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Takenaga, Hidenobu; Sakasai, Akira; Kubo, Hirotaka; Asakura, Nobuyuki; Schaffer, M. J.*; Petrie, T. W.*; Mahdavi, M. A.*; Baker, D. R.*; Allen, S. L.*; Porter, G. D.*; et al.
Nuclear Fusion, 41(12), p.1777 - 1787, 2001/12
Times Cited Count：22 Percentile：57.57(Physics, Fluids & Plasmas)no abstracts in English
Tokunaga, Shinsuke; Hoshino, Kazuo; Asakura, Nobuyuki; Shimizu, Katsuhiro; Hiwatari, Ryoji
no journal, ,
Satisfactory heat and particle exhaust capabilities against to large fusion output are both required for DEMO divertor design. It is expected that full-detach divertor is necessary to satisfy the demands. In such parameter regime, neutral-neutral collision (NNC) plays important role for neutral's density-pressure profile formation. In this study, NNC effect is implemented to divertor simulation code SONIC and its effect on detached divertor and exhaust are analyzed. It is apparently shown that neutral profile is poloidally/radially localized due to shrunk mean-free-path.
Asakura, Nobuyuki; Hoshino, Kazuo; Uto, Hiroyasu; Someya, Yoji; Tokunaga, Shinsuke; Shimizu, Katsuhiro; Suzuki, Satoshi; Tobita, Kenji; Ono, Noriyasu*; Ueda, Yoshio*; et al.
no journal, ,
Radiative cooling scenario by impurity seeding has been developed and the divertor geometry, and the plasma operation have been investigated for Demo with the fusion power of 1.5 GW, using SONIC simulation. Results showed the total peak heat load is reduced to less than 10 MWm
for the total radiation power fraction of 0.7-0.8. The heat load can be handled by the water-cooling and tungsten (W) monoblock target design, provided that Cu-alloy cooling pipe is applied. The design is applied only in the divertor target. F82H cooling pipe design will be applied for the divertor baffle and dome under higher neutron flux and lower heat load condition. Heat transport analysis of the target design and cooling-water pipes showed that the divertor design can handle the heat load distribution. The conceptual design study of the Demo divertor and power exhaust is presented. Development issues of physics, engineering and plasma material interaction from ITER technology will be also discussed.
Fukuda, Makoto*; Hirano, Koichiro; Tokunaga, Kazutoshi*; Ezato, Koichiro*
no journal, ,
Tungsten which is used as a plasma-facing material for ITER divertor is expected to receive heat flux under various conditions during ITER operation. Therefore, it is necessary to understand the modification of tungsten surface under various heat load conditions. In this work, as part of the investigation of the repeated short pulse heat load effect on tungsten, the effect of multiple irradiation (3MeV, 5Hz) with a negative hydrogen ion beam was evaluated. As a result, unevenness and cracks were observed on the surface after irradiation, and different surface modification behavior was observed compared with previous experiment which performed with almost constant heat load (10s On and 20-30 s Off as one cycle).
