Nuclear heat, disruption loads and other AC losses and their impact on the ITER toroidal field coils conductor design

In the framework of the re-design of the ITER magnets, with the objective of reducing the dimensions and therefore the cost of the machine, the reduction of the nuclear shielding thickness at the critical inboard side of the plasma appears as a useful factor. However, thinner shielding results in extra nuclear power deposition on both the case and the conductors of the toroidal field coils. These heat loads are added to other heat power sources such as AC losses & joint resistance in the conductor cooling loops and eddy currents, conduction and radiation in the case cooling loops. The various impacts of such an environment for the conductor design are reviewed. The thermal analysis of the cooling of both the conductor and the case is made for the particular case of a plasma disruption, during which a significant amount of energy is deposited in the case. Particular attention is paid to the heat transfer between the case and the winding pack and the impact on the temperature rise at the conductor. The maximum allowable nuclear heat deposition on the case/conductor is derived.