Solid beryllium tiles for the JET pumped divertor

JET is the largest magnetically-confined fusion experiment in operation today. Plasma facing components of JET made of solid beryllium have sustained for periods of up to 1 second localized fluxes of up to 25 W/mm2. In the new phase of operations foreseen for 1993 onwards peak heat fluxes of this magnitude will be swept across surfaces in contact with the plasma in order to reduce erosion and to increase the pulse length. Both low cycle (∼ 10 cycles) and high cycle (∼ 3 x 103 cycles) fatigue response of prototypes have been studied in a test-bed for heat loads in the range 13-25 W/mm2 and with peak strain rates of up to 1.5 mm/mm/sec