FPGA를 이용한 항공기 가스터빈 엔진제어장치의 RTCA DO-254 보증 방안에 관한 연구

김희주(Heuijoo Kim),김병현(Byunghyun Kim),하성기(Sunggi Ha),최희주(Heeju Choi),배경호(Kyungho Bae),전용우(Yongwoo Jun) 항공우주시스템공학회 2014 항공우주시스템공학회 학술대회 발표집 Vol.2014 No.10

An Efficient Thermal Management Method of Decay Heat in a Disposal Container for Deep Geological Disposal

Jongyoul Lee,Heuijoo Choi,Dongkeun Cho 한국방사성폐기물학회 2022 한국방사성폐기물학회 학술논문요약집 Vol.20 No.2

Currently, the most widely accepted disposal concept for long-term isolation of high level radioactive waste including spent nuclear fuels is to disposal in a deep geological repository designed and constructed with multiple barriers composed of engineered and natural barriers so that the waste can be completely isolated in a stable deep geological environment. In this concept, an important consideration is the heat generated from the waste due to the large amount of fission products present in the high level waste loaded in the disposal container. For safe and complete isolation of high level radioactive waste in the deep geology, the disposal concepts that meet the thermal requirements for the disposal system design have been developed by harmonizing the thermal characteristics of engineered and natural barriers in Korea. In this paper, the deposition hole configuration and the decay heat dissipation area (surface area) of disposal container were considered for the efficient thermal management in the deep geological disposal concept. Heat transfer through the waste form, its container and surrounding components and the rock will be mainly by conduction. Heat transfer by radiation and convection can be negligible after backfilling. When considering heat conduction, according to Fourier’s law, if the thermal conductivity of the repository components is the same, the greater the heat dissipation area and the adjacent temperature gradient, the greater the conduction effect. Therefore, rather than the conventional concept of loading 4 PWR spent fuel assemblies per disposal container and placing one disposal container in a deposition hole, it is better to load one assembly per disposal container and place 4 disposal containers in a deposition hole. In this case, it was found that the disposal area could be reduced through efficient thermal management. Considering this thermal management method as an alternative to the concept of deep geological disposal, additional research is needed.

Iodine Depositon onto Chinese Cabbage

Hansoo Lee,Heuijoo Choi,Hee-Suk Kang,Donghan Yu,Dong-Kwon Keum,Kwang-Mook Lim,Hyo-Kook Park,Yong Ho Choi,Chang Woo Lee 대한방사선방어학회 2004 방사선방어학회지 Vol.29 No.3

Strategies and Design Requirements for a High-efficiency Disposal Concept of PWR Spent Nuclear Fuels in Korea

Jongyoul Lee,Heuijoo Choi,Dongkeun Cho 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.1

In order to use nuclear energy stably, high level radioactive waste including spent nuclear fuel that is inevitably discharged from nuclear power plants after electricity generation must be managed safely and isolated from the human living area for a long period of time. In consideration of the accumulated amount of spent nuclear fuel anticipated according to the national policy for HLW management, the area required for the deep geological repository facility is expected to be very large. Therefore, it is essential to conduct various studies to optimize the area required for the disposal of spent nuclear fuel in cases where the nationally available land is extremely limited, such as in Korea. In this study, as part of such research, the strategies and the requirements for the preliminary design of a high efficiency repository concept of spent nuclear fuel were established. For PWR spent nuclear fuel, seven assemblies of spent nuclear fuel can be accommodated in a disposal canister, and high burnup of spent nuclear fuel was taken into consideration, and the source terms such as the amount and time of discharge and disposal were based on the 2nd national basic plan. By evaluating the characteristics, the amount of decay heat that can be accommodated in the disposal canister was optimized through the combination of seven assemblies of spent nuclear fuel. The cooling period of the radiation source for the safety assessment of the repository system was set at 55 years, and the operation of the repository would start from 2070 and then the disposal schedule would be conducted according to the disposal scenario based on the national basic plan. With these disposal strategies described above, the main requirements for setting up the conceptual design of the high efficiency repository system to be carried out in this study were described below. • A combination of seven spent nuclear fuels with high heat and spent nuclear fuels with low heat was loaded into a disposal canister, and the thermal limit per disposal canister was 1,600 W. • In order to maintain the long-term performance of the repository, the maximum temperature design limit in the buffer material was set to 130°C. • In the deep disposal environment, the safety factor [yield strength/maximum stress] required to maintain the structural stability of the disposal canister should be maintained at 2.0 or higher so that integrity of the canister can be maintained even under long-term hydrostatic pressure and buffer swelling pressure in the deep disposal environment. • The repository should have a maximum exposure dose of 10 mSv/yr or less, which is the legal limit in case of a single event such as an earthquake, and the risk level considering natural phenomena and human intrusion, which is less than the legal limit of 10-6/yr. These strategies and requirements can be used to develop the high-efficiency geological disposal concept for spent nuclear fuels as an alternative disposal concept.

Analysis of Changes in Reference Spent Nuclear Fuels Decay Heat Applied to the Reference Disposal Concepts

Jongyoul Lee,Heuijoo Choi,Dongkeun Cho 한국방사성폐기물학회 2022 한국방사성폐기물학회 학술논문요약집 Vol.20 No.1

The research for the safe management of high-level waste in Korea has been conducted by the Korea Atomic Energy Research Institute since 1997, and the results have formed the basis of the national basic plan for the high-level waste management and the revised national basic plan. In the future, it is evolving and developing R&D focusing on securing technologies for demonstration of the disposal technologies and R&D to develop disposal concepts that increase safety and improve efficiency. Efficient management of heat generated from high-level radioactive waste, including spent nuclear fuel, is an important factor in establishing the disposal concepts because it must be in harmony with key factors such as repository layout, waste disposal container specifications, and design and operation for the barriers of the disposal system. For safe and complete isolation of highlevel radioactive waste in the deep geology, the disposal systems that meet the thermal requirements for the disposal system design have been developed by harmonizing the thermal characteristics of engineered and natural barriers in Korea. These disposal systems were based on low burn-up spent nuclear fuel characteristics generated in the early stages of nuclear power generation, and next, based on the high-level wastes from recycling process of the high burn-up spent nuclear fuels, and were the direct disposal systems for the high burn-up spent nuclear fuels. So, it is necessary to track and analyze the change process in the decay heat characteristics of the high-level waste to be disposed of in order to improve the disposal concept, which enhances the safety of disposal and the utilization of the national land. Therefore, in this paper, the process of change in decay heat of reference spent nuclear fuels for disposal applied to the disposal concepts from the initial stage of development of high-level waste disposal technology to the present in Korea is analyzed.

Preliminary Evaluation of Domestic Applicability of Deep Borehole Disposal System

Jongyoul Lee,Minsoo Lee,Heuijoo Choi,Kyungsu Kim,Dongkeun Cho 한국방사성폐기물학회 2018 방사성폐기물학회지 Vol.16 No.4

현재 기준개념으로 개발하여 상용화 단계에 있는 심층 동굴 처분기술에 대한 대안으로서 지질학적 조건이 더 안정적인 지하 3~5 km의 심도에 사용후핵연료를 포함한 고준위폐기물을 처분하는 심부시추공 처분기술의 국내 적용 가능성을 예비 평가 하였다. 이를 위하여 심부시추공 처분개념의 기술적 적용성 분석에 필요한 국내 기반암 분포특성 및 심부시추공 처분부 지적합성 평가 기술 분석과 대구경 심부시추기술을 평가하였다. 이들 분석결과를 바탕으로 심부시추공 처분시스템 설계 기준 및 요건에 적합한 심부시추공 처분용기 및 밀봉시스템 개념을 설정하여 예비 기준 심부시추공 처분 개념을 도출하였다. 그리고 도출된 예비 기준 처분시스템에 대하여 열적 안정성 및 그래픽 처분환경에서의 처분공정 모사 등 다양한 성능평가를 수행하고 이들을 종합하여 심부시추공 처분시스템의 국내 적용성에 대하여 다양한 관점에서의 예비평가를 수행하였다. 결론적으로, 심부시추공 처분시스템은 처분심도와 단순한 방법으로 인하여 안전성 및 경제적 타당성 측면에서 많은 장점이 있지만, 불확실성을 줄이고 인허가를 획득하기 위해서는 이 기술에 대한 현장실증이 필수적이다. 본 연구결과는 사용후핵연료 관리 국가정책 수립을 위한 공학적 근거자료로 활용이 가능하며, 심부시추공 처분기술에 관심을 갖는 방사성폐기물 관리 이해당사자들에게 필요한 정보자료로 제공될 수 있다. As an alternative to deep geological disposal technology, which is considered as a reference concept, the domestic applicability of deep borehole disposal technology for high level radioactive waste, including spent fuel, has been preliminarily evaluated. Usually, the environment of deep borehole disposal, at a depth of 3 to 5 km, has more stable geological and geo-hydrological conditions. For this purpose, the characteristics of rock distribution in the domestic area were analyzed and drilling and investigation technologies for deep boreholes with large diameter were evaluated. Based on the results of these analyses, design criteria and requirements for the deep borehole disposal system were reviewed, and preliminary reference concept for a deep borehole disposal system, including disposal container and sealing system meeting the criteria and requirements, was developed. Subsequently, various performance assessments, including thermal stability analysis of the system and simulation of the disposal process, were performed in a 3D graphic disposal environment. With these analysis results, the preliminary evaluation of the domestic applicability of the deep borehole disposal system was performed from various points of view. In summary, due to disposal depth and simplicity, the deep borehole disposal system should bring many safety and economic benefits. However, to reduce uncertainty and to obtain the assent of the regulatory authority, an in-situ demonstration of this technology should be carried out. The current results can be used as input to establish a national high-level radioactive waste management policy. In addition, they may be provided as basic information necessary for stakeholders interested in deep borehole disposal technology.

Evaluation of Silicon Carbide (SiC) for Deep Borehole Disposal Canister

Minsoo LEE,Jongyoul LEE,Heuijoo CHOI,MalGoBalGaeBitNaLa YOO,Sunghoon JI 한국방사성폐기물학회 2018 방사성폐기물학회지 Vol.16 No.2

To overcome the low mechanical strength and corrosion behavior of a carbon steel canister at high temperature condition of a deep borehole, SiC ceramics were studied as an alternative material for the disposal canister. In this paper, a design concept for a SiC canister, along with an outer stainless steel container, was proposed, and its manufacturing feasibility was tested by fabricating several 1/3 scale canisters. The proposed canister can contain one PWR assembly. The outer container was also prepared for the string formation of SiC canisters. Thermal conductivity was measured for the SiC canister. The canister had a good thermal conductivity of above 70 W·m-1·K-1 at 100℃. The structural stability was checked under KURT environment, and it was found that the SiC ceramics did not exhibit any change for the 3 year corrosion test at 70℃. Therefore, it was concluded that SiC ceramics could be a good alternative to carbon steel in application to deep borehole disposal canisters.

Thermal conductivity of compacted bentonite as a buffer material for a high-level radioactive waste repository

Lee, Jae Owan,Choi, Heuijoo,Lee, Jong Youl Pergamon Press 2016 Annals of nuclear energy Vol.94 No.-

<P><B>Abstract</B></P> <P>Bentonite buffer is one of the major barrier components of a high-level radioactive waste (HLW) repository, and the thermal conductivity of the bentonite buffer is a key parameter for the thermal performance assessment of the HLW repository. This study measured the thermal conductivity of compacted bentonite as a buffer material and investigated its dependence upon various disposal conditions: the dry density, water content, anisotropic structure of the compacted bentonite, and temperature. The measurement results showed that the thermal conductivity was significantly influenced by the water content and dry density of the compacted bentonite, while there was not a significant variation with respect to the temperature. The anisotropy of the thermal conductivity had a negligible variation for an increasing dry density. The present study also proposed a geometric mean model of thermal conductivity which best fits the experimental data.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The thermal conductivities were measured under various disposal conditions. </LI> <LI> They were significantly influenced by the water content and dry density. </LI> <LI> They were not sensitive to the temperature and the anisotropic structure. </LI> <LI> A new model of thermal conductivity was proposed for the thermal analysis. </LI> </UL> </P>

항공기용 가스터빈 엔진의 전자식 엔진제어장치(EECU) 아키텍처 설계에 관한 연구

곽도협(Dohyup Kwak),김병현(Byunghyun Kim),김희주(Heuijoo Kim),김영진(Youngjin Kim),박건국(Konkuk Park),최희주(Heeju Choi),배경호(Kyungho Bae) 항공우주시스템공학회 2013 항공우주시스템공학회 학술대회 발표집 Vol.2013 No.10

Proposal of an Improved Concept Design for the Deep Geological Disposal System of Spent Nuclear Fuel in Korea

Jongyoul Lee,Inyoung Kim,HeeJae Ju,Heuijoo Choi,Dongkeun Cho 한국방사성폐기물학회 2020 방사성폐기물학회지 Vol.18 No.S

Based on the current high-level radioactive waste management basic plan and the analysis results of spent nuclear fuel characteristics, such as dimensions and decay heat, an improved geological disposal concept for spent nuclear fuel from domestic nuclear power plants was proposed in this study. To this end, disposal container concepts for spent nuclear fuel from two types of reactors, pressurized water reactor (PWR) and Canada deuterium uranium (CANDU), considering the dimensions and interim storage method, were derived. In addition, considering the cooling time of the spent nuclear fuel at the time of disposal, according to the current basic plan-based scenarios, the amount of decay heat capacity for a disposal container was determined. Furthermore, improved disposal concepts for each disposal container were proposed, and analyses were conducted to determine whether the design requirements for the temperature limit were satisfied. Then, the disposal efficiencies of these disposal concepts were compared with those of the existing disposal concepts. The results indicated that the disposal area was reduced by approximately 20%, and the disposal density was increased by more than 20%.