Structural analysis of the ITER EDA magnet system

The most recent design of the ITER magnet system is easier to assemble and is expected to be more conventionally manufactured. A stainless steel case with pancake wound plates replaces the earlier poloidally wrapped plate toroidal Field (TF) coil design. The number of TF coils has been reduced from 24 to 20 to ease access. The price for these improvements has been an increase in radial build of the TF coil, and a reallocation of space within the reactor. The TF and central solenoid (CS) are still bucked, making their interface an important area to simulate in structural models. Out-of-plane (OOP) forces are no longer supported by keys between TF legs. The TF case is strong enough to support most of the load when, it in turn, is supported by additional external structures. The most significant of these structures are the upper and lower crowns. A fluted torque shell on the outside of the CS provides a bearing surface for the TF and this along with the CS, and the TF inner legs, takes the global twist applied to the central column of the machine. A US Home team contribution has been a large scale global finite element model which addresses details of construction, and results of this model are presented. Cyclic case bending, torque shell shear, CS shear, the effects of assembly gaps, are presented. The case supports a large portion of the OOP loading, and the possibility of removal or simplifications in the OOP structures is discussed. CS shear stresses from local conductor behavior are combined with the shears from the global behavior and the total shear is compared with the insulation shear allowable used in the ITER EDA. A smaller structural model has been used to simulate multiple pulse, frictional effects, and results of this model are shown