An empirical potential for simulating hydrogen isotope retention in highly irradiated tungsten

TL;DR

This paper develops and tests a new empirical potential for simulating hydrogen isotope behavior in highly irradiated tungsten, enabling large-scale molecular dynamics studies of defect interactions and trap mutation mechanisms.

Contribution

The paper introduces a tungsten-hydrogen empirical potential optimized for defect interactions and elastic properties, suitable for large-scale irradiation simulations.

Findings

Potential accurately models elastic properties and defect interactions.

Energy ordering of defects varies with hydrogen-to-defect ratio.

Potential enables exploration of trap mutation mechanisms.

Abstract

We describe the parameterization of a tungsten-hydrogen empirical potential designed for use with large-scale molecular dynamics simulations of highly irradiated tungsten containing hydrogen isotope atoms, and report test results. Particular attention has been paid to getting good elastic properties, including the relaxation volumes of small defect clusters, and to the interaction energy between hydrogen isotopes and typical irradiation-induced defects in tungsten. We conclude that the energy ordering of defects changes with the ratio of H atoms to point defects, indicating that this potential is suitable for exploring mechanisms of trap mutation, including vacancy loop to plate-like void transformations.