Increase Jc by Improving the Array of Nb3Sn strands for Fusion Application

This proposal is in answer to Topic 68, Advanced Technologies and Materials for Fusion Energy Systems, subtopic (c) Superconducting Magnets and Materials. Work has started worldwide for the design of an advanced fusion project beyond the present funded ITER demonstration. The future fusion reactor design will require lower cost, much higher performing superconductor wires in the 14-20 T range. For this higher performing strand, it will require a totally differently designed Nb3Sn superconductor, very high Jcs at 15T, but we still need to maintain the low AC loss of present ITER fusion superconductors. This proposal Phase I and potential II will investigate a lower cost, high Jc, low AC loss Nb3Sn superconductor that can meet the needs of future fusion applications. For this SBIR Phase I and II we will demonstrate a Nb3Sn strand with better array that will have 3 times better Jc at 12T-4.2K than present day ITER superconductors, and 2 times the Jc performance of present day ITER (12T-4.2K specification) at 15T, but with AC losses at or below present day fusion strands. Commercial Applications and Other Benefits: A large market for Nb3Sn wire is for fusion magnets. Tons of strands are needed for the ITER projects. The other commercial applications besides fusion are high field 7-11T MRI, NMR systems, and superconducting accelerators - protron radiation for cancer treatment, SMES, and high field magnetic separation. According to a U.S. EPA article, more than 97% of the 15,000 accelerators in use around the world have commercial applications, e.g. in the diagnosing and treating of cancer, the locating of oil and minerals in the earth, the processing semiconductor chips for computers, the determination of the age of materials through radiocarbon dating, the sterilizing of medical equipment and food products