Modeling of diffusivity of tritium interacting with F centers in Li2O

The diffusivity of tritium interacting with F centers in Li2O was modeled with a kinetic Monte Carlo simulation and classical diffusion theory. The migration energy and trapping/detrapping energy were set according to the previous studies using quantum mechanical calculations. The constructed mode clearly showed that the tritium diffusivity was lowered by F centers. It was also shown that the diffusion coefficient of tritium interacting with F centers depended not only on the concentration of F centers and on the trapping/detrapping energy, but also on the concentration of hydrogen isotopes (H + D + T). It was indicated that inclusion of hydrogen isotopes (H2, D2, etc.) in purge gas would suppress the influence of radiation defects on the tritium diffusivity, and thus reduce the uncertainty, which is caused by radiation defects, in tritium recovery rate under fusion reactor conditions.