Cracking behavior of tungsten armor under ELM-like thermal shockloads II: A revised prediction for crack appearance map

In this work, the surface cracking features of tungsten armor under thermal shock loads by edge-localized mode (ELM) were investigated by means of computational fracture mechanics analysis. For the simulation it was assumed that a small crack was initiated at low temperature after the shut-off of thermal load in contrast to the previous studies where the presence of a crack before thermal loading was assumed. The threshold power density for surface cracking was predicted to range between 0.3 and 0.6 GW/m2 while the threshold of base temperature lay between 200 and 400 °C. The theoretically predicted damage map agreed well with the experimental data from electron beam irradiation tests. The current simulation model turned out to match better to the real experimental observation than the previous predictions where the threshold base temperature lies roughly between 400 and 600 °C.