HIGH JC, LOW AC LOSS Nb3Sn Superconductor for 16-20 T Fusion

Statement of the problem or situation that is being addressed This proposal is submitted in response to the SBIR/STTR OFFICE OF FUSION ENERGY SCIENCES Topic 25, “Superconducting Magnets, (a) Superconducting Magnetic Technology”. Grant applications are sought to develop innovative and advanced superconducting materials and manufacturing processes that have a high potential for improved conductor performance and low fabrication costs. Work has started worldwide for the conceptual design of DEMO (DEMOnstration Power Plant), intended to build upon the expected success of the ITER experimental nuclear fusion reactor. This industrial fusion reactor will require lower cost, much higher performing superconductor wires in the 14-20 T range and in higher nuclear irradiation environments, provide improved access/maintenance or allow for wider operating ranges in temperature or pulsed magnetic fields. With the use of higher performing superconductor, the amount of strands needed for a given cable will be less to generate the same field, which will reduce the cost of the superconducting magnets. Hence high performance, low loss and low cost Nb3Sn is still a good choice for advanced fusion projects. Hyper Tech’s newly developed Nb3Sn wire with artificial pinning center (APC) reaches Bc2 of 28 T, the 3-4 times Jc of ITER spec, and good wire drawability. This conductor will have a price matching the regular Nb3Sn wire which is much less expensive than the REBCO and BSCCO 2212 conductors. This APC Nb3Sn is a good candidate for future fusion projects in the 14-20T field as stated in the solicitation 25 (a). General statement of how this problem is being addressed In this phase I, we will develop an APC Nb3Sn wire specifically for fusion application. We will select the right alloy and make high account restack Nb3Sn wires and draw them down to the size which will meet the AC loss requirement for fusion wire while having a few times higher Jc than the current ITER Nb3Sn wire. Then we will scale up the billet size and make multiple km length wire to demonstrate its drawabilty, high non-Cu Jcs while keeping low AC losses. Commercial applications and other benefits Commercial Applications –A large market for Nb3Sn wire is for fusion magnets. Tons of strands are needed for the ITER and later DEMO projects. The other commercial applications besides fusion are high field 7-11T MRI, NMR systems, 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 diagnosis and treatment of cancer, the locating of oil and minerals in the earth, the processing of semiconductor chips for computers, the determination of the age of materials through radiocarbon dating, the sterilizing of medical equipment and food products.