Transverse Load Degradation in Nb3Sn Cable-in-Conduit Conductors with Different Cable Pattern

摘要

Irreversible degradation, likely due to microscopic filament damage, has been observed in the past years for large size Nb3Sn cable-in-conduit conductors (CICC) exposed to high electromagnetic transverse load. An R&D program at CRPP is aimed to investigate, by comparison of six conductors with parametric layout variation, the effect of strand layout, thermal strain and cable pattern on the transverse load degradation, including cyclic load. The present work reports the test results in the SULTAN facility of two Nb3Sn cable-in-conduit conductor samples with identical parameters (144 strands, void fraction, jacket material) except the cabling pattern, either braid or triplet based. The pattern of strand crossovers affects the transverse load transmission. The dc performance difference due transverse load degradation is about 10% in favor of the braided CICC. Conclusion is drawn on the impact of conductor parameters on performance degradation.