reinforcement cases were modeled. The external force causing damage to the container was set equivalent to the impact of a 9-m fall, accounting for the height of the vault at the near-surface disposal facility. The reinforcement methods with a high contribution to the structural performance of the container were concluded to be lattice and column reinforcements.

• Environmental Analysis Health and Toxicology
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• v.31
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• pp.6.1-6.10
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• 2016

Objectives This study examined the spatial distribution and the extent of soil contamination by heavy metals resulting from primitive, unconventional informal electronic waste recycling in the Agbogbloshie e-waste processing site (AEPS) in Ghana. Methods A total of 132 samples were collected at 100 m intervals, with a handheld global position system used in taking the location data of the soil sample points. Observing all procedural and quality assurance measures, the samples were analyzed for barium (Ba), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), mercury (Hg), nickel (Ni), lead (Pb), and zinc (Zn), using X-ray fluorescence. Using environmental risk indices of contamination factor and degree of contamination ($C_{deg}$), we analyzed the individual contribution of each heavy metal contamination and the overall $C_{deg}$. We further used geostatistical techniques of spatial autocorrelation and variability to examine spatial distribution and extent of heavy metal contamination. Results Results from soil analysis showed that heavy metal concentrations were significantly higher than the Canadian Environmental Protection Agency and Dutch environmental standards. In an increasing order, Pb>Cd>Hg>Cu>Zn>Cr>Co>Ba>Ni contributed significantly to the overall $C_{deg}$. Contamination was highest in the main working areas of burning and dismantling sites, indicating the influence of recycling activities. Geostatistical analysis also revealed that heavy metal contamination spreads beyond the main working areas to residential, recreational, farming, and commercial areas. Conclusions Our results show that the studied heavy metals are ubiquitous within AEPS and the significantly high concentration of these metals reflect the contamination factor and $C_{deg}$, indicating soil contamination in AEPS with the nine heavy metals studied.

• Resources Recycling
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• v.25 no.3
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• pp.43-48
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• 2016

Cement manufacturing plant uses various kinds of industrial/municipal waste. The waste contains considerable amount of potassium, chlorine and small amount of heavy metal. Many researches were performed to fabricate valuable resources from the waste. In this study, various methods, which dissolves and crystallizes potassium/chlorine to extract potassium chloride, were experimented. Especially amount of water, slurry temperature, and stirring time were controlled. Then kind of heavy metal and content of potassium chloride were analyzed. The yield of potassium chloride increased, as the amount of water for slurry increased but it increased slightly, when the water content was over 200%. The yield tended to increase, when the temperature of slurry was over a certain point. The yield did not increase in case of over 10 minutes stirring time. The kind and content of heavy metal in potassium chloride were various according to stirring time. The main heavy metals were Pb, Cu, and $Cr^{6+}$.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.14 no.4
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• pp.411-422
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• 2016

Recently, because the wet pool storage facilities of NPPs in Korea has become saturated, there has been much active R&D on an interim dry storage system using a transportation and storage cask. Generally, the shielding evaluation for the design of a spent fuel transportation and storage cask is performed by the design basis fuel, which selects the most conservative fuel among the fuels to be loaded into the cask. However, the loading of actual spent fuel into the transportation metal cask is not limited to the design basis fuel used in the shielding evaluation; the loading feasibility of actual spent fuel is determined by the shielding evaluation that considers the characteristics of the initial enrichment, the maximum burnup and the minimum cooling period. This study describes a shielding analysis method for determining the minimum cooling period of spent fuel that meets the domestic transportation standard of the dual purpose metal cask. In particular, the spent fuel of 3.0~4.5wt% initial enrichment, which has a large amount of release, was evaluated by segmented shielding calculations for efficient improvement of the results. The shielding evaluation revealed that about 81% of generated spent fuel from the domestic nuclear power plants until 2008 could be transported by the dual purpose metal cask. The results of this study will be helpful in establishing a technical basis for developing operating procedures for transportation of the dual purpose metal cask.

• Journal of Radiation Protection and Research
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• v.38 no.4
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• pp.228-233
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• 2013

It has been continuously generated the requirement for the replacement of the main components such as a steam generator due to the deterioration of the nuclear power plant all around the world. Also, a large amount of radioactive metal was generated during the decommissioning in a short period. It is required to make an accurate measurement of the residual radioactivity for recycling the metal waste for releasing from regulatory control. In planning the measurement procedures, the influence of geometry, self-absorption, density and other relevant factors on the representativeness of the measurements should be considered for the decommissioning metal waste. In this study, the method for measurement procedures, the source term evaluation, the ways to secure representative samples, the measurement device for wide area and the self-absorption correction factors for different density were evaluated. The metal samples for measurement were prepared for securing the simple geometry and representative by melting process. The developed correction method for measuring the radioactivity a variety density of metal waste could improve the reliability of the evaluation results for clearance.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.699-704
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• 2001

Until recently, disposal to landfill has been the most convenient way to deal with the increasing amount of residues the shredding industries produce. But the shortage of such disposal sites and the risk that liquid drained from these waste dusts may pollute ground water have increased the environmental pressures to find more effective solutions. The present study is an alternative approach that suggests identifying waste dusts characteristics and selecting an appropriate binder for hazardous materials to reduce the amount of contaminants (mainly lead) that were leaking into the soil. Investigations on the characteristics of automobiles waste dusts show that these materials are composed mainly of cottons and sponge like substances, plastics, rubber, glasses and gravel, metals, and electric wires. Besides, the percentage in weight of organic (inflammable) materials is about 70% and the lead contamination, which has not a ionic but a particulate nature, is particularly remarkable in cottons and sponge like materials. Binding additives such as K-20 and sodium carbonate were not effective but the addition of 5 % of cement (in weight of the investigated sample) followed by a 3-minute stirring and a 4-hour storage could drastically reduce the run off of lead below the maximum authorized level. No addition of water was necessary in this method.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.220-225
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• 2003

Generally, liquid radioactive wastes generated in nuclear power plant exist in powder form which do not contain moisture through the evaporating process of the Liquid Waste Management System and drying process of the Concentrated Waste Drying System. This powder form wastes are blended homogeneously with paraffin solidification agent and packed in metal drum to ensure its stability during handling and disposal. However, it was experienced that the powder form wastes were not blended homogeneously and separated into two layers in metal drum, on the other hand, a Portion of powder was adhered and solidified to the Inside parts of facility during the blending process. And the flaw of blending process above would come in case the mole ratio of Boron to Sodium in liquid radioactive wastes exceeds 0.2.

• Journal of the Korean Geotechnical Society
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• v.20 no.3
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• pp.119-128
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• 2004

Environmental impact of waste tires as gound-reinforcing material is studied. Analysis for chemical compounds and toxic effect were performed on effluents from twelve lysimeters in which waste tires were mixed with sand and three initially different environmental solutions of acidic, neutral, and basic circulated through the mixture. The test results of effluents collected from the lysimeters provided that the contaminant concentrations were lower than those of Korean drinking water standards for all the selected and tested metal elements. While iron concentration increased slightly with the exposure period, other metal concentrations decreased with the number of circulation times. From the comparison with previous investigations, the contaminant concentration decreased with the increase of tire size, i.e. increases with the increase of the exposed surface of tire metals. From the toxicity tests, no deteriorative effect was observed and it could be concluded that waste tires are not biologically hostile materials.

• Journal of the Korea Organic Resources Recycling Association
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• v.17 no.4
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• pp.81-90
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• 2009

About 35 domestic incinerators are being operated currently. There is waste management policy to reuse waste efficiently and reduce waste through incineration which include reuse, recycling and energy recovery. However, there is a critical social issue that some heavy metals(Cu, Pb) were found in bottom ash from incineration of waste. After incineration, bottom ash is treated with chemicals to prevent second pollution of heavy metals from bottom ash and increase efficiency of heavy metal stabilization.

• Journal of Korea Society of Waste Management
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• v.35 no.8
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• pp.721-730
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• 2018

We investigated the effects of heavy metals in cement in the last 3 years and the amount of waste in the cement manufacturing process. The result shows that the average $Cr^{6+}$ content in cement products is controlled at 10 mg/kg. Cu and Pb have lower detection tendency in white cement than in ordinary portland cement. In addition, heavy metals such as Cd show a certain level of detection regardless of the input wastes. Copper slag and phosphate gypsum are the main influencing factors on the heavy metals in cement products. In auxiliary fuels, plastics waste and wood waste are considered to affect heavy metals in cement products. Alternative raw materials are considered to be affected by the alternative raw materials managed as byproducts. In the case of supplementary fuels, auxiliary fuels managed as waste instead of auxiliary fuels managed as byproducts affect the heavy metals in cement. This study examined the input amount without considering the heavy metals in each waste. Therefore, the result may vary in different situations, and further research must be conducted to supplement the findings. However, if the heavy-metal contents in the waste are constant, it can be used as a reference material for the control of heavy metals in cement products.