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Nobuta, Yuji*; Yamauchi, Yuji*; Hino, Tomoaki*; Akamaru, Satoshi*; Hatano, Yuji*; Matsuyama, Masao*; Suzuki, Satoshi; Akiba, Masato
Fusion Engineering and Design, 87(7-8), p.1070 - 1073, 2012/08
Times Cited Count:2 Percentile:17.09(Nuclear Science & Technology)Nobuta, Yuji*; Yokoyama, Kenji; Kanazawa, Jun*; Yamauchi, Yuji*; Hino, Tomoaki*; Suzuki, Satoshi; Ezato, Koichiro; Enoeda, Mikio; Akiba, Masato
Journal of Nuclear Materials, 417(1-3), p.607 - 611, 2011/10
Times Cited Count:2 Percentile:17.82(Materials Science, Multidisciplinary)Ito, Tatsuya*; Yamauchi, Yuji*; Hino, Tomoaki*; Shibayama, Tamaki*; Nobuta, Yuji*; Ezato, Koichiro; Suzuki, Satoshi; Akiba, Masato
Journal of Nuclear Materials, 417(1-3), p.1147 - 1149, 2011/10
Times Cited Count:13 Percentile:68.15(Materials Science, Multidisciplinary)Hino, Tomoaki*; Shibata, Hironobu*; Yamauchi, Yuji*; Nobuta, Yuji*; Suzuki, Satoshi; Akiba, Masato
Journal of Nuclear Materials, 417(1-3), p.713 - 717, 2011/10
Times Cited Count:8 Percentile:51.99(Materials Science, Multidisciplinary)Nobuta, Yuji*; Arai, Takashi; Yagyu, Junichi; Masaki, Kei; Sato, Masayasu; Tanabe, Tetsuo*; Yamauchi, Yuji*; Hino, Tomoaki*
Journal of Nuclear Materials, 390-391, p.643 - 646, 2009/06
Times Cited Count:5 Percentile:35.16(Materials Science, Multidisciplinary)The hydrogen and deuterium retention in gap side surfaces of the first wall tiles exposed to DD and HH discharges in JT-60U were investigated. The hydrogen and deuterium retention and boron deposition increased with the gap width. The depth profile of deuterium was very similar to that of boron, indicating that deuterium was incorporated with boron. Thick carbon deposition layer ( 1e
m) was observed in the gap of inboard tile and the atomic ratio in (H+D)/C at the carbon layer was estimated to be approximately 0.15. This value is higher than that observed in the divertor region. In this study, the H+D amount in gap side surfaces of the first wall was of the order of 1e23
1e24m
.
Yoshida, Masafumi; Tanabe, Tetsuo*; Nobuta, Yuji*; Hayashi, Takao; Masaki, Kei; Sato, Masayasu
Journal of Nuclear Materials, 390-391, p.635 - 638, 2009/06
Times Cited Count:9 Percentile:52.21(Materials Science, Multidisciplinary)We have investigated hydrogen isotopes retention in the outboard first wall tiles of JT-60U by means of TDS, SIMS and SEM. The outboard first wall tiles of JT-60U are mostly eroded. The total retention (H+D) normalized by a unit area and integrated NBI time in the eroded first wall tiles and the eroded divertor tiles were nearly the same, in spite of the lower temperature of the first wall. Differently from divertor tiles, in which H retention was dominated owing to HH discharges preformed after DD discharges, deuterium is dominated in hydrogen isotopes retention and penetrates deeper from the surface. This is attributed to injection of high energy D and difficulty of isotopic replacement owing to their lower temperature. The integrated amount over the whole surface could be appreciably large. This type of hydrogen retention could be also possible for the metallic wall.
Ueda, Yoshio*; Fukumoto, Masakatsu*; Watanabe, Jun*; Otsuka, Yusuke*; Arai, Takashi; Asakura, Nobuyuki; Nobuta, Yuji*; Sato, Masayasu; Nakano, Tomohide; Yagyu, Junichi; et al.
Proceedings of 22nd IAEA Fusion Energy Conference (FEC 2008) (CD-ROM), 8 Pages, 2008/10
Deposition profiles of tungsten released from the outer divertor were studied in JT-60U. A neutron activation method was used for the first time to accurately measure deposited tungsten. Surface density of tungsten in the thick carbon deposition layer can be measured by this method. Tungsten was mainly deposited on the inner divertor (around inner strike points) and on the outer wing of the dome. Toroidal distribution of the W deposition was significantly localized near the tungsten released position, while other metallic impurities such as Fe, Cr, Ni were distributed more uniformly. These data indicate that inward drift in the divertor region played a significant role in tungsten transport in JT-60U.
Ashikawa, Naoko*; Kizu, Kaname; Yagyu, Junichi; Nakahata, Toshihiko*; Nobuta, Yuji; Nishimura, Kiyohiko*; Yoshikawa, Akira*; Ishimoto, Yuki*; Oya, Yasuhisa*; Okuno, Kenji*; et al.
Journal of Nuclear Materials, 363-365, p.1352 - 1357, 2007/06
Times Cited Count:11 Percentile:60.25(Materials Science, Multidisciplinary)no abstracts in English
Nobuta, Yuji; Masaki, Kei; Arai, Takashi; Sakasai, Akira; Miya, Naoyuki; Tanabe, Tetsuo*
Europhysics Conference Abstracts (CD-ROM), 31F, 4 Pages, 2007/00
no abstracts in English
Nobuta, Yuji; Masaki, Kei; Arai, Takashi; Sakasai, Akira; Miya, Naoyuki; Tanabe, Tetsuo*
no journal, ,
no abstracts in English
Yoshida, Masashi*; Tanabe, Tetsuo*; Oya, Yasuhisa*; Masaki, Kei; Nobuta, Yuji; Hayashi, Takao; Sato, Masayasu
no journal, ,
no abstracts in English
Suzuki, Satoshi; Ito, Tatsuya*; Nobuta, Yuji*; Yamauchi, Yuji*; Hino, Tomoaki*; Ezato, Koichiro; Yokoyama, Kenji; Akiba, Masato
no journal, ,
A reduced activation ferritic-maternstic steel, F82H, is one of candidate structural materials for the first wall of fusion machines. For F82H, retention and desorption behavior of F82H has not been clarified though such behavior is considered to be significant from the plasma density control and safety points of view. In this study, F82H samples were irradiated by hydrogen ion in JAEA. In addition, these samples with surface defects were also irradiated by deuterium ion to investigate the retention and the desorption behavior based on its surface defects. As a result, while the amount of the deuterium retention has not been changed at a holding temperature below 550 K, it is significantly decreased at a holding temperature over 770 K.
Masuzaki, Suguru*; Tokitani, Masayuki*; Miyamoto, Mitsutaka*; Nobuta, Yuji*; Ueda, Yoshio*; Ono, Noriyasu*; Sakamoto, Mizuki*; Ashikawa, Naoko*; Nakano, Tomohide; Itami, Kiyoshi
no journal, ,
A design of the movable material probe system for JT-60SA is proposed. The system provides the opportunity for inserting material specimens and diagnostics into the plasma vacuum vessel, and for specimens changing during experimental campaign. The system will consist of manipulator, gate-valves, working chamber and pumps. The system is under consideration to be installed in a bottom port. It will contribute to plasma-wall interaction studies in JT-60SA.
Nakahata, Toshihiko*; Oya, Yasuhisa*; Yoshikawa, Akira*; Suda, Taichi*; Oyaizu, Makoto*; Ashikawa, Naoko*; Nishimura, Kiyohiko*; Yagyu, Junichi; Kizu, Kaname; Nobuta, Yuji; et al.
no journal, ,
no abstracts in English
Ashikawa, Naoko*; Nishimura, Kiyohiko*; Masuzaki, Takashi*; Sagara, Akio*; Oyabu, Nobuyoshi*; Kizu, Kaname; Yagyu, Junichi; Nobuta, Yuji; Ishimoto, Yuki*; Miya, Naoyuki; et al.
no journal, ,
no abstracts in English
Fukumoto, Masakatsu*; Otsuka, Yusuke*; Ueda, Yoshio*; Tanabe, Tetsuo*; Sakasai, Akira; Masaki, Kei; Arai, Takashi; Yagyu, Junichi; Nobuta, Yuji; Kubo, Hirotaka; et al.
no journal, ,
no abstracts in English