Decrease of blistering on Helium irradiated tungsten surface via transversal release of helium from the grooved surfaces

Abstract

• A new way to reduce blistering that the nano-channels were fabricated on the tungsten surface by FIB • The presence of " grooved surfaces " contributes to reduce blisters and inhibit the rapid growth of He blisters. • He-induced blistering shows a clear crystal orientation dependence. Although tungsten is considered as one of the primary candidates for plasma-facing material (PFM) in future fusion reactors, blistering induced by plasma irradiation adversely affects fusion reactors. To overcome blistering, in this study, we proposed an approach to reduce the blistering by releasing hydrogen or helium (H/He) through the grooved surfaces of PFM. In order to verify the feasibility of this approach and the effectiveness of the transverse release of H/He, the deep grooves as the channel simulants on the tungsten surface were fabricated with different spacing using focused ion beam (FIB). The result of helium irradiation shows that the presence of grooved surfaces can reduce blisters and inhibit the rapid growth of He blisters. In addition, the blistering reduced significantly with decreasing groove spacing, especially when the groove spacing is less than 2 µm. In addition, He-induced blistering shows obvious crystal orientation dependence, and the (001) surface shows the most serious radiation damage.