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Yamamoto, Masanori; Watanabe, Kazuhiro; Yamanaka, Haruhiko; Takemoto, Jumpei; Yamashita, Yasuo*; Inoue, Takashi
JAEA-Technology 2010-029, 60 Pages, 2010/08
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.
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:70.17(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.
Shirasu, Noriko; Kuramoto, Kenichi; Nakano, Yoshihiro; Yamashita, Toshiyuki; Kimura, Yasuhiko; Nihei, Yasuo; Ogawa, Toru
Journal of Nuclear Materials, 376(1), p.88 - 97, 2008/05
Times Cited Count:13 Percentile:63.78(Materials Science, Multidisciplinary)The concept of the rock-like oxide (ROX) fuel has been developed for the annihilation of excess plutonium in light water reactors. Irradiation tests and post-irradiation examinations were carried out on candidate ROX fuels. The ternary fuel of YSZ-spinel-corundum system, the single-phase fuels of YSZ, the particle dispersed fuels of YSZ in spinel or corundum matrix, and the blended fuels of YSZ and spinel or corundum matrix were fabricated and submitted to irradiation tests. The fuels containing spinel showed chemical instabilities with the vaporization of MgO component, which caused fuel restructuring. The swelling behavior was improved with the particle-dispersed fuels. However, the particle-dispersed fuels showed higher fractional gas release (FGR) than blended type fuels. The FGR of YSZ single-phase fuels were comparable to what would be expected for UO fuels. The YSZ single-phase fuel showed the best irradiation performance among the ROX fuels investigated.
Shirasu, Noriko; Kuramoto, Kenichi*; Yamashita, Toshiyuki; Ichise, Kenichi; Ono, Katsuto; Nihei, Yasuo
Journal of Nuclear Materials, 352(1-3), p.365 - 371, 2006/06
Times Cited Count:4 Percentile:30.30(Materials Science, Multidisciplinary)To evaluate irradiation behavior of the ROX fuel, irradiation experiment was carried out using 20% enriched U instead of Pu. Three fuels were prepared; a single phase fuel of YSZ containing UO (U-YSZ), two particle-dispersed fuels of U-YSZ particle in spinel or corundum matrix. The U-YSZ particles were prepared by crashing presintered U-YSZ pellets and by sieving them. These fuels were irradiated in Japan Research Reactor No.3 for 13 cycles, about 300 days. Though many cracks were observed in the pellets by X-ray photographs, significant appearance changes were not observed for all fuel pins. Distribution of typical FPs was analyzed by the scanning over the fuel pin. Non-volatile nuclide remained in the fuel pellet. On the other hand, a part of Cs moved to the gaps between the pellets and to the insulators. Cs and Cs showed different distributions at the plenum. Fuel pellets were taken out from fuel pins without bonding. Spinel decomposition and subsequent restructuring were not observed probably due to low irradiation temperature.
Watanabe, Kazuhiro; Kashiwagi, Mieko; Kawashima, Shuichi*; Ono, Yoichi*; Yamashita, Yasuo*; Yamazaki, Choji*; Hanada, Masaya; Inoue, Takashi; Taniguchi, Masaki; Okumura, Yoshikazu; et al.
Nuclear Fusion, 46(6), p.S332 - S339, 2006/06
Times Cited Count:33 Percentile:71.74(Physics, Fluids & Plasmas)no abstracts in English
Ueno, Fumiyoshi*; Nagae, Yuji; Nemoto, Yoshiyuki*; Miwa, Yukio*; Takaya, Shigeru; Hoshiya, Taiji; Tsukada, Takashi*; Aoto, Kazumi; Ishii, Toshimitsu*; Omi, Masao*; et al.
JNC TY9400 2005-013, 150 Pages, 2005/09
None
Ueno, Fumiyoshi; Nagae, Yuji*; Nemoto, Yoshiyuki; Miwa, Yukio; Takaya, Shigeru*; Hoshiya, Taiji*; Tsukada, Takashi; Aoto, Kazumi*; Ishii, Toshimitsu; Omi, Masao; et al.
JAERI-Research 2005-023, 132 Pages, 2005/09
JAERI and JNC have started a JAERI-JNC joint research program in fiscal year 2003, which has been aimed for efficient progress and synergistic effect on the research activities in both Institutes. This study has been chosen one of the joint research themes because it has been our common objective in the field of structural materials of FBR and LWR components. The purpose of the study is to clarify damage mechanism of structural materials used under irradiation, and then to develop the methods for damage evaluation and detection in earlier stage of progressing process of damage. In fiscal year 2004 and 2005, micro-corrosion measurement, electrochemical corrosion test and leakage magnetic flux density measurement apparatuses were developed and equipped in two hot facilities and irradiated and unirradiated crept specimens, irradiated high purity model austenitic stainless alloys were also prepared and applied to this study. These apparatuses and specimens were used for damage evaluation, and these feasibilities for nuclear power plant materials were studied.
Nakajima, Kunihisa; Arai, Yasuo; Yamashita, Toshiyuki
Journal of Physics and Chemistry of Solids, 66(2-4), p.639 - 642, 2005/02
Times Cited Count:2 Percentile:12.51(Chemistry, Multidisciplinary)PuCd intermetallic compound was prepared by heating pure Pu and Cd metals at about 950K. PuCd was found to be a prototype of CdI by means of powder X-ray diffractometry. Mass-spectrometric experiment was performed in the temperature range of 650-770K. It was found that the vapor pressures of Cd over PuCd+Pu were three to five orders of magnitude lower than those over Cd in this temperature range. From these vapor pressures, Gibbs free energy of formation of PuCd was evaluated.
Shirai, Osamu; Kato, Tetsuya*; Iwai, Takashi; Arai, Yasuo; Yamashita, Toshiyuki
Journal of Physics and Chemistry of Solids, 66(2-4), p.456 - 460, 2005/02
Times Cited Count:8 Percentile:36.48(Chemistry, Multidisciplinary)Electrochemical behaviors of PuN and (U, Pu)N in the LiCl-KCl eutectic melt containing UCl and PuCl at 773 K were investigated by cyclic voltammetry. The electrochemical dissolution of PuN and (U, Pu)N began nearly at -1.0 V vs. the Ag/AgCl reference electrode. The rest potentials of PuN and (U, Pu)N were observed at about 0.15 V more negative potential than that of UN since the equilibrium potential of UN is about 0.15 V more positive than that of PuN. In the cyclic voltammogram measured by using (U, Pu)N as the working electrode, a steep rise of the positive current was observed at more positive potential than -0.4 V in analogy with the cyclic voltammogram measured by using UN as the working electrode. In addition, there were two anodic current waves in the voltammogram with (U, Pu)N, though the wave form was not clear. This indicates that UN and PuN would be dissolved independently irrespective of formation of the solid solution, (U, Pu)N.
Sawa, Kazuhiro; Yamashita, Toshiyuki; Minato, Kazuo; Arai, Yasuo; Konashi, Kenji*
Nihon Genshiryoku Gakkai-Shi, 44(9), p.657 - 662, 2002/09
no abstracts in English
Serizawa, Hiroyuki; Nakajima, Kunihisa; Arai, Yasuo; Yamashita, Toshiyuki; Kuramoto, Kenichi; Kinoshita, H.*; Yamanaka, Shinsuke*; Uno, Masayoshi*; Kurosaki, K.*
Progress in Nuclear Energy, 38(3-4), p.237 - 240, 2001/02
Times Cited Count:5 Percentile:38.62(Nuclear Science & Technology)no abstracts in English
Arai, Yasuo; Yamashita, Toshiyuki
Proc. of 2nd Seminar on the New Fuel Technology toward the 21st Century, p.1 - 7, 1997/00
no abstracts in English
Nishimoto, Wataru*; Kimuro, Harumi*; Ishibashi, Seijiro*; Miyahara, Shuji*; Yamashita, Saburo*; Hayashi, Mitsuo*; Suzuki, Yoji*; Hirose, Yasuo*
PNC TJ118 85-06VOL2, 221 Pages, 1985/04
None
Nishimoto, Wataru*; Kimuro, Harumi*; Ishibashi, Seijiro*; Miyahara, Shuji*; Yamashita, Saburo*; Hayashi, Mitsuo*; Suzuki, Yoji*; Hirose, Yasuo*
PNC TJ118 85-06VOL1, 21 Pages, 1985/04
no abstracts in English
Maejima, Tetsuya; Watanabe, Kazuhiro; Kashiwagi, Mieko; Yamanaka, Haruhiko; Terunuma, Yuto; Umeda, Naotaka; Dairaku, Masayuki; Tobari, Hiroyuki; Yamashita, Yasuo*; Shibata, Naoki; et al.
no journal, ,
no abstracts in English
Yamashita, Junichi*; Fukasawa, Tetsuo*; Kawamura, Fumio*; Hoshino, Kuniyoshi*; Sasahira, Akira*; Minato, Kazuo; Akabori, Mitsuo; Arai, 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.
Tobari, Hiroyuki; Umeda, Naotaka; Watanabe, Kazuhiro; Inoue, Takashi; Sakamoto, Keishi; Yamashita, Yasuo*
no journal, ,
no abstracts in English
Kobayashi, Hidekazu; Yokozawa, Takuma; Yamashita, Teruo; Nagai, Takayuki; Amamoto, Ippei; Ayame, Yasuo
no journal, ,
no abstracts in English