Impact of plastic deformation on retention under pure D or He high flux plasma expose

Abstract

The retention of deuterium (D) and helium (He) is studied in pure tungsten after high flux mono-plasma exposure. The recrystallized and plastically deformed tungsten samples are studied to clarify the impact of the material microstructure, in particular dislocation density, on the trapping and release of D and He. Thermal Desorption Spectroscopy (TDS) measurements are performed to reveal the release stages and quantify the retention. Preliminary transmission electron microscopy study was applied to clarify the microstructural modifications induced by the plasma exposure to support the discussion and conclusions. It has been demonstrated that plastic deformation causes considerable suppression of He release within the explored limit of the TDS temperature – 1300 K. This is opposite to what is found for the pure D exposure, where the plastic deformation evidently enhances the D retention, given equivalent exposure conditions in terms of surface temperature and ion fluence. Keywords: Tungsten, He-H exposure, High flux plasma, Deformation