Disruption simulation effects on SiC/C and CFC composites as plasma-facing materials

Abstract The effects of abnormal discharges in tokamaks have been simulated by means of an electron-beam gun with pulse length from 1 to 20 ms and power peak density ranging between 1×108 and 4 × 1010 W.m−2. Physical and chemical changes induced by thermal shock on SiC/C and CFC composites have been compared with modifications occurring in the same materials during our previous investigations under steady-state high-flux plasma irradiation in a plasma-material interaction facility. Experimental results obtained by EB-disruption simulation effects through SEM and AES data on the SiC/C and CFC specimens analyzed agree well with a numerical simulation of disruptive events carried out using the Heating-6 thermal code. Furthermore, the damage produced (such as microstructural changes, fissures, preferential sublimation) confirms that a disruption is the most critical event for the plasma-facing material lifetime. The measured chemical composition changes, according to AES data, indicate that a C-depletion of t...