The ITER magnet system program-design and R&D

The International Thermonuclear Experimental Reactor (ITER) will demonstrate the scientific and technological feasibility of fusion energy. The superconducting coils for the ITER reactor will require about 1200 tonnes of Nb₃Sn strand and 650 tonnes of NbTi strand in 20 toroidal field (TF) coils (675 tonnes each), a central solenoid (1350 tonnes), and 7 poloidal field coils (4300 tonnes total). A worldwide R&D program is underway to verify design criteria for conductors and materials and to develop manufacturing processes for conductors and model coils. The model coils involve two major activities: one for the central solenoid which consists of the fabrication of a 600 MJ model coil at about 150 tonnes and one for the TF coil with a model coil at about 80 MJ and 50 tonnes. Features of the full scale magnet designs and of the R and D program are described