The role of the graphite divertor tiles in helium retention on the LHD wall

Makoto Oya, G. Motojima, M. Tokitani, H. Tanaka, S. Masuzaki, Y. Ueda

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

In this study, global particle balance of helium (He) long pulse discharge with graphite divertor in the Large Helical Device (LHD) and He retention in graphite from lab-scale experiments were compared in order to determine the role of the graphite divertor in He retention on the LHD wall. Global He particle balance analysis was conducted in long-pulse discharges in LHD with only turbo molecular pump. The analysis showed that static He retention was ∼2.9 × 1022 He and the ratio of retained He (= retention over fluence) was ∼0.45%. In the lab-scale study, He retention was measured by Thermal Desorption Spectroscopy (TDS) after ion irradiation or plasma exposure. The ratio of retained He were 0.1 ∼ 0.5% in all conditions, which was well consistent with LHD results. Therefore, it may be concluded that graphite divertor tiles have an important role in He absorption in the LHD wall at the initial phase of discharges.

Original languageEnglish
Pages (from-to)58-62
Number of pages5
JournalNuclear Materials and Energy
Volume13
DOIs
Publication statusPublished - Dec 1 2017
Externally publishedYes

Fingerprint

Helium
Graphite
tiles
Tile
graphite
helium
molecular pumps
Thermal desorption spectroscopy
Ion bombardment
pulses
ion irradiation
fluence
desorption
Pumps
Plasmas

All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics
  • Materials Science (miscellaneous)
  • Nuclear Energy and Engineering

Cite this

The role of the graphite divertor tiles in helium retention on the LHD wall. / Oya, Makoto; Motojima, G.; Tokitani, M.; Tanaka, H.; Masuzaki, S.; Ueda, Y.

In: Nuclear Materials and Energy, Vol. 13, 01.12.2017, p. 58-62.

Research output: Contribution to journalArticle

Oya, Makoto ; Motojima, G. ; Tokitani, M. ; Tanaka, H. ; Masuzaki, S. ; Ueda, Y. / The role of the graphite divertor tiles in helium retention on the LHD wall. In: Nuclear Materials and Energy. 2017 ; Vol. 13. pp. 58-62.
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