Abstract

The blisters formation and destruction induced by the deuterium ions on a polycrystalline tungsten wereinvestigated with varying irradiation deuterium ion fluence from 3.04 × 1023to 1.84 × 1025D m−2s−1and an fixed irradiated ion energy of 100 eV in an electron cyclotron resonance plasma source, whichwas similar to the far-scrape off layer region in the nuclear fusion reactors. Target temperature wasmonitored during the irradiation. Most of blisters formed easily on the grain with (1 1 1) plane orientationwhich had about 250 nm in diameter. In addition, the areal number density of blisters increased withincreasing the ion fluence under the surface temperature reaching to about 900 K. When the fluenceexceeded 4.6 × 1024D m−2, the areal number density of the blister decreased. It could be explained thatthe destruction of the blister was initiated by erosion at the boundary region where the thickness ofblister lid was thin and the sputtering yield was high by oblique incident ions, resulting in remaining thelid open, e.g., un-eroded center dome. It is possible to work as a tungsten dust formation from the plasmafacing divertor material at far-SOL region of fusion reactor.

https://doi.org/10.1016/j.fusengdes.2016.02.033