Microstructure dependence of deuterium retention and blistering in the near-surface region of tungsten exposed to high flux deuterium plasmas of 38 eV at 315 K

Shu, Wataru; Kawasuso, Atsuo; Miwa, Yukio; Wakai, Eiichi  ; Luo, G.-N.*; Yamanishi, Toshihiko

The dependence of deuterium retention and blistering upon the microstructures of tungsten exposed to 38 eV plasma were studied with TDS, PA and SEM. For samples exposed to higher fluences (up to 10 D/m), a peculiar phenomenon of bursting release of deuterium was found obviously in TDS spectra, where sudden spikes appeared. SEM observations also confirmed the phenomenon of bursting of blisters, even for the single crystal tungsten (111) exposed to 10 D/m at room temperature. The preliminary PA measurements suggested that the vacancy concentration in the near-surface region of the partially-recrystallized tungsten increased after the exposure, and electron back-scattering diffraction (EBSD) results showed that blisters appeared predominantly on the grains with nearly (111) surface orientation.