The controlled exhaust of power and particles from a hot fusion plasma, through the ‘divertor' area of the reactor, is arguably the biggest challenge facing a future fusion power plant using the tokamak design. The extreme power loadings (>10 megawatts per square metre – higher than that on a spacecraft re-entering Earth's atmosphere) in a conventional divertor would require regular replacement of reactor components and adversely affect the economics and cost of electricity. Divertor and exhaust physics is therefore a major part of EUROfusion's reactor design work as part of its EU Roadmap to the Realisation of Fusion Energy.
MAST Upgrade's flexible divertor design is already focussed on studying a range of configurations which could solve this problem. These include the new ‘Super X' divertor, designed to cool particles down by steering them on a longer exhaust path out of the plasma.
The plasma exhaust funding will give MAST Upgrade an unrivalled capability over the coming years by: increasing the tokamak’s plasma heating power; installing a cryoplant for the divertor; improving plasma fuelling systems; upgrading plasma control hardware and software; and adding extra diagnostic equipment for measuring plasma exhaust data.
These upgrades will allow fusion scientists to improve their understanding of plasma exhaust physics and enable better predictive modelling of this issue for the prototype fusion powerplant DEMO.
Head of MAST Upgrade Operations, Andrew Kirk, was responsible for putting together the funding bid, said: “MAST Upgrade provides a uniquely flexible test bed for plasma exhaust physics in all divertor configurations. This extra funding will enhance our capabilities even further, enabling MAST Upgrade to assess alternative divertors for use in the first fusion power plants.”
