The applicability of the react-and-wind technique to the ITER-TF coil with a Nb 3Al conductor

Abstract

The ITER-TF coil whose size is a 17 m height and a 11.5 m wide, has been designed with maximum field of 13 T in winding. At present the TF coil is considered to be fabricated with a wind-react-transfer technique using Nb 3Sn conductors. However, recently the development of Nb 3Al conductors is advanced with rapidity. The critical current density of more than 700 A/mm 2 within non-copper has been achieved. Furthermore, the degradation of the critical current density at 0.4% strain and at 12 T was only 5% for a Nb 3Al strand in comparison with 20% for a Nb 3Sn strand. Therefore, we have tried to investigate if the ITER-TF coil could be fabricated with the react-and-wind technique using Nb 3Al conductor, by which high reliability of the coil fabrication and reduction of the fabrication cost are realized. As the result, it was found that the fabrication of the ITER-TF coil is possible within 0.4% strain in Nb 3Al strand with no changes of the present coil and conductor dimensions.