研究報告35 - 1 論文 - Original
LHDプラズマに曝したステンレス鋼の表面変質とヘリウムの吸蔵・放出
Surface Properties and Retention of Helium in Stainless Steel Exposed to LHD Plasmas
吉田直亮1、湯上尚之2、木村陽太2、藤原正1、
荒木邦明1、吉原麗子1、渡邊英雄1、時谷政行3、増崎貴3、波多野雄治4、
松山政夫4、大矢恭久3、奥野健二5
1九州大学応用力学研究所、816-8580 春日市春日公園6-1
2九州大学大学院総合理工学研究科、816-8580 春日市春日公園6-1
3自然科学研究機構核融合科学研究所、509-5292 土岐市下石町322-6
4富山大学研究推進機構水素同位体科学研究センター、930-8555 富山市五福3190
5静岡大学大学院理学領域、422-8529 静岡市駿河区大谷836
N. Yoshida1, N. Yugami2, Y. Kimura2, T. Fujiwara1, K. Araki1, R. Yoshihara1,
H. Watanabe1,
M. Tokitani3, S. Masuzaki3, Y. Hatano4, M. Matsuyama4, Y. Oya5, K. Okuno5
1Research Institute for Applied Mechanics, Kyushu University, Kasuga-Koen, Kasuga, Fukuoka 816-8580, Japan
2Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga-Koen, Kasuga, Fukuoka 816-8580, Japan
3National Institute for Fusion Science, Oroshi, Toki, Gifu 509-5292, Japan
4 Hydrogen Isotope Research Center, Organization for Promotion or Research, University of Toyama, Gofuku, Toyama 930-8555, Japan
5Faculty of Science, Shizuoka University, Ohya, Suruga-ku, Shizuoka 422-8529, Japan
Abstract
Modification of the plasma facing surface of LHD and its effects on the retention and desorption of He were examined by exposing 316L stainless steel coupons to LHD plasmas.
In the erosion dominant area, formation of dense He bubbles and mixing of deposited impurities (C, O, Fe, Cr, Ni) occurred in a subsurface region of about 20 nm-thick. In the deposition dominant area, the surface was covered by a porous carbon rich layer. Retention of He was saturated in both areas. In the erosion dominant area, He was trapped by the radiation-induced defects formed in the very thin subsurface region.
The concentration of He trapped in the impurity deposition (He/C) in the deposition dominant area was estimated to be 0.9%.