Isobe, Kanetsugu; Kawamura, Yoshinori; Iwai, Yasunori; Oyaizu, Makoto; Nakamura, Hirofumi; Suzuki, Takumi; Yamada, Masayuki; Edao, Yuki; Kurata, Rie; Hayashi, Takumi; et al.
Fusion Engineering and Design, 98-99, p.1792 - 1795, 2015/10
Activities on Broader Approach (BA) were started in 2007 on the basis of the Agreement between the Government of Japan and the EURATOM. The period of BA activities consist of Phase1 and Phase2 dividing into Phase 2-1 (2010-2011), Phase 2-2 (2012-2013) and Phase 2-3 (2014-2016). Tritium technology was chosen as one of important R&D issues to develop DEMO plant. R&D activities of tritium technology on BA consist of four tasks. Task-1 is to prepare and maintain the tritium handling facility in Rokkasho BA site in Japan. Task 2, 3 and 4 are main R&D activities for tritium and these are focused on: Task-2) Development of tritium accountancy technology, Task-3) Development of basic tritium safety research, Task-4) Tritium durability test. R&D activities of tritium technology in Phase 2-2 were underway successfully and closed in 2013.
Hayashi, Takumi; Nakamura, Hirofumi; Kawamura, Yoshinori; Iwai, Yasunori; Isobe, Kanetsugu; Yamada, Masayuki; Suzuki, Takumi; Kurata, Rie; Oyaizu, Makoto; Edao, Yuki; et al.
Fusion Science and Technology, 67(2), p.365 - 370, 2015/03
Edao, Yuki; Kawamura, Yoshinori; Kurata, Rie; Fukada, Satoshi*; Takeishi, Toshiharu*; Hayashi, Takumi; Yamanishi, Toshihiko
Fusion Science and Technology, 67(2), p.320 - 323, 2015/03
The present study aims at obtaining fundamental knowledge for tritium transfer behavior and interaction between tritium and paint coated on concrete walls. The amounts of tritium penetration and release in cement paste with epoxy and urethane paint coatings were measured. The tritium penetration amounts were increased with the HTO exposure time. Time to achieve each saturate tritium value was more than 60 days for cement paste coated with epoxy paint and with urethane paint, while cement paste without paint took 2 days to achieve it. Tritium penetration rates were estimated by an analysis of diffusion model. Although their paint coatings were effective for reduction of tritium penetration through the cement paste exposed to HTO for a short period, the amount of tritium trapped in the paints became large for a long time. This work has been performed under the collaboration research between JAEA and Kyushu University.
Kobayashi, Makoto*; Wang, W.*; Kurata, Rie; Matsuyama, Masao*; Hayashi, Takumi; Yamanishi, Toshihiko; Asakura, Yamato*; Oya, Yasuhisa*; Okuno, Kenji*
Fusion Science and Technology, 60(1), p.403 - 406, 2011/07
The trapping and release mechanisms of hydrogen isotopes for the stainless steel (SS) oxidized at various temperatures were investigated. The oxide layer was mainly consisted of iron oxides (FeO) and its decomposition temperature was almost consistent with the release temperature of deuterium, where major chemical form was a molecular deuterium (D). The deuterium retention was increased as the oxidation temperature increased. It was considered that the thickness of oxide layer would make a large influence on the retention of hydrogen isotopes. On the other hand, the amount of released deuterium as heavy water (DO) was independent with oxidation temperature. It was considered that the formation of hydrogen isotope as water form was depended on the amount of FeO on the top most surface layer of SS.
Ashikawa, Naoko*; Asakura, Nobuyuki; Hayashi, Takao; Fukumoto, Masakatsu; Kurata, Rie*; Kobayashi, Makoto*; Muroga, Takeo*; Oya, Yasuhisa*; Okuno, Kenji*
no journal, ,
Dust control is an important issue related to tritium retentions in thermonuclear fusion devices with magnetic confinements. In particular, remained hydrogen isotope in dust particles at shadow areas are serious problem related the limitation t capacity in ITER. In previous work of dust collection in LHD and JT-60U, typical diameters of dust particles were shown to be 0.001-10 micron in LHD, and 0.1-100 micron in JT-60U. Some tokamak device groups in TFTR, TEXTOR, JT-60 and JET tried to measure the hydrogen isotopes retentions in dust particles. However, they measured the retention only in the dust flakes with sizes exceeding about 10 microns. In this study, we tried to measure hydrogen isotope retentions in the dusts with small amount including those with small diameters. The estimation of the amount of remained hydrogen isotopes in the dust particles will be useful to estimate tritium inventory and optimize cleaning methods specific dusts in ITER and future fusion devices.
Hayashi, Takumi; Nakamura, Hirofumi; Iwai, Yasunori; Kawamura, Yoshinori; Isobe, Kanetsugu; Yamada, Masayuki; Suzuki, Takumi; Kurata, Rie; Edao, Yuki; Perevezentsev, A.*
no journal, ,
no abstracts in English