Study of Beryllium Damage Under ITER-Relevant Transient Plasma and Radiative Loads

Beryllium will be used as a plasma-facing material for the ITER first wall. It is expected that erosion of beryllium under transient plasma loads such as the edge-localized modes (ELMs) and disruptions will determine the lifetime of the ITER first wall. The results of recent experiments with the Russian beryllium of TGP-56FW ITER grade on the QSPA-Be plasma gun facility are presented. The Be/CuCrZr mock-ups were tested by deuterium plasma and radiative streams both with pulse duration of 0.5 ms and heat loads of 0.5 and 0.4 MJ/m², correspondingly. Experiments were performed at 250 °C. The beryllium mock-ups were exposed to up to 100 shots. After 10, 40 and 100 shots, the evolution of surface microstructure and crack morphology were investigated as well as beryllium mass loss under the erosion process. The deuterium retention in erosion products was also studied by the thermal desorption method.