Manufacture and Initial Thermo-Fluid Measurements on a Heat Sink Module for Potential Applications in a DEMO

The necessity to handle heat loads in the MW/m² range has become increasingly prevalent in a number of industries. Termed high-heat flux cooling, some of the most challenging conditions in this field occur at the first wall and divertor regions of a fusion tokamak. Steady-state heat fluxes here may reach values in excess of 10 MW/m² in some areas for a first stage DEMO. The situation is exasperated further by the environment within the machine, which severely alters material properties with time. Even coolant choice itself can have an impact beyond thermal considerations through tritium inventory and neutron activation. Successfully addressing these issues is of critical importance to the development of commercial fusion power. A number of heat sink modules utilising jet impingement in a flat plate geometry were manufactured using diffusion bonding. Each sample produced was subject to leak and hydrostatic pressure measurements, together with further non-destructive analyses. Thermo-fluid measurements were performed on the components in a purpose built facility employing water as the coolant at pressures of up to 200 bar. To replicate the thermal boundary conditions a resistive thin-film heater technique was utilised. This allowed heat fluxes in the MW/m² range to be applied to the modules. The results indicate that the concept may be a viable alternative heat sink candidate for first wall or divertor applications in a DEMO, but that further research is required to optimise certain aspects of the design.