Tokamak Energy’s world-first Demo4 superconducting magnet system will have an incredible 12 million amps of electricity running through its central column to replicate fusion energy power plant forces.
It is four times greater than the current passing through the company’s ST40 tokamak and 120,000 times more than a typical 100-amp UK average home.
Creating clean fusion energy requires strong magnetic fields to confine and control the extremely hot hydrogen fuel, which becomes a plasma several times hotter than the centre of the Sun.
Ahead of an in-depth overview of Demo4 presented today (11/7) at the Institute of Electrical and Electronics Engineers (IEEE) Symposium on Fusion Engineering (SOFE) in Oxford, Tokamak Energy’s Graham Dunbar, Technical Lead, also said the 18 Tesla system will be nearly a million times stronger than the Earth’s magnetic field.
He explained: “Demo4 will be a complete balanced set of magnets shaped in a tokamak configuration. Importantly, it will allow us to create substantial magnetic forces and test them in fusion power plant-relevant scenarios for the first time. The learnings from this unique system will push forward our understanding of the technology required to deliver clean, secure and affordable fusion power in the 2030s.”
Demo4 consists of 44 individual magnetic coils manufactured using 38 kilometres of ground-breaking 12mm wide high temperature superconducting (HTS) tape, which carries currents with zero electrical resistance and requires five times less cooling power than traditional superconducting materials.
The system will operate in a vacuum at an extremely low temperature of minus 253 C – 20 degrees above absolute zero – achieved by 10 closed-cycle cryocoolers. It will also demonstrate the potential of HTS magnets for other important applications.
Strong magnetic fields are generated by passing large electrical currents through arrays of electromagnet coils that will surround the plasma in future power plants. The magnets are wound with precision from state-of-the-art HTS tapes, which are multi-layered conductors made mostly of strong and conductive metals, but with a crucial internal coating of ‘rare earth barium copper oxide’ (REBCO) superconducting material.
Final assembly and testing at Tokamak Energy’s headquarters in Milton Park, near Oxford, will take place in 2024.