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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.
Mao, G.; Chiba, Satoshi; Greiner, W.*; Oyamatsu, Kazuhiro*
International Journal of Modern Physics E, 9(2), p.185 - 192, 2000/04
Times Cited Count:0 Percentile:0.01(Physics, Nuclear)no abstracts in English
Mao, G.; Chiba, Satoshi; Greiner, W.*; Oyamatsu, Kazuhiro*
JAERI-Research 99-072, p.15 - 0, 1999/12
no abstracts in English
Maruyama, Toshiki; Niita, Koji*; Oyamatsu, Kazuhiro*; Maruyama, Tomoyuki*; Chiba, Satoshi; Iwamoto, Akira
Nuclear Physics A, 654(3-4), p.908C - 911C, 1999/00
no abstracts in English
Maruyama, Toshiki; Niita, Koji*; Oyamatsu, Kazuhiro*; Maruyama, Tomoyuki*; Iwamoto, Akira; Chiba, Satoshi
Physical Review C, 57(2), p.655 - 665, 1998/02
Times Cited Count:107 Percentile:97.06(Physics, Nuclear)no abstracts in English
Tanaka, Shingo; Sato, Haruo; Niizato, Tadafumi; Amano, Kenji; Nohara, Tsuyoshi; Iwatsuki, Teruki; Murakami, Hiroaki; Sugita, Yutaka; Nakayama, Masashi; Abe, Hironobu; et al.
no journal, ,
The sorption distribution coefficients of cesium and iodine onto the soil are studied. The batch sorption experiments were conducted onto the 24 specimens obtained from 11 sites (12 geoslicers) at each two different depth compartment. The experiments were based on the way standardized by Atomic Energy Society of Japan. The Kd values of cesium ranged from 1,000 to 100,000 ml/g, corresponding to the result that most of the cesium in the investigation sites are stayed in the surface of the ground. On the other hand, the Kd values of iodine ranged from 0.4 to 150 ml/g. It is likely that the difference of Kd values is affected by not only the chemical form of the elements between cesium and iodine, but also mineral composition, cation and anion exchange capacities, content of organic matter, and so on. This investigation initially focuses on varieties of soil, such as sandy or clayey soil, and soil colors.
Chiba, Kazuhiro*; Takano, Nao*; Yamamoto, Mitsuru*; Teranishi, Mika*; Hase, Yoshihiro; Sakamoto, Ayako; Tanaka, Atsushi; Hidema, Jun*
no journal, ,
no abstracts in English