An investigation was made of the physical origin of H–He interactions in W in terms of optimal charge density by calculating the energetics and diffusion properties using a first-principles method. On the one hand, a strong attraction was demonstrated, between H and He in W, which originated from the charge density redistribution due to the presence of He driving H segregation towards He. This could block the permeation of H deeper into the bulk and thus suppress H blistering. On the other hand, it was demonstrated that He, rather than H, preferred energetically to occupy the vacancy centre due to its closed-shell structure, which could block H2 formation at the vacancy centre. This was because He caused a redistribution of charge density inside the vacancy to make it 'non-optimal' for the formation of H2 molecules, which could be treated as the initial nucleation of the H bubbles. It was therefore proposed that H retention and blistering in W could be suppressed by doping with noble-gas elements.

Towards Suppressing H Blistering by Investigating the Physical Origin of the H–He Interaction in W. H.B.Zhou, Y.L.Liu, S.Jin, Y.Zhang, G.N.Luo, G.H.Lu: Nuclear Fusion, 2010, 50[11], 115010