An experimental study of the melting and vaporization of a solid wall subjected to high heat flux

The first wall in a fusion reactor will be subjected to a very high heat flux due to a plasma disruption, which can result in melting and vaporization. This will determine the lifetime of the wall. Analytical predictions of the melt layer thickness and the amount of vaporization have been carried out for several reactor designs. The experimental data base, however, has been very limited for confirmation of these predictions. This paper presents experimental data on the melting and vaporization of type 304 stainless steel, alminum and zinc samples. They were subjected to a simulated plasma disruption by a 100 kV electron beam for loading times of 91 to 174 msec with a heat flux up to 100 MW/m2. The melt layer thickness and the amount of vaporization were measured as a function of absorbed heat flux. These data show good agreement with the analytical predictions, both qualitatively and quantitatively. (author)