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Ikeda, Yoshitaka; Okano, Fuminori; Sakasai, Akira; Hanada, Masaya; Akino, Noboru; Ichige, Hisashi; Kaminaga, Atsushi; Kiyono, Kimihiro; Kubo, Hirotaka; Kobayashi, Kazuhiro; et al.
Nihon Genshiryoku Gakkai Wabun Rombunshi, 13(4), p.167 - 178, 2014/12
The JT-60U torus was disassembled so as to newly install the superconducting tokamak JT-60SA torus. The JT-60U used the deuterium for 18 years, so the disassembly project of the JT-60U was the first disassembly experience of a fusion device with radioactivation in Japan. All disassembly components were stored with recording the data such as dose rate, weight and kind of material, so as to apply the clearance level regulation in future. The lessons learned from the disassembly project indicated that the cutting technologies and storage management of disassembly components were the key factors to conduct the disassembly project in an efficient way. After completing the disassembly project, efforts have been made to analyze the data for characterizing disassembly activities, so as to contribute the estimation of manpower needs and the radioactivation of the disassembly components on other fusion devices.
Ikeda, Yoshitaka; Okano, Fuminori; Hanada, Masaya; Sakasai, Akira; Kubo, Hirotaka; Akino, Noboru; Chiba, Shinichi; Ichige, Hisashi; Kaminaga, Atsushi; Kiyono, Kimihiro; et al.
Fusion Engineering and Design, 89(9-10), p.2018 - 2023, 2014/10
Times Cited Count：2 Percentile：16.44(Nuclear Science & Technology)Disassembly of the JT-60U torus was started in 2009 after 18-years D
operations, and was completed in October 2012. The JT-60U torus was featured by the complicated and welded structure against the strong electromagnetic force, and by the radioactivation due to D-D reactions. Since this work is the first experience of disassembling a large radioactive fusion device in Japan, careful disassembly activities have been made. About 13,000 components cut into pieces with measuring the dose rates were removed from the torus hall and stored safely in storage facilities by using a total wokers of 41,000 person-days during 3 years. The total weight of the disassembly components reached up to 5,400 tons. Most of the disassembly components will be treated as non-radioactive ones after the clearance verification under the Japanese regulation in future. The assembly of JT-60SA has started in January 2013 after this disassembly of JT-60U torus.
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)Kubo, Junichi*; Rahman, N.*; Takahashi, Nobuaki; Kawai, Takahiko*; Matsuba, Go*; Nishida, Koji*; Kanaya, Toshiji*; Yamamoto, Masahide*
Journal of Applied Polymer Science, 112(3), p.1647 - 1652, 2009/05
Times Cited Count：25 Percentile：62.54(Polymer Science)Aiming at improvement of mechanical and dielectric properties of poly(vinyl alcohol) (PVA) we prepared composites of PVA and magnesium nitrate. It was found that the composites were very soft and rubber-like, and the glass transition temperature decreased with increasing the salt concentration. Wide-angle X-ray diffraction and small-angle X-ray scattering revealed that the crystallites of PVA were destroyed by the additive and it was a cause of the softening.
Fuchimukai, Junichi*; Yamaguchi, Hitoshi*; Meguro, Yoshihiro; Kubota, Toshio*; Igarashi, Shukuro*
Solvent Extraction Research and Development, Japan, 13, p.139 - 146, 2006/00
no abstracts in English
D
) in JT-60UNakano, Tomohide; Higashijima, Satoru; Kubo, Hirotaka; Yagyu, Junichi; Arai, Takashi; Asakura, Nobuyuki; Itami, Kiyoshi
Journal of Nuclear Materials, 313-316(1-3), p.149 - 152, 2003/03
Times Cited Count：29 Percentile：85.65(Materials Science, Multidisciplinary)In JT-60U, boronization using hydride-decaborane (BD) was performed to reduce oxygen impurity and particle recycling. A problem of the boronization was that hydrogen originating from hydride-decaborane diluted core deuterium plasmas. In order to minimize the number of conditioning tokamak discharges, boronization using deuterated-decaborane (BD) has been introduced recently. In order to investigate durability of the boronization effects, discharges with an identical condition were repeated. Boronization using 20 g of deuterated-decaborane could reduce a core oxygen content from 
1.9% to only 1.3% in L-mode discharges with a neutral beam heating power of 4 MW. Boronization using 70 g of deuterated-decaborane reduced the core oxygen content from 2.2% to 0.5%. After the boronization using 70 g of deuterated-decaborane ( thickness of the Boron layer 135 nm ), the core oxygen content increased gradually from 0.5% to 1% in 400 shots.
Y.S.Soebianto*; Katsumura, Yosuke*; Ishigure, Kenkichi *; *; *; Kudo, Hisaaki; Seguchi, Tadao
Radiation Physics and Chemistry, 48(4), p.449 - 456, 1996/00
Times Cited Count：11 Percentile：68.11(Chemistry, Physical)no abstracts in English
Y.S.Soebianto*; *; Katsumura, Yosuke*; Ishigure, Kenkichi *; *; *; *; Kudo, Hisaaki; Seguchi, Tadao
JAERI-Conf 95-003, 0, p.96 - 100, 1995/03
no abstracts in English
Y.S.Soebianto*; *; Katsumura, Yosuke*; Ishigure, Kenkichi*; *; Kudo, Hisaaki; Seguchi, Tadao
Polym. Degrad. Stab., 50, p.203 - 210, 1995/00
Times Cited Count：28 Percentile：76.3(Polymer Science)no abstracts in English
Y.S.Sobianto*; Katsumura, Yosuke*; *; *; Kudo, Hisaaki; Seguchi, Tadao
DEI-93-156, p.27 - 34, 1993/12
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
Kubo, Hirotaka; Arai, Takashi; Hasegawa, Koichi; Hoshi, Ryo*; Kawashima, Hisato; Maesaki, Yoshitaka; Masaki, Kei; Sawai, Hiroaki; Shibanuma, Kiyoshi; Tabe, Masato; et al.
no journal, ,
The JT-60SA tokamak, which is a large superconducting tokamak, needs to be assembled consistently with high precision; assembly of the JT-60SA tokamak has been studied. The absolute coordinate system for the assembly is defined on the basis of the coordinate system of the JT-60 torus hall. The origin ((x, y, z) = (0, 0, 0)) of the absolute coordinate system is defined to be the center of the VV in the plasma operation. A consistent global scenario of the assembly is studied. Assembly procedures and tools for major components such as the TFCs are studies.
Kawashima, Hisato; Kubo, Hirotaka; Arai, Takashi; Masaki, Kei; Yagyu, Junichi; Hasegawa, Koichi; Shibanuma, Kiyoshi
no journal, ,
The design study of JT-60SA has been carried out efficiently using the CAD system. Main components such as the vacuum vessel (VV) were distinguished for 24 items and CAD designers began with the design of parts and assembly on every item. Basic design is almost completed except the manufactured apparatuses such as VV. All components are being integrated as the large-assembly to study the interference and accessibility among those components. This large-assembly model consists of 10,000 parts and 4 GB volume at present, corresponding the largest scale structure in this field. Special difficulties are produced as that the existing computer (PC) cannot cover enough and CAD data of each component must be managed unified. Therefore, it is carried out to optimize the PC, to reduce the volume using the favorable function of CAD, and to introduce the data management system. Thus, handling of JT-60SA large-assembly model, which becomes a large scale more, is in progress.
Arai, Takashi; Hasegawa, Koichi; Hoshi, Ryo; Kawashima, Hisato; Kubo, Hirotaka; Masaki, Kei; Sawai, Hiroaki; Shibanuma, Kiyoshi; Tsukao, Naohiro; Yagyu, Junichi; et al.
no journal, ,
In a JT-60SA project, JT-60U is repaired to superconductivity tokamak JT-60 SA as a satellite tokamak plan by "broad approach (BA) activities towards realization of the early stage of nuclear fusion energy" who carries out by Japan-Europe cooperation. JT-60SA is built in the torus hall of a JT-60 experiment building main part after demolition of JT-60U equipment. In JT-60 SA, arrangement examination and an interference check are performed about the apparatus of the structure which becomes intricate intricately using a 3D-CAD model. A plan for the three-dimensional measuring instrument (laser tracker) which is leading-edge technology to perform position measurement is carried out. The laser tracker is highly precise as compared with the usual measuring instrument, and can make a fabrication error small as much as possible. A lecture describes position measurement together with an assembly procedure.
