Molecular dynamics simulation of radiation damage in bcc tungsten

Molecular dynamics (MD) simulations are performed to assess the primary damage due to high-energy neutron irradiation in bcc tungsten. For short-range interactions two different universal potentials are used, while for long-range interactions, two empirical embedded atom method (EAM) tungsten potentials are used. The short-range and long-range potentials are smoothly connected. Additionally, truncation of the electron density function at low distances is used. Statistically meaningful Frenkel pairs (FP) are counted and interstitial dumbbell orientations and interstitial or vacancy cluster counts are obtained. In addition, an approach to assess the volume influenced by the cascades based on a standard deviation ellipsoid is presented. A critical review of present and existing MD results is performed, and an attempt is made to clarify the roles played by the empirical potentials and by the temperature.