Speaker
Keisuke Azuma
(Graduate School of Science)
Description
Tungsten (W) is a candidate for plasma facing materials in D-T fusion reactors due to its higher melting point and lower sputtering yield. During the plasma operation, W will be exposed to energetic particles including hydrogen isotopes, neutrons, and impurities like carbon (C). It is well known that hydrogen isotopes are trapped in the defects produced by the energetic particle irradiation. In addition, a W-C mixed layer suppresses the deuterium (D) diffusion. Therefore, it is important to evaluate the synergetic Fe2+2+ and C++ implantation effect on D retention behavior for W under various damage distribution profiles. In this study, the irradiation damages were introduced by 6 MeV Fe2+2+ implantation with the damage concentration of 0.01, 0.1, and 1 dpa (displacement per atom). Then, 10 keV C++ implantation for these samples was performed with the damage concentration of 1.14 and 11.4 dpa. According to SRIM, implantation depth of Fe2+2+ and C++ is about 1.5 µm and 0.05 µm, respectively. Thereafter, 3 keV D2++ was implanted with the ion fluence of 1.0 × 102222 D++ m-2-2, and thermal desorption spectroscopy (TDS) measurements were performed to evaluate the D2 desorption behavior. The experimental results indicated that C++ implantation enhanced D retention trapped by vacancies, but D retention was diminished in C++ implanted W with higher fluence due to a decrease of the number of D trapping site as C++ trapped by vacancies increased. Additionally, it was also found that D was trapped by the high density of dislocation loops introduced by C++ implantation, and D retention behavior adsorbed from the surface was not controlled by Fe2+2+ implantation damage level. However, D was diffused toward the bulk and was trapped by stable voids introduced by Fe2+2+ implantation even if the dense damages were introduced by C++ implantation near the surface.
Co-authors
Buchenauer Dean
(Sandia National Laboratories, Livermore, CA, United States)
Chikada Takumi
(Graduate School of Science, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka, 422-8529, Japan)
Fujita Hiroe
(Graduate School of Science, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka, 422-8529, Japan)
Hatano Yuji
(Hydrogen Isotope Research Center, University of Toyama, 3190 Gohuku, Toyama, 930-8555, Japan)
Hu Cui
(Faculty of Science, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka, 422-8529, Japan)
Keisuke Azuma
(Graduate School of Science, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka, 422-8529, Japan)
Oya Yasuhisa
(Graduate School of Science, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka, 422-8529, Japan)
Sakurada Shodai
(Graduate School of Science, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka, 422-8529, Japan)
Shimada Masashi
(Idaho National Laboratory, Idaho, Falls, ID, United States)
Uemura Yuki
(Graduate School of Science, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka, 422-8529, Japan)
Yoshida Naoaki
(Research Institute for Applied Mechanics, Kyushu University, 6-1, Kasugakoen, Kasuga, Fukuoka, Japan)
