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Providing sustainable fusion energy requires strong magnetic fields to confine and control hydrogen fuel, which becomes a plasma several times hotter than the Sun inside a tokamak reactor.
Although most radiation from high-energy plasma neutrons will be absorbed by the tokamak’s shielding, the magnets must be able to withstand secondary gamma rays to maintain efficient power plant operations. Gamma rays are a form of electromagnetic radiation, similar to X-rays.
Tokamak Energy built and commissioned its specialist gamma radiation cryostat system – a vacuum device to provide thermal insulation for the magnets – at its Oxfordshire headquarters, as part of its mission to deliver fusion power in the 2030s.
The bespoke test system will now be disassembled, shipped, and rebuilt at the Gamma Irradiation Facility (GIF) at the US Department of Energy’s Sandia Laboratories in Albuquerque.
The facility is one of the few places in the world capable of housing the system while also exposing the high temperature superconducting (HTS) magnets to a power plant representative of gamma radiation, a Tokamak announcement said.
“Our pioneering magnet technology must withstand extreme conditions to keep fusion power plants running in the future,” said HTS magnet development manager Dr Rod Bateman.
“The specialist Sandia Laboratory is ideally configured to test magnet durability and performance when exposed to gamma radiation. It is essential to push the boundaries now as we scale up our operations towards commercial fusion.”
Research and analysis on sets of individual magnets will run for six months at the New Mexico facility, which is reportedly so powerful it can do a 60-year lifetime test in just two weeks.
GIF facility supervisor Don Hanson said: “The GIF is a unique facility that can provide high doses of gamma radiation to large test objects. We look forward to working with Tokamak Energy to advance fusion technologies.”
In February, Tokamak completed building a world-first set of magnet coils using 38 kilometres of HTS tape, which carries currents with zero electrical resistance and reportedly requires five-times less cooling power than traditional materials.
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