Speaker
Yasuhisa Oya
(College of Science)
Description
Silicon carbide (SiC) is considered to be used for blanket modules for high temperature gas–cooling system in D-T fusion reactors, as SiC/SiC composites. During D-T fusion operation, SiC will be exposed to heavy radiation conditions by neutron and/or gamma-ray. These radiation induces the formation of various damages by a collision process and an electron excitation process, leading to the retention enhancement of hydrogen isotopes including tritium. In this study, 6.4 MeV Fe3+3+ and/or gamma ray irradiations were performed for SiC and thereafter D2++ implantation or D2 gas exposure experiment was done. Their D retention and chemical behaviors were evaluated by thermal desorption spectroscopy (TDS) and X-ray photoelectron spectroscopy (XPS).
Disk type beta-SiC was used as a sample. After annealing at 1173 K, 6.4 MeV Fe3+3+ implantation with a damage concentration of 0.2 dpa was performed at DuET tandem accelerator at Kyoto University. Cobalt-60 gamma ray irradiation was performed up to the dose of 400 kGy. Thereafter, 1 keV D2++ was implanted with a fluence of 1.0×102222 D++ m-2 -2 at room temperature. In addition, D2 gas exposure experiment was also performed at 100 kPa for 20 hours. The TDS measurement showed that D2 desorption was consisted of two stages located at 890 K and 1080 K, attributing to be the desorption of D bound to Si as Si-D bond and that bound to C as C-D bond, respectively. For radiation exposed SiC, both of D retentions as both stages 1 and 2 were increased as D2++ fluence increased, which was quite different from that for undamaged SiC, suggesting that the formation of dangling bonds enhanced D trapping efficiency. The detail D trapping behavior and change of chemical state for SiC was discussed in the presentation.
Co-authors
Hiroe Fujita
(Graduate School of Science and Technology, Shizuoka University, Shizuoka, Japan)
Hiroto Matsuura
(Radiation Research Center, Osaka Prefecture University, Osaka, Japan)
Keisuke Azuma
(Graduate School of Science and Technology, Shizuoka University, Shizuoka, Japan)
Kenta Yuyama
(Graduate School of Science, , Shizuoka University, Shizuoka, Japan)
Masafumi Akiyoshi
(Radiation Research Center, Osaka Prefecture University, Osaka, Japan)
Shodai Sakurada
(Graduate School of Science and Technology, Shizuoka University, Shizuoka, Japan)
Sosuke Kondo
(Institute of Advanced Energy, Kyoto University, Kyoto, Japan)
Takumi Chikada
(College of Science, Academic Institute, Shizuoka University, Shizuoka, Japan)
Tatsuya Hinoki
(Institute of Advanced Energy, Kyoto University, Kyoto, Japan)
Yasuhisa Oya
(College of Science, Academic Institute, Shizuoka University, Shizuoka, Japan)
Yuki Uemura
(Graduate School of Science and Technology, Shizuoka University, Shizuoka, Japan)
