The manufacture of poloidal field coil No 3 (PF3) for the International Thermonuclear Experimental Reactor (ITER), which is being built in France has been completed. It is the final poloidal field coil and was produced for ITER at the Poloidal Field Coils Winding Facility at the construction site in Cadarache.
Six poloidal field coils will be positioned horizontally around the ITER vacuum vessel and D-shaped toroidal field coils to help shape the plasma and keep it in suspension away from the walls.
The fabrication of PF3 – one of the two largest ring-shaped coils, measuring 24 metres in diameter – marked the high point of technical and organisational expertise that had been accumulated since manufacturing began in the Winding Facility in late March 2017. The first coil to come off the production line in 2021 (PF5) had required three and half years of work. Although 30% larger and wound with 20% more superconducting cable, PF3 was finalised in two years and nine months a reduction of 15 months in fabrication time.
The smaller PF1 coil – measuring 9 metres in diameter and weighing 200 tonnes – was produced by Russia under a contract signed in 2011. It was delivered to the ITER site in February.
The PF6 coil – weighing 350 tonnes and having an external diameter of about 11.2 metres – was manufactured by the Institute of Plasma Physics of the Chinese Academy of Sciences, a member of the China-France TAC1 consortium led by China National Nuclear Corporation subsidiary China Nuclear Power Engineering. The PF6 coil is the heaviest of ITER's superconducting magnets and the bottom-most of the six circular magnets surrounding ITER's vacuum chamber and the first one to be inserted in the tokamak pit. Installation of the PF6 coil was completed in April by TAC1.
The four other coils – PF2, PF3, PF4 and PF5 – have been produced by Europe at the Cadarache site. Ranging in diameter from 17 to 24 metres and weighing 200 to 400 tonnes, these coils are too big to be manufactured off site and shipped to ITER. In April 2021, the first European-made coil, PF5, completed all manufacturing and testing and was removed from the facility and stored until its installation in September 2021. PF2 and PF4 have also been completed and put into storage. PF3 has now been safely stored next to its quasi twin PF4 and the smaller PF2.
Image (top): The PF3 is transferred to the storage facility to await installation (courtesy of ITER)
Image (bottom): Six ring-shaped poloidal field coils are situated outside of the toroidal field magnet structure to shape the plasma and contribute to its stability by ''pinching'' it away from the walls. The two bottom coils, PF6 and PF5, have already been lowered into the Tokamak assembly pit (courtesy of ITER)
