Development of oxidation-resistant tungsten-based alloys for first wall application in DEMO

In this talk, the development status of self-passivating W-Cr-Y alloys manufactured by powder metallurgy is reviewed. This development has been started to prevent the potential release of volatile, neutron activated tungsten oxides from a pure W first wall (FW) in case of a loss-of-coolant accident (LOCA) with simultaneous air ingress, where temperatures of the in-vessel components exceeding 1000°C are expected. Properties relevant for the case of a LOCA, as the oxidation resistance, are reviewed. Besides, other material properties relevant for operation under normal conditions are presented, as the thermal and mechanical properties including thermal shock resistant in case of ELMS, resistance to high heat fluxes, thermal stability of the microstructure and D retention among others. Finally, methods for joining these alloys to Eurofer by brazing and by diffusion bonding using HIP are shown.