Design of a brazing connector for DEMO in-vessel components

• A conceptual design of a RH compatible pipe connection system based on brazing has been developed to be used in the DEMO breeding blanket.
• Numerical analyses have been performed to evaluate the capabilities of the induction heating system and to pre-size its main parameters and geometries.
• The induction heating system provides a fast way to ensure the sealing of pipes.
• Screwing/unscrewing of stiffening captive bolts can slow down the maintenance procedure. An alternative clamped union based on a mechanical connector has been proposed.
• Transmutation in the selected materials does not seem to be an issue, since the reduction of mass for the main elements of the different components is very low.

The cost of electricity generated by fusion power will be strongly conditioned by the availability of future reactors. One key issue is the developing of feasible quick pipe connectors for the connection/disconnection of critical in-vessel components during maintenance operations. Brazing is a widely used joining technique which produces leak-proof high strength joints, with excellent stress distribution, little distortion and minimum oxidation. This work presents a design of a self-brazing/debrazing connector to be used with helium, lead–lithium and water pipes in DEMO. The remote handling compatible design includes an induction heating system, a brazing atmosphere supply, an inspection system (leak testing), a bolted/clamped union to provide stiffness against disruptions and thermal loads, and a positioning and alignment system.