Magnet protection spurs tokamak fusion development

Tokamak Energy has developed a new magnet protection technology that promises to bring spherical tokamak power plants to market sooner.

The Oxford firm’s ST-40 fusion prototype is claimed to be the most advanced compact spherical compact tokamak in the world and is planned to reach plasma temperatures above 100m degrees Celsius in 2021. To achieve these temperatures – and deliver energy gain from fusion – scientists use high temperature superconducting (HTS) magnets to control the plasma.

Tokamak Energy said it has developed and tested ‘partial insulation’, a new magnet technology which allows these magnets to be built at power plant scale, and which is simpler than traditional systems used to protect HTS magnets at extreme temperatures.

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“For the first time, this latest test gives fusion developers an option for a new design of superconducting magnet that will be resistant to damage, reducing the cost and complexity of damage mitigation systems and the threat of downtime,” Chris Kelsall, CEO of Tokamak Energy said in a statement.

“The world needs energy that is clean, secure, cheap and globally deployable, and the magnets Tokamak Energy is developing will enable this future. Tokamak Energy’s two world leading core technologies – the spherical tokamak and HTS magnets – are central to the company’s mission to develop economic fusion in compact power plants.”

magnet protection
Next generation magnet technology paves the way to commercial fusion power (Image: Tokamak Energy )

High magnetic fields are necessary for tokamaks to contain the superheated fuel, and higher magnetic fields enable a smaller tokamak, which in turn feeds into the commercial viability of fusion.

After validating the new ‘partial insulation’ for HTS magnets, Tokamak Energy is now building a new test facility to explore the interaction of multiple magnets and validate their use within a full tokamak system for the first time. Testing is slated for 2022.

“This impressive demonstration of partial insulation technology opens the door to a new frontier in magnet technology, enabling the novel technology we have developed for our spherical tokamaks to be utilised in a wide range of emerging applications that need high field compact HTS magnets,” said Robert Slade, Advanced Technology Applications director at Tokamak Energy.