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To use nuclear energy sustainably, spent nuclear fuel, classified as high-level radioactive waste and inevitably discharged after electricity generation by nuclear power plants, must be managed safely and isolated from the human environment. In Korea, the land area is limited and the amount of high-level radioactive waste, including spent nuclear fuels to be disposed, is relatively large. Thus, it is particularly necessary to maximize disposal efficiency. In this study, a high-efficiency deep geological repository concept was developed to enhance disposal efficiency. To this end, design strategies and requirements for a high-efficiency deep geological repository system were established, and engineered barrier modules with a disposal canister for pressurized water reactor (PWR)-type and pressurized heavy water reactor type Canada deuterium uranium (CANDU) plants were developed. Thermal and structural stability assessments were conducted for the repository system; it was confirmed that the system was suitable for the established strategies and requirements. In addition, the results of the nuclear safety assessment showed that the radiological safety of the new system met the Korean safety standards for disposal of high-level radioactive waste in terms of radiological dose. To evaluate disposal efficiency in terms of the disposal area, the layout of the developed disposal areas was assessed in terms of thermal limits. The estimated disposal areas were 2.51 km2 and 1.82 km2 (existing repository system: 4.57 km2) and the excavated host rock volumes were 2.7 Mm3 and 2.0 Mm3 (existing repository system: 4.5 Mm3) for thermal limits of 100 °C and 130 °C, respectively. These results indicated that the area and the excavated volume of the new repository system were reduced by 40–60% compared to the existing repository system. In addition, methods to further improve the efficiency were derived for the disposal area for deep geological disposal of spent nuclear fuel. The results of this study are expected to be useful in establishing a national high-level radioactive waste management policy, and for the design of a commercial deep geological repository system for spent nuclear fuels.

This paper presents a unified solution method to investigate the free vibration behaviors of a laminated composite conical shell, a cylindrical shell, and an annular plate with variable thickness and arbitrary boundary conditions using the Haar wavelet discretization method (HWDM). Theoretical formulation is established based on the first-order shear deformation theory (FSDT), and displacement components are extended to the Haar wavelet series in the axis direction and trigonometric series in the circumferential direction. The constants generated by the integration process are disposed by boundary conditions, and thus the equations of the motion of the total system, including the boundary condition, are transformed into algebraic equations. Then, the natural frequencies of the laminated composite structures are directly obtained by solving these algebraic equations. The stability and accuracy of the present method are verified through convergence and validation studies. The effects of some material properties and geometric parameters on the free vibration of laminated composite shells are discussed and some related mode shapes are given. Some new results for laminated composite conical shell, cylindrical shell, and annular plate with variable thickness and arbitrary boundary conditions are presented, which may serve as benchmark solutions.

This study suggests a simple economic model to analyze electricity grid that consists of different power sources. The substitutability of renewable energy for nuclear power in Korean electricity transmission network is investigated by suggested model. The monthly data from January 2006 to December 2013 reported by Electricity Power Statistics Information System (EPSIS) of Korea Power EXchange (KPX) are used. To estimate the elasticities of substitution among four power sources (i.e. coal, natural gas, nuclear power, and renewable energy), this paper uses the trans-log cost function model on which local concavity restrictions are imposed. The estimated Hicks-Allen and Morishima elasticity of substitution shows that renewable electricity and nuclear power are complementary. The results also evidenced that renewable electricity and fossil fueled thermal power generation are substitutes. Keywords: Elasticity of substitution, Grid stabilization, Energy policy, Nuclear power, Renewable energy

This paper describes a hardware-in-the-loop simulation system for the validation of a vehicle body electronic control unit. The hardware-in-the-loop simulation system consists of three parts: a real-time target machine, an electronic control unit, and a signal conditioning unit, which regulates the voltage levels between the real-time target and the electronic control unit. The real-time target machine generates switch and feedback signals to the electronic control unit. The software model, representing body electronics hardware, such as a power seat and power trunk, runs inside a real-time target machine. The software model is composed of a mechanical part that represents the dynamic behaviors and an electronic part to calculate the motor speeds, current, and electronic loads under various conditions. The hardware-in-the-loop test was carried out for two different large passenger vehicle electronic control units, since the purpose of this research is to validate the various electronic control units by just simply modifying the corresponding vehicle model, the power seat, and the power trunk. Test results indicate that the developed software model can effectively replace the real hardware, and that this virtual model can be used to validate the signal logic between the electronic control unit and the model. In addition, the electrical robustness of the electronic control unit was validated by applying surge currents to the electronic control unit. [ABSTRACT FROM AUTHOR]

Background A reproducible large animal model of bile duct dilation for the preclinical testing of new biliary devices and for training endoscopic biliary intervention is required. Surgical methods are mainly used to produce large animal models of biliary obstruction. Objective To develop an animal model of bile duct dilation using endoscopic methods and to compare the merits of endoclips and detachable snares for the obstruction of major duodenal papillae. Design Proof of concept experimental study. Settings Animal laboratory. Interventions Endoscopic clipping of the major duodenal papilla or closure of the major duodenal papilla with a detachable snare. Main Outcome Measurements Feasibility, efficacy, and safety of endoscopic methods to develop swine models with bile duct dilation were estimated by degree of dilation at the common bile duct (CBD), intrahepatic duct (IHD), and gallbladder (GB). Results All animals survived until the end of the experiment. Clipping of the major duodenal papilla and closure of the major duodenal papilla with a detachable snare were performed successfully in all swine. No technical difficulty or adverse event occurred during the procedures. Biliary dilatations in all animals were observed on cholangiograms (mean Δ% of postprocedural and preprocedural maximum diameters: CBD, 301%; IHD, 223.5%; GB, 34.8%). Degree of bile duct dilation in the snare group tended to be greater (CBD, 367.3%; IHD, 298.3%; GB, 47.8%) than in the endoclip group (CBD, 234.7%; IHD, 148.7%; GB, 21.8%), but this difference was not significant. An analysis of degrees of dilation according to location in the biliary tree showed that the GB was not dilated as well as the CBD or IHD. Limitations Animal model. Conclusion The 2 endoscopic procedures described are effective and safe for creating a swine model of bile duct dilation and could be helpful for training biliary intervention and for endoscopic biliary studies. [ABSTRACT FROM AUTHOR]

Photoreactable chitosan derivative have been prepared by introducing azido phenyl groups to amino groups of low molecular weight chitosan to facilitate the immobilization of growth factors. The prepared azidophenyl chitosan was characterized by Fourier transform infrared FTIR, proton nuclear magnetic resonance 1H NMR, scanning electron microscope SEM. Cytotoxicity of prepared azidophenyl chitosan derivative was confirmed by MTT assay. Cell culture on the surfaces coated azidophenyl chitosan derivative was also carried out and cell adhesion was observed between azidophenyl chitosan derivative and cells. And the released rate of protein from azidophenyl chitosan derivative was measured using albumin instead of growth factors for check on effect of the prepared azidophenyl chitosan derivative. As a result of that, relations among the concentration of azidophenyl chitosan derivative, releasing period of albumin and the quantity of released albumin was confirmed. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [ABSTRACT FROM AUTHOR]