TESTING OF FULL-SIZE HIGH-CURRENT SUPERCONDUCTORS IN SULTAN-III

The high field test facility SULTAN III in operation at PSI/Switzerlan d tests full size industrial prototype superconductors for fusion appl ications such as ITER. The facility provides a background field of up to 11 T over a length of 58 cm. A 50 kA superconducting transformer wo rks as a very low noise current source which allows a criterion of 0.1 muV/cm to determine the superconducting to normal transition. Three 3 .6 m long cable-in-conduit conductors based on both NbTi and Nb3Sn, de veloped by different manufacturers, suitable for the central solenoid and toroidal field coils of ITER, have been tested so far. This paper presents the results of extensive measurements of critical current and current sharing temperature of the Nb3Sn conductors in the 8 - 11 T r ange for temperatures between 4.5 K and 11 K. Voltage versus current c urves have been analyzed with respect to the n value. The manufacturin g of a high quality joint between two Nb3Sn conductors after heat trea tment is reported, together with some measurements of the joint resist ance.