Commonwealth Fusion Systems (CFS) is pursuing a high-field approach to fusion energy, which enables the development of smaller, lower cost tokamaks on a faster timeline. CFS has recently completed the manufacturing and demonstration of a Toroidal Field Model Coil, and is scheduled to demonstrate a net-energy fusion device, SPARC, by 2025 and commercialize fusion with ARC in the 2030s. The key enabling technology for the design of such high-field magnets is 2G REBCO HTS wire, tens of thousands of kilometers of which are required.
Magnets in SPARC and ARC will operate at high field (~ 20 T) and low temperature (~ 20 K) and will be subject to significant mechanical force and neutron flux. HTS wound into magnets will be positioned in varying orientations relative to varying background fields, and will experience additional handling during winding and soldering processes. Therefore detailed characterization of the critical current of HTS wires as a function of field, temperature, and angle are essential for the design and confirmation of conformance of HTS used in high-field fusion magnets. This presentation will further discuss relevant material properties and requirements as well as design-relevant data and testing methods.