LAUSR

Abstract Molecular dynamics (MD) methods have been employed to study the formation and growth of helium (He) bubble in bulk tungsten (W) from the atomic-level perspective. The primary variables examined are: irradiation temperature up to 2100 K, He concentration up to 10000 appm in order to study the effects of temperature and He concentration on micro-structural evolution, especially the He evolution. He atoms whose number ranged from 40 to 160 are randomly added to the tetrahedral interstice or octahedral interstice in the W matrix. The results show that the average size of He-V clusters increases with increasing in the temperature and He concentration in general. It is found that the He/V ratios of He-V clusters are mainly ranged from 1.5 to 4 after their nucleation with high He/V ratio more than 6. And the He/V ratio may be influenced greatly by the nearby He-V clusters. This is to be studied in the further work to understand how the He-V clusters interact in bulk W. These results can also provide input parameters to larger scale simulations methods, such as in kinetic Monte Carlo methods and rate theory.