Strand resistance distribution in an improved full size joint for the ITER conductors

An improved joint layout layout is proposed for the electrical connections of the large Nb3Sn cable-in-conduit conductors for the Central Solenoid and Toroidal Field coils of ITER, International Thermonuclear Experimental Reactor. The driving design criteria are a reliable electrical performance and an easy manufacturing procedure, limiting the risk of failure and allowing generous assembly tolerances. The development results are reported, as well as the manufacture of a hairpin joint using sections of the ITER CS conductor. The joint sample has been used to investigate the resistance between strand pairs belonging to the two conductor sections. From the distribution of the strand-to-strand resistance, it is possible to infer the current distribution in the conductor under DC conditions, what is a crucial issue for the stability analyses.