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Inoue, Yuki; Yamada, Junya; Hamaguchi, Takumi; Seya, Natsumi; Muto, Yasunobu; Nohara, Naofumi; Oishi, Tetsuya; Hashimoto, Makoto
JAEA-Data/Code 2024-017, 109 Pages, 2025/03
JAEA-Data-Code-2024-017.pdf:4.54MB
This report presents the results of environmental radiation monitoring at Oarai Nuclear Engineering Institute, JAEA for 10 years from 2011 to 2021 after the accident at the Fukushima Daiichi Nuclear Power Station. Database of monitoring results are included as an appendix. Environmental transfer parameters, deposition velocity, resuspension factor, concentration factor and distribution coefficient, are calculated as an Appendix.
Takabe, Yugo; Otsuka, Noriaki; Fuyushima, Takumi; Sayato, Natsuki; Inoue, Shuichi; Morita, Hisashi; Jaroszewicz, J.*; Migdal, M.*; Onuma, Yuichi; Tobita, Masahiro*; et al.
JAEA-Technology 2022-040, 45 Pages, 2023/03
JAEA-Technology-2022-040.pdf:6.61MB
Because of the decommission of the Japan Materials Testing Reactor (JMTR), the domestic neutron irradiation facility, which had played a central role in the development of innovative nuclear reactors and the development of technologies to further improve the safety, reliability, and efficiency of light water reactors, was lost. Therefore, it has become difficult to pass on the operation techniques of the irradiation test reactors and irradiation technologies, and to train human resources. In order to cope with these issues, we conducted a study on the implementation of irradiation tests using overseas reactors as neutron irradiation sites as an alternative method. Based on the "Arrangement between the National Centre for Nuclear Research and the Japan Atomic Energy Agency for Cooperation in Research and Development on Testing Reactor," the feasibility of conducting an irradiation test at the MARIA reactor (30 MW) owned by the National Centre for Nuclear Research (NCBJ) using the temperature control system, which is one of the JMTR irradiation technologies, was examined. As a result, it was found that the irradiation test was possible by modifying the ready-made capsule manufactured in accordance with the design and manufacturing standards of the JMTR. After the modification, a penetration test, an insulation continuity test, and an operation test in the range of room temperature to 300
C, which is the operating temperature of the capsule, were conducted and favorable results were obtained. We have completed the preparations prior to transport to the MARIA reactor.
Tobita, Kenji; Nishio, Satoshi*; Enoeda, Mikio; Nakamura, Hirofumi; Hayashi, Takumi; Asakura, Nobuyuki; Uto, Hiroyasu; Tanigawa, Hiroyasu; Nishitani, Takeo; Isono, Takaaki; et al.
JAEA-Research 2010-019, 194 Pages, 2010/08
JAEA-Research-2010-019-01.pdf:48.47MBJAEA-Research-2010-019-02.pdf:19.4MB
This report describes the results of the conceptual design study of the SlimCS fusion DEMO reactor aiming at demonstrating fusion power production in a plant scale and allowing to assess the economic prospects of a fusion power plant. The design study has focused on a compact and low aspect ratio tokamak reactor concept with a reduced-sized central solenoid, which is novel compared with previous tokamak reactor concept such as SSTR (Steady State Tokamak Reactor). The reactor has the main parameters of a major radius of 5.5 m, aspect ratio of 2.6, elongation of 2.0, normalized beta of 4.3, fusion out put of 2.95 GW and average neutron wall load of 3 MW/m
. This report covers various aspects of design study including systemic design, physics design, torus configuration, blanket, superconducting magnet, maintenance and building, which were carried out increase the engineering feasibility of the concept.
Tobita, Kenji; Nishio, Satoshi; Enoeda, Mikio; Kawashima, Hisato; Kurita, Genichi; Tanigawa, Hiroyasu; Nakamura, Hirofumi; Honda, Mitsuru; Saito, Ai*; Sato, Satoshi; et al.
Nuclear Fusion, 49(7), p.075029_1 - 075029_10, 2009/07
Times Cited Count：145 Percentile：97.41(Physics, Fluids & Plasmas)Recent design study on SlimCS focused mainly on the torus configuration including blanket, divertor, materials and maintenance scheme. For vertical stability of elongated plasma and high beta access, a sector-wide conducting shell is arranged in between replaceable and permanent blanket. The reactor adopts pressurized-water-cooled solid breeding blanket. Compared with the previous advanced concept with supercritical water, the design options satisfying tritium self-sufficiency are relatively scarce. Considered divertor technology and materials, an allowable heat load to the divertor plate should be 8 MW/m or lower, which can be a critical constraint for determining a handling power of DEMO (a combination of alpha heating power and external input power for current drive).
Dairaku, Masayuki; Watanabe, Kazuhiro; Tobari, Hiroyuki; Kashiwagi, Mieko; Inoue, Takashi; Sakamoto, Keishi; Hanada, Masaya; Akino, Noboru; Ikeda, Yoshitaka; Yamamoto, Takumi*
JAEA-Technology 2008-091, 23 Pages, 2009/03
JAEA-Technology-2008-091.pdf:5.82MB
A plasma generator whose inner dimensions are 25 cm in width, 59 cm in length, and 31 cm in depth for a high power and long pulse ion source in neutral beam injector has been designed and fabricated. The plasma generator has a beam extraction area of 12 cm in width and 46 cm in length. A target of the output beam using the plasma generator is to produce deuterium positive ion beams up to 120 keV, 65 A for longer than 200 s pulses. Arrangement of the permanent magnets and filaments has been designed by using an electron trajectory simulation code to produce uniform and high density plasma with high proton yield. Cooling channels have been also designed to operate the long pulse plasma generation with a 100 kW arc discharge power.
Ushigusa, Kenkichi; Seki, Masahiro; Ninomiya, Hiromasa; Norimatsu, Takayoshi*; Kamada, Yutaka; Mori, Masahiro; Okuno, Kiyoshi; Shibanuma, Kiyoshi; Inoue, Takashi; Sakamoto, Keishi; et al.
Genshiryoku Handobukku, p.906 - 1029, 2007/11
no abstracts in English
Tobita, Kenji; Nishio, Satoshi; Sato, Masayasu; Sakurai, Shinji; Hayashi, Takao; Shibama, Yusuke; Isono, Takaaki; Enoeda, Mikio; Nakamura, Hirofumi; Sato, Satoshi; et al.
Nuclear Fusion, 47(8), p.892 - 899, 2007/08
Times Cited Count：61 Percentile：86.25(Physics, Fluids & Plasmas)The concept for a compact DEMO reactor named "SlimCS" is presented. Distinctive features of the concept is low aspect ratio (
= 2.6) and use of a reduced-size center solenoid (CS) which has a function of plasma shaping rather than poloidal flux supply. The reduced-size CS enables us to introduce a thin toroidal field (TF) coil system which contributes to reducing the weight and construction cost of the reactor. SlimCS is as compact as advanced commercial reactor designs such as ARIES-RS and produces 1 GWe in spite of moderate requirements for plasma parameters. Merits of low-, i.e. vertical stability for high elongation and high beta limit are responsible for such reasonable physics requirements.
Ninomiya, Hiromasa; Akiba, Masato; Fujii, Tsuneyuki; Fujita, Takaaki; Fujiwara, Masami*; Hamamatsu, Kiyotaka; Hayashi, Nobuhiko; Hosogane, Nobuyuki; Ikeda, Yoshitaka; Inoue, Nobuyuki; et al.
Journal of the Korean Physical Society, 49, p.S428 - S432, 2006/12
To contribute DEMO and ITER, the design to modify the present JT-60U into superconducting coil machine, named National Centralized Tokamak (NCT), is being progressed under nationwide collaborations in Japan. Mission, design and strategy of this NCT program is summarized.
Tobita, Kenji; Nishio, Satoshi; Sato, Masayasu; Sakurai, Shinji; Hayashi, Takao; Shibama, Yusuke; Isono, Takaaki; Enoeda, Mikio; Nakamura, Hirofumi; Sato, Satoshi; et al.
Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM), 8 Pages, 2006/10
no abstracts in English
Ikeda, Yoshitaka; Umeda, Naotaka; Akino, Noboru; Ebisawa, Noboru; Grisham, L. R.*; Hanada, Masaya; Honda, Atsushi; Inoue, Takashi; Kawai, Mikito; Kazawa, Minoru; et al.
Nuclear Fusion, 46(6), p.S211 - S219, 2006/06
Times Cited Count：65 Percentile：86.93(Physics, Fluids & Plasmas)Recently, the extension of the pulse duration up to 30 sec has been intended to study quasi-steady state plasma on JT-60U N-NBI system. The most serious issue is to reduce the heat load on the grids for long pulse operation. Two modifications have been proposed to reduce the heat load. One is to suppress the beam spread which may be caused by beamlet-beamlet interaction in the multi-aperture grid due to the space charge force. Thin plates were attached on the extraction grid to modify the local electric field. The plate thickness was optimized to steer the beamlet deflection. The other is to reduce the stripping loss, where the electron of the negative ion beam is stripped and accelerated in the ion source and then collides with the grids. The ion source was modified to reduce the pressure in the accelerator column to suppress the beam-ion stripping loss. Up to now, long pulse injection of 17 sec for 1.6 MW and 25 sec for 
1 MW has been obtained by one ion source with these modifications.
Tobita, Kenji; Nishio, Satoshi; Enoeda, Mikio; Sato, Masayasu; Isono, Takaaki; Sakurai, Shinji; Nakamura, Hirofumi; Sato, Satoshi; Suzuki, Satoshi; Ando, Masami; et al.
Fusion Engineering and Design, 81(8-14), p.1151 - 1158, 2006/02
Times Cited Count：128 Percentile：98.92(Nuclear Science & Technology)no abstracts in English
Inoue, Takumi*; Sueoka, Atsuo*; Maehara, Takeshi*; Nakano, Hiroshi*; Kanemoto, Hiroyuki*; Murakami, Yukitaka*
Nihon Kikai Gakkai Rombunshu, C, 72(714), p.380 - 387, 2006/02
None
Umeda, Naotaka; Yamamoto, Takumi; Hanada, Masaya; Grisham, L. R.*; Kawai, Mikito; Oga, Tokumichi; Akino, Noboru; Inoue, Takashi; Kazawa, Minoru; Kikuchi, Katsumi*; et al.
Fusion Engineering and Design, 74(1-4), p.385 - 390, 2005/11
Times Cited Count：9 Percentile：51.09(Nuclear Science & Technology)In negative ion based neutral beam injector (N-NBI) for JT-60U, some modifications for extent pulse duration from 10 second, which is design value, to 30 second was conducted. Main limit to prevent pulse extension was heat loads onto grounded grid in an ion source and onto beam limiter placed at 22 m from the ion source. To reduce these heat loads, beam extraction area was optimized and the limiter was changed to one which had about twice thermal capacity. As a result of these modifications, the temperature rise of the water which was cooling grounded grid could be suppressed under 40 degree, which can operate in steady state condition. The temperature rise of the limiter could be restricted to 60%. Untill now the beam pulse extended to 17 second of 1.6MW power at 366keV energy, and injection of 30 seconds will be achieved in next experiment.
Inoue, Takashi; Hanada, Masaya; Iga, Takashi*; Imai, Tsuyoshi; Kashiwagi, Mieko; Kawai, Mikito; Morishita, Takatoshi; Taniguchi, Masaki; Umeda, Naotaka; Watanabe, Kazuhiro; et al.
Fusion Engineering and Design, 66-68, p.597 - 602, 2003/09
Times Cited Count：21 Percentile：77.00(Nuclear Science & Technology)The neutral beam (NB) injection has been one of the most promising methods for plasma heating and current drive in tokamak fusion devices. JAERI has developed high energy electrostatic accelerators for the NB systems in JT-60U and ITER. Recent progress on this R&D are as follows: 1) In the JT-60U NB system, some of the beams has been deflected due to distorted electric field in the accelerator, resulting in an excess heat load on the NB port. By correcting the electric field, a continuous injection of H
beam was succeeded for 10 s with the NB power of 2.6 MW at 355 keV. 2) To increase the beam energy, a metal structure called stress ring was designed. The ring reduces electric field concentration at the triple junction point (interface between metal and dielectric insulator inside vacuum). Initial test of the accelerators with the stress rings has shown higher voltage hold off performance in both accelerators for JT-60U and ITER R&D than that without rings.
Kawai, Mikito; Akino, Noboru; Ebisawa, Noboru; Grisham, L. R.*; Hanada, Masaya; Honda, Atsushi; Inoue, Takashi; Kazawa, Minoru; Kikuchi, Katsumi*; Kuriyama, Masaaki; et al.
Fusion Science and Technology, 44(2), p.508 - 512, 2003/09
Times Cited Count：6 Percentile：40.50(Nuclear Science & Technology)The negative ion source for negative ion based neutral beam injector(N-NBI) of JT-60U aims at generating a negative ion beam with 500 keV and 22A for 10s. The N-NBI system was completed in 1996, followed by starting the efforts to increase beam power and energy. (1)Spatial non-uniformity of the source plasma causes position-dependent divergence of a beamlet due to mis-matching of local beam perveance. A part of the divergent energetic beams is intercepted by the grids and resultantly produce the excessive heat load of the grids and/or induce the high voltage breakdown. So several techniques to take measures against and to correct the non-uniformity in these sources were implemented. (2)Correction of beamlet deflection by adjusting the electric field at the extraction grids. It improved the beam divergence and then decreased an excessive heat load of a beam limiter by more than 50 %. As a result, the maximum injection power 6.2MW and beam pulse duration 10 seconds were obtaind.
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.
Umeda, Naotaka; Grisham, L. R.*; Yamamoto, Takumi; Kuriyama, Masaaki; Kawai, Mikito; Oga, Tokumichi; Mogaki, Kazuhiko; Akino, Noboru; Yamazaki, Haruyuki*; Usui, Katsutomi; et al.
Nuclear Fusion, 43(7), p.522 - 526, 2003/07
Times Cited Count：39 Percentile：72.22(Physics, Fluids & Plasmas)The Negative-ion based Neutral Beam Injection System (N-NBI) for JT-60U has been operating for plasma heating and non-inductive current drive since 1996. The target is inject of neutral beam into plasma with beam energy 500 keV, injection power 10 MW, for 10 seconds. Until now pulse duration time was restricted up to 5.3 seconds because of larger heat load of port limiter. Recently from the measurement of beam profile at 3.5m downstream from the ion source, it was found that the outermost beamlets in each segment were deflected outward. It was caused by non-uniform electric field by grooves. By improving this, outermost beamlet deflection angle was decreased from 14 mrad to 4 mrad. In this result, 10 seconds injection, which is target parameter, has achieved at 355 keV, 2.6MW, while pulse length was restricted up to 5.3 seconds by larger heat load of port limiter.
Watanabe, Kazuhiro; Amemiya, Toru*; Hanada, Masaya; Iga, Takashi*; Imai, Tsuyoshi; Inoue, Takashi; Kashiwagi, Mieko; Kuriyama, Masaaki; Morishita, Takatoshi; Okumura, Yoshikazu; et al.
Review of Scientific Instruments, 73(2), p.1090 - 1092, 2002/02
Times Cited Count：18 Percentile：64.98(Instruments & Instrumentation)no abstracts in English
Irifune, Tetsuo*; Kuroda, Koji*; Nishiyama, Norimasa*; Inoue, Toru*; Funamori, Nobumasa*; Uchida, Takeyuki*; Yagi, Takehiko*; Utsumi, Wataru; Miyajima, Nobuyoshi*; Fujino, Kiyoshi*; et al.
Geophysical Monograph 101 (Properties of Earth and Planetary Materials at High Pressure and Temperature), p.1 - 8, 1998/00
no abstracts in English
Hayashi, Takumi; Konishi, Satoshi; Ohira, Shigeru; Nakamura, Hirofumi; Inoue, Masahiko*; Watanabe, Tetsuo*; Hirata, Kazuhiro*; Naruse, Yuji; Okuno, Kenji; Barnes, J. W.*; et al.
JAERI-M 93-094, 54 Pages, 1993/03
no abstracts in English
