Abstract : A bulk tungsten tile with conventional and shaped castellation structures was exposed to various plasmas in KSTAR during 2012 campaign, in order to verify the functions of the shaped castellation designed for ITER divertor. The thermal response of the tile during the campaign was measured by thermocouples. The tungsten tile was collected after the campaign and the castellation structures were examined. The deposition inside the gap was studied to identify the contributions of ions and charge exchange neutrals. The shaped castellation shows smaller penetration depth of ions by a factor of ~1/2 than that of conventional one, thus less deposition inside the gap which is consistent with the prediction made by SPICE2 code. It seems that blister formation and cracking have occurred during plasma shots.

https://doi.org/10.1016/j.fusengdes.2014.01.033