Modeling D retention in W under D ions and neutrons irradiation

Graphical abstract: The behaviors of D in W under D and neutron irradiation for different cases are investigated. The calculated results are comparable with experiments very well, such as, depth profiles and the amount of D retained in W under D+ implantation with different irradiation conditions, which could provide upgrade understandings on the ions radiation effects of plasma-facing materials. Highlights: ► An improved cluster dynamics model has been developed to study the effect of D retention in W. ► The competition of trapping and diffusion effects dominates the behaviors of D in W. ► Ion-induced and natural defects give rise to the features of the depth distribution of D in W. ► Neutron synergistic irradiation changes the depth distribution but the amount of D retained in W. - Abstract: The behaviors of deuterium (D) retention in tungsten (W) under D and neutron irradiation are investigated using an improved cluster dynamics model. The effects of different factors are considered in detail, including ion energy, fluence and irradiation temperature. The calculated results for different cases are comparable with experiments much well. It shows that the competition of trapping and diffusion effects dominates the behaviors of D in W. Different mechanisms give rise to the corresponding features in four typical zones of the depth distribution of D in W, i.e., the trapping of D by ion-induced vacancies to a peak in the near surface (0–0.2 μm), the recombination of ion-induced self-interstitial atoms with vacancies/deuterium-vacancy clusters to a decrease in the sub-surface (0.2–3 μm), D diffusion and accumulated by inherent vacancies to a platform in the range of 3 μm to tens of microns and the limit of diffusion to a reduction along depth in the bulk. The synergistic effect of neutron irradiation changes the depth distribution itself but the amount of D retained in W.