Effects of grain structure on D retention in W under simultaneous D-He irradiation

Abstract Despite numerous studies on D retention in tungsten, there is over an order of magnitude spread in results throughout the temperature range 400–800 K. Furthermore, comparisons of results from studies on the effect of grain structure also show inconsistencies. In the current study, specimens of polycrystalline (PCW) and recrystallized W (RCW) were studied under D + -only and simultaneous D + -He + (SIM D + -He + , 3% He + ) irradiation at 500 eV/D + , 500 eV/He + , 300–700 K, 5.6–8.4 × 10 19 D/m 2 s flux, and 1 × 10 24 D/m 2 fluence. No significant difference was observed between PCW and RCW for total D retention or trapping energies, although the addition of He + suppressed blistering and reduced D retention. The PCW and RCW may have similar D retention because the differences in grain boundary densities are not significant. The effects of addition of He + are consistent with mechanisms previously discussed in literature.