Effect of Re and Os in W under irradiation; Comparison between numerical and experimental results

Suzudo, Tomoaki   ; Tsuru, Tomohito   ; Hasegawa, Akira*

Tungsten is expected to be a promising plasma-facing material for future fusion devices, but radiation-induced precipitation (RIP), which leads the material to hardening, is a concern at their practical use. One of the keys to accurate prediction of the emergence of RIP is stability and migration of solute atoms, rhenium (Re) and osmium (Os), that are produced by nuclear transmutation through irradiation. We conduct a series of numerical simulations using ab initio and an atomic kinetic Monte Carlo method to examine the behaviour of these solute elements. We find that tungsten interstitial atoms displaced by radiation favourably form mixed dumbbell with the solute atoms, and these mixed dumbbells have 3D motion instead of 1D motion of SIAs.