Gas-cooled high performance divertor for a power plant

Designing divertor target plates for a fusion power plant is a challenging task because they have to allow exceptionally high heat fluxes, deliver heat to the power conversion system at a temperature suitable for high efficiency, and use a coolant compatible with the blanket system. These requirements are different from the case of an experimental reactor (e.g. ITER) where copper can be used as heat sink. In a power plant, the use of cold water as divertor coolant would waste 10–20% of the total power, with a comparable reduction of thermal efficiency. This paper proposes a helium cooled divertor concept that is intended to reach 10 MW/m2 peak surface heat flux. The evolution of the design, by strictly applying high heat flux criteria to an existing porous medium concept, is presented. Enhanced heat transfer is achieved by a pin fin array on the cooling channel wall. An operating point is selected, and finite element analyses performed to establish temperature and stress levels in a divertor target plate. Results indicate that the design meets the requirements.