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Yama, Masaki*; Tatsuno, Masahiro*; Kato, Takeo*; Matsuo, Mamoru
Physical Review B, 104(5), p.054410_1 - 054410_9, 2021/08
Times Cited Count：10 Percentile：50.62(Materials Science, Multidisciplinary)Moriyama, Shinichi; Seki, Masami; Terakado, Masayuki; Shimono, Mitsugu; Ide, Shunsuke; Isayama, Akihiko; Suzuki, Takahiro; Fujii, Tsuneyuki; JT-60 Team
Fusion Engineering and Design, 74(1-4), p.343 - 349, 2005/11
Times Cited Count：7 Percentile：43.83(Nuclear Science & Technology)no abstracts in English
Seki, Masami; Moriyama, Shinichi; Shinozaki, Shinichi; Hasegawa, Koichi; Hiranai, Shinichi; Yokokura, Kenji; Shimono, Mitsugu; Terakado, Masayuki; Fujii, Tsuneyuki
Fusion Engineering and Design, 74(1-4), p.273 - 277, 2005/11
Times Cited Count：3 Percentile：23.49(Nuclear Science & Technology)no abstracts in English
Ban, Yasutoshi; Asakura, Toshihide; Morita, Yasuji
Proceedings of International Conference on Nuclear Energy System for Future Generation and Global Sustainability (GLOBAL 2005) (CD-ROM), 5 Pages, 2005/10
An idea for controlling Np behavior in the Purex process is that Np(VI) extracted by TBP is selectively reduced to Np(V) by salt-free reagents and separated from U and Pu. Allylhydrazine is expected as a selective Np(VI) reductant from a view point of reduction rates for Np(VI) and Pu(IV). To confirm the applicability of allylhydrazine, a continuous counter-current back-extraction test of Np(VI) has been carried out using a miniature mixer-settler that consists of two steps: U-Pu recovery (3 stages) and Np separation (4 stages). Experimental results show that at least 90% of Np in feed are back-extracted and separated from U and Pu, therefore, it is confirmed that allylhydrazine is expected to be a selective salt-free reductant of Np(VI).
Moriyama, Kiyofumi; Takagi, Seiji; Muramatsu, Ken; Nakamura, Hideo; Maruyama, Yu
Proceedings of 2005 International Congress on Advances in Nuclear Power Plants (ICAPP '05) (CD-ROM), 9 Pages, 2005/05
The containment failure probability due to ex-vessel steam explosions were evaluated for a BWR Mk-II model plant. The evaluation was made for two scenarios: a steam explosion in the pedestal area, or in the suppression pool. A probabilistic approach, Latin Hypercube Sampling (LHS), was applied for the evaluation of steam explosion loads, in which a steam explosion simulation code JASMINE was used as a physics model. The fragility curves connecting the steam explosion loads and containment failure were developed based on simplified assumptions on the containment failure scenarios. The mean conditional probabilities of containment failure per occurrence of a steam explosion were 
for suppression pool and 
for pedestal area. Note that the results depend on the assumed range of input parameters and fragility curves that involve conservatism and simplification.
Maebara, Sunao; Goniche, M.*; Kazarian, F.*; Seki, Masami; Ikeda, Yoshitaka; Imai, Tsuyoshi*; Beaumont, B.*
Review of Scientific Instruments, 76(5), p.053501_1 - 053501_7, 2005/05
Times Cited Count：1 Percentile：9.94(Instruments & Instrumentation)Development of a plasma facing module using Cold Isostatic Pressing Graphite (CIPG) had been done for a heat-resistant LHCD antenna. A thin stainless film (10
m), molybdenum film (10m) and copper film (50m) are laid to overlap each other on the CIPG materials, the CIPG surfaces were successfully coated with copper layer by diffusion bonding method. This module has four waveguides and a water cooling channel, the length is 206 mm. High power long pulse operation was successfully achieved up to 250 kW (125 MW/m
)/700s. The module has been successfully tested at a RF power density which is equivalent, in terms of RF electric field (5kV/cm), to the one proposed for the LHCD antenna of ITER-FEAT. The outgassing rate of the copper-coated CIPG is estimated to be 3.2-5.1
10
Pa.m
/s.m at 100
C, it is assessed that a pumping system is not required to evacuate the pressure in the LHCD antenna.
Ide, Shunsuke
Purazuma, Kaku Yugo Gakkai-Shi, 81(3), p.167 - 170, 2005/03
Non-inductive current drive (CD) by radio-frquency waves in the lower hybrid range of frequency (LHRF) is one of most powerful scheme to drive a plasma current and control the current profile of a tokamak plasma externally. This paper reviews recent achievement of CD by LHRF (LHCD) in tokamak experiments with special emphasis on steady state tokamak operation and profile control in an advanced tokamak.
Sato, Masayasu; Isayama, Akihiko; Inagaki, Shigeru*; Nagayama, Yoshio*; Kawahata, Kazuo*; Iwama, Naofumi*
Europhysics Conference Abstracts (CD-ROM), 29C, 4 Pages, 2005/00
no abstracts in English
Sato, Masayasu; Isayama, Akihiko; Inagaki, Shigeru*; Nagayama, Yoshio*; Kawahata, Kazuo*; Iwama, Naofumi*
Proceedings of 13th Joint Workshop on Electron Cyclotron Emission and Electron Cyclotron Resonance Heating, p.89 - 94, 2005/00
no abstracts in English
n eigenmodesTodo, Yasushi*; Nakajima, Noriyoshi*; Shinohara, Koji; Takechi, Manabu; Ishikawa, Masao; Yamamoto, Satoshi*
Proceedings of 20th IAEA Fusion Energy Conference (FEC 2004) (CD-ROM), 8 Pages, 2004/11
Linear properties and nonlinear evolutions of an energetic-ion driven instability in a JT-60U plasma were investigated using a simulation code for MHD and energetic particles. The spatial profile of the unstable mode peaks near the plasma center where the safety factor profile is flat. The real frequency of the mode is close to the experimental starting frequency of the fast frequency sweeping mode. The simulation results demonstrate that the energetic ion orbit width and the energetic ion pressure significantly broaden radial profile of the unstable mode. For the experimental condition of JT-60U, the energetic ions broaden the spatial profile of the unstable mode by a factor of 3. The unstable mode is primarily induced by the energetic particles. It is demonstrated that the frequency shifts both upward and downward in the nonlinear evolution at the rate close to that of the fast frequency sweeping mode. In addition to the energetic particle mode in JT-60U, an investigation of TAE in an LHD-like plasma using the simulation code for the helical coordinate system is reported.
Sato, Masayasu; Isayama, Akihiko; Inagaki, Shigeru*; Nagayama, Yoshio*; Kawahata, Kazuo*; Iwama, Naofumi*
Review of Scientific Instruments, 75(10), p.3819 - 3821, 2004/10
Times Cited Count：0 Percentile：0.00(Instruments & Instrumentation)no abstracts in English
Ida, Katsumi*; Fujita, Takaaki; Fukuda, Takeshi*; Sakamoto, Yoshiteru; Ide, Shunsuke; Toi, Kazuo*; Inagaki, Shigeru*; Shimozuma, Takashi*; Kubo, Shin*; Idei, Hiroshi*; et al.
Plasma Physics and Controlled Fusion, 46(5A), p.A45 - A50, 2004/05
Times Cited Count：19 Percentile：51.88(Physics, Fluids & Plasmas)no abstracts in English
Sasajima, Tadayuki; Yagyu, Junichi; Miyo, Yasuhiko; Miya, Naoyuki; Sakakibara, Satoru*
KEK Proceedings 2003-16 (CD-ROM), 4 Pages, 2004/02
no abstracts in English
Hosoyama, Hiroki*; Sueoka, Michiharu; Suzuki, Takahiro
KEK Proceedings 2003-16 (CD-ROM), 4 Pages, 2004/02
no abstracts in English
Ishii, Kazuhiro*; Seki, Masami; Shimono, Mitsugu; Terakado, Masayuki; Igarashi, Koichi*; Takahashi, Masami*
JAERI-Tech 2003-079, 22 Pages, 2003/10
JAERI-Tech-2003-079.pdf:3.01MB
In JT-60U, the study of current drive by radio-frequency (RF) waves in lower hybrid range of frequency (LHRF) has been done as one of research and development works aiming at steady state operation of tokamaks. The main subject of hardware and technology development in this study is to develop a high power LHRF antenna, the main component of the system. The LHRF antenna is set closely to plasma to efficiently inject RF power into it. The LHRF antenna normally receives heat loads from the plasma, and it is required to inject high RF power. Then, it has become a problem that the antenna mouth was melted by excessive heat loads from plasma or it was melted and deformed by RF discharges. As a counter measurement against this, the LHRF antenna has been conditioned to improve its stand-off voltage capability. Furthermore, by monitoring the temperature of the LHRF antenna, adjusting its position, developing a injection method of power modulation even for current drive, and setting an arc sensor which picks up the RF discharge, the damage of the antenna mouth has been suppressed.
Takenaga, Hidenobu; Oyama, Naoyuki; Fujita, Takaaki; Yamada, Hiroshi*; Nishimura, Kiyohiko*; Tanaka, Kenji*; Sakamoto, Ryuichi*
Annual Report of National Institute for Fusion Science; April 2003 - March 2004, P. 12, 2003/10
no abstracts in English
during counter NBIsayama, Akihiko; Oyama, Naoyuki; Fujita, Takaaki; Inagaki, Shigeru*; Watanabe, Kiyomasa*; Toi, Kazuo*
Annual Report of National Institute for Fusion Science; April 2003 - March 2004, P. 23, 2003/10
no abstracts in English
Fujii, Tsuneyuki; Kasugai, Atsushi; JT-60 Team
Proceedings of 20th IEEE/NPSS Symposium on Fusion Engineering (SOFE 2003), p.222 - 227, 2003/10
The key factors to realize highly integrated performance plasma performances are control of profiles of current, pressure, rotation and so on. Therefore, several types of heating and current drive systems, ECH, LH, ICH, negative and positive ion based NBI systems, have been introduced into JT-60U. The ECH system with output power 4MW at 110 GHz has been developed using four 1 MW gyrotrons. The gyrotron has achieved 1MW-5sec output of the designed value by suppressing the parasitic oscillation with SiC RF absorber built-in. This gyrotron may get higher output power because it can adjust the anode voltage and extend the range of oscillation parameters. The NBI system has been attained 5.8 MW at 400 kV of beam energy with the negative ion based one and 28 MW with the positive ion based one. In a development work of the negative ion based NBI system, a detailed study on beamlet steering for multi-beam focusing was done, including of the space charge effects among beamlets. Then, 2.6 MW for 10s has been achieved.
Shimono, Mitsugu; Seki, Masami; Terakado, Masayuki; Igarashi, Koichi*; Ishii, Kazuhiro*; Takahashi, Masami*; Shinozaki, Shinichi; Hiranai, Shinichi; Sato, Fumiaki*; Anno, Katsuto
JAERI-Tech 2003-075, 29 Pages, 2003/09
JAERI-Tech-2003-075.pdf:4.62MB
no abstracts in English
Kaneko, Osamu*; Yamamoto, Takumi; Akiba, Masato; Hanada, Masaya; Ikeda, Katsunori*; Inoue, Takashi; Nagaoka, Kenichi*; Oka, Yoshihide*; Osakabe, Masaki*; Takeiri, Yasuhiko*; et al.
Fusion Science and Technology, 44(2), p.503 - 507, 2003/09
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)High energy negative-ion-based neutral beam injection (N-NBI) is expected as an efficient and reliable tool of heating and current driving for reactor plasmas such as ITER. A world wide activity on developing technology of negative ion production and beam formation started in 1980's and the great progress has been achieved up to now. In particular, Japan has two large projects that planned adopting N-NBI for real plasma experiments; the JT-60U tokamak and the LHD heliotron, which further motivated the R&D activity. These R&D programs were carried out at JAERI and NIFS separately in Japan, and both were successfully done. The first beam injection experiment was made on the JT-60U in 1996, followed by the LHD in 1998. They were the first experiments on heating plasma by high energy beam in tokamaks and in stellerators, and the obtained results were very promising.
