Pancake-wound central solenoid coil for ITER

The central solenoid (CS) coil of the Reduced Technical Objective/Reduced Cost (RTO/RC) ITER is structurally independent from the toroidal magnet system and consists of 6 modules. The Nb/sub 3/Sn superconducting cable is a similar design to that of the CS model coil. The pancake-wound technique has been selected to allow non-uniform current distributions along the vertical axis since this is important for plasma shape control. The CS winding radial build should be minimized to provide as much flux as possible. Two alternatives for the CS conduit reinforcement are being considered: a co-wound reinforcing strip and a reinforcing armor around a circular tube. Separation forces between modules are supported by the axial pre-compression structure. The performance of the CS structure has been assessed using an axisymmetric finite element model of the winding structure at the CS mid-plane.