Performance of a `react and wind´ 12 T KfK-NET-TF subsize conductor under static and cyclic axial strain

A forced flow Nb₃Sn subsize conductor for the 12-T Next European Torus (NET) toroidal field coils fabricated by the react-and-wind process was developed. It consists of a flat core housing the Nb₃Sn cable soldered between two stabilizing copper units which are surrounded by a stainless steel jacket. The jacket was tightly drawn onto the already reacted cable. Critical current, I_c , vs. both magnetic field, B, and axial strain, ∈ _a, measurements show that this delicate procedure has not adversely affected the I_c vs. (B,∈_a) characteristic. At B=12 T the I_c vs. ∈_a curve exhibits a maximum of I_c=5.25 kA at a prestrain of ∈_a=0.36% which degrades to I_c=3.93 kA at ∈_a=0. This behavior is not influenced by 10³ strain cycles between 0.1 and 0.36% strain. The results have demonstrated both the mechanical integrity and the predicted properties of react-and-wind conductors