http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Nb 첨가 Zr 합금의 열처리 조건에 따른 LiOH 용액에서의 부식특성 연구
김현길,정용환,김도훈 대한금속재료학회(대한금속학회) 2000 대한금속·재료학회지 Vol.38 No.5
In order to develop the new zirconium alloys for cladding materials, the effects of Nb addition and the final heat treatment on the microstructure and corrosion characteristics of Zr-xNb(x = 0.2, 1.0 wt.%) alloys were investigated. The 1.0Nb alloy showed higher corrosion resistance than 0.2Nb alloy at 360℃, 70 ppm LiOH solution. The microstructure of oxide films that having equal oxide thickness has been characterized by TEM. The oxide of 1.0Nb alloy was mainly composed of columnar grains but the oxide of 0.2Nb alloys was mainly composed of equiaxed grains. From the XRD analysis of equal oxide thickness, the oxide of 1.0Nb alloy has higher tetra-ZrO₂ volume fraction than 0.2Nb alloys. Also when hydrogen pick-up content and fraction were measured with the corroded specimens of 0.2, 1.0Nb alloy at pre and post transition region, the hydrogen pick-up content and fraction were lower in 1.0Nb than 0.2Nb alloy. From the final heat treatment effect, the 1.0Nb alloy was affected annealing temperature but the 0.2Nb alloy was not.
김현길,김도훈,정용환 대한금속재료학회 2002 대한금속·재료학회지 Vol.40 No.11
The oxidation characteristics with orientation of an unalloyed Zr were investigated. From the Zr crystal bar, the specimen representing a single crystal was prepared to be coarse enough to have its grain be 4×4×1 ㎣ in size. After identifying the crystallographic orientations and planes by XRD, the samples were cut out in such a way as the cutting planes could correspond to the desired crystallographic planes. Oxidation tests were carried out in water at 360℃. The oxidation rate of the (1120) prismatic plane was faster than that of the (0002) basal plane. The analysis of oxide using the synchrotron XRD revealed that the zirconia grown at the basal plane had the preferred (200) plane in mono-ZrO_2, while the zirconia at the prismatic plane grew at both the (200) and (002) planes of mono-ZrO_2. In addition, the oxide layer that had formed at the basal plane having only one preferred growth plane exhibited a high fraction of columnar oxide and a relatively wide range of protective barrier layer. These results mean that the characteristics of the preferred planes of mono-ZrO_2 play an important role on the oxidation rate of Zr single crystal.
Development Status of Accident-tolerant Fuel for Light Water Reactors in Korea
김현길,양재호,김원주,구양현 한국원자력학회 2016 Nuclear Engineering and Technology Vol.48 No.1
For a long time, a top priority in the nuclear industry was the safe, reliable, and economicoperation of light water reactors. However, the development of accident-tolerant fuel (ATF)became a hot topic in the nuclear research field after the March 2011 events at Fukushima,Japan. In Korea, innovative concepts of ATF have been developing to increase fuel safetyand reliability during normal operations, operational transients, and also accident events. The microcell UO2 and high-density composite pellet concepts are being developed as ATFpellets. A microcell UO2 pellet is envisaged to have the enhanced retention capabilities ofhighly radioactive and corrosive fission products. High-density pellets are expected to beused in combination with the particular ATF cladding concepts. Two conceptsdsurfacemodifiedZr-based alloy and SiC composite materialdare being developed as ATF cladding,as these innovative concepts can effectively suppress hydrogen explosions and the releaseof radionuclides into the environment.
Properties of Zr Alloy Cladding after Simulated LOCA Oxidation and Water Quenching
김현길,김일현,정양일,박정용,정용환 한국원자력학회 2010 Nuclear Engineering and Technology Vol.42 No.2
In order to study the cladding properties of zirconium after a loss-of-coolant accident (LOCA)-simulation oxidation and water quenching test, commercial Zircaloy-4 and two kinds of HANA claddings were oxidized at temperatures ranging from 900ºC to 1250ºC and exposed for 300 s, and then cooled to 700ºC before quenching. Microstructural observations were made to evaluate the matrix characteristics with the chemical compositions after the LOCA-simulation test. Ring compression testing was then performed to compare the ductile behaviour of the HANA and Zircaloy-4 claddings. An X-ray diffraction (XRD) analysis was carried out for temperatures ranging from room temperature to 1250ºC for the oxide layer to verify the oxide crystal structure at each oxidation temperature.
THE EFFECTS OF CREEP AND HYDRIDE ON SPENT FUEL INTEGRITY DURING INTERIM DRY STORAGE
김현길,정용환,김규태 한국원자력학회 2010 Nuclear Engineering and Technology Vol.42 No.3
Recently, many utilities have considered interim dry storage of spent nuclear fuel as an option for increasing spent fuel storage capacity. Foreign nuclear regulatory committees have provided some regulatory and licensing requirements for relatively low- and medium-burned spent fuel with respect to the prevention of spent fuel degradation during transportation and interim dry storage. In the present study, the effect of cladding creep and hydride distribution on spent fuel degradation is reviewed and performance tests with high-burned Zircaloy-4 and advanced Zr alloy spent fuel are proposed to investigate the effect of burnup and cladding materials on the current regulatory and licensing requirements. Creep tests were also performed to investigate the effect of temperature and tensile hoop stress on hydride reorientation and subsequently to examine the temperature and stress limits against cladding material failure. It is found that the spent fuel failure is mainly caused by cladding creep rupture combined with mechanical strength degradation and hydride reorientation. Hydride reorientation from the circumferential to radial direction may reduce the critical stress intensity that accelerates radial crack propagation. The results of cladding creep tests at 400ºC and 130MPa hoop stress performed in this study indicate that hydride reorientation may occur between 2.6% to 7.0% strain in tube diameter with a hydrogen content range of 40-120ppm. Therefore, it is concluded that hydride re-orientation behaviour is strongly correlated with the cladding creep-induced strain,which varies as functions of temperature and stress acting on the cladding.