INDUSTRIAL-DEVELOPMENT OF INTERNAL TIN NB3SN STRANDS FOR HIGH-FIELD APPLICATIONS

Europa Metalli - LMI, in the framework of the NET-ITER project on ther mocontrolled nuclear fusion, has developed and optimized the fabricati on technology for internal tin multifilamentary Nb3Sn strands. The ITE R project technical specifications require strands with high critical currents (700 A/mm(2)) associated with low hysteresis. losses (< 600 m J/cm(3) - 3 + 3 T). Modifications to the conductor lay-out were gradua lly carried out during development of the strands thus maintaining the high critical currents and reducing the losses. Current densities of 850 A/mm(2) with losses of 550 mJ/cm(3) were reached. Furthermore, the manufacturing technology developed by Europa Metalli LMI enables indu strial unit lengths greater than 1 Kilometre to be obtained. This pape r reports activities which have led to the manufacturing of the conduc tor fulfilling ITER specifications.