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The Tokamak Physics Experiment (TPX) will be the first Tokamak using superconducting magnets for both the poloidal and toroidal field. It is designed for advanced Tokamak physics experiments in steady-state and long-pulse operation. The TPX superconducting magnets use an advanced cable-in-conduit conductor (CICC) design similar to that developed in support of the International Thermonuclear Experimental Reactor (ITER). The toroidal field magnets provide 4.0 T at 2.25 m with a stored energy of 1.05 GJ. The poloidal field magnets provide 18.0 V-s to ohmically start and control long burns of a 2.0 MA plasma.

The Fusion ENgineering International eXperiment (FENIX) Test Facility has been operational since 1991 at the Lawrence Livermore National Laboratory for testing the International Thermonuclear Experimental Reactor (ITER) prototype conductors. These conductors are designed to operate stably with transport current of more than 40 kA at a magnetic field of 13 T. The FENIX facility consists of four magnet sets that are configured to allow easy access to the 40-cm high-field region with a test cross-section area of 10 * 15 [cm.sup.2]. FENIX provides test conditions that closely simulate many of the ITER magnet operation modes. Performed experiments include measurements of critical current, current-sharing temperature, forced-flow properties, stability, joint performance and cyclic fatigue effects. This paper describes the design and performance of these experiments.

The results of tests carried out on three Nb3Sn cable-in-conduit conductors are discussed. The tests, which investigated the viability of the superconducting elements for the Next European Torus program, were conducted under conditions exceeding the conductor's rated capacity. The results provide a measure of the temperature margin during dc operation and the pressure drop.