PERFORMANCE OF GRAPHITES AND TUNGSTEN DURING EXPOSURE TO PULSED PLASMAS

Heat fluences of 1-10 MJ/m2 and greater over 0.1-1 msec pulse durations are expected on the surfaces of plasma-facing components in large tokamaks during a plasma disruption. The formed vapor plasma (the boundary layer) absorbs a large fraction of the incident energy, and thus acts as a self protecting layer (vapor shield). Carbon materials (pyrolytic graphite and other graphite grades)) are used as plasma-facing components, and tungsten and refractory materials are potential candidates. The experimental test facility SIRENS has been used to expose carbon and tungsten materials to heat fluences between 0.2 and 6 MJ/m2 for 100-mu-s duration to characterize the performance of such materials under typical heat loading conditions.