Initial experiments carried out at the Culham Science Centre near Oxford have shown that the novel concept – known as a ‘Super-X divertor’ – has delivered a tenfold reduction in the excess heat endured by vital components. The results mean that compact tokamaks could theoretically operate for years instead of months without these components being replaced, massively increasing uptime and making compact fusion a much more realistic commercial prospect.
While cutting edge fusion research projects like ITER will hopefully soon demonstrate that energy gain from fusion is possible, there is a parallel race going on to make fusion financially viable. Small, compact tokamaks could form part of a future clean energy network, but generate huge amounts of excess heat which must be efficiently dispersed if uptime is to be maintained.
The Super-X divertor uses magnetic fields to guide exceptionally hot plasma on a meandering journey that allows it to cool significantly before coming into contact with material components. MAST Upgrade experiments, which have been running since October 2020, have shown that the Super-X divertor reduces the heat on these material surfaces by a factor of ten, something the UKAEA claims is a ‘game-changer’ for fusion energy.
“These are fantastic results. They are the moment our team at UKAEA has been working towards for almost a decade,” said the UKAEA’s lead scientist at MAST Upgrade, Dr Andrew Kirk.
“We built MAST Upgrade to solve the exhaust problem for compact fusion power plants, and the signs are that we’ve succeeded. Super-X reduces the heat on the exhaust system from a blowtorch level down to more like you’d find in a car engine. This could mean it would only have to be replaced once during the lifetime of a power plant.
“It’s a pivotal development for the UK’s plan to put a fusion power plant on the grid by the early 2040s – and for bringing low-carbon energy from fusion to the world.”
According to the UKAEA, the success of the Super-X divertor is major step forward in the development of STEP (Spherical Tokamak for Energy Production), the commercial fusion power plant concept it hopes to deliver by the early 2040s.