Plasma and Fusion Research

Volume 15, 1505081 (2020)

Overview Articles

Dynamics of Hydrogen Isotope Absorption and Emission of Neutron-Irradiated Tungsten
Takeshi TOYAMA1), Miyuki YAJIMA2), Noriyasu OHNO3), Tatsuya KUWABARA3), Vladimir Kh. ALIMOV1,4,5) and Yuji HATANO6)
1)
Institute for Materials Research, Tohoku University, Oarai 311-1313, Japan
2)
National Institute for Fusion Science, Toki 509-5292, Japan
3)
Graduate School of Engineering, Nagoya University, Nagoya 464-8063, Japan
4)
National Research Centre “Kurchatov Institute”, Moscow 123182, Russia
5)
A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Moscow 119071, Russia
6)
Hydrogen Isotope Research Center, Organization for Promotion of Research, University of Toyama, Toyama 930-8555, Japan
(Received 13 March 2020 / Accepted 29 September 2020 / Published 19 November 2020)

Abstract

This overview presents recent results regarding hydrogen isotope absorption and emission dynamics in neutron-irradiated tungsten (W) using our recently developed Compact Diverter Plasma Simulator (CDPS), a linear plasma device in a radiation-controlled area. Neutron irradiation to 0.016 - 0.06 displacement per atom resulted in a significant increase in deuterium (D) retention due to trapping effects of radiation-induced defects. We analyzed the dependency of D retention on the D plasma fluence by exposing neutron-irradiated pure W to D plasma at 563 K over a range of D fluence values. The total retention was revealed to be proportional to the square root of D fluence, indicating that the implanted D atoms first occupy the defects caused by neutron-irradiation near the surface and then the defects located in deeper regions. We further investigated the effects of post-plasma annealing on D emission; neutron-irradiated pure W was exposed to D plasma at 573 K and was then annealed at the same temperature for 30 hours. Approximately 10% of the absorbed D was released by annealing, suggesting that a heat treatment of the plasma-facing component of a fusion reactor at moderately elevated temperatures could contribute to the removal of accumulated hydrogen isotopes. The experimental results obtained in this study were only available by investigating neutron-irradiated specimens with the CDPS system, which will be essential for future studies of material behavior and plasma-wall interactions in the fusion reactor environment.

Keywords

tungsten, neutron irradiation, TDS, deuterium

DOI: 10.1585/pfr.15.1505081

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References

  • [1] Y. Ueda et al., Physica Scripta T145, 014029 (2011).
  • [2] A. Hasegawa et al., Mater. Trans. 54, 466 (2013).
  • [3] J. Roth et al., Phys. Scr. T145, 014031 (2011).
  • [4] M. Shimada et al., J. Nucl. Mater. 415, S667 (2011).
  • [5] Y. Hatano et al., Mater. Trans. 54, 437 (2013).
  • [6] Y. Hatano et al., Nucl. Fusion 53, 073006 (2013).
  • [7] Y. Hatano et al., J. Nucl. Mater. 438, S114 (2013).
  • [8] K. Ohsawa et al., J. Nucl. Mater. 458, 187 (2015).
  • [9] T. Toyama et al., J. Nucl. Mater. 499, 464 (2018).
  • [10] K. Ohsawa et al., J. Nucl. Mater. 527, 151825 (2019).
  • [11] N. Ohno et al., Plasma Fusion Res. 12, 1405040 (2017).
  • [12] W.R. Wampler et al., Nucl. Fusion 49, 115023 (2009).
  • [13] D.G. Whyte, J. Nucl. Mater. 390-391, 911 (2009).
  • [14] M. Yajima et al., Nucl. Mater. Energy 21, 100699 (2019).
  • [15] D. Mueller et al., J. Nucl. Mater. 241-243, 897 (1997).
  • [16] V. Kh. Alimov et al., Nucl. Fusion 60, 096025 (2020).
  • [17] T. Troev et al., Nucl. Instrum. Meth. B 267, 535 (2009).
  • [18] G.R. Longhurst et al., TMAP4 User's Manual, https://doi.org/10.2172/7205576 (1992).
  • [19] O.V. Ogorodnikova, J. Nucl. Mater. 522, 74 (2019).
  • [20] R.A. Anderl et al., Fusion Technol. 21, 745 (1922).
  • [21] R. Frauenfelder, J. Vac. Sci. Technol. 6, 388 (1969).
  • [22] V. Kh. Alimov et al., J. Nucl. Mater. 417, 572 (2011).
  • [23] V. Kh. Alimov et al., J. Nucl. Mater. 420, 370 (2012).