AbstractThe preparative experimental and analysis work as well as the code development for testing the ITER (International Thermonuclear Experimental Reactor) TFMC, one of the large projects of the ITER research and development programme, is described. The expected critical currents of the Nb3Sn superconducting cable are derived from the numerous short sample strand and subcable measurements. A data set of the thermo-hydraulic properties of the bundle conductor with a central channel was elaborated in experiments as an input for the thermo-hydraulic calculation codes gandalf and mithrandir combined with the hydraulic network code flower. On this basis, the quench behaviour and the injection of gaseous heated helium slugs for determining the operation limits are treated. The mechanical behaviour of the test configuration was investigated by a finite element calculation. The winding type in which the conductor is embedded in radial plates has to be considered for transient voltage peaks as an electrical network. Arising over-voltages by resonance frequencies in the winding pack have to be considered for the integration of the electrical insulation system of the TFMC. Numerous sensors are installed to compare the predicted values and behaviour with the measurements.