A Proposed Prototype Coil R&D Program for ITER

Abstract

The ITER Magnetics R&D plan developed during the Conceptual Design Activity identified the need to build both central solenoid (CS) and toroidal field (TF) model coils. In the CDA plan both model sets were circular. The CS model coil would have an inner diameter of 2 m, a field of 13 T and no case, whereas the TF model coils would have a 4 m diameter, a field of 11 T field, and a surrounding case. The U.S. has proposed instead that the TF model coil be down sized and made noncircular, so that a 2 m x 3.5 m model can be combined with the CS model coils, still allowing full simulation of the ITER TF stresses. This smaller assembly of coils, which would use full-scale conductors, would be less expensive to build, and would be more suitable for conducting an extensive set of cyclic extended performance tests. To compensate for the loss of large coil fabrication with the down-sizing of the TF model coil, the U.S. has propose that a full-scale ITER TF magnet double pancake, or two layers of a nested shell concept, be fabricated from production conductor, and that the coil element and its structure be cold tested in a prototypical “Q/A Production Test.”