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Decay Heat Estimation of Spent Fuel Assemblies for Decommissioning of Kori Units 3 and 4
Wonjune Mah,Chang-Lak Kim,Sun-kee Lee 한국방사성폐기물학회 2022 한국방사성폐기물학회 학술논문요약집 Vol.20 No.2
This paper mainly focuses on the maximum decay heat estimation generated from spent fuel assemblies in the spent fuel pool of Kori units 3&4 at the beginning decommissioning. It is assumed that the spent fuel pool is fully occupied with 2,260 spent fuel assemblies, same as its design capacity. In addition, equally 56.5 spent fuel assemblies have been generated per year. The minimum cooling time is five years considering the transition phase between the permanent shutdown and the amendment of Operating License for decommissioning. Sending and receiving of spent fuel assemblies to/from other units are neglected. Seven representative spent fuel assembly groups are established based on the burnup rate and cooling time. Conservatively high values for the burnup rates and low values for the cooling times are applied. Calculation of the decay heat of each representative group has been performed by using ORIGEN decay solver of SCALE. Then, total decay heat has been calculated based on this. Group 1, 2, and 3 contain comparatively old spent fuel assemblies with 45 GWd/tU burnup rate and 20~30 cooling years. The calculation shows 489~586 watts of decay heat per assembly. Group 4, 5, 6, and 7 contain comparatively new spent fuel assemblies with 55 GWd/tU burnup rate and 5~20 cooling years. The calculation shows 741~1,483 watts of decay heat per assembly. The total maximum decay heat therefore is estimated as 1,609,459 watts.
Wonjune Mah,Chang-Lak Kim 한국방사성폐기물학회 2022 방사성폐기물학회지 Vol.20 No.3
Operating and decommissioning nuclear power plants generates radioactive waste. This radioactive waste can be categorized into several different levels, for example, low, intermediate, and high, according to the regulations. Currently, low and intermediate-level waste are stored in conventional 200-liter drums to be disposed. However, in Korea, the disposal of intermediate-level radioactive waste is virtually impossible as there are no available facilities. Furthermore, large-sized intermediate- level radioactive waste, such as reactor internals from decommissioning, need to be segmented into smaller sizes so they can be adequately stored in the conventional drums. This segmentation process requires additional costs and also produces secondary waste. Therefore, this paper suggests repurposing the no-longer-used spent nuclear fuel casks. The casks are larger in size than the conventional drums, thus requiring less segmentation of waste. Furthermore, the safety requirements of the spent nuclear fuel casks are severer than those of the drums. Hence, repurposed spent nuclear fuel casks could better address potential risks such as dropping, submerging, or a fire. In addition, the spent nuclear fuel casks need to be disposed in compliance with the regulations for low level radioactive waste. This cost may be avoided by repurposing the casks.
전자정부사업 역량강화 연수의 미시적 효과 : 나이지리아 전자정부 사업 사례연구
배원준(Wonjun Bae),장우찬(Woochan Chang) 한국국제협력단 2019 국제개발협력 Vol.14 No.2
본 연구는 나이지리아 전자정부 역량강화사업의 연수과정을 소재로, 역량강화 연수가 참가자 개인에 미치는 영향과 전자정부 사업의 목표인 업무 재설계(Government Process Re-Engineering)를 달성하는 데 필요한 조건을 확인하였다. Kirkpatrick(1994)의 이론에 따라 개인의 교육훈련 효과를 (1) 교육 과정에 대한 만족도, (2) 교육을 통해 얻게 된 기능, 태도 또는 지식, (3) 실제 일어난 행동 변화, 즉 교육장에서 배운 지식의 현업 활용도, (4) 교육과정 참가로 인해 교육 참가자가 창출하는 조직 차원의 성과로 나누어 보았으며, 맥니마 분석을 통해 연수과정이 참가자의 자기효능감을 유의미하게 증대시키는 것을 확인했다. 다중회귀분석을 활용해 현업 활용도의 증대요인을 분석한 결과, 부처의 정보화 수준이 가장 중요한 것으로 드러났으며, 이는 초점집단면접을 통해서도 확인되었다. This study aimed to assess the impact of an e-government training on individuals and to identify the conditions required for the training to achieve re-engineering of the government process, which is the objective of the e-government projects. We focused on the case of “Capacity Building of e-Government in Nigeria” by the Korea International Cooperation Agency. Adopting the theory of Kirkpatrick (1994), we collected and analyzed data by gauging (1) satisfaction, (2) knowledge, skills, or attitudes, (3) actual transfer or implementation, and (4) change at the organizational level derived from the training. We confirmed through a McNemar Test that the training improved the self-efficacy of the participants to a significant extent. By correlation and multivariate regression analyses, we found that the informatization level of the department is the most important factor in the training transfer.
Diesel Surrogate 상세 반응 기구를 이용한 HCCI엔진의 연소 특성
이원준(Wonjun Lee),이승로(Seungro Lee),이창언(Chang-Eon Lee) 한국연소학회 2010 KOSCOSYMPOSIUM논문집 Vol.- No.41
Homogeneous charge compression ignition(HCCI) is the best concept able to provide low NOx and PM in diesel engine emissions. This new alternative combustion process is mainly controlled by chemical kinetics in comparison with the conventional combustion in internal combustion engine. In this paper, detailed kinetic reaction mechanism of diesel surrogate was investigated to understand the diesel HCCI engine combustion. And we was investigated combustion characteristics of the new diesel surrogate(heptane/toluene mixture fuel). Especially we study deep into a ignition timing and emission gas according to heptane/toluene mixture ratio and EGR.
Diesel Surrogate 상세 반응 기구를 이용한 HCCI 엔진의 연소 특성에 관한 수치해석 연구
이원준(Wonjun Lee),이승로(Seungro Lee),이창언(Chang-Eon Lee) 한국연소학회 2011 한국연소학회지 Vol.16 No.2
Homogeneous charge compression ignition(HCCI) is the best concept able to provide low NOx and PM in diesel engine emissions. This new alternative combustion process is mainly controlled by chemical kinetics in comparison with the conventional combustion in internal combustion engine. In this paper, combustion characteristics of HCCI engine with suggested diesel surrogate(heptane/toluene mixture fuel) reaction mechanism were numerically investigated by heptane/toluene mixture ratio and EGR ratio. As results, the ignition timing became faster with increasing of heptane, and an initial oxidation and the ignition timing of the mixture fuel were affected by heptane and toluene, respectively.
EGR 가스의 성층화 조건에 따른 HCCI엔진의 연소 특성
이원준(Wonjun Lee),이승로(Seungro Lee),이창언(Chang-Eon Lee) 한국자동차공학회 2010 한국자동차공학회 학술대회 및 전시회 Vol.2010 No.11
Homogeneous charge compression ignition(HCCI) is the best concept able to provide low NOx and PM in diesel engine emissions. This new alternative combustion process is mainly controlled by chemical kinetics in comparison with the conventional combustion in internal combustion engine. However HCCI engine’s operation have an excessive rate of pressure rise during combustion. So the purpose of this study solve this problem with EGR gas’s concentration stratification and thermal stratification for reducing the pressure rise in HCCI engine combustion. And we study characteristics of combustion and emissions gas. The reaction mechanism using a this research is diesel surrogate which is composed of heptane/toluene blend fuel.