Deuterium recombination coefficient on tungsten surface determined by plasma driven permeation

•Deuterium plasma driven permeation experiments were performed for W rod sample.•Deuterium recombination coefficient on W surface is obtained by combing the PDP and GDP results.•Deuterium permeation rate through a 8 mm thick W under ITER divertor relevant conditions are estimated by HIDT simulation...

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Bibliographic Details
Published in:Fusion engineering and design 2020-11, Vol.160, p.111853, Article 111853
Main Authors: Zhao, Mingzhong, Yamazaki, Shota, Wada, Takuro, Koike, Ayaka, Sun, Fei, Ashikawa, Naoko, Someya, Yoji, Mieno, Tetsu, Oya, Yasuhisa
Format: Article
Language:English
Subjects:
Deuterium
Elongation
Hydrogen isotope
Hydrogen isotopes
Hydrogen storage
Ion flux
Penetration
Plasma
Plasma driven permeation
Radio frequency
Recombination coefficient
Tungsten
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Summary:•Deuterium plasma driven permeation experiments were performed for W rod sample.•Deuterium recombination coefficient on W surface is obtained by combing the PDP and GDP results.•Deuterium permeation rate through a 8 mm thick W under ITER divertor relevant conditions are estimated by HIDT simulation code. Deuterium (D) plasma driven permeation (PDP) experiments for tungsten (W) samples were conducted by a linear radio frequency (RF) plasma device. In the PDP experiment, the W sample surface is perpendicular to the grain elongation direction. The D ion flux is in the order of 1021 m−2 s−1 determined by a double Langmuir probe. The results show that bias had a limited effect on the D plasma driven permeation behavior. The D recombination coefficient on W surface is obtained at the temperature ranging from 740 K to 1031 K. The experimentally measured recombination coefficient for a pristine W surface is lower than that for a clean W surface. The effect of recombination coefficient on the D permeation and retention behaviors in W are studied by Hydrogen Isotope Diffusion and Trapping (HIDT) simulation code. The low recombination coefficient leads to a high D concentration in W and a high permeation rate at the back surface. The D permeation rate through a 8 mm thick W with a pristine surface is estimated to be 8.1 × 1018 D m s−1 under the incident ion flux of 1 × 1024 m−2 s−1 and temperature of 1173 K.
ISSN:0920-3796
1873-7196
DOI:10.1016/j.fusengdes.2020.111853