Skip to Main Content
The Large Coil Task (LCT) is an international collaboration under the auspices of the International Energy Agency (IEA) among the United States, EURATOM, Japan, and Switzerland to develop large superconducting toroidal field magnets for tokamak fusion reactors. Six 2.5-m*3.5-m bore coils capable of producing 8 T were fabricated, three by the US and one each by the other participants, and assembled in a toroidal array in the International Fusion Superconducting Magnet Test Facility (IFSMTF) at the Oak Ridge National Laboratory (ORNL). The coils were widely different in design with three cooled by pool-boiling helium at atmospheric pressure and three cooled for forced-flow helium at supercritical pressure (1.5 MPa). An overview is given of the various single-coil and six-coil array tests, to design point and beyond, and also the symmetric torus tests that were performed. All six coils exceeded the design goals, both as single coils and in six-coil toroidal tests. In the symmetric torus set, a maximum field of 9 T was reached in all coils simultaneously. Only brief summary is given of the specific thermal and mechanical experiments that were also conducted.