Spatial periodic and homogeneous transverse stress loading on ITER TF Nb3Sn bronze and internal tin strand

摘要

The transport properties of the superconducting Nb3Sn layers in the strandsstrongly depend on the strain state. Knowledge of the influence of axialstrain, periodic bending and contact stress on the critical current (Ic) of theused Nb3Sn strands is inevitable to gain sufficient confidence in an economicdesign and stable operation of ITER CICCs. In the past years we have measuredthe Ic and n-value of various ITER Nb3Sn strands with different layout in theTARSIS facility, when subjected to spatial periodic contact stress at atemperature of 4.2 K and in a magnet field of 12 T. Recently we have made thesetup suitable for application of homogeneous load along the length of the wire(125 mm) in order to evaluate possible differences related to spatial stressand possible current distribution. We present an overview of the resultsobtained so far on an ITER TF bronze and internal tin strand.