Behaviour of carbon and beryllium under thermomechanical loads

An extensive test program has been set up to evaluate the performance of beryllium, carbon materials and tungsten as plasma facing materials for the divertor in thermonuclear fusion devices. Experiments described in this paper represent pre-irradiation testing being part of a comprehensive study on neutron damage of several plasma facing materials and components. Thermal shock tests were carried out with several grades of beryllium, carbons and tungsten, at heat loads up to 5.3 MJ/m(2). In these experiments CFC materials and tungsten show less erosion than the beryllium grades. Best erosion behaviour of the beryllium grades is observed for S 65-C and for TGP-56. Steady state heating tests with actively cooled Be/Cu samples and CFC/metal samples, respectively were performed at loadings up to 5.8 MW/m(2). The main objective of these tests was the pre-selection of components to be included in a neutron irradiation program and to determine the heat removal efficiency before neutron irradiation. All samples investigated in steady state heating tests (Be/Cu and CFC modules) did not show any indications of failure, and are thus qualified to be used in the forthcoming neutron irradiation program. CFC modules however, show a strong variation of surface temperature due to the deviations in thermal conductivity of the CFC materials.