http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
양용식,Yang, Yong-Sik 한국방위산업진흥회 1992 國防과 技術 Vol.- No.164
1925년 화학무기의 사용을 금지하는 제네바의정서가 발표된 이후 금년 6월 22일 제네바 군축위원회에서 보다 포괄적인 내용의 화학무기 금지협정 안이 마련되어 내년초 국제조약으로 발효될 전망입니다 현재까지 화학무기 금지를 위한 국제적인 노력과 화학무기 실태를 분석해 볼때, 이번 금지협정안의 실효성을 높이고 화학무기의 위협으로부터 벗어나기 위해 화학방어 기술개발에 더욱 노력해야 할 것입니다
최적 핵연료 접촉 열전도도 모델 개발을 위한 예비 연구
양용식(Yong Sik Yang),신창환(Chang Hwan Shin) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.5
A gap conductance is very important factor which can affect nuclear fuel temperature. Especially, in case of an annular fuel, a gap conductance effect can lead an unexpected heat split phenomena which is caused by a large difference of an inner and outer gap conductance. The gap conductance mechanism is very complicated behavior due to the its strong dependency on microscopic factors such as a contact surface roughness, local contact pressure and local temperature. In this paper, for the decision of test temperature and pressure range, a procedure and calculation results of in-reactor fuel temperature and pressure analysis are summarized which can be applied to test equipment design and determination of test matrix. Based upon analysis results, it is concluded that the minimum and maximum test temperature are 300℃ and 530℃ respectively, and the maximum pellet/cladding interfacial contact pressure should be observed up to 45㎫.
양용식(Yong Sik Yang),전태현(Tae Hyun Chun),신창환(Chang Hwan Shin),송근우(Kun Woo Song) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.11
The surface heat flux of nuclear fuel rod is the most important factor which can affect safety of reactor and fuel. If fuel rod surface heat flux exceeds the CHF(Critical Heat Flux), fuel can be damaged. In case of double cooled annular fuel, which is under developing, contains two coolant channels. Therefore, a generated heat in the fuel pellet can move to inner or outer channel and heat flow direction is decided by both sides heat resistance which varied by dimension and material property change which caused by temperature and irradiation. The new program(called DUO) was developed. For the calculation of surface heat flux, a both sides convection by inner/outer coolant, s gap temperature jump and conduction in the fuel are modeled. Especially, temperature and time dependent fuel dimension and material property change are considered during the iteration. A sample calculation result shows that the DUO program has sufficient performance for annular fuel thermal hydraulics design.
고연소도 사용후 핵연료의 가열산화와 고온가열을 통한 미세조직 변화고찰
김대호,방제건,양용식,송근우,이형권,권형문,Kim Dae Ho,Bang Jae Geun,Yang Yong Sik,Song Keun Woo,Lee Hyung Kwon,Kwon Hyung Moon 한국방사성폐기물학회 2005 방사성폐기물학회지 Vol.3 No.4
The morphology of the high burnup $UO_2$ spent fuel, which was oxidized and annealed in a PIA (Post Irradiation Annealing) apparatus, has been observed. The high burnup fuel irradiated in Ulchin Unit 2, average rod burnup 57,000 MWd/tU, was transported to the KAERI's PIEF. The test specimen was used with about 200 mg of the spent $UO_2$ fuel fragment of the local burnup 65,000 MWd/tU. This specimen was annealed at $1400^{\circ}C$ for 4hrs after the oxidation for 3hrs to grain boundary using the PIA apparatus in a hot-cell. In order to oxidize the grain boundary, the oxidation temperature increased up to $500^{\circ}C$ and held for 3hrs in the mixed gas (60 ml He and 100 ml STD-air) atmosphere. The amount of 85Kr during the whole test process was measured to know the fission gas release behavior using the online system of a beta counter and a gamma counter. The detailed micro-structure was observed by a SEM to confirm the change of the fuel morphology after this test. As the annealing temperature increased, the fission products were observed to move to the grain surface and grain boundary of the $UO_2$ matrix. This specimen was re-structured through the reduction process, and the grain sizes were distributed from 5 to $10\;{\mu}m$.
경수로 핵연료 열-구조 연계 해석을 위한 다차원 간극 열전도도 모델 개발
김효찬(Hyo Chan Kim),양용식(Yong Sik Yang),구양현(Yang Hyun Koo) 대한기계학회 2014 大韓機械學會論文集A Vol.38 No.2
경수로 핵연료가 원자로내에서 연소되는 동안 핵연료 펠릿에서부터 피복관까지 온도해석은 핵연료 안전 해석에 있어 중요한 요소이며, 경수로 핵연료 온도 해석을 하기 위해서는 간극 모델 개발이 필수적이다. 간극 열전도도는 특성상 간극 두께값에 의존적이게 되며 이러한 특성으로 인해 다차원 간극 열전도도 모델이 비선형적 거동을 보인다. 본 연구에서는 선형화된 다차원 간극 열전도도 모델 개발을 위해 가상 연결 간극 요소를 제안하였다. 제안된 간극 연결 요소에 간극 열전도도를 적용하기 위해 등가 열전달 계수를 정의하였다. 제안된 모듈을 평가하기 위해 상용코드 ANSYS APDL 을 이용하여 열-구조 연계 해석 모듈을 구현하였으며, 다양한 예제를 통해 정확성과 수렴성을 평가하였다. A light water reactor (LWR) fuel rod consists of zirconium alloy cladding tube and uranium dioxide pellets with a slight gap between them. The modeling of heat transfer across the gap between fuel pellets and the protective cladding is essential to understanding fuel behavior under irradiated conditions. Many researchers have been developing fuel performance codes based on finite element method (FE) to calculate temperature, stress and strain for multidimensional analysis. The gap conductance model for multi-dimension is difficult issue in terms of convergence and nonlinearity because gap conductance is function of gap thickness which depends on mechanical analysis at each iteration step. In this paper, virtual link gap element (VLG) has been proposed to resolve convergence issue and nonlinear characteristic of multidimensional gap conductance. In terms of calculation accuracy and convergence efficiency, the proposed VLG model has been evaluated for variable cases.
김선기,방제건,김대호,임익성,양용식,송근우,김용수,Kim, Sun-Ki,Bang, Je-Geon,Kim, Dae-Ho,Lim, Ik-Sung,Yang, Yong-Sik,Song, Kun-Woo,Kim, Yong-Soo 한국재료학회 2008 한국재료학회지 Vol.18 No.11
Oxide effects experiments on massive hydriding reactions of Zr alloy with hydrogen gas were carried out at $400^{\circ}C$ under 1 atm in a $H_2$ environment with a thermo-gravimetric apparatus (TGA). Experimental results for oxide effects on massive hydriding kinetics show that incubation time is not proportional to oxide thickness. The results also show that the massive hydriding kinetics of pre-filmed Zr alloys follows linear kinetic law and that the hydriding rates are similar to that of oxide-free Zr alloys once massive hydriding is initiated. Unlikely microstructure of the oxide during incubation time, physical defects such as micro-cracks and pores were observed in the oxide after incubation time. Therefore, it seems that the massive hydriding of Zr alloys can be ascribed to short circuit paths and mechanical or physical defects, such as micro-cracks and pores in the oxide, rather than to hydrogen diffusion through the oxide resulting from the increase of oxygen vacancies in the hypo-stoichiometric oxide.