Plasma-wall interactions in tungsten in presence of fusion neutrons: molecular simulations and surrogate ion irradiation experiments

Tungsten will be used in ITER divertor which is also one of the candidate materials for future fusion reactors such as DEMO. In this work, we discuss plasma-wall interactions and fuel retention in tungsten in presence of fusion neutrons. This will be approached using consistent multi-scale scheme of neutron damage in tungsten starting from neutronics calculations. The radiation damage studies using Molecular dynamics simulations and binary collision Monte Carlo methods. The collision cascade generate stable vacancy-interstitial pairs (Frenkel pairs) with in MD simulation time scales. At higher irradiation energies we have observed interstitial clustering. The vacancies are in immobile in the simulation time scales. In comparison to the standard binary collision models, the observed number of stable Frenkel pairs in MD simulations is much smaller which is attributed to the recombination of the displaced atoms during the thermal spike. The difference in the thermal spike relaxation with and without electronic losses will be shown. The difference between interacting and non-interacting cascades in defect formation will also be discussed where the latter can contribute to the observed microstructure in ion-irradiation experiments. The vacancy clusters observed in experiments due to surrogate ion-irradiation will also be discussed in the presentation, where we discuss the challenges in interpreting the experimental data of radiation damage