Toroidal field model coil programme for the ITER tokamak

The ITER toroidal field coil (TFC) system is made of 20 toroidal field coils, each consisting of a winding pack enclosed in a vacuum tight case, about 17 m high and 12 m wide. The winding pack is pancake wound and uses a circular conductor embedded in radial plates. Each turn is insulated from the enclosing plate, and the plates are insulated from each other. These radial plates transfer the forces acting on each conductor directly to the casings without accumulation of forces on the turn insulation. The winding pack is wrapped in a ground insulation, the outer surface of which is matched to the case. There is no bond between winding pack and case. The in-plane hoop forces of the coil are carried by the combined structure of plates and case, and the case provides most of the bending and torsional rigidity. The: conductor jacket is thin and only provides a containment for helium.