Manufacturing and testing of large-scale mock-ups of ITER plasma facing components in Russia

Various ITER plasma facing components (PFC) are described, such as first wall (FW), start-up limiter and divertor vertical target (VT). Manufacturing and testing of large-scale mock-ups is the final stage on the long way of structure optimization and selection of the most reliable and cheap manufacturing technologies. For the FW and limiter mock-ups fast brazing of Be tiles to CuCrZr heat-sink by brazing alloy STEMET-1101 was successfully applied. Testing of the FW large-scale mock-up up to 5000 cycles at 1 MW/m2 did not reveal any damages of BeCu joints. For CuCrZr–SS bimetallic heat-sink/support structure two alternative joining technologies (HIP—for the limiter mock-up and CuCrZr casting onto solid SS—for the FW mock-up) were used. For divertor target mock-up the following technologies were used: pure Cu casting onto W tiles; fast brazing of WCu bimetallic tiles onto CuCrZr heat-sink; explosion bonding and CuCrZr casting as two alternatives for manufacturing of hermetic CuCrZr–SS structure of hypervapotron type; laser welding for attachment of heat-sink elements to support plate (SSSS welds). Results of thermocycling testing of all mock-ups at operational heat loads are presented. Recommendations for further improvement and characterization of above-mentioned technologies for ITER application are given.