Industrial development of internal tin Nb/sub 3/Sn strands for high field applications

Europa Metalli-LMI, in the framework of the NET-ITER project on thermocontrolled nuclear fusion, has developed and optimized the fabrication technology for internal tin multifilamentary Nb/sub 3/Sn strands. The ITER project technical specifications require strands with high critical currents (700 A/mm/sup 2/) associated with low hysteresis losses (<600 mJ/cm/sup 3/-3+3 T). Modifications to the conductor layout were gradually carried out during development of the strands thus maintaining the high critical currents and reducing the losses. Current densities of 850 A/mm/sup 2/ with losses of 550 mJ/cm/sup 3/ were reached. Furthermore, the manufacturing technology developed by Europa Metalli-LMI enables industrial unit lengths greater than 1 kilometre to be obtained. This paper reports activities which have led to the manufacturing of the conductor fulfilling ITER specifications.<>