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Uto, Hiroyasu; Takase, Haruhiko; Sakamoto, Yoshiteru; Tobita, Kenji; Hiwatari, Ryoji; Mori, Kazuo; Kudo, Tatsuya; Someya, Yoji; Asakura, Nobuyuki
no journal, ,
This presentation describes conceptual design of in-vessel component including conducting shell in DEMO design activities, in order to propose feasible DEMO reactor from plasma vertical stability and engineering viewpoint. The conducting shell design for plasma vertical stability was clarified from the plasma vertical stability analysis, and a conceptual design divided in the toroidal direction for the blanket remote maintenance was proposed. We evaluated dependence of the plasma vertical stability on the conducing shell parameters and electromagnetic force at plasma disruption by using a numerical simulation code (EDDYCAL) with actual shape and position of the vacuum vessel and in-vessel components. The calculation results showed that the double-loop shell has the most effect on plasma vertical stability. On the other hand, while the electromagnetic force at the plasma disruption is a few times larger than no conducting shell case because of larger eddy current on conducting shell.
Idomura, Yasuhiro
no journal, ,
Decaying turbulence simulations of ion temperature gradient driven (ITG) turbulence with adiabatic electrons and ion temperature gradient driven trapped electron mode (ITG-TEM) turbulence with kinetic electrons are performed using a full-f gyrokinetic code. Nonlinear critical temperature gradients exceeding linear critical temperature gradients are observed in both simulations, and mechanisms to sustain them are investigated. It is found that unlike zonal flows in the ITG turbulence, the ITG-TEM turbulence produces corrugated electron density profiles, which form radial electric fields with strong shear following a force balance relation.
Kawai, Chika; Idomura, Yasuhiro; Maeyama, Shinya*; Ogawa, Yuichi*
no journal, ,
To investigate relations between self-organization and flow structure formation in magnetized plasmas, energy spectrum structures of electron turbulence are estimated by gyrokinetic simulations. It is found that the existence of zonal flow formation is affected by the plasma density and the temperature ratio between ions and electrons, which change wave dispersion induced by diamagnetic rotation. Depending on saturation amplitudes of turbulence, zonal flow formation processes are varied from an inverse energy cascade due to self-organization to a modulational instability due to direct mode coupling. These results suggest that structures of electron turbulence are significantly changed by macroscopic plasma parameters.
Nabara, Yoshihiro; Suwa, Tomone; Ozeki, Hidemasa; Sakurai, Takeru; Kajitani, Hideki; Iguchi, Masahide; Hemmi, Tsutomu; Nunoya, Yoshihiko; Isono, Takaaki; Matsui, Kunihiro; et al.
no journal, ,
no abstracts in English
Takechi, Manabu; Matsunaga, Go; Sasajima, Tadayuki; Yagyu, Junichi; Kawamata, Yoichi; Kurihara, Kenichi; Nakamura, Kazuo*
no journal, ,
no abstracts in English
Okano, Fuminori; JT-60SA Team
no journal, ,
no abstracts in English
Inoue, Takashi; Kusama, Yoshinori; Sugimoto, Makoto; Okuno, Kiyoshi; Nakajima, Hideo
no journal, ,
At present, construction of ITER is in progress at its site in south France, Saint Paul Lez Durance, and in parallel, fabrication of ITER core components and systems are also on-going at 7 Parties. Japan have already completed fabrication of the TF coil superconducting conductors of Japanese share. The TF coil and CS coil conductors are already in production phase for real ITER components. For neutral beam (NB) system, whole system equivalent to that of ITER is being manufactured in advance to test the system at NB test facility (NBTF) at Padua Italy. The power supply components produced in Japan have departed in October 2015 as the 1st shipment to Italy. Outline of design, R&D, and procurement of components of Japanese share, such as Electron Cyclotron system, Blanket remote handling system, Diagnostics (Poloidal polarimeter, Edge Thomson scattering, Divertor impurity monitor and IR thermography etc.), Divertor outer target and Test Blanket Module (TBM) are also reported.
Miyata, Yoshiaki; Suzuki, Takahiro; Urano, Hajime; Takechi, Manabu; Ide, Shunsuke
no journal, ,
In the plasma equilibrium control for tokamak devices, after the plasma shape reconstruction system identifies the plasma quantities from the magnetic measurements such as the magnetic sensor and poloidal magnetic field coil, the plasma equilibrium controller operates the actuator to bring the identified plasma quantities closer to the target ones by feedback control action. The influences of potential magnetic measurement noise on the plasma equilibrium control in JT-60SA is quantitatively evaluated and the techniques for mitigating the influences are reported.
Nozawa, Takashi; Okubo, Nariaki; Ozawa, Kazumi; Tanigawa, Hiroyasu
no journal, ,
A silicon carbide matrix composite is a candidate functional material for liquid breeding DEMO blanket. In this design, structural stability is essential to ensure overall function of the component and hence damage tolerance of the required function needs to be well understood. This study aims to identify the effects of macro/micro damages, e.g., mechanical failure and irradiation-induced damage, on electrical properties of SiC materials by AC impedance measurement and microstructural observation.
Wakasa, Arimitsu; Namekawa, Masakazu; Urano, Hajime; Hayashi, Nobuhiko; Ide, Shunsuke; Ozeki, Takahisa
no journal, ,
no abstracts in English
Matsuyama, Akinobu; Aiba, Nobuyuki; Yagi, Masatoshi
no journal, ,
no abstracts in English
Tobita, Kenji
no journal, ,
no abstracts in English
Sasaki, Shunichi; Hanada, Masaya; Akino, Noboru; Kojima, Atsushi; Komata, Masao; Mogaki, Kazuhiko; Endo, Yasuei; Shimizu, Tatsuo; Ozeki, Masahiro; Nemoto, Shuji
no journal, ,
no abstracts in English
Yoshida, Masafumi; Hanada, Masaya; Kojima, Atsushi; Kashiwagi, Mieko; Watanabe, Kazuhiro; Tobari, Hiroyuki; Umeda, Naotaka; Hiratsuka, Junichi; Akino, Noboru; Dairaku, Masayuki
no journal, ,
no abstracts in English
Kojima, Atsushi; NB Heating Technology Group
no journal, ,
In JAEA, R&D for negative ion accelerators for JT-60SA and ITER is going on in order to obtain the long pulse acceleration of negative ions over 60 s. Up to now, the critical issues were the low voltage holding capability and high heat load of the accelerators. As for the voltage holding capability, the multi-aperture large-area grid has been investigated in terms of the area, multi-aperture and multi-grid effect on the voltage holding. As a result, high energy accelerations of 500 keV and 1 MeV for JT-60SA and ITER-prototype accelerators have been achieved. As for the heat load, compensation techniques toward beam deflection due to magnetic field in the accelerator has been developed by using 3D beam calculation. By combining the extraction grid having high cooling capability to this compensation technique, low heat load of 12% has been achieved, and long pulse acceleration of 700 keV beams has been realized.
Matsunaga, Go; Sakurai, Shinji; Takechi, Manabu; Tsuru, Daigo; Shibama, Yusuke; Murakami, Haruyuki; Yoshida, Kiyoshi
no journal, ,
no abstracts in English
Inoue, Shizuo; Shiraishi, Junya; Ide, Shunsuke; Isayama, Akihiko; Matsunaga, Go; Takechi, Manabu
no journal, ,
no abstracts in English
Honda, Mitsuru; Nakata, Motoki*
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no abstracts in English
Yoshida, Maiko
no journal, ,
Yong scientists have been exchanged their views and issues of fusion energy and science at an informal session in the annual meeting of the Japan Society of Plasma Science and Nuclear Fusion Research (JSPF). In this annual meeting, we discuss issues of future of fusion energy and science in Japan Universities on "Informal meeting by fusion science young scientists, role of young scientists in DEMO design era". In this talk, the JT-60SA research plan, theory and simulation codes, diagnostics, relation between DEMO and JT-60SA and collaboration between JAEA and Japan Universities will be reported and discussed with young scientists.
Hemmi, Tsutomu; Kajitani, Hideki; Matsui, Kunihiro; Mizutani, Takumi; Yamane, Minoru; Sakaguchi, Kaori; Ando, Shinji; Takano, Katsutoshi; Koizumi, Norikiyo
no journal, ,
JAEA has responsibility of procurement of 9 ITER Toroidal Field (TF) coils in ITER. Prior to TF coil fabrication, JAEA started to fabricate three dummy double pancakes (DPs) in order to confirm the commissioning of the facilities for DP fabrication and establish the manufacturing process of the DP. Fabrication of the dummy DP as full-scale trials has been started from October, 2013. In this full-scale trial, the control of conductor length with 
0.01%, flatness of radial plate (RP) with 2 mm and flatness of DP after CP welding with 2 mm were achieved and conductor elongation due to heat treatment was evaluated. Based on these results, TF coil winding has been started. The conductor winding has been already completed for 11 DPs of the TF coil and 10 DPs were heat treated. The conductor elongation is within expected value of 0.02%.