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Hoshino, Kazuo; Shimizu, Katsuhiro; Kawashima, Hisato; Takizuka, Tomonori*; Nakano, Tomohide; Ide, Shunsuke
Contributions to Plasma Physics, 54(4-6), p.404 - 408, 2014/06
Times Cited Count：16 Percentile：61.17(Physics, Fluids & Plasmas)no abstracts in English
Shibanuma, Kiyoshi; Arai, Takashi; Hasegawa, Koichi; Hoshi, Ryo; Kamiya, Koji; Kawashima, Hisato; Kubo, Hirotaka; Masaki, Kei; Saeki, Hisashi; Sakurai, Shinji; et al.
Fusion Engineering and Design, 88(6-8), p.705 - 710, 2013/10
Times Cited Count：10 Percentile：61.16(Nuclear Science & Technology)Ide, Shunsuke; Aiba, Nobuyuki; Bolzonella, T.*; Challis, C. D.*; Fujita, Takaaki; Giruzzi, G.*; Joffrin, E.*; Hamamatsu, Kiyotaka; Hayashi, Nobuhiko; Honda, Mitsuru; et al.
Proceedings of 24th IAEA Fusion Energy Conference (FEC 2012) (CD-ROM), 8 Pages, 2013/03
Ueda, Yoshio*; Oya, Kaoru*; Ashikawa, Naoko*; Ito, Atsushi*; Ono, Tadayoshi*; Kato, Daiji*; Kawashima, Hisato; Kawamura, Gakushi*; Kenmotsu, Takahiro*; Saito, Seiki*; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 88(9), p.484 - 502, 2012/09
no abstracts in English
Kawashima, Hisato; Hoshino, Kazuo; Shimizu, Katsuhiro; Takizuka, Tomonori; Ide, Shunsuke; Sakurai, Shinji; Asakura, Nobuyuki
Journal of Nuclear Materials, 415(Suppl.1), p.S948 - S951, 2011/08
Times Cited Count：8 Percentile：53.37(Materials Science, Multidisciplinary)The divertor design of the JT-60SA tokamak device is finalized according to the engineering requirements and the physical analyses with the SONIC code simulations. Assuming the steady-state high beta core plasmas with 41 MW heating power, high heat and particle fluxes flowing out from core to SOL arrive at the divertor targets and give a large heat load. From the engineering viewpoint, the allowable heat load is restricted below 15 MW/m
by the tolerability of the target material and structure. As a scenario to reduce the heat load, the vertical target configuration is adopted to receive the heat load on the wide area. In addition, the V-shaped corner is set to enhance the recycling at the outer side divertor where receives a relatively large heat load. Then, the remote radiative cooling is optimized by control of the D
gas puffing, the impurity seeding and the divertor pumping.
Kamada, Yutaka; Barabaschi, P.*; Ishida, Shinichi; Ide, Shunsuke; Lackner, K.*; Fujita, Takaaki; Bolzonella, T.*; Suzuki, Takahiro; Matsunaga, Go; Yoshida, Maiko; et al.
Nuclear Fusion, 51(7), p.073011_1 - 073011_11, 2011/07
Times Cited Count：64 Percentile：92.1(Physics, Fluids & Plasmas)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.
Oshima, Takayuki; Fujita, Takaaki; Seki, Masami; Kawashima, Hisato; Hoshino, Katsumichi; Shibanuma, Kiyoshi; Verrecchia, M.*; Teuchner, B.*
Journal of Plasma and Fusion Research SERIES, Vol.9, p.620 - 624, 2010/08
For interface control and assembly, the CAD data will be exchanged and integrated in a new Data Base server installed at Naka for JT-60SA, where a common computer network efficiently connected between the Naka site for JAEA and the Garching site for F4E is needed to be established. To ensure the design environments, a VPN (Virtual Private Network) was introduced with CAD LAN on computer network physically-separated from JAEA intranet area and firewall. In July 2009, a new VPN connection between the Naka and Garching sites has been successfully demonstrated using IPSec-VPN technology with a commercial and cost-effective firewall/router for security. The VPN technology would provide a common platform for the development of remote experimentation techniques on JT-60SA between Rokkasho and Naka in collaboration with activities of the ITER Remote Experimentation Centre for the IFERC Project at Rokkasho.
Asakura, Nobuyuki; Shimizu, Katsuhiro; Kawashima, Hisato; Tobita, Kenji; Takizuka, Tomonori
Journal of Plasma and Fusion Research SERIES, Vol.9, p.136 - 141, 2010/08
Design of the power handling for the demo tokamak reactor, SlimCS (R = 5.5 m, R/a = 2.6) with the fusion power of 3 GW and the exhausted power of 500 MW was investigated. First results of the SONIC simulation (two dimensional plasma fluid code, i.e. SOLDOR, neutral Monte Carlo code, i.e. NEUT2D, and two dimensional impurity Monte Carlo code, i.e. IMPMC) of the edge and divertor plasmas with the intensive Ar seeding were presented. Distributions of the Ar ions and radiation loss are compared with those in the previous work with a constant impurity concentration of Ar (nAr/ni) and the non-coronal radiation model for the radiation power function. At the same time, heat loading to the divertor and the first wall is investigated in the radiative plasma operation of the demo reactor.
Shibanuma, Kiyoshi; Arai, Takashi; Kawashima, Hisato; Hoshino, Katsumichi; Hoshi, Ryo; Kobayashi, Kaoru; Sawai, Hiroaki; Masaki, Kei; Sakurai, Shinji; Shibama, Yusuke; et al.
Journal of Plasma and Fusion Research SERIES, Vol.9, p.276 - 281, 2010/08
The JT-60 SA project is a combined project of JA-EU satellite tokamak program under the Broader Approach (BA) agreement and JA domestic program. Major components of JT-60SA for assembly are vacuum vessel (VV), superconducting coils (TF coils, EF coils and CS coil), in-vessel components such as divertor, thermal shield and cryostat. An assembly frame (with the dedicated cranes), which is located around the tokamak, is adopted to carry out effectively the assembly of tokamak components in the tokamak hall, independently of the facility cranes in the building. The assembly frame also provides assembly tools and jigs with jacks to support temporarily the components as well as to adjust the components at right positions. In this paper, the assembly scenario and scequence of the major components such as VV and TFC and the concept of the assembly frame including special jigs and fixtures are discussed.
Oya, Kaoru*; Inai, Kensuke*; Shimizu, Katsuhiro; Takizuka, Tomonori; Kawashima, Hisato; Hoshino, Kazuo; Hatayama, Akiyoshi*; Toma, Mitsunori*; Tomita, Yukihiro*; Kawamura, Gakushi*; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 85(10), p.695 - 703, 2009/10
no abstracts in English
Ozeki, Takahisa; Hayashi, Nobuhiko; Honda, Mitsuru; Aiba, Nobuyuki; Hamamatsu, Kiyotaka; Shimizu, Katsuhiro; Kawashima, Hisato; Hoshino, Kazuo; Takizuka, Tomonori; Tokuda, Shinji
Journal of Plasma and Fusion Research SERIES, Vol.8, p.1138 - 1142, 2009/09
Fujimoto, Kayoko; Nakano, Tomohide; Kubo, Hirotaka; Sawada, Keiji*; Takizuka, Tomonori; Kawashima, Hisato; Shimizu, Katsuhiro; Asakura, Nobuyuki
Plasma and Fusion Research (Internet), 4, p.025_1 - 025_7, 2009/08
The volume recombination in detached divertor plasmas is a key process to reduce the ion flux to the divertor plates. Two-dimensional measurement is one of the ways to investigate a spatial structure of the volume recombination. In this work, the deuterium Balmer-series lines from a detached divertor plasma were observed two-dimensionally with a spatial resolution of 1 cm and were reconstructed into two-dimensional emissivities with a tomography technique. The ratio of the D
to the D
emissivity was compared to that calculated by the collisional-radiative model. This ratio could not be explained only by the excitation of D by electron impact, indicating that the volume recombination contributed to the D emission. This is the case for the region above the inner strike point with 8 cm and 4 cm, respectively, in the r- and the z-direction on the poloidal cross-section.
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：137 Percentile：97.72(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).
Takenaga, Hidenobu; Kawashima, Hisato; Nishio, Satoshi; Tobita, Kenji
Fusion Science and Technology, 57(1), p.94 - 102, 2009/06
Times Cited Count：5 Percentile：35.74(Nuclear Science & Technology)A fuelling scenario in a fusion reactor has been investigated, where tritium is fuelled in the main plasma and deuterium is fuelled in both the main plasma and the edge plasma. The tritium fuelling in the main plasma minimizes the tritium fuelling rate necessary for sustaining the high tritium density in the main plasma, resulting in the minimum tritium recycling level at the fixed pumping fraction. The deuterium fuelling in the main plasma sustains the high deuterium density in the main plasma and the deuterium fuelling in the edge plasma enhances the deuterium recycling level for reducing the divertor temperature. Based on this scenario, particle balance was quantitatively investigated using the SlimCS design parameters at 2.95 GW fusion output with consideration of confinement times separately defined for the particles fuelled in the main plasma and the edge plasma.
Sakurai, Shinji; Kawashima, Hisato; Higashijima, Satoru; Shimizu, Katsuhiro; Masaki, Kei; Asakura, Nobuyuki; Shibama, Yusuke; Sakasai, Akira
Journal of Nuclear Materials, 390-391, p.891 - 894, 2009/06
Times Cited Count：1 Percentile：10.22(Materials Science, Multidisciplinary)The entire plasma facing components should be water-cooled in JT-60SA. A cassette module of divertor is introduced for remote maintenance. The divertor targets are mounted on the cassette. A brazed carbon fiber composite target is promising candidate for the divertor target. The latest results of mock-ups test clarified that thermal fatigue life cycles are more than 1000 cycles of 15 MW/m
10 sec. The divertor is designed to control divertor detachment for heat load reduction. The vertical targets and a "V-shaped corner" like as that in ITER are adopted to enhance detachment. Divertor heat load and pumping efficiency has been evaluated, using 2D plasma fluid (SOLDOR) and neutral Monte-Carlo (NEUT2D) code. The plasma detachment occurs near the outer-strike point within the "V-shaped corner", which results in low peak heat flux density 5.8 MW/m for the case with additional gas puff of 510
/s compared to 11.4 MW/m for the case without "V-shaped corner".
Nakano, Tomohide; Kubo, Hirotaka; Asakura, Nobuyuki; Shimizu, Katsuhiro; Kawashima, Hisato; Higashijima, Satoru
Journal of Nuclear Materials, 390-391, p.255 - 258, 2009/06
Times Cited Count：22 Percentile：80.43(Materials Science, Multidisciplinary)Therefore it is concluded that the dominant radiator, C
, is produced by ionization of C
and recombination of C
at similar rates around the X-point in the detached plasma, and that C is the second biggest radiator. Further the transport loss of C will be investigated by an impurity transport code (IMPMC), in addition to comparison of the radiation power and atomic processes.
Asakura, Nobuyuki; Ono, Noriyasu*; Tanaka, Hirohiko*; Kawashima, Hisato; Nakano, Tomohide
Journal of Nuclear Materials, 390-391, p.364 - 367, 2009/06
Times Cited Count：4 Percentile：30.49(Materials Science, Multidisciplinary)Characteristics of the fluctuations at three locations (Low-Field-Side midplane, X-point, and High-Field-Side SOLs) of the JT-60U SOL were investigated in L-mode and ELMy H-mode plasmas. Influence of their poloidal asymmetry at the LFS and HFS on the parallel plasma flow was investigated. For the L-mode, poloidal asymmetry in djs/
js
was enhanced at the LFS midplane (40-60%), while it was small (10-20%) at the HFS SOL and LFS X-point. On the other hand, djs/js was similar (20-30
) for the ELMy H-mode. Statistical properties (Skewness) and their poloidal asymmetry were different in the ELMy H-mode and L-mode plasmas. In the ELMy H-mode, positive S (= 0.3-0.5) was seen near the separatrix. However, in the L-mode, larger S (=0.5-0.9) was observed at the LFS midplane, and it extended to the far SOL (r 10 cm). In-out asymmetry in the intermittent transport will contribute to produce the SOL flow pattern.
Shimizu, Katsuhiro; Takizuka, Tomonori; Kawashima, Hisato
Journal of Nuclear Materials, 390-391, p.307 - 310, 2009/06
Times Cited Count：11 Percentile：59.85(Materials Science, Multidisciplinary)The divertor plasma should be cooled significantly by impurities to reduce the heat load onto the divertor plate up to the permissible level in fusion reactor. To achieve enhanced radiation, the control method for impurity retention in the divertor region should be established. Aiming at this impurity control, we have investigated the impurity generation and transport. 2D multi-fluid divertor codes have been developed, where the impurity transport is solved as fluid species. On the other hand, we have developed a impurity transport modelling IMPMC based on Monte-Carlo techniques. The MC approach provides the modelling method to take into account the kinetic effect and the complex dissociation processes of hydrocarbons. Using the IMPMC, the kinetic effect of thermal force on He transport is investigated for JT-60SA detached plasma. Without the recycling process, the kinetic effect of the thermal force is found to increase the He density in the divertor region by a factor of 2, compared with the conventional (fluid) evaluation. However, the kinetic effect is masked by the recycling at the target plates.
Tanaka, Hirohiko*; Ono, Noriyasu*; Asakura, Nobuyuki; Tsuji, Yoshiyuki*; Kawashima, Hisato; Takamura, Shuichi*; Uesugi, Yoshihiko*; JT-60U Team
Nuclear Fusion, 49(6), p.065017_1 - 065017_7, 2009/06
Times Cited Count：38 Percentile：78.35(Physics, Fluids & Plasmas)Comparison between fluctuation characteristics at high-field-side (HFS) and low-field-side (LFS) scrape off layers (SOLs) has been made, for the first time, in the L mode plasma of the JT-60U tokamak using reciprocating Langumuir probes. Statistical analysis based on probability distribution function (PDF) was employed to describe intermittent (non-diffusion) transport in SOL plasma fluctuations. The positive bursty events appeared most frequently at LFS midplane associated with blobby plasma transport, then the PDF is strongly skewed positively, while the PDF in HFS SOL is close to Gaussian distribution. Conditional averaging analysis of the positive bursty events at LFS midplane indicates the intermittent feature with a rapid increase and a slow decay is similar to that of plasma blobs theoretically predicted. Statistical self-similarity was also investigated with Fourier power spectrum and statistics of waiting-time and duration-time of the fluctuation.
