Design and fabrication of indigenous 30 kA Nb3Sn CICC for fusion relevant superconducting magnet

Abstract

“Magnet Technology Development Group” is engaged in focused research and development of indigenous fusion relevant superconducting magnet at Institute for Plasma Research in association with various R&D organizations. The fusion relevant superconducting magnet is under development using a cable in conduit conductor (CICC) with operating current of 30 kA at 12 T and 4.22 K. The 30 kA CICC has been designed in square cross-section (30 mm × 30 mm) consisting twisted Nb3Sn strands and copper strands as superconducting cable, SS316LN tubes as jacket material and SS304L foil as wrapping around the cabled strands. It has been designed on the basis of required critical design parameters, operation requirements and mechanical consideration during its fabrication. Cabling technology required for twisting of Nb3Sn and Copper strand in required configuration of cable is discussed in this paper. The effect of heat treatment on SS316LN jacket material as well as on Nb3Sn strands is mentioned in paper. 100 m long Nb3Sn based CICC is manufactured by pulled through technology on dedicated jacketing line. The manufacturing parameters and quality procedures for development of CICCs is successfully established and have been demonstrated with fabrication of 100 m Nb3Sn based CICC without any technical difficulties.