Design and development of a pair of 10 kAHTS current leads for the NHMFL 45 hybrid magnet system

During a planned replacement of one of the three superconducting coils in the outsert magnet of the 45 T Hybrid, there is an opportunity to replace the existing pair of standard helium-vapor-cooled current leads with a pair of leads incorporating high-temperature superconductor (HTS) sections. A conceptual design for these leads has been completed, and various critical components have been modeled and tested. The design includes an integral liquid-nitrogen reservoir at the interface between resistive and HTS sections, automatic liquid-nitrogen level control, a resistive heat-exchanger section cooled by nitrogen vapor, an HTS section with integral stainless-steel shunt for protection, and an interface to the low-temperature superconductor bus. A detailed design is presently underway and fabrication tooling and techniques are being developed. We present design details, projected performance, results of development testing, and plans for manufacturing and acceptance testing.