[en] This report describes the fundamentals of the Laser Induced Breakdown Spectroscopy(LIBS), and it describes the quantitative analysis method in the vacuum condition to obtain a high measurement accuracy. The LIBS system employs the following major components: a pulsed laser, a gas chamber, an emission spectrometer, a detector, and a computer. When the output from a pulsed laser is focused onto a small spot on a sample, an optically induced plasma, called a laser-induced plasma (LIP) is formed at the surface. The LIBS is a laser-based sensitive optical technique used to detect certain atomic and molecular species by monitoring the emission signals from a LIP. This report was described a fundamentals of the LIBS and current states of research. And, It was described a optimization of measurement condition and characteristic analysis of a LIP by measurement of the fundamental metals. The LIBS system shows about a 0.63 ∼ 5.82% measurement errors and calibration curve for the 'Cu, Cr and Ni'. It also shows about a 5% less of a measurement errors and calibration curve for a Nd and Sm. As a result, the LIBS accuracy for a part was little improved than preexistence by the optimized condition

[en] The purpose of this study is to model the interaction between austenitic stainless steel and liquid gallium at a high temperature to predict the weight loss for potential application as a target material or coolant in an advanced nuclear system. In the present study, models for liquid gallium corrosion with austenitic stainless steel are studied and discussed. This paper presents a mathematical analysis of liquid gallium corrosion, especially the surface recession due to solubility and diffusion, in a static cell, as well as the mass exchange at the liquid/solid interface. Also, a mathematical analysis of liquid gallium alloy (Ga–Sn–Zn) corrosion is conducted in order to study its effect on the diffusion behavior after the addition of alloying elements. The results show that the predicted corrosion behavior agrees well with experimental data and the weight loss of austenitic stainless steel are significantly reduced in gallium alloy compared to those in pure gallium at high temperatures

[en] Lignocellulose crops serve as an excellent feedstock for biofuels because of their reduced costs and net carbon emission, and higher energy efficiency. To estimate more suitable lignocellulosic crops, we compared the contents of lignin, cellulose, and hemicellulose in miscanthus, switchgrass, sorghum, and reed (from 14 accessions according to the collection site) in the leaves and stems and expressed these as % content based on dry weight. This study shows that miscanthus, switchgrass, and sorghum are valuable lignocellulosic crops owing to the significantly lower lignin content than that in reed, among both whole crops as well as specific plant parts. Although switchgrass has been reported to possess the highest polysaccharide content among the crops examined; our results showed no difference at a 5% significance level. Our study also showed that Miscanthus sacchariflorus possesses lower lignin and higher polysaccharide content in its leaves and stalks compared to the other Miscanthus species. Furthermore, M. sacchariflorus also showed lower lignin and higher polysaccharide contents than those in switchgrass. It is possible that M. sacchariflorus is a better resource than switchgrass, although these content assays showed no differences at the 5% significance level. M. sacchariflorus plants collected in Hacheonri, Jejudo, Korea (MFJH), contained 14.12% lignin and 64.23% holocellulose, indicating that Korean miscanthus is a competitive bioenergy crop compared to foreign crops such as switchgrass, which is widely used in the United States. - Highlights: • Types of crops compared are miscanthus, switchgrass, sorghum, and reed. • Of the total content of materials in these plants, 60% consists of cellulose and hemicellulose. • Stalks tend to have a higher content of the major component than leaves. • Reed is less valuable than other crop because of higher lignin contents. • Miscanthus sacchariflorus is more valuable than other Miscanthus species.

[en] The containment building is responsible to isolate and protect internal devices against external conditions like earthquake, hurricane and impact loading. It has also to protect leakage of radioactivity, like LOCA (Loss Of Coolant Accident), when severe accidents occurred. Meanwhile, social awareness such as terrorism has been increased globally after international aircraft crashes at World Trade Center and Pentagon. In this paper, FE (Finite Element) analyses according to variation of crash locations and speeds were carried out to examine the aircraft crash impact on a domestic containment building. In this paper, numerical analyses of aircraft crash on NPP's containment building were performed taking into account different locations and aircraft speeds. (1) Amounts of concrete failure were dependent on the crash locations and the connector was the most delicate location comparing to the dome and wall part. (2) Maximum stress values generated at the liner plate and rebars did not exceed their UTS values

[en] IVR (In-Vessel Retention) through ERVC (External Reactor Vessel Cooling) is one of effective management options against severe accident situations in a nuclear power plant. Accordingly, lots of researches for thermal-hydraulic and structural integrity have been performed to evaluate the IVR-ERVC. In this paper, verification of a preceding study and further analysis were carried out to resolve some of uncertainties in the structural integrity assessment method. In this paper, sensitivity analyses to examine a RPV integrity were carried out. Temperature and stress distributions and histories according to different analysis step procedures and heat transfer methods were compared. Since the maximum stress appeared in the metal layer due to higher thermal flux, corresponding creep rupture analysis is necessary for detailed structural integrity assessment of the RPV under IVR-ERVC condition

[en] If HELB (High Energy Line Break) accident occurs in NPPs (Nuclear Power Plants), not only environmental effect such as release of radioactive material but also secondary structural defects should be considered. Sudden pipe rupture causes ejection of fluid with high temperature and pressure, which acts as a thrust force on the ruptured pipe. Pipe whip phenomenon caused by the thrust force may lead to generation of defects around the components such as safe-related injection pipes and other structures. In this paper, FE analyses to examine the effect of the pipe whip on components and structures were carried out under HELB scenarios. Particularly, total of 6 break locations were selected for structural integrity assessment. The thrust force obtained from the RELAP5 was applied to FE analyses as loading condition

[en] The aim of this study is to examine effect of the blast wave according to pipe break position through FE (Finite Element) analyses. If HELB (High Energy Line Break) accident occurs in nuclear power plants, not only environmental effect such as release of radioactive material but also secondary structural defects should be considered. Sudden pipe rupture causes ejection of high temperature and pressure fluid, which acts as a blast wave around the break location. The blast wave caused by the HELB has a possibility to induce structural defects around the components such as safe-related injection pipes and other structures.

[en] In order to determine sonographic characteristic of renal tuberculosis, we retrospectively collected 27 cases during a 5 year period. Infected kidneys showed large size (52%) and lobulating contour (76%). In 19 cases of increased parenchymal echogenicity, most of them (16 cases) showed decreased parenchymal thickness. We divided hydronephrotic patterns into 4 categories; predominant calyceal dilatation with mild or no pelvic dilatation (67%), focal calyectasis without pelvic dilation (15%), parenchymal cavitation without hydronephrosis (11%) and proportional hydronephrosis with calyceal deformity (7%). Our findings suggest that disproportional hydronephrosis would be the characteristic finding of renal tuberculosis

[en] The conceptual design of the spent nuclear fuel (SNF) disposal system is significant in that it must maintain the safety for a very long period in consideration of geological characteristics. A buffer, one of the important components of the SNF disposal system, minimizes the inflow of groundwater and relieves the shock caused by a mechanical factor. In order to construct an optimal disposal system, as decay heat of SNF causes temperature variation in the buffer that affects the mechanical performance of the system, it is substantial to estimate accurately the temperature variation. Therefore, in this study, the disposal environment required for thermal evaluation of buffer was established by reflecting domestic conditions. Using this setting value, the thermal evaluation of buffer was performed according to the distance between disposal pits and the change of overpack material in the disposal cask. As a result of the evaluation, it was confirmed that most of the cases had satisfied the criteria of thermal safety, but some of the cases had not

[en] A single canister causes a maximum temperature of 75 ~ 90 degrees Celsius in the heat generating canister depending on the decay heat power. Fig. 1 shows the dimensions and layout of the disposal hole and backfill from the SKB. In this study, thermal analysis results for the KBS-3(V) type are verified and based on this model, the results of the thermal analysis for determining the interval of the disposal space to minimize the area of the Korean HLW repository system. The spacing between disposal holes is one of the important factors in minimizing the disposal area. Therefore, the result of thermal analysis over time is an important parameter to determine the spacing between disposal holes. The numerically and analytically calculated temperature profile histories on the disposal area is an important results, since it proves that the analytic solution using effective design for disposal hole.