JT-60SA TF coils have reached their destination

Coil #17 unpacked behind its predecessor, TF coil #9. Each TF coil measures 7.5 x 4.5 metres and weighs 22 tonnes as shown here together with its Outer Intercoil Structure

After their intense journey by road, air and sea, the JT-60SA Toroidal Field (TF) coils #17 and #20 reached the JT-60SA Naka site in Japan on Wednesday morning (21 February).

The supply of the TF coils has been one of the most challenging ever for the F4E Team charged with delivering the Broader Approach projects. The systems supplied by Europe have typically been assigned to a single “Voluntary Contributor” each – the fusion research institutions in Belgium, France, Germany, Italy and Spain appointed by their governments to make the in-kind contributions. For the TF coils it was more complex, with the work shared between France, Italy and F4E itself.

F4E was responsible for the supply of the superconductors (cabled and jacketed by ICAS, Italy, from strand made by Furukawa, Japan) and all of the fasteners (TDI, France and CECOM, Italy). ENEA was responsible for providing all the coil casings (contracted to Walter Tosto, Italy) while CEA dealt with the Outer Intercoil Structures (contracted to SDMS, France) and the “gravity supports” that will hold up the whole magnet assembly (contracted to Alsyom, France). The actual winding and integration of the coils was split between ENEA (ASG, Italy) and CEA (GE, France). Finally all the coils were tested by CEA in Saclay, France.

Of course, F4E had to ensure that all the cogs and wheels of this complex mechanism ran smoothly. “We are the ‘grease’,” explains Enrico Di Pietro, Head of the JT-60SA Unit within F4E. “We facilitate European collaboration and keep everyone working together”. That means a great deal of interface management, both technical and human.

After ten years of juggling different budgets and schedules, cultures and priorities, procedures and personalities, the TF coils are finally ready – and in fact most of them are already installed, following the assembly procedure painstakingly prepared by F4E in consultation with QST, the Japanese ITER Domestic Agency.

The mechanical assembly of all TF coils, to make up the magnetic cage where the plasma will be confined within the JT-60SA machine, will be completed by the summer 2018

The first twelve TF coils assembled in the JT-60SA tokamak.