• Proceedings of the Korean Nuclear Society Conference
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• 1997.05b
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• pp.555-560
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• 1997

원자력발전소의 전열관 보수용접기술은 원전시설의 수명연장을 목적으로 개발된 기술이며, 손상된 Inconel 600 전열관 내부에 Inconel 690 재질의 sleeve tube을 삽입한 후 용접을 하는 방법으로 수행된다. 증기발생기 전열관 sleeve 레이저 용접의 기본개념은 방사능지역 외부의 발진기로부터 발진된 레이저빔을 광섬유를 이용하여 장거리(200미터 이상) 전송하여 전열관 내부의 광학계 및 회전장치를 이용하여 전열관을 용접하는 방법이다. 본 연구에서는 펄스형 레이저의 용접 변수인 펄스폭, 반복율, 첨두출력 및 용접속도를 변화시키면서 용입상태를 측정하였고, 용접된 시편에 열처리 여부와 부식실험을 위한 C-ring 시편을 제작하여 caustic test를 위해 auto-clave vessel에서 1,000 시간 실험을 실시하였다.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.06a
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• pp.158-166
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• 2004

The optimal conditions are obtained for the decomposition of solid radioactive wastes, including ion exchange resin, zeolite, active charcoal, and sludge from nuclear power plant. In the process of decomposing the radioactive wastes were used the microwave acid digestion method with mixed acid. The solution after acid digestion by the following method was colorless and transparent. Each solution was analyzed with ICP-AES and AAS and the recovery yield for 5 different elements added the simulated radioactive wastes were over 94%. As an effective pre-treatment, the proposed microwave acid digestion conditions concerning the chemical trait of each radioactive waste are expected to be generally applied to above-mentioned radioactive wastes from nuclear power plant hereafter.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.78-82
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• 2003

For the decomposition of laundry wastewater containing Fe-EDTA produced from the steam generators in nuclear power plants, Supercritical Water Oxidation (SCWO) Process, Photocatalytic Oxidation (PO) Process, and Dielectric Barrier Discharge (DBD) Atmospheric Pressure Plasma Process were evaluated. Even though EDTA was converted over 99.98 % by the SCWO process, it was estimated that the countermeasure against corrosion of the equipment should be reinforced for the process stability. It was considered that the PO process is not appropriate for the decomposition of high concentrated laundry wastewater since the conversion ratio of EDTA was around 10 %. Finally, High efficiency of the decomposition of organic matter (methylene blue) was obtained using DBD process even low energy was supplied. However there is still room for the evaluation of EDTA decomposition in order that the DBD process should be applied for the field samples.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2010.10a
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• pp.241-245
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• 2010

화재방호에 성능기반 개념을 도입함에 따라 화재모델링의 활용도는 점점 높아지고 있다. 본 연구의 목적은 FDS를 이용하여 원자력발전소 펌프실의 윤활유 화재 시 케이블의 손상여부를 평가하고, 확인분석을 통해 화재모델링의 적합성을 파악하는 데 있다. 화재는 펌프 주변의 누출된 윤활유에서 발생하며 화원의 면적은 $2.75m^2$이고 단위면적당 열방출율은 $1,794kW/m^2$로 가정하였다. 계산결과, 고온기체층의 온도는 $400^{\circ}C$를 상회하고 있으나 케이블 트레이의 온도는 $50^{\circ}C$ 아래로 예측되고 있어 본 화재시나리오에서 케이블의 건전성은 유지되고 있으며 밀폐된 격실에서의 대형화재는 환기지배형 화재가 된다는 것을 보여주고 있다. 또한 확인분석 결과, 화재 시나리오의 주요 변수인 열방출율, 격실크기 그리고 강제 환기 변수가 확인계산 범위 내에 있어 본 계산결과는 NUREG-1824의 확인요건을 만족하고 있다. 따라서 펌프실 윤활유 화재에 대한 모델링의 적합성을 확인하였다.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.5
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• pp.517-523
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• 1999

The Start-up transformers or on-site stand-by transformers are installed for the start-up and shut-down of generator and emergency status in unclear power plant. The on-site power supply configuration using these transformers must be detemined by considering configuration requirements, site characteristics, reliability and availability severely because it is remarkably important for safety and benefit of plant. The start-up or stand-by power supply configuration has been determined considering only safety requirements and construction cost up to now in Korea. I study various reliability estimating methods for the prediction of availability, and estimate the unavailability for the start-up power supply system of two 1,000㎿ unclear power plants. I also detemine the reliability and unavailability and unavailavility of equipment, system and configuration using FTA method.

• Environmental and Resource Economics Review
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• v.27 no.2
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• pp.261-286
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• 2018

This paper evaluated the economic feasibility of the life extension of Kori unit 1 and Wolsong unit 1 according to the types of the nuclear power plants (NPPs) and the life extension period comparing to the levelized costs of energy (LCOE) of the new NPPs, coal-fired plants (CFPs), and combined cycle gas turbine (CCGTs) which proposed in the $7^{th}$ Basic Plan for Electricity Supply and Demand. The economic feasibility of the life extension of NPPs using LCOE method is affected by the types of NPPs, lifetime extension periods, discount rate, and capacity factor. According to the analysis results, the pressurized light water reactor (PWR) is more economical than the pressurized heavy water reactor (PHWR). Comparing the economical efficiency between the life extension of NPPs and other alternatives, the operation of the PWR for 20 years is more economical than the one of new NPPs and CFPs. However, 20 years of life extension of PHWR is more economical than the CCGTs, but less economical than new NPPs and CFPs. In summary, the 20 years of life extension of the NPPs seems to be more, especially for the PWR, which is more cost effective than other generation alternatives. Therefore, the government policy of the life extension of NPPs need to be a selective approach that simultaneously considers both safety and economics rather than closing all NPPs.

• Journal of the East Asian Society of Dietary Life
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• v.17 no.6
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• pp.808-815
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• 2007

Four different herbs, including rosemary, oregano, basil and sage, along with green tea were individually added to ground beef at different percentages: 0.5, 1.0, and 1.5, respectively. The sensory qualities of the five natural herbs and their antioxidant effects were evaluated using Beef-Yukwonjeon. For the sensory evaluation results, the 0.5% herb addition and the control group generally showed higher acceptability scores than the 1.0% or 1.5% herb addition groups. In particular, the Yukwonjeon made with 0.5% green tea showed higher preferences in the acceptance tests and ranking tests. However, the sensory differences among samples were reduced after 3 days of storage at $6^{\circ}C$. For the results of lipid oxidation without storage, the TBARS values of the herb addition groups were slightly lower than the value of the control group, but not significantly(p>0.05). However, the antioxidant effects of each herb showed higher values over a longer storage period as well as at the higher herb concentrations. The antioxidant effects of the herbs during 7 days' of storage at $6^{\circ}C$ were evaluated as $10.0{\sim}38.5%$ reductions in TBARS values as compared to the group without herbs. Furthermore, the antioxidant effects of the herbs during 30 days' of storage at $-20^{\circ}C$ were shown as $16.8{\sim}27.8%$ reductions in the TBARS value. The green tea showed the highest antioxidant activity against lipid oxidation, because it was acceptable at higher concentrations in the sensory evaluation. These results indicate the potential to produce better quality beef-Yukwonjeon, with herbs, especially green tea.

• Journal of Energy Engineering
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• v.11 no.1
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• pp.18-25
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• 2002

One of the most serious concern in nuclear power plant piping maintenance is thickness reduction due to flow-accelerated corrosion (FAC). Since the FAC occurs under specific conditions of pH, dissolved oxygen, temperature, flow velocity, steam quality of the fluid and materials and geometry of the piping, a systematic approach is required for managing the FAC problem. In this study, construction of a secondary piping database, analyzing the FAC rate using the database and predicting the residual life was performed for a domestic CANDU nuclear power plant. Also FAC mechanism and factors affecting FAC were reviewed. By showing a case study on analysis for a pipe line between a separator and a flash tank, a procedure for managing FAC problem is suggested. The procedure proposed in this paper can be widely applied to the secondary piping of other domestic nuclear polder plants.

• Fire Science and Engineering
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• v.21 no.2 s.66
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• pp.98-104
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• 2007

This study is related with the fire risk assessment for fire area at nuclear power plant by use of FDS (Fire Dynamics Simulator) that is a computational fluid dynamics (CFD) model of fire-driven fluid flow. The major purpose of this research is to analyze the sensitivity of the fire modeling when the heat release rate that is an important input variable is changed as well as when the grid size that is a critical factor of the fire model is modified. The result is presented at the conclusion with some comments for CFD model application.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2005.06a
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• pp.457-463
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• 2005

KHNP(Korea Hydro and Nuclear Power Ltd., Co.) is developing a HIC transport package which is satisfying domestic and IAEA regulations and NETEC(Nuclear Environment Technology Institute) is conducting a conceptual design. In this study, the shielding thickness was calculated using the data from radionuclide assay program which is currently using in nuclear sites and Micro Shield code. Considering the structural safety, carbon steel was chosen as shielding material and the shielding thickness was calculated for 500 R/hr and 100 R/hr at HIC surface, respectively. Through the shielding analysis, it was evaluated that the regulation limit is satisfied when the shielding thickness is 22 cm for 500 R/hr and 17 cm for 100/hr.