• Proceedings of the Korean Magnestics Society Conference
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• 2003.12a
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• pp.158-158
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• 2003

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.991-992
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• 2008

• Proceedings of the Korean Vacuum Society Conference
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• 2001.02a
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• pp.214-214
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• 2001

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.941-942
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• 2012

• Proceedings of the Materials Research Society of Korea Conference
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• 1998.08a
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• pp.112.3-112
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• 1998

• Proceedings of the Korean Vacuum Society Conference
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• 1998.02a
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• pp.134-134
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• 1998

• Proceedings of the Materials Research Society of Korea Conference
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• 1998.08a
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• pp.140.4-140
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• 1998

• Nuclear Engineering and Technology
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• v.50 no.1
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• pp.54-67
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• 2018

There have been recent efforts to establish methods for high-fidelity and multi-physics simulation with coupled thermal-hydraulic (T/H) and neutronics codes for the entire core of a light water reactor under accident conditions. Considering the computing power necessary for a pin-by-pin analysis of the entire core, subchannel-scale T/H analysis is considered appropriate to achieve acceptable accuracy in an optimal computational time. In the present study, the applicability of in-house code CUPID of the Korea Atomic Energy Research Institute was extended to the subchannel-scale T/H analysis. CUPID is a component-scale T/H analysis code, which uses three-dimensional two-fluid models with various closure models and incorporates a highly parallelized numerical solver. In this study, key models required for a subchannel-scale T/H analysis were implemented in CUPID. Afterward, the code was validated against four subchannel experiments under unheated and heated single-phase incompressible flow conditions. Thereafter, a subchannel-scale T/H analysis of the entire core for an Advanced Power Reactor 1400 reactor core was carried out. For the high-fidelity simulation, detailed geometrical features and individual rod power distributions were considered in this demonstration. In this study, CUPID shows its capability of reproducing key phenomena in a subchannel and dealing with the subchannel-scale whole core T/H analysis.

• Journal of The Korean Astronomical Society
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• v.36 no.spc1
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• pp.21-27
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• 2003

In the present study, we have investigated morphology and evolution of small-scale Ha dynamic features on the quiet sun by analyzing video magnetograms and high resolution Ha images simultaneously taken for 5 hours at Big Bear Solar Observatory on April 18, 1997. From comparisons between time sequential longitudinal magnetograms and H$\alpha$ images covering $150" {\times} 150"$, several small-scale H$\alpha$ dynamic features have been observed at a site of magnetic flux cancellation. A close relationship between such features and cancelling magnetic fluxes has been revealed temporarily and spatially. Our results support that material injection by chromospheric magnetic reconnect ion may be essential in supporting numerous small-scale H$\alpha$ dynamical absorption features, being in line with recent observational studies showing that material injection by chromospheric magnetic reconnect ion is essential for the formation of solar filaments.

• Journal of the Korean institute of surface engineering
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• v.49 no.4
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• pp.339-343
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• 2016

ASTM T23 steel with a composition of Fe-2.25%Cr-1.6%W corroded at 600 and $700^{\circ}C$ for 5-70 h in $N_2$/(0.5, 2.5)%$H_2S$-mixed gas at 1 atm. It corroded rapidly, forming the outer FeS scale and the inner (FeS, $FeCr_2O_4$)-mixed scale. The ensuing outward diffusion of $Fe^{2+}$ ions during corrosion led to the protrusion of FeS platelets over the outer FeS scale. The formation of FeS at the surface facilitated the oxidation of Cr to $FeCr_2O_4$ in the inner scale. Since the nonprotective FeS scale existed over the whole scale, T23 steel displayed poor corrosion resistance in the $H_2S$-containing atmosphere.