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1
화학당량에 따른 우라니아의 핵분열 기체 확산 계수 측정

김희문(H. Kim),박광헌(K. Park),김봉구(B. G. Kim),주용선(Y. S. Choo),김건식(K. S. Kim),송근우(K.W. Song),홍권표(K. P. Hong),강영환(Y. H. Kang) 한국표면공학회 2002 한국표면공학회지 Vol.36 No.1
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  ScienceON
  
  DBpia
The diffusion coefficient of Xe-133 was obtained from an annealing test. The specimens were made from a UO₂ single crystal powder with natural enrichment. Weight and grain size were 300mg and 23(㎛, respectively. Oxygen potentials were obtained from an oxygen sensor. Released fractions were obtained from both results of gamma scans and quantitative analysis with MCNP code, The annealing test was performed at three temperatures at once. Diffusion coefficients of Xe-133 were calculated using slope of Booth theory in each O/M ratios. Activation energy and the pre-exponential factor of the diffusion coefficient were obtained. The activation energy of near stoichiomeric UO₂ is 310 kJ/mol. The measured values of near stoichiometric UO₂ are very close to other data available. Diffusion coefficients increase with hyper-stoichiometry, due to higher concentration of cation vacancies.
2
냉간가공한 오스테나이트계 강재의 극저온 특성에 미치는 Ni 및 N의 영향

최진일(J. I. Choe),주기남(K. N. Choo),강영환(Y. W. Kang) 한국표면공학회 2004 한국표면공학회지 Vol.37 No.1
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  ScienceON
  
  KCI
  
  DBpia
Cryogenic characteristics of austenitic stainless steel based on 304 steel with nickel and nitrogen were investigated at room temperature and -196℃. The alloys were fabricated by vacuum arc furnace and cold working after homogenization treatment. The addition of nickel and nitrogen decreased the stability of δ-ferrite and induced the stability against the formation of martensite to result significantly in enhancing ductility at -196℃. Nitrogen reduced Md temperature, which was beneficial to the tensile strength and elongation at 25℃ and -196℃.
3
요드분위기에서 지르칼로이 피복재의 저변형율속도 의존성(I)

최용,강영환,류우석,임창생,Choi, Y.,Kang, Y.H.,Ryu, W.S.,Rim, C.S. Korean Nuclear Society 1985 Nuclear Engineering and Technology Vol.17 No.3
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온도 및 연신율 변촤가 Zircaloy-4의 요드 응력부식 거동에 미치는 영향을 30$0^{\circ}C$에서 일정 하중법과 300, 350, 40$0^{\circ}C$에서 일정 연신율법으로 ($10^{-5}$sec~$10^{-6}$ sec) 3.34mg $I_2$/㎤의 요드분위기에서 연구하였다. 요드 응력부식균열에 대한 저항성은 온도가 상승하거나 변형속도가 감소하면 감소했고 파손 시간과 응력과의 관계는1/tf∝exp (0.3$\sigma$/$\sigma$uTs-31.5)로 표시할 수 있었다. 30$0^{\circ}C$에서 요드 응력 부식 균열에 대한 저항성을 불활성 분위기에서의 파손에너지에 대한 요드분위기에서의 파손 에너지의 비율로 표시할 때 변형속도가 7.6$\times$$10^{-6}$ sec 부근에서 저항성이 가장 낮았고 온도가 35$0^{\circ}C$, 40$0^{\circ}C$ 로 증가함에 따라 보다 높은 변형속도에서 최저 저항성을 나타내는 경향을 보였다. 요드 응력부식 균열의 파단면에서 준-벽계 파면(quasi-cleavage fracture)을 관찰했다. 전술한 결과에 의하면 Zircaloy-4의 요드 응력부식균열의 기구에 있어서 보호 피막파손단계 (film rupture step)가 중요한 과정으로 추정된다. The effects of temperature and strain rate on the I-SCC behaviors of Zircaloy-4 were investigated by constant load test at 30$0^{\circ}C$ and constant elongation rate test at 300, 350 and 40$0^{\circ}C$ in 3.34mg $I_2$/㎤. The results showed that I-SCC susceptibility increased as the strain rate decreased or the temperature increased. The empirical relation between the stress and the time to failure at 30$0^{\circ}C$ was given by 1/ $t_{f}$∝exp (0.3$\sigma$/$\sigma$$_{UTS}$-31.5) When the I-SCC susceptibility was expressed by the ratio of fracture energy in iodine atmosphere to that in the inert atmosphere, severe I-SCC susceptibility was found near 7.6$\times$10$^{-6}$ sec at 30$0^{\circ}C$ and the maximum point of I-SCC susceptibility tended to shift to the higher strain rate with increasing the temperature. The quasi-cleavage fracture was observed in I-SCC fracture surface. From these results, it was certain that the film repture step was involved as an important process in the I-SCC mechanism of Zircaloy-4.4.