Hefei Fusion

The write-up

A 582-ton superconducting magnet built for fusion research. Built in Hefei for China's CRAFT fusion test facility.

1. Exhibit A

   Completed in June 2026

   On June 27, 2026, the toroidal field (TF) magnet, the largest component of CRAFT, completed its final manufacturing steps and passed acceptance testing. CRAFT is a national research facility in Hefei for testing key fusion-reactor systems.

2. Exhibit B

   The numbers

   A single TF magnet measures 21 m long, 12 m wide and 3.3 m high and weighs 582.4 t. It operates at 98 kA and stores 120 GJ. Sixteen such magnets would produce 6.5 T at the plasma center and 14.5 T at the coils.

3. Exhibit C

   Compared with ITER

   According to ASIPP, the magnet has 1.3 times the volume and three times the stored energy of an ITER TF magnet. The institute describes it as the world's largest fusion-reactor superconducting magnet.

4. Exhibit D

   What it does

   Toroidal field magnets create the field that confines plasma at hundreds of millions of degrees and reduces particle damage to the vessel walls. They must run reliably for 60 years at very low temperatures, high currents and high radiation.

5. Exhibit E

   How it was tested

   The project took six years. Conductor samples were tested thousands of times at 4.2 K, with cycles at 100 kA and 12 T. A high-temperature-superconducting central solenoid coil also completed full-parameter testing the same day.