Description of the BPX toroidal field coil support structure

The Burning Plasma Experiment (BPX) toroidal field (TF) coil design is based on a wedged inner leg support concept with the rear leg of each coil contained in a stainless-steel case. The cases are welded together to form a continuous structure that provides support for both in-plane and overturning forces. The 18 coils and cases are grouped into three coil modules to facilitate remote replacement in the event of a coil failure. The coils are a modified Bitter design with radially oriented flat plate conductors of high-performance, beryllium-copper. The coils are precooled with liquid nitrogen. The inner leg temperature rises to room temperature at the end of the pulse and approximately 1 h is required to cool down the coil after a full power pulse. An important consideration in the design is that the structure should be robust and use conventional materials. In addition to describing the structural design, the author discusses the applied loads, the design approach, and the fabrication sequence