Design Study of a 50-kA React-and-Wind Bi-2212 Cable for Fusion Magnet

In the last few years, the current density of Bi-2212 wires has been greatly improved by filament densify technologies. One further step toward applications in fusion magnets is to design a high current cable, which must overcome the drawbacks of Bi-2212 wires: brittleness and complex heat treatment process. In this article, react-and-wind flat cables are proposed. With react-and-wind technique, a larger number of choices of jacket and quench protection materials are available including stainless steel and copper, both of which are widely used for Nb3Sn and NbTi superconducting cables but are not directly usable for wind-and-react Bi-2212 cables due to their reaction during heat treatment. Two wires, representing, respectively, modest and top performance of the state-of-the-art wires, are considered. Several cable layouts are studied in terms of dimension, compaction rate, and transverse mechanical pressure. Materials for quench protection and jacket materials are also discussed.