Simulation of cascades in tungsten–helium

Abstract

Helium (He) is present in fusion reactor wall materials, and its effect on radiation damage must be taken into account. The effect of He on displacement cascades in tungsten (W) has been studied using molecular dynamics simulations. Three different W–W potentials were compared and found to differ, especially for the clustering of the vacancies formed in the cascades. While there are differences in the amounts of damage depending on the potential, the overall effect of He in interstitial positions was to increase the amount of damage, while He in substitutional positions reduces it, due to the effect He has on the recombination of tungsten interstititals.

Keywords:

• tungsten
• helium
• radiation damage
• displacement cascade

Notes

Note

1. K. Nordlund: PARCAS computer code. The main principles of the molecular dynamics algorithms are presented in 24,25. The adaptive time step and electronic stopping algorithms are the same as in 26.