A Fully Automatic Press for Mechanical and Electrical Testing of Full-Size ITER Conductors under Transverse Cyclic Load

Abstract

A cryogenic cable press has been built and recently modified to investigate the life time properties and changes in the mechanical and electrical properties of full-size ITER (International Thermonuclear Experimental Reactor) conductors. The press is a fully automatically controlled operating system designed to test Cable-In-Conduit Conductors (CICC) under transverse variable load along 40,000 cycles at temperatures from 4.2 to 300 K. The designed lifetime of the press, with moving parts and minimized friction at cryogenic temperatures, is at least a few millions of cycles. The maximum press load is 320 kN with a stroke of 5.5 mm. The maximum sample length amounts to 400 mm. The force on the cable and the compression are monitored simultaneously in order to determine the mechanical cable deformation properties and losses. A superconducting dipole coil integrated in the press surrounding the sample, provides the DC and AC magnetic field required to perform magnetization measurements with pick-up coils. In addition, interstrand resistance (Rc) measurements are carried out. To date, more than ten full-size CICC samples have been tested, each subjected to 40,000 cycles. All samples show changes in Rc, coupling loss and mechanical properties with cycling, some of them are quite significant, depending on themore » specific conductor properties. Some typical design features of the press are presented and discussed.« less