Empirical investigation of factors affecting the stability of cable-in-conduit superconductors

Abstract

Experiments investigating the stability of cable-in-conduit superconductors were performed using test conductors composed of small, quadruplex cables enclosed in steel tubes. To examine the effects of a variation in stabilizer resistivity, all test conductors contained two strands of identical NbTi/Cu composite superconductor and two strands of solid copper. The grade of copper was varied for each test conductor so that a different net stabilizer resistivity existed for each conductor. When these conductors were operated outside the range of multiple stability, tests showed that their stability was negligibly affected by stabilizer resistivity; conversely, the range of operating currents for which multiple stability occurs was affected. However, the surprising result of this study is that stability is apparently affected when a large fraction of the copper stabilizer is segregated into separate cable strands. These observations are compared with other data in the literature.