Instability of molten beryllium layers during ITER thermal quenches

Abstract

The production and dynamics of beryllium melt pools are simulated in conditions relevant to unmitigated thermal quenches in ITER. Rayleigh–Taylor instabilities fed by Lorentz forces due to induced eddy currents are found to result in significant material losses from droplet ejection, corresponding to equivalent eroded depths up to 500 μm. Different thermal and electromagnetic loading scenarios are investigated, demonstrating a strong dependence of wall damage on the intensity of the heat and current pulses. The contribution of convection flows stemming from surface tension gradients along the plasma–liquid interface is also elucidated.