EVALUATION OF COOLING CONCEPTS AND SPECIMEN GEOMETRIES FOR HIGH HEAT-FLUX TESTS ON NEUTRON-IRRADIATED DIVERTOR ELEMENTS

To assess the lifetime and the long term heat removal capabilities of plasma facing components in future thermonuclear fusion reactors, neut ron irradiation and subsequent high heat flux (HHF) tests will be of g reat importance. The effect of neutron damage will be simulated in mat erial test reactors. To investigate the behaviour of components subjec ted to heat loads during normal and off-normal conditions, a 60 kW ele ctron beam teststand (Julich Divertor Test Facility in Hot Cells (JUDI TH)) has been installed in a hot cell which can be operated by remote handling techniques. In this facility inertially cooled test coupons c an be handled as well as small actively cooled mock-ups. The irradiati on of complete divertor modules however requires greater efforts. To i nvestigate specific problems such as neutron induced changes in the pe rformance of the braze interface, small test coupons without active co oling capabilities may be suitable. ITER relevant temperature gradient s and resulting stress fields can be established during transient heat ing by electron beam methods. The only reasonable alternatives to this procedure are actively cooled test specimens or small divertor module s. A special clamping mechanism for test samples with an integrated co olant channel has been developed and tested. This experimental procedu re is an attractive and cost effective alternative comparing large sca le tests on complete divertor modules.