Analysis and interpretation of the full set (2000–2002) of TCS tests in conductor 1A of the ITER Central Solenoid Model Coil Original Research Article

The full set of TCS measurements performed during 2000–2002 on conductor 1A of the ITER Central Solenoid Model Coil (CSMC) of the International Thermonuclear Experimental Reactor (ITER) is analysed with the extensively validated M&M code. Under the assumptions of uniform strand properties and uniform current distribution among strands, the performance of this “average” strand in the cable is deduced from the best fit of the measured voltage–inlet temperature characteristics. Two fitting parameters are chosen: an ad-hoc additional contribution ‘εextra’ to the longitudinal strain of the average strand in the cable, and the average-strand (or cable “effective”) index ‘n’ of the electric field–current density characteristic. It is shown that the average strand in the CSMC performed less well than expected from the strand database––an increasingly negative εextra being needed to reproduce the coil behaviour at increasing transport currents, and that the cable effective n is clearly below the measured n of the strand. It is argued that this average-strand performance reduction in the CSMC is most likely related to mechanical load effects.