Toroidal field coils
Europe completes all "double pancakes"
3 Dec 2018
Each one of ITER's giant, D-shaped toroidal field coils is built from seven "double pancakes"—layers of spiralled conductor that carry electrical current. Contractors to the European Domestic Agency have now realized 70 of these 16-metre-tall components, completing the scope required for the fabrication of ten toroidal field coils.
At ASG Superconductors, a D-shaped double pancake is transferred to the laser welding station (background). Seventy double pancakes—or seven per coil—were produced in this facility. The winding of a double pancake is the first step in the production of a toroidal field coil.
From the completion of the first full-size prototype in 2013, through the series winding of 70 double pancakes, it has been a highly technical industrial journey.
The winding of the double pancakes is considered the most challenging phase of magnet coil fabrication, consisting of bending conductor lengths along a D-shaped double spiral trajectory. As the conductor must fit precisely inside the radial plate groove, it is vital to control its trajectory in the double pancake and in the groove of the radial plate with extremely high accuracy. The trajectory of the conductor, in particular, must be controlled with an accuracy as high as 0.01 percent.
The completion of the 70 double pancakes is an important milestone for the European Domestic Agency, Fusion for Energy, and its suppliers Iberdrola Ingeniería y Construcción (project management, quality assurance, and planning); ASG Superconductors SpA (design of process, plant and tooling, manufacturing); and Elytt Energy SL (design and manufacturing of turn insulation, pancake impregnation plant/tooling), and radial plate manufacturers CNIM and SIMIC.
See the full report on the European Domestic Agency website.