THE EFFECT OF STATIC AND CYCLIC AXIAL STRAIN ON LC OF CABLE IN CONDUIT NET SUBCABLES

The effect of static and cyclic axial strain, epsilon(a), on the critical current, I(c), of Nb3Sn "Cable in Conduit" (ClC) subconductors has been measured at I(c) less-than-or-equal-to 10 KA and magnetic fields of B less-than-or-equal-to 12.5 T. The conductors exhibit a maximum of I(c) at epsilon(a) almost-equal-to 0.7% and a degradation of I(c) being about 50% at epsilon(a) = O and B = 12.5 T. As a major result, the I(c) vs epsilon(a) characteristic is unaffected up to 10(3) strain cycles at epsilon(a) less-than-or-equal-to 1%. The subcables were fabricated by ABB within the frame of the European Fusion Technology Program designing a 40 KA/12.5 T CIC conductor for the NET OH coils following the "wind and react" technique. Two different types of cable were developed, based either on a braid or on a triplet cable, inserted in a stainless steel jacket with 44% void fraction. For both cables a "modified jelly roll" (MJR) processed basic Nb3Sn wire was used.