Design and Laser Powder Bed Fusion Additive Manufacturing of Copper Alloy Heat Sink for Electron Beam Converter

This paper describes the design of water-cooling type heat sink to be used for an electron beam converter using additive manufacturing of copper alloy, CuCrZr, for the purpose of producing molybdemum-99 and Technetium from molybdemum-100 in a superconductive accelerator facility. One main challenge of this heat sink design is that all the solid part in the electron beam scanning region becomes the heat source. Therefore, this study focused on the design of heat conduction paths considering the manufacturability to convey the heat from the outer case, where the maximum temperature was observed, to inner cooling plates. The temperature-dependent thermal properties were measured as well as the density and mechanical properties. The unsteady-state heat conduction analysis, partially considering the uncertainty in the heat transfer coefficient, revealed that the heat conduction paths worked well to reduce the maximum temperature, and that the higher thermal conductivity with the increase of the temperature contributed to convey the heat effectively. The designed heat sink was successfully manufactured by laser powder bed fusion additive manufacturing. Self-supported circular holes in curved vertical walls for the assemblability with the main structure were manufactured without distortion.