Mechanical behaviour of ITER central solenoid

The ITER Magnet system consist of 4 sub-systems, i.e. 18 Toroidal Field Coils (TF-coil), a central Solenoid (CS), 6 Poloidal Field Coils (PF-coil) and 3 sets of Correction Coils (CC). The Central Solenoid contributes a) to the inductive flux to drive the plasma, b) to the shaping of the field lines in the divertor region and to c) the vertical stability control. The CS performance is fatigue limited, mainly by the stress levels in the conductor jacket and in the pre-compression structure needed to keep the modules in contact as much as possible during the repulsive forces which can arise in operation. The choice of the jacket material and its impact on the pre-compression structure have been investigated by performing finite element analyses with 2D/3D global and local models. A large number of loading conditions and two material options for the pre-compression structure have been considered. The results obtained are used for the structural assessment (static and fatigue) resulting in the present baseline design.