Recent findings on blistering and deuterium retention in tungsten exposed to high-fluence deuterium plasma

Shu, Wataru; Kawasuso, Atsuo; Yamanishi, Toshihiko

Tungsten is a most promising plasma facing material because of its high melting point. The blistering and deuterium retention in recrystallized tungsten samples were investigated by using simulated edge-plasma of fusion reactors. High-dome blisters appeared at the tungsten surface after deuterium plasma exposure, and their ratios of height against chord of the blisters were even one-order greater that reported before. In addition, there was a cavity in the inside of small blisters, whereas there was a void/crack along the grain boundary beneath the big blister and there is no lid for big blisters. Besides the strong dependence upon the exposure temperature, blistering and deuterium retention also showed significant dependence upon the features of microstructure.