Fabrication and assembly of a single turn coil Tokamak

Multiturn tokamak magnets technologies have been developed during the last four decades. Some of the methods and procedures developed for multiturn coils can be applied to single-turn-coils. However, innovative techniques for fabrication and assembly are being developed specifically for single turn coil tokamks. The proposed IGNITEX (Texas Fusion Ignition Experiment) concept (1.5 m major radius) utilizes single-turn coils for both the TF and poloidal-field (PF) systems. The single turn, TF coil is composed of wedge shaped, high strength, copper-alloy plates. The number of plates required is determined by the maximum thickness availability of the conductor material. An existing 0.06-scale prototype, single turn TF coil uses a beryllium-copper alloy (Brush Wellman Alloy No. 3HT). Radical rings located at the top and bottom of the coil hold the TF assembly together. The TF coil terminals extend radially outward; several plates are connected in parallel to form a sector which is then connected to a HPG module. The assembly procedure for the IGNITEX TF coil prevents a stack-up of angular tolerances. Stiffness of the TF coil is simply a function of conductor material and flatness tolerance of the conductor plates. In conventional TF coils, insulation dictates the maximum operating stresses and temperatures dominate the overall magnet stiffness. Buckling due to axial preload is less probable in a single turn, TF coil than in conventional TF magnet designs