Develop Nb3Sn Strands for Advanced Fusion Application with High Jc at High Field and Low AC Loss, Topic 19c

This proposal is submitted in response to Topic 19, Advanced Technologies and Materials for Fusion Energy Systems, subtopic (c) Superconducting Magnets and Materials. 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 Tube type Nb3Sn is the only strand type we know of that has demonstrated the high Jc, Je, Ic, and low AC losses needed for future fusion applications in the 14-20T range. In this phase I, firstly we will demonstrate we could fabricate 3-5 kilometers long Tube type Nb3Sn strand with 2-3 times the current ITER Jc while keeping its loss within the ITER AC loss requirement, secondly we will develop a new advanced Nb3Sn wire which will have 4-6 times the current ITER Jc while having small deff. In this Phase I, firstly we will focus on the super high count restack Nb3Sn tube type conductor, and the goal is to make 3 km piece length of 0.82 mm wire which will have 3 times better Jc at 12T-4.2K than present day ITER superconductors, and 3 times the Jc performance of present day ITER conductor at 15T, but with AC losses at or below present day fusion strands. Secondly we will develop a new advanced Nb3Sn wire (involving artificial pinning center) which will have 4-6 times the current ITER Jc while having small deff. 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.