Central solenoid

Only two more to go

On 19 December 2024, one year almost to the day after it was delivered, a fourth module was installed on top of the existing central solenoid stack. Standing on its bespoke platform, the massive, tower-like structure being assembled in the ITER Assembly Hall (left) now reaches approximately two-thirds of its final height. Procured by the United States, the central solenoid modules (6 plus one spare) are manufactured by General Atomics near San Diego.

With a fourth module now in place, the massive, tower-like superconducting magnet being assembled in the ITER Assembly Hall now reaches approximately two-thirds of its final height.

Two more modules need to be stacked and connected to finalize the assembly of the 1,000-tonne superconducting magnet whose role is to induce and sustain a powerful current (15 MA) inside the plasma.

Handling the 2-metre-tall, 110-tonne cylindrical component is a particularly delicate task. Contrary to the vast majority of ITER machine components, which are lifted by way of hooks and attachments, a central solenoid module requires nine powerful wedge pads located at the bottom of a lifting fixture (right), each one exerting a radial force of 220 kN (equivalent to 22 tonne-force) on nine friction pads distributed around the cylinder—a bit like grasping a giant bowl of cereal by exerting pressure from the outside.