A Novel “Test Arrangement for Strain Influence on Strands” (TARSIS): Mechanical and Electrical Testing of ITER Nb3Sn Strands

Abstract

Knowledge on the deformation state of the strands in International Thermonuclear Experimental Reactor (ITER) type Cable‐In‐Conduit Conductors (CICC) and its impact on both the transport properties and the superconducting transition is essential for optimal cable and magnet design. To date a relatively large part of the attention is concentrated on the influence of purely axial strain on the performance of Nb3Sn strands and sub‐size cables. However, local deformations such as strand‐to‐strand, strand to conduit contact pressure and strand bending will occur as well in multi strand CICC’s experiencing an electromagnetic load. More basic experimental verification is required on strand level from virgin state towards multi‐cyclic loading. Therefore a new test arrangement is developed in which the influence of various principle deformation states that occur in a CICC, i.e. local transverse deformations, transverse homogeneous loads, bending and axial load, can be studied separately or combined. Beside precise displacement and force measurements for stress‐strain analysis, the voltage‐current and voltage‐temperature characteristics are traced. A description of TARSIS is presented and the first preliminary results on periodical strand bending are reported.