Multiple irradiation experiment of tungsten materials by negative hydrogen ion beam, 2; Evaluation as material for ITER divertor

Fukuda, Makoto*; Hirano, Koichiro  ; Tokunaga, Kazutoshi*; Ezato, Koichiro*

Tungsten which is used as a plasma-facing material for ITER divertor is expected to receive heat flux under various conditions during ITER operation. Therefore, it is necessary to understand the modification of tungsten surface under various heat load conditions. In this work, as part of the investigation of the repeated short pulse heat load effect on tungsten, the effect of multiple irradiation (3MeV, 5Hz) with a negative hydrogen ion beam was evaluated. As a result, unevenness and cracks were observed on the surface after irradiation, and different surface modification behavior was observed compared with previous experiment which performed with almost constant heat load (10s On and 20-30 s Off as one cycle).