• The Korean Journal of Nuclear Medicine Technology
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• v.15 no.2
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• pp.104-110
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• 2011

Purpose: The object evaluation method about medical institutes of these days increases credibility of consumers about medical services by conducting a certification system about medical institutes. In addition, as nuclear medicine test rooms and diagnosis test medicine room adopt many kinds of international certification systems, the matters regarding safety management of test rooms are being regarded as important. Since the blood test rooms of nuclear medicine are exposed to many harmful factors such as infection from clinical specimen and radioactive isotope reagent, there is a need to pay lots of attention to the safety management of staff and patients. Therefore, this study discusses safety management activities of staff and patients, which are conducted in the blood test rooms of the nuclear medicine department in Asan Medical Center. Materials and Methods: In the blood test rooms of the nuclear medicine department in Asan Medical Center, the matters regarding comprehensive safety management by the person in charge of safety management are offered and all staff members of the test rooms apply them into work. Safety management education is regularly conducted according to established regulations, and infection is prevented through implementation of wearing personal protectors and hand sanitation during test work. In addition, technical safety guides and accident guides for interruption of electric power are provided against emergencies. Through infection management guides, infection prevention and preparation methods for infection are learned and radioactive isotope management, safety management about reagent use and safety guides about harmful chemical substances are being applied to work. Results: The blood test rooms of the nuclear medicine department apply safety management regulations to work. Under the situation where hand sanitation should be conducted, hands are washed to prevent infection between staff and patients, and for preventing infection from clinical specimen, personal protectors are worn. The reagent, which is classified as harmful substance, is separately stored to be easily recognized, radioactive wastes and general medical wastes are also safely managed. Through these lots of safety management activities, safety management awareness of staff members is enhanced, and patients are protected from many dangers. Conclusion: Staff members of the blood test rooms of the nuclear medicine department should be fully aware of safety management regulations and apply them to work. When better safety management suggestions are made, they need to be examined and applied for increasing quality of safety management for staff and patients.

• Economic and Environmental Geology
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• v.55 no.6
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• pp.737-760
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• 2022

For the geological disposal of high-level radioactive wastes (HLW), an understanding of deep subsurface environment is essential through geological, hydrogeological, geochemical, and geotechnical investigations. Although South Korea plans the geological disposal of HLW, only a few studies have been conducted for characterizing the geochemistry of deep subsurface environment. To guide the hydrogeochemical research for selecting suitable repository sites, this study overviewed the status and trends in hydrogeochemical characterization of deep groundwater for the deep geological disposal of HLW in developed countries. As a result of examining the selection process of geological disposal sites in 8 countries including USA, Canada, Finland, Sweden, France, Japan, Germany, and Switzerland, the following geochemical parameters were needed for the geochemical characterization of deep subsurface environment: major and minor elements and isotopes (e.g., ³⁴S and ¹⁸O of SO₄^2-, ¹³C and ¹⁴C of DIC, ²H and ¹⁸O of water) of both groundwater and pore water (in aquitard), fracture-filling minerals, organic materials, colloids, and oxidation-reduction indicators (e.g., Eh, Fe²⁺/Fe³⁺, H₂S/SO₄^2-, NH₄⁺/NO₃^-). A suitable repository was selected based on the integrated interpretation of these geochemical data from deep subsurface. In South Korea, hydrochemical types and evolutionary patterns of deep groundwater were identified using artificial neural networks (e.g., Self-Organizing Map), and the impact of shallow groundwater mixing was evaluated based on multivariate statistics (e.g., M3 modeling). The relationship between fracture-filling minerals and groundwater chemistry also has been investigated through a reaction-path modeling. However, these previous studies in South Korea had been conducted without some important geochemical data including isotopes, oxidationreduction indicators and DOC, mainly due to the lack of available data. Therefore, a detailed geochemical investigation is required over the country to collect these hydrochemical data to select a geological disposal site based on scientific evidence.

• Economic and Environmental Geology
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• v.31 no.6
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• pp.527-534
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• 1998

Excavation of underground openings changes stress distribution around the opening. The survey of this disturbed zone in excavation is very important to design and construct underground facilities, such as tunnel, gas and oil storage, power plant and disposal site of high- and low-level radioactive wastes. This paper presents a zoning of rock masses with tunnel excavation using PS logging. Compressional and shear wave velocities are measured in boreholes drilled in the tunnel wall, which was constructed with blasting and/or machine excavation. The disturbed zone in excavation can be estimated by comparing PS logging data with a tomographic image of compressional wave velocity and compressional and shear wave velocities of core samples. In the side wall of tunnel, the disturbed zone reaches 1.5 m and 1.0 m in thickness for blocks of blasting and machine excavations, respectively. In the roof of tunnel, however, the disturbed zone is 1.0 m and 0.75 m thick for the two blocks. These results show that the width of the disturbed zone is larger in the side wall of tunnel than in the roof, and 1.3 to 1.5 times larger for the blasting excavation than for the machine excavation.

• Journal of Energy Engineering
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• v.20 no.3
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• pp.236-241
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• 2011

In this study, considering a degree of proliferation resistance and sustainability, development status of perspective recycling systems for spent nuclear fuels (SNF) is comprehensively reviewed on the basis of the urgent needs of sustainable management measures for high level radioactive wastes such as spent nuclear fuels (SNF).

• The Korean Journal of Ceramics
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• v.6 no.1
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• pp.47-52
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• 2000

Lanthanides such as La, Gd and Ce have recognized as elements of high level radioactive wastes immobilized by forming solid solution with $CaTiO_3$. For easy forming solid solution between $CaTiO_3$and lanthanides, the combustion synthesis process was applied and the powder characteristics and sinterability were investigated. The proper selection of the type and the composition of fuels are important to get the crystalline solid solution of $CaTiO_3$and lanthanides. When glycine or the mixtures of urea and citric acid with stoichiometric composition was used as a fuel, the solid solution of $CaTiO_3$with $La_2O_3$or $Gd_2O_3$or $CeO_2$was produced very well by the combustion process. The combustion synthesized powder seemed to have a good sinterability with the linear shrinkage of more than 25% up to $1500^{\circ}C$, while that of the solid state reacted powder was less than 10% at the same condition.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.1
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• pp.73-80
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• 2016

The preliminary test for the dual mode plasma torch system was carried out to explore the operation properties in advance. The dual mode plasma torch system that is able to operate in transferred, non-transferred, or dual mode is very adequate for melting the mixed wastes including nonconductive materials such as concrete, asbestos, etc. since it exploits both the high efficiency of heat transfer to the melt in transferred mode and stable operation in non-transferred mode. Also, system operation including restarting is reliable and very easy. A stationary melter with a refractory structure was designed and manufactured considering the melting behavior of slags to minimize the refractory erosion. The power supply for the dual mode plasma torch system built with high power insulated gate bipolar transistor (IGBT) modules has functions for both current control and voltage control and is sufficient to suppress the harmonics during the operation of the plasma torch. The power supply provides two different voltages for transferred operation and non-transferred. It is confirmed that the operation voltage in transferred is always higher than non-transferred. The dual mode plasma torch system was successfully developed and is under operation for a melting experiment to optimize operation data.

• Resources Recycling
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• v.8 no.3
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• pp.18-25
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• 1999

The study on the electrosorption of cobalt ions onto a porous activated carbon fiber (ACF) was performed to treat radioactive liquid wastes resulting from chemical or electrochemical decontamination and to regenerate the spent carbon electrode, Cyclic voltammetry was investigated on a rotating-disk electrode (RDE) to determine the region of potentials within which only double-layer charging should occur. The application of an electric potential increased the sorption of the cobalt ions. The adsorbed cobalt Ions could be released into the solution by reversing the appling potential, showing the reversibility of the process.

• Journal of Nuclear Fuel Cycle and Waste Technology
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• v.1 no.1
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• pp.29-35
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• 2013

The United States Department of Energy (US DOE) is conducting research and development (R&D) activities under the Used Fuel Disposition Campaign (UFDC) to support storage, transportation, and disposal of used nuclear fuel (UNF) and wastes generated by existing and future nuclear fuel cycles. R&D activities are ongoing at nine national laboratories, and are divided into storage, transportation and disposal. Storage R&D focuses on closing technical gaps related to extended storage of UNF. Transportation R&D focuses on ensuring transportability of UNF following extended storage, and addressing data gaps regarding nuclear fuel integrity, retrievability, and demonstration of subcriticality. Disposal R&D focuses on identifying geologic disposal options and addressing technical challenges for generic disposal concepts in mined repositories in salt, clay/shale, and granitic rocks, and deep borehole disposal. UFDC R&D goals include increasing confidence in the robustness of generic disposal concepts, reducing generic sources of uncertainty that may impact the viability of disposal concepts, and developing science and engineering tools to support the selection, characterization, and licensing of a repository. The US DOE has also initiated activities in the Nuclear Fuel Storage and Transportation (NFST) Planning Project to facilitate the development of an interim storage facility and to support transportation infrastructure in the near term.

• Korean Journal of Soil Science and Fertilizer
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• v.19 no.3
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• pp.251-268
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• 1986

Selecting a site for the safe disposal of radioactive waste requires the evaluation of a wide range of geologic, mineralogic, hydrologic, and physicochemical properties. Although highly diverse, these properties are in fact interrelated. Site requirements are also diverse because they are influenced by the nature of the radionuclides in the waste, for example, their half-lives, specific energy, and chemistry. A fundamental consideration in site selection is the mineralogy of the host rock, and one of the most ubiquitous mineral groups is clay minerals. Clays and clay minerals as in situ lithologic components and engineered barriers may playa significant role in retarding the migration of radionuclides. Their high sorptivity, longevity (stability), low permeability, and other physical factors should make them a very effective retainer of most radionuclides in nuclear wastes. There are, however, some unanswered questions. For example, how will their longevity and physicochemical properties be influenced by such factors as radionuclide concentration, radiation intensity, elevated temperatures, changes in redox condition, pH, and formation fluids for extended periods of time? Understanding of mechanisms affecting clay mineral-radionuclide interactions under prevailing geochemical conditions is important; however, the utilization of experimental geochemical information related to physicochemical properties of clays and clay-bearing materials with geohydrologic models presents a uniquely challenging problem in that many assessments have to be based on model predictions rather than on experiments. These are high-priority research investigations that need to be addressed before complete reliance for disposal area performance is made on clays and clay minerals.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.19 no.3
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• pp.339-352
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• 2021

Legacy waste from the decommissioned A-1 nuclear power plant in the Slovak Republic is scheduled for immobilisation within a tailored alkali borosilicate glass formulation, as part of ongoing site cleanup. The aqueous durability and characterisation of a simulant glass wasteform for Chrompik III legacy waste, was investigated, including dissolution experiments up to 112 days (90℃, ASTM Type 1 water). The wasteform was an amorphous, light green glassy product, with no observed phase separation or crystalline inclusions. Aqueous leach testing revealed a suitably durable product over the timescale investigated, comparing positively to other simulant nuclear waste glasses and vitreous products tested under similar conditions. Iron and titanium rich precipitates were observed to form at the surface of monolithic samples during leaching, with the formation of an alkali deficient alteration layer behind these at later ages. Overall this glass appears to perform well, and in line with expectations for this chemistry, although longer-term testing would be required to predict overall durability. This work will contribute to developing confidence in the disposability of vitrified Chrompik legacy wastes.