[en] To complete the KSTAR neutral beam facility, the I and C (Instrumentation and Control) of KSTAR NBI(Neutral Beam Injector) will be also implemented. The goal of this research is to design EPICS (Experiment Physics and Industrial Control System) based I and C for KSTAR NBI, During about 10 years, KAERI has already installed and operated the neutral beam facility in the test stand, and has many operation experience and material for a new neutral beam facility. Using this experience and material, the new I and C for KSTAR NBI will be improved and implemented, and complied with KSTAR discharge scenario and operation sequence

[en] To design high power pulse power supplies, especially in huge power supplies have not designed till now, it is necessary to analyze a system's characteristics and relations with another systems as well as to know high voltage, high current control technologies. Contents of this project are; - Analysis of the changed designs of the AC/DC converters. - Setup of the PSIM model for the calculation of the junction temperature of the converter thyristors. - Finalize the converter's simulation modules and estimate the parallel number of an arm for each converter. - Fix the protection sequence and make a simulation. - Stability check of the power distribution system against the reactive power effect. - Design of small size hardware AC/DC converter. The results of these studies may used as one of references for practical designs of the power supplies and also used for developing Tokamak type fusion reactors in the future

[en] ○ The target of this study are to upgrade of an high power RF ion source for National Fusion Program as follows; - development of high power RF antenna to increase the plasma efficiency ○ Also the development of high voltage feedthru for potable neutron generator has been done as follows; - improvement of high voltage characteristics - deuterium beam extraction - measurement of neutron generation ○ This will contribute to National Fusion Program and development of commercial high current RF ion source and neutron generator.

[en] To design high power pulse power supplies, especially in huge power supplies have not designed till now, it is necessary to analyze a system's characteristics and relations with another systems as well as to know high voltage, high current control technologies. Contents of this project are; - Study for the engineering designs changed recently by ITER Organization(IO) and writing specifications for the power supplies to reduce project risk. - Detailed analysis of the AC/DC Converters and writing subtask reports on the Task Agreement. - Study for thyristor numbers, DCR's specifications for Korea-China sharing meetings. - Study for the grounding systems of the ITER power supply system. The results may used as one of reference for practical designs of the high power coil power supplies and also may used in various field such as electroplating, plasma arc furnaces, electric furnaces

[en] A 14.5 GHz electron cyclotron resonance ion source has been designed and fabricated at KAERI (Korea Atomic Energy Research Institute) to produce multi-charged ion beams (particularly C⁶⁺ ion beams) for medical applications. During the first beam extraction experiments with the developed ion source, it was found that C⁴⁺ beam of 15 eμA and Ar¹⁵⁺ beam of 1 eμA were the optimized beam current. A big current loss was made along the beam transport path from the ion source to the entrance port of an analyzing magnet because of long beam line and small acceptance of the magnet. A new Einzel lens is added in the beam line to minimize the beam loss, and the second beam extraction experiments have been made. In this paper the beam experimental results with the KAERI ion source, including the hard X-ray spectrum from the ECR plasma and the emittance measurement results of carbon beam, will be discussed.

[en] Final destination of the project is to establish the research basis of heating and current drive for large tokamak, such as KSTAR, or next generation fusion reactor through the neutral beam injection (NBI). On the 1^st-stage to achieve the objectives: 1) Required capability of an ion source(with an output power of 2 MW neutral beam, a beam energy of 100 keV) which is a main component of KSTAR NBI-1 system was proven by the design, manufacturing, and performance test during the past three years. 2) Until the development of new ion source, the NB heating experiments were performed to achieve the NB heating of KSTAR plasma with more than 1.0 MW for the 2^nd-year and more than 1.5 MW for the 3^rd-year by using a prototype ion source upgraded for the 1^st-year. From these experiments, the heating power above the H-mode threshold was supplied to the H-mode operation of KSTAR plasma and contributed to the NB diagnostics, such as CES and MSE, by using the NB. Finally, the basis of NB heating and current drive for the KSTAR was prepared by the 1^st-stage research

[en] An experimental neutral beam injection system, called as the NB Test-stand(NBTS), was developed and being operated until this time from 1996 in the Korea Atomic Energy Research Institute(KAERI). The KAERI has supported the design and fabrication of power supply(PS) system, control and data acquisition(CODAQ) system, and beamline(BL) system for the first KSTAR NBI(NBI-1), based on the experience of development and experiments in the NBTS. Therefore, the KAERI was involved in the effective development of PS system, CODAQ system, and BL system for the NBI-1 device. The KAERI has participated in the beam extraction and initial operation of NBI-1 system, based on these experiences of design, fabrication, and operation for the NBI device, and has developed the optimal and reliable operation technologies for the KSTAR NBI-1 device. The KAERI has done the effective arc discharge experiments in the NBI-1 system and has developed the optimal ion beam and neutral beam extractions and neutral beam injection technology. Therefore, the KAERI has importantly and critically contributed the injection of deuterium neutral beam into the KSTAR core plasmas. The operation and maintenance technologies of NBI system, developed in the NBI-1 device, is convinced of the important basis for the development of NBI-2 system in the future

[en] Ion optics of three accelerator geometries was studied in terms of an analytic linear optics analysis, a numerical simulation using the IGUN program, an optical multichannel measurement of Doppler-shifted H_α lines, and a water-flow calorimetry on the beam absorbing target. In general, there was a reasonable agreement observed between the four analysis methods and thus the theoretical analyses can be utilized with confidence for design iteration

[en] This paper employs a stochastic frontier analysis (SFA) to examine cost efficiency and scale economies in Taiwan Power Company (TPC) by using the panel data covering the period of 1995-2006. In most previous studies, the efficiency estimated by the Panel Data without testing the endogeneity may bring about a biased estimator resulting from the correlation between input and individual effect. A Hausman test is conducted in this paper to examine the endogeneity of input variables and thus an appropriate model is selected based on the test result. This study finds that the power generation executes an increasing return to scale across all the power plants based on the pooled data. We also use installed capacity, service years of the power plant, and type of fuel as explanatory variable for accounting for the estimated cost efficiency of each plant by a logistic regression model to examine the factor affecting the individual efficiency estimates. The results demonstrate that the variable of installed capacity keeps a positive relationship with cost efficiency while the factor of working years has a negative relationship.

[en] The first neutral beam (NB) injection system of the Korea Superconducting Tokamak Advanced Research (KSTAR) tokamak was partially completed in 2010 with only 1/3 of its full design capability, and NB heating experiments were carried out during the 2010 KSTAR operation campaign. The ion source is composed of a JAEA bucket plasma generator and a KAERI large multi-aperture accelerator assembly, which is designed to deliver a 1.5 MW, NB power of deuterium at 95 keV. Before the beam injection experiments, discharge, and beam extraction characteristics of the ion source were investigated. The ion source has good beam optics in a broad range of beam perveance. The optimum perveance is 1.1-1.3 μP, and the minimum beam divergence angle measured by the Doppler shift spectroscopy is 0.8 deg. The ion species ratio is D⁺:D₂⁺:D₃⁺= 75:20:5 at beam current density of 85 mA/cm². The arc efficiency is more than 1.0 A/kW. In the 2010 KSTAR campaign, a deuterium NB power of 0.7-1.5 MW was successfully injected into the KSTAR plasma with a beam energy of 70-90 keV. L-H transitions were observed within a wide range of beam powers relative to a threshold value. The edge pedestal formation in the T_i and T_e profiles was verified through CES and electron cyclotron emission diagnostics. In every deuterium NB injection, a burst of D-D neutrons was recorded, and increases in the ion temperature and plasma stored energy were found.