THERMOMECHANICAL BEHAVIOR OF ACTIVELY COOLED, BRAZED DIVERTOR COMPONENTS UNDER CYCLIC HIGH HEAT-FLUX LOADS

Actively cooled divertor mock-ups consisting of various low-Z armor ti les brazed to refractory metal heat sinks were tested in the electron beam test facility at Julich. Screening and thermal cycling tests were performed on the mock-ups to estimate the overall thermal performance under cyclic high heat flux (HHF) loadings. By detecting the temperat ure of the armor surface and the braze laver, it was possible to asses s the heat removal capability and the accumulation of interfacial dama ge. Microstructures were investigated to elucidate the degradation of the joints. Finite element analyses are carried out for the simulated HHF test conditions. Temperature fields and thermal stresses are calcu lated for a typical divertor module. The nature of thermomechanical be havior of the divertor mock-ups under cyclic HHF loadings is discussed . (C) 1997 Elsevier Science B.V.