Nuclear fusion reactors based on the tokamak design rely on the divertor to extract heat and impurities from the plasma. This divertor is typically designed using a combination of tungsten tiles, to handle the high heat load of the plasma facing, and a precipitation-hardened copper alloy tube, to transport the coolant. In the UKAEA design, the tube and a set of tiles are brazed together to form a test assembly, which will be exposed to cyclic high heat loading as part of an accelerated lifetime test. The integrity of the brazed interface and any residual (thermal) stresses are important performance indicators and these will be studied prior to and after thermal cycling.