TOWARD LONG-PULSE, HIGH-PERFORMANCE DISCHARGES IN TORE-SUPRA - EXPERIMENTAL KNOWLEDGE AND TECHNOLOGICAL DEVELOPMENTS FOR HEAT EXHAUST

In view of high-power, long-pulse steady-state operation, Tore Supra h as incorporated in its design the active control of heat and particles in a realistic environment. In the early experimental phase of Tore S upra, the first generation of plasma-facing components was tested, and these tests provided much physics and technological information and i lluminated various operational difficulties. In particular, these expe riments revealed the weakness of the graphite-to-metal brazing process originally adopted for actively cooled high-heat-flux components. Con sequently, a new inner-wall technology was developed in 1994 and is to be tested in 1995-1996 with a totally rebuilt 40-deg toroidal sector. A carbon-fiber-reinforced carbon-metal compound is based on the newes t brazing technology and rigorous quality control. Components such as the toroidal pump limiter and the guard limiters of plasma-heating ant ennas are being developed in the same way. For structures where brazin g is difficult, boron carbide-coated components have been developed an d installed in Tore Supra. For lower heat fluxes, a bolted concept has been designed and tested. The influence of inner-first-wall misalignm ent in Tore Supra on the power exhaust limitation of brazed components has been studied. Results from the technological development for the different power exhaust systems and the associated experimental knowle dge obtained during plasma operation in Tore Supra are presented.