• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.13 no.1
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• pp.45-53
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• 2015

Since the commercial operation of Kori Unit #1 nuclear power plant(NPP) started in 1978, 23 units at present are operating in Korea. Radioactive wastes will be steadily generated from these units and accumulated. In addition, the life-extension of NPPs, construction of new NPPs and decontamination and decommissioning research facilities will cause radioactive wastes to increase. Recently, Korea has revised the new classification criteria as was proposed by IAEA. According to the revised classification criteria, low-level, very-low-level and exempt waste are estimated to about 98% of total disposal amount. In this paper, current status of overseas cases and disposal method with new classification criteria are analyzed to propose the most reasonable method for estimating the amount of decommissioning waste when applying the new criteria.

• Journal of Radiation Protection and Research
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• v.24 no.2
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• pp.101-108
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• 1999

The influence of the relative humidity, the temperature and the velocity of supply air on evaporation rate has been studied with non-boiling forced evaporation system in order to treat very low level radioactive liquid wastes produced from the decontamination and decommissioning activities. Experimental data on the evaporation rate have been obtained with the divers variables and experimental equation of air velocity was also obtained by the correlation of those data. The decontamination factor of this system was also obtained by the experimental data from a simulated liquid waste containing Cs-137 radio isotope ; $DF=10^4$. Since the commercial system will be operated for the treatment of the very low level radioactive liquid waste produced from decontamination & decommissioning of TRIGA Mark-II&III research reactor, the environmental assessment has been conducted to improve the operational safety. Exposure dose rate for an individual member of general public was assessed, and it showed that it was very lower than individual dose limits. The release of radioactivity of radioisotope material (Cs-137) to the environment was assessed, and result showed that it was $4.637{\times}10^{-14}\;{\mu}Ci/cc$.

• Nuclear Engineering and Technology
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• v.55 no.1
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• pp.52-62
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• 2023

Various decontamination technologies have been developed for removing contaminated areas in industries. Although it is important to consider parameters such as safety, cost, and time when selecting the decontamination technology, till date their comparative study is missing. Furthermore, different decontamination technologies influence the decontamination effects in different ways. Therefore, this study compares different decontamination techniques for the steam generator using a multicriteria decision-making method. A steam generator is a large device comprising both low- and very low-level waste (LLW, VLLW) and reflects the difference in weights of the standards according to the classification of the waste. For LLW and VLLW decontaminations, chemical oxidizing reduction decontamination (CORD) and decontamination grit blasting were used as the preferred techniques, respectively, considering the purpose of decontamination differs based on the initial state of waste. An expert survey revealed that safety in LLW and waste minimization in VLLW exhibited high preference. This evaluation method can be applied not only to the comparison between each process, but also to the creation of process scenarios. Therefore, determining the decontamination approach using logical decision-making methods may improve the safety and economic feasibility of each step in the decommissioning process and ensure a public acceptance.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.244.1-244.1
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• 2010

Bio energy development by using Low Calorific Gas Turbine(LCGT) has been developed for New & Renewable energy source for next generation power system, low fuel and operating cost method by using the renewable energy source in landfill gas (LFG), Food Waste, water waste and Livestock biogas. Low calorific fuel purification by pretreatment system and carbon dioxide fixation by green house system are very important design target for evaluate optimum applications for bio energy. Main problems and accidents of Low Calorific Gas Turbine system was derived from bio fuel condition such as hydro sulfide concentration, siloxane level, moisture concentration and so on. Even if the quality of the bio fuel is not better than natural gas, LCGT system has the various fuel range and environmental friendly power system. The mechanical characterisitics of LCGT system is a high total efficiency (>70%), wide range of output power (30kW - 30MW class) and very clean emmission from power system (low NOx). Also, we can use co-generation system. A green house designed for four different carbon dioxide concentration from ambient air to 2000 ppm by utilizing the exhaust gas and hot water from LCGT system. We look forward to contribute the policy for Renewable Portfolio Standards(RPS) by using LCGT power system.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.17 no.4
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• pp.437-445
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• 2019

After the permanent shutdown of K1 in 2017, decommissioning processes have attracted great attention. According to the current decommissioning roadmap, the dismantling of the activated components of K1 may start in 2026, following the removal of its spent fuel. Since the reactor vessel (RV) and reactor vessel internal (RVI) of K1 contain massive components and are relatively highly activated, their decommissioning process should be conducted carefully in terms of radiological and industrial safety. For achieving maximum efficiency of nuclear waste management processes for K1, we present activation analysis of the segmentation process and waste classification of the RV and RVI components of K1. For RVI, the active fuel regions and some parts of the upper and lower active regions are classified as intermediate-level waste (ILW), while other components are classified as low-level waste (LLW). Due to the RVI's complex structure and high activation, we suggest various underwater segmentation techniques which are expected to reduce radiation exposure and generate approximately nine ILW and nineteen very low level waste (VLLW)/LLW packages. For RV, the active fuel region and other components are classified as LLW, VLLW, and clearance waste (CW). In this case, we suggest in-situ remote segmentation in air, which is expected to generate approximately forty-two VLLW/LLW packages.

• Proceedings of the Korean Nuclear Society Conference
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• 2004.10a
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• pp.1275-1276
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• 2004

• Nuclear Engineering and Technology
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• v.56 no.3
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• pp.941-948
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• 2024

The effects of radiation on the corrosion of canister materials were investigated for the reliable disposal of high-level radioactive waste. The test specimens were gamma-irradiated at a very low dose rate of approximately 0.1 Gy/h for six and twelve months. The copper and cast iron species were less corroded when irradiated. It is hypothesized that gamma rays suppress the formation of lower-enthalpy species like metal oxides and activate reductive reactions. In contrast, it was difficult to evaluate the effect of radiation on the corrosion of titanium and stainless steel.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.13 no.1
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• pp.63-72
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• 2015

The low and intermediate-level radioactive waste generated in Korea is disposed of at Wolsong Disposal Facility. For the safety of a disposal facility, it must be assessed by considering some abnormal scenarios including human intrusion as well as those by natural phenomena. The human intrusion scenario is a scenario that an incognizant man of the disposal facility will be occurred by the drilling. In this paper, the well usage scenario was classified into the human intrusion event as the probability of the well drilling is very low during the man's lifecycle and then was assessed by using conservative assumptions. This scenario was assessed using the dilution factor of contaminants released from a disposal facility and then it was introduced the applied methodology in this study. The assessed scenario using this methodology is satisfied the regulatory limits.

• Korean System Dynamics Review
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• v.7 no.1
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• pp.119-146
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• 2006

City of Gyeongju's referendum finally offered the long-waited low-level radioactive waste disposal site in November 2005. Gyeongju's positive decision was due to the various economic rewards and incentives the national government promised to the city. 300 million won for an accepting bonus, 8.5 billion won, annual revenue fro the entry quantity of waste into the city's disposal site, the location of the headquarter building of the Korean Hydro and Nuclear Power Co., and the accelerator research center. All of the above will affect the city's infrastructure and the citizens' economic and cultural lives. Population, land use, economic structure, environment and quality of life will be affected. Some will be very positive, and some will be positive. This research project will see the future of the city and forecast the demographic, economic, physical and environmental changes of the city via computer simulation's system dynamics technique. This kind of simulation will help City of Gyeongju's what to prepare for the future. The population forecasting of the year 2026 will be 289,069 with the waste disposal site, and 279,131 without the waste disposal site in Gyeongju. The waste disposal site and the relocation of the company headquarters and location of the accelerator research center will attract 9,938 individuals more with 511 manufacturing shops and 1944 service jobs. The population increase will bring 3,550 more houses constructed in the city. Land use will also be affected. More land will be developed. However, mad, water plant and waste water plant will not be expanded as much. The city's financial structure will be expanded, due to the increased revenues from the waste disposal site, and property tax revenues from the middle-class employees of the company, and the high-powered scientists and technologists from the accelerator research center. All in an, the future of the city will be brighter after operating the nuclear waste disposal site inside the city.

• Journal of Environmental Health Sciences
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• v.20 no.4
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• pp.72-79
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• 1994

This study was performed to improve many problems of leaching test of industrial waste sludge analysis. We analyze sludges by variation of leachant, pH and leaching time.The results were as follows: 1. As leaching at pH 5.8 by our leaching test without control of pH during leaching, the leaching rates were very low as below 1%. 2. As leaching at pH 5.8 continuously by hydrochloric acid every 2 hour, the leaching rates were higher than before 1. 3. As leaching at pH 5.0 continuously by acetic acid every 2 hour, the leaching rates were higher than 1, 2. 4. The variations of leaching rate by leaching time were smaller increase after 10 hours than before. 5. It will be recommendable that the pH of leachant maintain constantly during leaching as level of acid rain, and the acetic acid is more effective than hydrochloric acid as leachant.