European conductor for ITER Toroidal Field coils ready

ITER will have 18 Toroidal Field (TF) coils. These “D” shaped gigantic superconducting magnets will create a powerful magnetic cage where the superhot plasma will be kept away from the walls of the vessel, the massive metallic box where the fusion reaction will occur. Europe is responsible for the production of 10 TF coils, nine of which will be used in the machine and one will be kept as spare. The remaining nine will be manufactured by Japan.

To manufacture these coils 88 km of conductor will be needed to nestle in the groves of the magnets. F4E together with its suppliers have successfully completed another milestone in the field of magnets by completing the production of the European share of the conductor used in Europe’s 10 TF coils. All in all 20 km have been produced and all pieces are progressively delivered to the ASG workshop where Europe is assembling the TF coils.

This is the outcome of more than six years of hard work, several interfaces and multiple suppliers. So how did we get here? F4E’s first-ever procurement was signed in area of magnets. Luvata was selected for the production of copper strand, one of the elements of the conductor. Subsequently, the production of niobium-tin (Nb3Sn) superconducting strand was signed with Oxford Instruments Superconducting Technology and Bruker European Advanced Superconductors, where they produced 60% and 40% respectively of the Nb3Sn strand needed to form the conductor. In a nutshell, around one third of the wire used in the fabrication of the conductor consists of copper and two thirds consist of superconducting wire. Then, the copper and superconducting wires enter the phase of cabling. The cable is afterwards inserted into a jacket and compacted, known as jacketing process. Next comes the spooling of the conductor, where more tests are carried out and finally the conductor is packed and delivered to the workshop where it will be fitted in the magnets. Cabling, jacketing and spooling were undertaken by the ICAS consortium bringing together ENEA, Tratos and Criotec. As always, works started with the fabrication of a dummy conductor and short qualification superconducting conductors and then moved on with the production of the real conductor to be used in ITER. Altogether 30 TF conductor lengths have been fabricated by ICAS.

All these steps have been successfully completed leading to further acceleration of the TF coils manufacturing. The completion of this task gives Thierry Boutboul, F4E Technical Officer overviewing this operation, a feeling of satisfaction due to the intensive follow-up and the fruitful collaboration with suppliers. For Alessandro Bonito-Oliva, F4E’s Project Manager for Magnets, this is another milestone ticked off the list giving him and his team more adrenaline to keep up the fast pace of the TF coils manufacturing.