World’s largest tokamak cools 330-ton superconducting magnet for fusion plasma

ITER’s Magnet Cold Test Facility has cooled a 330-ton toroidal field coil to 4 Kelvin, matching operating conditions for superconducting magnets.

Engineers are now beginning long-duration electrical trials to check performance, safety systems, insulation, and quench behavior before installation.

The tests are a key risk-reduction step for ITER’s reactor assembly and help validate Nb3Sn/Nb-Ti magnet technology.

Beyond ITER, the facility and expertise could support future commercial fusion projects.