The critical current of Nb3Sn wires for ITER as a function of the axial tension and compression

The influence of compressive and tensile axial strains on the critical current of various Nb3Sn conductors is investigated. The investigated multifilamentary wires are especially developed for the ITER project. The critical current is determined as a function of an axial tension in a standard pull set-up. These results are compared with the results that are obtained on a bending spring-type strain device. In this second device an axial compression larger than the integral thermal shrinkage of the matrix, can be achieved. A study of the field dependence of the critical current yields the strain dependence of the extrapolated upper-critical field versus the axial strain. A good correlation is found between the two different strain devices in the tensile strain regime. There is a difference in the (limited) compressive strain regime where such a comparison can be mad

Characterization tests of the Nb₃Sn calbe-in-conduit conductors for Se.C.R.E.T.S.

Two Nb3Sn cable-in-conduit conductors have been procured for Se.C.R.E.T.S. (Segregated Copper Ratio Experiment on Transient Stability). The two conductors are identical in the fractional cross sections. The only difference is the location of the copper stabilizer, included either as segregated copper wires or as copper shell in the superconducting strands. A number of characterization tests, on individual strands and cabled conductors, have been carried out to establish a solid data base for the assessment of the results in the main experiment