[Table of Contents]

Plasma and Fusion Research

Volume 10, 3405039 (2015)

Regular Articles

Carbon and Hydrogen Accumulation on Exhaust Duct in LHD
Kazunari KATAYAMA, Naoko ASHIKAWA1), Keiichiro UEHARA and Satoshi FUKADA
Interdisciplinary Graduate School of Engineering Science, Kyushu University, 6-1 Kasugakoen, Kasuga-shi, Fukuoka 816-8580, Japan
1)
National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Japan
(Received 25 November 2014 / Accepted 8 March 2015 / Published 16 April 2015)

Abstract

To consider carbon balance and hydrogen isotope balance in the fuel cycle system and tritium safety management of a fusion reactor, the evaluation of carbon and hydrogen isotope accumulation not only in the vacuum vessel but also in the exhaust system is necessary. In the present work, type 316 stainless steel substrates were installed at 4 locations in the exhaust duct of the Large Helical Device (LHD) during the 13th experimental campaign. By using the combustion method, the amount of carbon slightly adhering to the substrates, which cannot be measured by electric microbalances, was successfully quantified to be 2 µg/cm2. The hydrogen release behavior from the substrate was consistent with that from carbon deposition layer formed by hydrogen plasma sputtering. H/C ratio on the substrate was estimated to be about 1-1.5. Hydrogen incorporated into the metal deposit formed from type 316 stainless steel in the sputtering-deposition device in the laboratory can remain in the deposit even under high vacuum condition in the exhaust duct for a long period.

Keywords

carbon accumulation, hydrogen isotope accumulation, exhaust duct

DOI: 10.1585/pfr.10.3405039

Full Text

PDF format (1.3Mbytes) PDF Download

References

  • [1] J. Roth and C. Hopf, J. Nucl. Mater. 334, 97 (2004).
  • [2] W. Jacob, J. Nucl. Mater. 337-339, 839 (2005).
  • [3] R.-D. Penzhorn et al., Fusion Eng. Des. 56-57, 105 (2001).
  • [4] A. Sagara et al., J. Nucl. Mater. 313-316, 1 (2003).
  • [5] Y. Nobuta et al., J. Nucl. Mater. 329-333, 800 (2004).
  • [6] M. Tokitani et al., J. Nucl. Mater. 417, 668 (2011).
  • [7] Y. Nobuta et al., J. Nucl. Mater. 438, S1040 (2013).
  • [8] T. Tanabe et al., J. Nucl. Mater. 345, 89 (2005).
  • [9] Y. Hirohata et al., J. Nucl. Mater. 363-365, 854 (2007).
  • [10] K. Katayama et al., J. Nucl. Mater. 438, S1010 (2013).
  • [11] Y. Uchida et al., Fusion Sci. Technol. 54, 545 (2008).
  • [12] K. Katayama et al., Fusion Eng. Des. 86, 1702 (2011).
  • [13] H.G. Esser et al., J. Nucl. Mater. 363-365, 146 (2007).

This paper may be cited as follows:

Kazunari KATAYAMA, Naoko ASHIKAWA, Keiichiro UEHARA and Satoshi FUKADA, Plasma Fusion Res. 10, 3405039 (2015).