Induction brazing of DEMO's large bore cooling pipes

•Brazing has many advantages over welding; it could be a real alternative.•A test rig has been developed to join DN200 pipe sections with induction brazing.•Design supported by electromagnetic and thermal analysis; to be validated by tests.•99 percent of analysis run time saved with 2D analysis for spiral induction coil.•Heating power is concentrated to the first ∼2 mm of the pipe thickness. The DEMO first wall blanket components will be exposed to high neutron fluence and high levels of thermal energy, the latter being removed by a coolant fluid transmitted out of the reactor via service piping. Due to the thermal and nuclear loading on the first wall, the components will need to be periodically removed and replaced. Installation of new blankets requires the joining of their service pipes by remote handling. Brazing is one of the alternatives that are considered for joining the service pipes of the DEMO breeding blankets. This technique has great potential and has several major advantages over welding. The Fusion Technology Department of HUN-REN Centre for Energy Research (CER) has been working on the development of a viable brazing concept of thick, large bore pipes inside the ports of DEMO. Induction has been chosen as the heat source for the brazing operation, which is a well-studied technology and has many uses in the industry already. However, brazing in this size is a completely new horizon for induction heating so CER's work includes a significant amount of development. Firstly, the coil is naturally a bespoke component, which has been optimized by electromagnetic analysis. Secondly, a test rig has been designed and manufactured in-house by CER, to test the performance of the induction heater in a real scenario. This paper outlines the development strategy of the induction brazing of DEMO's large bore pipes.