Estimation of the dust production rate from the tungsten armour after repetitive ELM-like heat loads

Abstract

Experimental simulations for the erosion rate of tungsten targets under ITER edge-localized mode (ELM)-like surface heat loads of 0.75 MJ m−2 causing surface melting and of 0.45 MJ m−2 without melting have been performed in the QSPA-Kh50 plasma accelerator. Analytical considerations allow us to conclude that for both energy deposition values the erosion mechanism is solid dust ejection during surface cracking under the action of thermo-stress. Tungsten influx into the ITER containment of NW∼5×1018 W per medium size ELM of 0.75 MJ m−2 and 0.25 ms time duration has been estimated. The radiation cooling power of Prad=150–300 MW due to such influx of tungsten is intolerable: it should cool the ITER core to 1 keV within a few seconds.