Manufacturing and characterization of stainless steel/CuCrZr and stainless steel/Cu junction ring by explosive welding method

The most common material for heat sink used in actively cooled plasma facing components is CuCrZr, which is not easily welded to steel used for cooling pipes. This paper reports an alternative to the common solution using electron beam welding. This solution relies on a junction ring assembled by explosive welding. This junction has been successfully qualified using IRFM procedures, very close to ITER ones. It was then used for the manufacturing of baffle PFC. However, due to unexpected issues in welding CuCrZr (junction) to CuCrZr (baffle), a second kind of junction ring using pure Cu instead of CuCrZr is developed and successfully qualified following the same tests. Both types of junctions are currently used on baffle installed inside WEST tokamak, and their compatibility with the plasma operation will be definitely assessed.