US delivers 135-ton ‘beating heart’ magnet for world’s largest nuclear fusion reactor

US ITER has shipped the final busbars and leads for ITER’s 135-ton central solenoid magnet, completing a 15-year manufacturing effort.

The delivery clears a key hurdle as the fusion reactor moves closer to final assembly at the Cadarache site in France.

The central solenoid is a critical superconducting magnet that will help drive plasma current inside ITER’s tokamak.

The milestone highlights the U.S. role in building essential fusion hardware and in advancing carbon-free fusion energy research.