LONG-LENGTH Nb3Sn TUBULAR CURRENT-CARRYING ELEMENTS FOR AN AC SUPERCONDUCTING CABLE

Investigations carried out in our laboratory1 have shown that it is possible, in principle, to produce superconducting Nb3Sn diffusion claddings able to transfer ultrahigh transport currents (700 A/mm in the self-field at 4.2 K) at a low loss level in the superconductor (3–5 μV/cm2 at a surface current of 500 rms A/cm, frequency of 50 Hz, and 4.2 K). On the basis of experimental data on critical current and ac loss measurements as a function of conditions under which Nb3Sn is formed, the technology has been developed to deposit diffusion claddings of Nb3Sn with high superconducting characteristics on tubular surfaces. The developed technology may be used to produce current-carrying elements of a rigid superconducting cable used for electric power transmission lines, superconducting shields, and so on.