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Oshima, Katsumi; Oda, Yasuhisa; Takahashi, Koji; Terakado, Masayuki; Ikeda, Ryosuke; Hayashi, Kazuo*; Moriyama, Shinichi; Kajiwara, Ken; Sakamoto, Keishi
JAEA-Technology 2015-061, 65 Pages, 2016/03
JAEA-Technology-2015-061.pdf:24.28MB
In JAEA, an ITER relevant control system for ITER gyrotron was developed according to Plant Control Design Handbook. This control system was developed based on ITER CODAC Core System and implemented state machine control of gyrotron operation system, sequential timing control of gyrotron oscillation startup, and data acquisition. The operation of ITER 170 GHz gyrotron was demonstrated with ITER relevant power supply configuration. This system is utilized for gyrotron operation test for ITER procurement. This report describes the architecture of gyrotron operation system, its basic and detailed design, and recent operation results.
Kobayashi, Takayuki; Sawahata, Masayuki; Terakado, Masayuki; Hiranai, Shinichi; Ikeda, Ryosuke; Oda, Yasuhisa; Wada, Kenji; Hinata, Jun; Yokokura, Kenji; Hoshino, Katsumichi; et al.
Proceedings of 40th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz 2015) (USB Flash Drive), 3 Pages, 2015/08
A gyrotron for electron cyclotron heating and current drive (ECH/CD) has been developed for JT-60SA (Super-Advanced). In high-power, long-pulse operations, oscillations of 1 MW/100 s have been demonstrated at both 110 GHz and 138 GHz, for the first time. These results fully satisfied the requirements for JT-60SA. Moreover, it was experimentally shown that the higher power operation at each frequency is expected to be acceptable for this gyrotron from the viewpoint of heat load at the cavity resonator, collector, and stray radiation absorbers. An oscillation at 82 GHz, which is an additional frequency, has been demonstrated up to 2 s at the output power of 0.4 MW, so far. High power experiments toward higher power of 1.5 MW (110/138 GHz) and 1 MW (82 GHz) are ongoing.
Minami, Ryutaro; Kasugai, Atsushi; Takahashi, Koji; Kobayashi, Noriyuki*; Mitsunaka, Yoshika*; Sakamoto, Keishi
International Journal of Infrared and Millimeter Waves, 27(1), p.13 - 24, 2006/01
Times Cited Count：12 Percentile：53.63(Engineering, Electrical & Electronic)no abstracts in English
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：44.9(Nuclear Science & Technology)no abstracts in English
Fujii, Tsuneyuki; Seki, Masami; Moriyama, Shinichi; Terakado, Masayuki; Shinozaki, Shinichi; Hiranai, Shinichi; Shimono, Mitsugu; Hasegawa, Koichi; Yokokura, Kenji; JT-60 Team
Journal of Physics; Conference Series, 25, p.45 - 50, 2005/00
The JT-60U electron cyclotron range of frequency (ECRF) is utilized to realize high performance plasma. Its output power is 4 MW at 110 GHz. By controlling the anode voltage of the gyrotron used in the JT-60U ECRF heating system, the gyrotoron output can be controlled. Then, the anode voltage controller was developed to modulate the injected power into plasmas. This low cost controller achieved the modulation frequency 12 - 500 Hz at 0.7 MW. This controller also extended the pulse width from 5s to 16 s at 0.5 MW. For these long pulses, temperature rise of the DC break made of Alumina ceramics is estimated. Its maximum temperature becomes 
140 deg. From the analysis of this temperature rise, DC break materials should be changed to low loss materials for the objective pulse width of 30 s. The stabilization of neoclassical tearing mode (NTM) was demonstrated by ECRF heating using the real-time system in which the ECRF beams are injected to the NTM location predicted from ECE measurement every 10 ms.
Kasugai, Atsushi; Sakamoto, Keishi; Minami, Ryutaro; Takahashi, Koji; Imai, Tsuyoshi
Nuclear Instruments and Methods in Physics Research A, 528(1-2), p.110 - 114, 2004/08
Times Cited Count：23 Percentile：80.21(Instruments & Instrumentation)The development of the millimeter wave high power gyrotron with the development of a depressed collector, an over sized cavity and a synthesized diamond output window is under going in JAERI. The performances of 170 GHz, 0.9 MW for 9.2 s and 0.5 MW for 30 s were achieved up to now. It was clarified, however, that pulse extension of the gyrotron was limited by sudden outgassing due to stray RF power deposition to the bellows behind movable mirror. For suppression of stray RF power deposition, the structure of the bellows section was improved to avoid the direct power deposition and the surface of bellows was coated by copper for reduction of RF loss and increase of thermal conductivity. As a result of the modification, temperature increase of bellows was reduced to less than 1/10 and time constant of thermal diffusion shortened to 90 s from 270 s in comparison with before the modification. This indicates that the modification is quite effective for suppression of temperature increase.
Nakagawa, Tatsuo*; Mihara, Yorichika*; Komurasaki, Kimiya*; Takahashi, Koji; Sakamoto, Keishi; Imai, Tsuyoshi
Journal of Spacecraft and Rockets, 41(1), p.151 - 153, 2004/02
Times Cited Count：40 Percentile：88.62(Engineering, Aerospace)A launching experiment of a microwave-boosted vehicle model was carried out using the 110GHz, 1MW gyrotoron and a propulsive inpulse to lift up the vehicle was measured. The rf power and pulse was 1MW and 0.175 0.8msec. The launching mechanism is as follows. Plasma is produced in the nozzle of the vehicle model when the rf beam is injected toward it. The plasma heated by the rf beam can produce a shock wave that gives a propulsive impulse to the vehicle. Maximum momentum coupling coefficient from the impulse to the vehicle is 395N/MW which is comparable to that of a laser boosted vehicle. The rf pulse was 0.175msec. The coupling coefficient is limitted by the gyrtron operation in pulse length and can increase if the pulse length is shorter than 0.175msec.
Loring, M.*; Moriyama, Shinichi; Kasugai, Atsushi; Terakado, Masayuki; Nakayama, Nobuyoshi*; Iiyama, Toshimitsu*
Proceedings of 26th International Power Modulator Symposium and 2004 High Voltage Workshop, p.271 - 273, 2004/00
The control and protection of high power electron tubes has been a serious problem throughout the history of power electronics. This paper briefly covers the history of approaches used to meet these needs and discusses a modern solution which has uses in fusion research, accelerator, and commercial applications. The paper describes the design, development and performance history of a family of high voltage IGBT switches used for the control and protection of megawatt level gyrotrons in the JT60U facility. The switch systems described have been in use for several years. The demonstrated long, {over 20,000 system hours. (over 2,000,000 device hours)} life shows the inherent reliability of a well designed, properly operated HV DC IGBT switch system. This device has many other uses in modern high power electronic systems. In the application described, the switch carries current of the order of 100 amperes DC at 100 kV DC. The development was a joint effort of the Japan Atomic Energy Research Institute and the switch manufacturer, IDX Corporation.
Takahashi, Masami*; Seki, Masami; Shimono, Mitsugu; Terakado, Masayuki; Igarashi, Koichi*; Ishii, Kazuhiro*; Kasugai, Atsushi
JAERI-Tech 2003-080, 27 Pages, 2003/11
JAERI-Tech-2003-080.pdf:3.11MB
The JT-60U electron cyclotron heating (ECH) system has been introduced to suppress MHD instabilities via a current profile control by local heating or current drive. The ECH system consists of four 1MW-110GHz gyrotrons, four 60m transmission lines composed of a corrugated waveguide with a diameter of 31.75mm and two steerable type mirror antennas. Recently, a gyrotron developed for ITER has realized high power in an extremely high frequency range of millimeter waves although there was no high power source around 110GHz ten years ago. Therefore, it requires many techniques to operate the gyrotoron. The oscillation conditions had to be found at output power 1MW by adjusting the magnetic field parameters and anode voltage after heater aging. Then conditioning of the gyrotoron was done, where the pulse length is gradually extended in order to operate for 1sec level of pulse length. Consequently, 1MW-5sec of the designed value was achieved and the ECH system with four gyrotrons successfully injected the millimeter wave energy of 10MJ into plasmas, which is the world record.
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.
Sakamoto, Keishi; Kasugai, Atsushi; Ikeda, Yoshitaka; Hayashi, Kenichi*; Takahashi, Koji; Moriyama, Shinichi; Seki, Masami; Kariya, Tsuyoshi*; Mitsunaka, Yoshika*; Fujii, Tsuneyuki; et al.
Nuclear Fusion, 43(7), p.729 - 737, 2003/07
Development of high power gyrotrons at 170GHz and 110GHz have beed carried out. At 170GHz gyrotron that is required for ITER, high power outputs of 0.9MW/9sec, 0.75MW/17sec, 0.5MW/30sec, 0.3MW/60sec have been obtained. At 110GHz gyrotron for JT-60U, 1.2MW/4sec was obtained. The 110GHz gyrotron is under operation at 4MW electron cyclotron heating and current drive system on JT-60U.
Igarashi, Koichi*; Seki, Masami; Shimono, Mitsugu; Terakado, Masayuki; Ishii, Kazuhiro*; Takahashi, Masami*
JAERI-Tech 2003-030, 40 Pages, 2003/03
JAERI-Tech-2003-030.pdf:5.83MB
The JT-60U electron cyclotron heating (ECH) system can heat plasmas locally and drive a plasma current with four 1 MW-5 sec gyrotrons. The super conducting magnets (SCM) are required for oscillation of the gyrotron at a working frequency of 110 GHz. The SCM provides a high magnetic field of 4.5T at the cavity inside the gyrotron. This SCM system is characterized by (1) operation without liquid Helium owing to a 4 K-refrigerator applied to the magnetic coils, (2) easy maintenance. Operational experiences about the SCM system through a long term experiment for a high power gyrotron are very valuable. According to those operational experiences, it is clarified the 4 K-refrigerator should be renewed in oder to keep low temperature of the SCM. It is also found that 200 hours or less are required for the super conducting condition (
5K) after long stopping time of the refrigerator up to 150 hours. This is useful information for making a plan about ECH experiments.
Kasugai, Atsushi; Sakamoto, Keishi; Hayashi, Kenichi*; Takahashi, Koji; Shoyama, Hiroaki*; Kajiwara, Ken*; Ikeda, Yoshitaka; Kariya, Tsuyoshi*; Mitsunaka, Yoshika*; Fujii, Tsuneyuki; et al.
JAERI-Research 2002-027, 57 Pages, 2002/11
JAERI-Research-2002-027.pdf:3.6MB
no abstracts in English
Tsunematsu, Toshihide; Seki, Masahiro; Tsuji, Hiroshi; Okuno, Kiyoshi; Kato, Takashi; Shibanuma, Kiyoshi; Hanada, Masaya; Watanabe, Kazuhiro; Sakamoto, Keishi; Imai, Tsuyoshi; et al.
Fusion Science and Technology, 42(1), p.75 - 93, 2002/07
Times Cited Count：1 Percentile：10.15(Nuclear Science & Technology)Japanese contributions to ITER Engineering Design Activity are presented, together with an introduction of the objectives and design of the ITER whose program have been carried out through the international collaboration by EU, Japan, Russian Federation and the USA. New technologies have been produced through the development, fabrication and testing of scalable models in the fields of superconducting magnet, reactor structure with vacuum vessel, high-heat-flux plasma facing component, neutral beam injector, high-power mm-wave generator and so on. As major contributions from Japan, development and testing results of a 13-T, 640-MJ, Nb
Sn pulsed magnet, a 18-degree sector of vacuum vessel with a height of 15 m and a width of 9 m, CFC armors to CuCrZr cooling tube that withstood 20 MW/m
, a 31 mA/cm negative ion beam source, a 1-MeV beam-accelerator, a 1-MW 170-GHz gyrotron were described.
Department of Fusion Plasma Research
JAERI-Conf 2000-007, p.161 - 0, 2000/03
JAERI-Conf-2000-007.pdf:9.11MB
no abstracts in English
Shinozaki, Shinichi; Shimono, Mitsugu; Terakado, Masayuki; Anno, Katsuto; Hiranai, Shinichi; Ikeda, Yoshitaka; Ikeda, Yukiharu; Imai, Tsuyoshi; Kasugai, Atsushi; Moriyama, Shinichi; et al.
Proceedings of the 18th IEEE/NPSS Symposium on Fusion Engineering (SOFE '99), p.403 - 406, 1999/10
no abstracts in English
Tsuneoka, Masaki; Imai, Tsuyoshi; E.Bowles*; I.Benfatto*; *; *
Fusion Engineering and Design, 45(2), p.197 - 207, 1999/00
Times Cited Count：1 Percentile：13.12(Nuclear Science & Technology)no abstracts in English
Tsuneoka, Masaki; Kasugai, Atsushi; ; Sakamoto, Keishi; Imai, Tsuyoshi; Fujita, Hideo*; *; *; *; *; et al.
Int. J.Electronics, 86(2), p.233 - 243, 1999/00
Times Cited Count：10 Percentile：56.59(Engineering, Electrical & Electronic)no abstracts in English
Kasugai, Atsushi; Sakamoto, Keishi; Takahashi, Koji; Tsuneoka, Masaki; Imai, Tsuyoshi; O.Braz*; M.Thumm*
JAERI-Research 97-020, 7 Pages, 1997/03
JAERI-Research-97-020.pdf:0.56MB
no abstracts in English
Tsuneoka, Masaki; Fujita, Hideo*; Sakamoto, Keishi; Kasugai, Atsushi; Imai, Tsuyoshi; Nagashima, Takashi; *; *; *; *; et al.
Fusion Engineering and Design, 36(4), p.461 - 469, 1997/00
Times Cited Count：23 Percentile：84.21(Nuclear Science & Technology)no abstracts in English
