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Kashiwagi, Mieko; Taniguchi, Masaki; Kojima, Atsushi; Dairaku, Masayuki; Hanada, Masaya; Hemsworth, R. S.*; Mizuno, Takatoshi*; Takemoto, Jumpei; Tanaka, Masanobu*; Tanaka, Yutaka*; et al.
Proceedings of 23rd IAEA Fusion Energy Conference (FEC 2010) (CD-ROM), 8 Pages, 2011/03
At JAEA, a multi-aperture multi-grid accelerator has been developed for the ITER neutral beam system. A target is H
ion beam acceleration of 0.5 A (200 A/m
) at 1 MeV. In real accelerators, it was found that the voltage holding was about a half of that obtained in an ideal small electrode. After applying necessary gap length and radii of edges of grid supports to lower local electric field concentrations, the accelerator succeeded in sustaining 1 MV for 4000 s. As a result, beam parameters were increased to 879 keV, 0.36 A (157 A/m) at perveance matched condition from 796 kV, 0.32 A (140 A/m) reported in FEC2008. In the beam acceleration, the beamlet deflections due to magnetic field and space charge repulsion caused direct interceptions, that resulted in limitations in the beam energy and current. Compensation of these beamlet deflections has been tested applying aperture offset and field shaping plate, which were examined in a three-dimensional beam analysis.
Yamamoto, Masanori; Watanabe, Kazuhiro; Yamanaka, Haruhiko; Takemoto, Jumpei; Yamashita, Yasuo*; Inoue, Takashi
JAEA-Technology 2010-029, 60 Pages, 2010/08
JAEA-Technology-2010-029.pdf:10.49MB
A power supply for the ITER Neutral Beam Injector (NBI) is a DC ultra-high voltage (UHV) power supply to accelerate negative ion beams of 40 A up to an energy of 1 MeV. Japan Atomic Energy Agency as the Japan Domestic Agency for ITER contributes procurement of dc -1 MV main components such as step-up -1 MV transformers rectifiers, a high voltage deck 2, a -1 MV insulating transformer, a transmission line, a surge reduction system and equipments for site test. Design of the surge suppression in the NBI power supply is one of the key issues to obtain the stable injector performance. This report describes the design study using EMTDC code on the surge suppression by optimizing the core snubber and additional elements in the -1 MV power supply. The results show that the input energy from the stray capacitance to the accelerator at the breakdown can be reduced to about 25 J that is smaller than the design criteria of 50 J for the ITER NBI.
Bigi, M.*; De Lorenzi, A.*; Grando, L.*; Watanabe, Kazuhiro; Yamamoto, Masanori
Fusion Engineering and Design, 84(2-6), p.446 - 450, 2009/06
Times Cited Count：16 Percentile：70.97(Nuclear Science & Technology)The ITER NBI requires a five stage -1 MV power supply system under strict load protection for electric breakdowns. A circuit model of the power supply with MAMuG accelerator has been developed for the simulation of fast transients related to the accelerator breakdowns. The complex inductive and capacitive couplings were assessed by calculations with finite element techniques. The circuit model, developed to address a number of design issues requiring simulations at system level, is now ready for use - the optimization of passive protections being the most significant application.
Watanabe, Kazuhiro; Yamamoto, Masanori; Takemoto, Jumpei; Yamashita, Yasuo*; Dairaku, Masayuki; Kashiwagi, Mieko; Taniguchi, Masaki; Tobari, Hiroyuki; Umeda, Naotaka; Sakamoto, Keishi; et al.
Nuclear Fusion, 49(5), p.055022_1 - 055022_5, 2009/05
Times Cited Count：28 Percentile：70.93(Physics, Fluids & Plasmas)Japan Atomic Energy Agency as the Japan Domestic Agency (JADA) for ITER contributes procurement of dc -1 MV ultra-high voltage (UHV) components such as a dc -1 MV generator, a transmission line and a -1 MV insulating transformer for the ITER NBI power supply. Inverter frequency of 150 Hz in the -1 MV power supply and major circuit parameters have been proposed and adopted in the ITER NBI. The dc UHV insulation at the multi-layer insulation structure of the transformer for a long pulse up to 3600 s has been designed with electric field simulation. Based on the simulation overall dimensions of the dc UHV components have been finalized. The JADA contributes to provide an effective surge suppression system composed of core snubbers and resistors. Input energy into the accelerator from the power supply can be reduced to about 20 J which satisfies the design criteria of the total 50 J at -1 MV breakdown.
Watanabe, Kazuhiro; Yamamoto, Masanori; Takemoto, Jumpei; Yamashita, Yasuo*; Dairaku, Masayuki; Kashiwagi, Mieko; Taniguchi, Masaki; Tobari, Hiroyuki; Umeda, Naotaka; Sakamoto, Keishi; et al.
Proceedings of 22nd IAEA Fusion Energy Conference (FEC 2008) (CD-ROM), 7 Pages, 2008/10
The JADA contributes procurement of DC -1 MV ultra-high voltage (UHV) components such as a -1 MV DC generator, a transmission line and a -1 MV insulating transformer. The DC UHV insulation has been carefully analyzed since DC long pulse insulation is quite different from conventional AC insulation. The insulation structure has been designed and the overall dimensions of the DC UHV components have been finalized. The JADA contributes to provide an effective surge suppression system composed of core snubbers and resistors. Input energy into the accelerator from the power supply can be reduced to about 20 J which satisfies the design criteria of the total 50 J at -1 MV breakdown. From these studies, major technical issues were considered and the functional technical specifications of the UHV components have been developed for the procurement by the JADA.
Maebara, Sunao; Morimoto, Iwao*; Zheng, X.*; Watanabe, Akihiko*; Yamamoto, Masanori*; Sakamoto, Keishi; Shiho, Makoto
Shingaku Giho, 101(415), p.61 - 66, 2001/11
no abstracts in English
Yamamoto, Masanori; Watanabe, Kazuhiro; Inoue, Takashi; Yamashita, Yasuo*
no journal, ,
no abstracts in English
Watanabe, Kazuhiro; Yamamoto, Masanori; Taniguchi, Masaki; Umeda, Naotaka; Kobayashi, Kaoru; Hanada, Masaya; Kashiwagi, Mieko; Tobari, Hiroyuki; Dairaku, Masayuki; Sakamoto, Keishi; et al.
no journal, ,
Japan Atomic Energy Agency as a Japanese Domestic Agency will procure the high voltage part of the power supply for the ITER neutral beam injector (NBI). Design studies have been performed on high voltage components and a surge suppression system of the -1 MV power supply. It was confirmed by circuit analysis that an input energy from the power supply to the accelerator can be reduced to 20 joule which is smaller than the design criteria of 50 joule at 1 MV breakdowns. Present status of the development on the negative ion accelerators and high voltage bushing will be also reported.
Takemoto, Jumpei; Watanabe, Kazuhiro; Yamamoto, Masanori; Inoue, Takashi; Sakamoto, Keishi; Yamashita, Yasuo*
no journal, ,
no abstracts in English
