• Nuclear Engineering and Technology
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• v.51 no.3
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• pp.915-921
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• 2019

Radiation damage due to neutrons has been calculated in Ni-based alloys in Wolsong CANDU reactor environments. Two damage parameters are considered: displacement damage, and transmutation gas production. We used the SPECTER and SRIM computer codes in quantifying radiation damage. In addition, damage caused by Ni two-step reactions was considered. Estimations were made for the annulus spacers in a CANDU reactor that are located axially along a fuel channel and made of Inconel X-750. The calculation results indicate that the transmutation gas production from the Ni two-step reactions is predominant as the effective full power year increases. The displacement damage due to recoil atoms produced from Ni two-step reactions accounts for over 30% out of the total displacement damage.

• Polymer Science and Technology
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• v.15 no.6
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• pp.750-760
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• 2004

• Korean Journal of Materials Research
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• v.14 no.11
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• pp.813-820
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• 2004

The electrolytic reduction of spent oxide fuel involves the liberation of oxygen in a molten LiCl electrolyte, which is a chemically aggressive environment that is very corrosive for typical structural materials. So, it is essential to choose the optimum material for the process equipment handling molten salt. In this study, corrosion behavior of Haynes 263, 75, and Inconel X-750, 718 in molten salt of $LiCl-Li_{2}O$ under oxidation atmosphere was investigated at $650^{\circ}C\;for\;72\sim360$ hours. At $3\;wt\%\;of\;Li_{2}O$, Haynes 263 alloy showed the highest corrosion resistance among the examined alloys, and up to $8\;wt\%\;of\;Li_{2}O$, Haynes 75 exhibited the highest corrosion resistance. Corrosion products were formed $Li(Ni,Co)O_2,\;LiNiO_2\;and\;LiTiO_2\;and\;Cr_{2}O_3$ on Haynes 263, $Cr_{2}O_3,\;NiFe_{2}O_4,\;LiNiO_2,\;Li_{2}NiFe_{2}O_4,\;Li_{2}Ni_{8}O_10$ and Ni on Haynes 75, $Cr_{2}O_3,\;(Al,Nb,Ti)O_2,\;NiFe_{2}O_4,\;and\;Li_{2}NiFe_{2}O_4$ on Inconel X-750 and $Cr_{2}O_3,\;NiFe_{2}O_4\;and\;CrNbO_4$ on Inconel 718, respectively. Haynes 263 showed local corrosion behavior and Haynes 75, Inconel X-750, 718 showed uniform corrosion behavior.

• Korean Journal of Materials Research
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• v.16 no.9
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• pp.557-563
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• 2006

The electrolytic reduction of spent oxide fuel involves the liberation of oxygen in a molten LiCl electrolyte, which results in a chemically aggressive environment that is too corrosive for typical structural materials. So, it is essential to choose the optimum material for the process equipment handling molten salt. In this study, corrosion behavior of Inconel 713LC, MA 754, X-750 and 718 in the molten salt $LiCl-Li_2O$ under an oxidizing atmosphere was investigated at $650^{\circ}C$ for $72{\sim}216$ hours. Inconel 713LC alloy showed the highest corrosion resistance among the examined alloys. Corrosion products of Inconel 713LC were $Cr_2O_3,\;NiCr_2O_4$ and NiO, and those of Inconel MA 754 were $Cr_2O_3\;and\;Li_2Ni_8O_{10}$ while $Cr_2O_3,\;NiFe_2O_4\;and\;CrNbO_4$ were produced from Inconel 718. Also, corrosion products of Inconel X-750 were found to be $Cr_2O_3,\;NiFe_2O_4\;and\;(Cr,Nb,Ti)O_2$. Inconel 713LC showed local corrosion behavior and Inconel MA 754, 718, X-750 showed uniform corrosion behavior.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.18 no.3
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• pp.355-362
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• 2020

The corrosion behavior of the Inconel X-750 alloy was investigated for its potential application under a Cl₂-O₂ mixed gas flow in an Ar atmosphere. The corrosion rate was found to be negligible at temperatures up to 400℃ under a flow rate of 30 mL·min^-1 Cl₂ + 170 mL·min^-1 Ar, whereas an exponential increase was observed in the corrosion rate at temperatures greater than 500℃. The suppression of the corrosion reaction due to the presence of O₂ was verified experimentally at flow rates of 30 mL·min^-1 Cl₂ (4.96 g·m^-2·h^-1), 20 mL·min^-1 Cl₂ + 10 mL·min^-1 O₂ (2.02 g·m^-2 ·h^-1), and 10 mL·min^-1 Cl₂ + 20 mL·min^-1 O₂ (1.34 g·m^-2·h^-1) under a constant Ar flow rate of 170 mL·min^-1 at 600℃ for 8 h. The surface morphology analysis results revealed that porous surfaces with tunnel-type holes were produced under the Cl₂-O₂ mixed-gas condition. Furthermore, the effects of the Cl₂ flow rate on the corrosion rate were investigated, indicating that its impact was negligible within the range of 5-30 mL·min^-1 Cl₂ at 600℃.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.146-146
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• 2000

We have studied the etching of Si(100)-2xl by Cl and Br, using scanning tunneling microscopy to obtain morphological information that can be related to reaction and desorption pathways. Clean surfaces were exposed to molecular halogens at room temperature to produce well-defined chemisorption structures for coverages in the range 0.2-1.0 ML. Heating to 750-750 K induced etching by thermal desorpton. Analysis of the halogen concentration before and after heating indicated that the rates of desorption for SICl2 or SiBr2 were greatest for intermediate coverages and that etching was suppressed as saturation was reached. Hence, desorption is not simply proportional to the concentration of species that can form adsorbed precursors SiX2(a). Instead, it is directly coupled to the creation of monomer vacancies adjacent to the SiX2 (a) unit because this increases the lifetime of the excited state and increases the likelihood of its desorption. Increasing the surface concentration of halogens reduces the rate of vacancy formation. We show that these rates are also affected by a re-dimerization process in the high temperature Br-stabilized Si(100)-3xl reconstruction that increases the likelihood of siBr2(a) formation and enhances its desorption. I will also discuss recent result for F etching on Si(100)-2xl.

• Electrical & Electronic Materials
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• v.4 no.1
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• pp.1-11
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• 1991

소둔 및 급속응고된 FeA $l_{1-x}$M $n_{x}$ (x=0.05, 0.10, 0.15, 1.20, 0.25, 0.30, 0.35, 0.40) 합금의 자기적 성질을 77.deg.K~750.deg.K의 온도범위에서 비교 분석하였다. 소둔한 시편의 경우, x.leq.0.25일때는 상자성, x=0.30 및 0.35의 경우에는 초상자성, x=0.40은 강자성을 나타내었다. 그리고 급속응고한 시편의 경우에는 전 조성범위에서 초상자성을 나타내었다. 그리고 Mn의 양이 증가함에 따라 자화는 소둔 및 급속응고 시편에서 증가하는 현상을 보였으며 급속응고 시편이 소둔시편에 비해 대개 더 높은 자화를 나타내었다. 본 합금계에 있어 자성에 대한 국부환경 효과를 분석하여 보았다.다.

• Journal of the Korean Vacuum Society
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• v.11 no.4
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• pp.207-211
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• 2002

Band gap tuning by quantum well disordering in $In_{0.53}Ga_{0.47}As/InGaAsP(Q1.25)$ quantum well structure has been investigated using photoluminescence. The threshold temperature for the blue shift was about $750^{\circ}C$ , and the blue shift became larger as the annealing temperature increased. $SiO_2$ showed saturation as the annealing temperature increased. $SiN_x$caused larger blue shift than $SiO_2$, which is considered to be related to the low growth temperature of $SiN_x$. The diffusion of P and Ga are thought to be responsible for the blue shift of the $SiN_x$ and $SiO_2$capped quantum well disordering , respectively.

• Bulletin of the Korean Mathematical Society
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• v.47 no.4
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• pp.743-750
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• 2010

For several Banach spaces X and Y and operator ideal $\cal{U}$, if $\cal{U}$(X, Y) denotes the component of operator ideal $\cal{U}$; according to Freedman's definitions, it is shown that a necessary and sufficient condition for a closed subspace $\cal{M}$ of $\cal{U}$(X, Y) to have the alternative Dunford-Pettis property is that all evaluation operators $\phi_x\;:\;\cal{M}\;{\rightarrow}\;Y$ and $\psi_{y^*}\;:\;\cal{M}\;{\rightarrow}\;X^*$ are DP1 operators, where $\phi_x(T)\;=\;Tx$ and $\psi_{y^*}(T)\;=\;T^*y^*$ for $x\;{\in}\;X$, $y^*\;{\in}\;Y^*$ and $T\;{\in}\;\cal{M}$.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.750-754
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• 2003

본 논문에서는 X-선 관전류를 직접 검출하여 제어하는 2.4kW(80kv,30mA)급 최소형, 최경량 휴대용 X-선 발생 장치를 제안한다. 본 장치는 X-선발생을 위한 고전압 발생단에 모노탱크 블록 사용하였고, 고주파 고전압용 인버터에는 스위칭 전력소자로서 MOS-FET를 채용, 70kHz로 스위칭 함으로서 고전압 변압기를 비롯한 고전압 발생부의 크기와 무게를 최소화하였다. 또한, 설정 관전류에 대한 정밀한 제어를 위하여 2단계 모드로 필라멘트 예열을 행하여 관전류 응답특성을 개선하였으며 제안한 휴대용 X-선 발생장치의 부하변동에 따른 X-선 관전압과 관전류의 개선된 특징을 실험파형을 통하여 입증하였다.