Enhancement of hydrogen isotope retention capacity for the impurity deposited tungsten by long-term plasma exposure in LHD

Yasuhisa Oya, Suguru Masuzaki, Masayuki Tokitani, Naoaki Yoshida, Hideo Watanabe, Yuji Yamauchi, Tomoaki Hino, Mitsutaka Miyamoto, Yuji Hatano, Kenji Okuno

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Abstract

The stress relieved tungsten samples were placed at three positions, PI (sputtering erosion dominated area), DP (deposition dominated area) and HL (Higher heat load area) during 15th plasma experiment campaign in Large Helical Device (LHD) at National Institute for Fusion Science (NIFS), Japan and were exposed to ∼ 6700 shots of hydrogen plasma in a 15th long-term experiment campaign in LHD. Thereafter, the additional deuterium ion implantation to these tungsten samples was performed to evaluate the change of hydrogen isotope retention capacity in the samples by long-term plasma exposure. It was found that the carbon-dominant mixed-material layer with more than 100 nm thickness was formed on a wide area of the tungsten surface. The thicker mixed-material layer was formed on the DP sample, where the deuterium retention was about 21 times as high as that for pure W. The major desorption temperature of deuterium was shifted toward higher temperature side, which was comparable to the trapping characteristic of carbon or irradiation damages.

Original languageEnglish
Pages (from-to)1699-1703
Number of pages5
JournalFusion Engineering and Design
Volume88
Issue number9-10
DOIs
Publication statusPublished - Oct 1 2013

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All Science Journal Classification (ASJC) codes

  • Civil and Structural Engineering
  • Nuclear Energy and Engineering
  • Materials Science(all)
  • Mechanical Engineering

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