ITER energizes 330-tonne superconducting coil to 34 kA as full-current testing approaches

ITER has put 34,000 amperes through a superconducting magnet weighing 330 tonnes. In a 2 November announcement, the organization confirmed that its toroidal field coil TF17 had completed a 34 kA energization campaign after cooling to 4 K (about −269°C). That is half the coil's rated 68 kA current, but enough to compare its deformation under powerful electromagnetic forces with predictions from the structural model.

ITER's Magnet Cold Test Facility began operating in May, cooling the first coil, TF07, to 4 K and testing it at 10 kA. The electrical system was then upgraded for higher currents. During the early testing of TF17 in August, engineers found unexpectedly high resistance at a feeder joint. Oxidation on a contact surface was identified and corrected before the campaign reached 34 kA. Following the story from ITER's September report reveals how much the result depends not only on manufacturing a huge magnet, but also on getting its connections and power systems right.

TF17 was removed from the test facility on 30 October. After temporary storage, it is due to move into the Assembly Hall to become part of a final vacuum-vessel sector module.

The next test article will be spare coil TF19. ITER plans to start cooling it in April 2027, followed by 34 kA trials. Reinforcements to the facility are then planned ahead of energization at the rated 68 kA. High-voltage insulation and the coil's response to deliberate loss-of-superconductivity conditions are also on the agenda. The work links magnet engineering to cryogenics, power delivery, insulation and structural integrity.