Study of Tungsten as a Plasma-facing Material for a Fusion Reactor

The paper presents the development of experimental investigations and recent results of the impact on tungsten at high level of radiation damage under steady-state deuterium plasma. Tungsten is considered as a plasma facing material for a fusion reactor. The effect of fusion neutron impact is simulated by surrogate irradiations with high-energy ions. The primary defects at 1-100 dpa were produced in tungsten samples by He and C ions accelerated in the Kurchatov cyclotron to 3-10 MeV at the total fluence of 1017-1019 cm-2. The irradiated material was studied in deuterium plasma on the LENTA linear divertor simulator at the plasma fluence 1021-1022 D/cm2. Erosion dynamics, development of the surface microstructure and deuterium retention were analyzed. Increased deuterium retention detected previously in tungsten pre-irradiated by He ions was also registered (ERDA) on C-irradiated samples at 2-3 dpa. In contrast, a significant decrease in the D uptake has been observed on those samples operated in the experiments at 500 °C.