Molecular Dynamics Simulation of the Displacement Cascades in Tungsten with Interstitial Helium Atoms

Tungsten (W) is a promising candidate as for the plasma-facing material in future nuclear fusion reactors. The interstitial helium (He) atoms in bulk tungsten will degrade seriously the mechanical properties of tungsten. In the present paper the effect of interstitial He atoms on the production and evolution of defects in irradiated tungsten has been investigated using molecular dynamics (MD) simulations. Under the conditions of different primary-knocked atom (PKA) energies and irradiation temperatures, it is found that the interstitial He atoms increase the generation of Frenkel pairs, and this tendency can be greatly promoted by increasing the PKA energy and irradiation temperature. The interstitial He atoms can also increase the displacement cascade efficiency and impact greatly on the structure of radiation-induced defects in tungsten.