Cable tests for fusion reactors: Fermilab presents test stand with 15-tesla magnet
With its new MAGNES test bed, the US lab Fermilab wants to test superconducting cables for future fusion magnets under realistic conditions – with currents of up to 100,000 amps.
Photo: U.S. Department of Energy / Wikimedia Commons, Public domain (cropped and resized)
Video: YouTube · Fermilab · youtube.com
Fermi National Accelerator Laboratory near Chicago is launching a new test platform for superconducting cables: the MAGNet Environment Simulator, or MAGNES. It is jointly funded by the US Department of Energy's fusion office and its offices of high energy physics and nuclear physics. The background: tokamak fusion reactors need extremely powerful magnets to confine the superheated plasma. A new Fermilab video presents the project.
At its heart is a 15-tesla dipole magnet built by Lawrence Berkeley National Laboratory – about 300,000 times stronger than Earth's magnetic field, according to Fermilab; a typical hospital MRI machine generates 1.5 to 3 tesla. It will be installed in a pit about 5.5 metres deep and nearly 1.5 metres in diameter, cooled to roughly 2 to 4 degrees above absolute zero. "MAGNES is designed to simulate the environment that cables would experience inside a magnet," said Stephen Gourlay, director of the Magnet Technology Division. Currents of up to 100,000 amps are to pass through the test cables; the first cable tests are expected in summer 2028.
Researchers will also explore the upper temperature limits of superconductors, since higher operating temperatures could lower cooling costs. According to Fermilab, no other US facility can currently replicate such cable tests at this scale. The next step is to build an anti-cryostat, which will allow samples to be controlled from cryogenic to room temperature.