Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Yoshinuma, Akihiko; Shiotsuki, Masao; Nakayama, Jiro
Chiso Shobun Taisho Hoshasei Haikibutsu No Hinshitsu Manejimento, Chiso Shobun-nioite Hitsuyo To Kangaerareru Koreberu Hoshasei Haikibutsu "Garasu Kokatai" No Kino To Yoken Hokokusho (Internet), 54 Pages, 2011/03
no abstracts in English
Yoshinuma, Akihiko; Shiotsuki, Masao
Chiso Shobun Taisho Hoshasei Haikibutsu No Hinshitsu Manejimento, Chiso Shobun-nioite Hitsuyo To Kangaerareru Koreberu Hoshasei Haikibutsu (Garasu Kokatai) No Tokusei, Hokokusho/Nihon Genshiryoku Gakkai "Chiso Shobun Taisho Hoshasei Haikibutsu No Hinshitsu Manejimento" Tokubetsu Senmon Iinkai, 67 Pages, 2010/01
In the conference for environmental preservation technical cooperation, JAEA accepted the cooperation request from JNFL, which is concerned with the technical information necessary for study of quality management for geological disposal waste including vitrified high radioactive waste. For this study, offering the technical information by JAEA and proceeding the study with cooperation of Atomic Energy Society of Japan were scheduled in the conference between JAEA, JNFL, power companies, and NUMO, which treat, store and dispose vitrified high radioactive waste. Furthermore, the characteristic of waste necessary for design and safety assessment of geological disposal facilities, the records appropriate for the characterization, etc. were discussed in the above conference.
Ida, Katsumi*; Sakamoto, Yoshiteru; Yoshinuma, Mikiro*; Takenaga, Hidenobu; Nagaoka, Kenichi*; Hayashi, Nobuhiko; Oyama, Naoyuki; Osakabe, Masaki*; Yokoyama, Masayuki*; Funaba, Hisamichi*; et al.
Nuclear Fusion, 49(9), p.095024_1 - 095024_9, 2009/09
Times Cited Count：31 Percentile：71.94(Physics, Fluids & Plasmas)Dynamics of ion internal transport barrier (ITB) formation and impurity transport both in the Large Helical Device (LHD) heliotron and JT-60U tokamak are described. Significant differences between heliotron and tokamak plasmas are observed. The location of the ITB moves outward during the ITB formation regardless of the sign of magnetic shear in JT-60U and the ITB becomes more localized in the plasma with negative magnetic shear. In LHD, the low Te/Ti ratio (
1) of the target plasma for the high power heating is found to be necessary condition to achieve the ITB plasma and the ITB location tends to expand outward or inward depending on the condition of the target plasmas. Associated with the formation of ITB, the carbon density tends to be peaked due to inward convection in JT-60U, while the carbon density becomes hollow due to outward convection in LHD. The outward convection observed in LHD contradicts the prediction by neoclassical theory.
Ida, Katsumi*; Sakamoto, Yoshiteru; Inagaki, Shigeru*; Takenaga, Hidenobu; Isayama, Akihiko; Matsunaga, Go; Sakamoto, Ryuichi*; Tanaka, Kenji*; Ide, Shunsuke; Fujita, Takaaki; et al.
Nuclear Fusion, 49(1), p.015005_1 - 015005_7, 2009/01
Times Cited Count：14 Percentile：44.93(Physics, Fluids & Plasmas)Transport analysis during the transient phase of heating (a dynamic transport study) applied to the plasma with internal transport barriers (ITBs) in the Large Helical Device (LHD) heliotron and the JT-60U tokamak is described. In the dynamic transport study the time of transition from the L-mode plasma to the ITB plasma is clearly determined by the onset of flattening of the temperature profile in the core region and a spontaneous phase transition from a zero curvature ITB (hyperbolic tangent shaped ITB) or a positive curvature ITB (concaved shaped ITB) to a negative curvature ITB (convex shaped ITB) and its back-transition are observed. The flattening of the core region of the ITB transition and the back-transition between a zero curvature ITB and a convex ITB suggest the strong interaction of turbulent transport in space.
Ida, Katsumi; Sakamoto, Yoshiteru; Takenaga, Hidenobu; Oyama, Naoyuki; Ito, Kimitaka*; Yoshinuma, Mikiro*; Inagaki, Shigeru*; Kobuchi, Takashi*; Isayama, Akihiko; Suzuki, Takahiro; et al.
Physical Review Letters, 101(5), p.055003_1 - 055003_4, 2008/08
Times Cited Count：34 Percentile：79.28(Physics, Multidisciplinary)A spontaneous transition phenomena between two meta-stable states of plasmas with internal transport barrier (ITB), that are characterized by different radial profiles of second derivative of ion temperature inside the ITB region where the ion temperature gradient is large, is observed in the steady-state phase of magnetic shear in the negative magnetic shear plasma in JT-60U tokamak. The curvature asymmetry factor evaluated from the radial profile of second derivative of ion temperature profiles changes from 0.08 (symmetric curvature ITB) to -0.43 (asymmetric curvature ITB) during transition phase.
Motojima, Osamu*; Yamada, Hiroshi*; Komori, Akio*; Oyabu, Nobuyoshi*; Muto, Takashi*; Kaneko, Osamu*; Kawahata, Kazuo*; Mito, Toshiyuki*; Ida, Katsumi*; Imagawa, Shinsaku*; et al.
Nuclear Fusion, 47(10), p.S668 - S676, 2007/10
Times Cited Count：34 Percentile：73.64(Physics, Fluids & Plasmas)The performance of net-current free heliotron plasmas has been developed by findings of innovative operational scenarios in conjunction with an upgrade of the heating power and the pumping/fuelling capability in the Large Helical Device (LHD). Consequently, the operational regime has been extended, in particular, with regard to high density, long pulse length and high beta. Diversified studies in LHD have elucidated the advantages of net-current free heliotron plasmas. In particular, an internal diffusion barrier (IDB) by a combination of efficient pumping of the local island divertor function and core fuelling by pellet injection has realized a super dense core as high as 5
10
m
, which stimulates an attractive super dense core reactor. Achievements of a volume averaged beta of 4.5% and a discharge duration of 54 min with a total input energy of 1.6 GJ (490 kW on average) are also highlighted. The progress of LHD experiments in these two years is overviewed by highlighting IDB, high-beta and long pulse.
Motojima, Osamu*; Yamada, Hiroshi*; Komori, Akio*; Oyabu, Nobuyoshi*; Kaneko, Osamu*; Kawahata, Kazuo*; Mito, Toshiyuki*; Muto, Takashi*; Ida, Katsumi*; Imagawa, Shinsaku*; et al.
Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM), 12 Pages, 2007/03
The performance of net-current free Heliotron plasmas has been developed by findings of innovative operational scenarios in conjunction with an upgrade of the heating power and the pumping/fueling capability in the Large Helical Device (LHD). Consequently, the operational regime has been extended, in particular, with regard to high density, long pulse length and high beta. Diversified studies in LHD have elucidated the advantages of net-current free heliotron plasmas. In particular, an Internal Diffusion Barrier (IDB) by combination of efficient pumping of the local island divertor function and core fueling by pellet injection has realized a super dense core as high as 510m, which stimulates an attractive super dense core reactor. Achievements of a volume averaged beta of 4.5 % and a discharge duration of 54-min. with a total input energy of 1.6 GJ (490 kW in average) are also highlighted. The progress of LHD experiments in these two years is overviewed with highlighting IDB, high 
and long pulse.
