First measurement of the current sharing temperature at 80 kA in the ITER toroidal field model coil (TFMC)

摘要

The first measurement of the Tcs at 80 kA was successfully performed in the ITER TFMC. Two resistive heaters are available on the inlet piping of the P1.1 and P1.2 pancakes, and can be independently operated. An "optimum" heating scenario, based on the multi-step (staircase) strategy developed before the tests, was determined and used for Tcs measurement. The test ended with the quench of the coil, followed by the dump. A normal zone was originated first in the P1.2 conductor, with the inlet helium temperature in P1.2 of about 8.7 to 8.9 K just before the quench, as expected from previous analysis. The results of the test are presented and analysis is performed for an accurate assessment of Tcs, evaluating the effects of Joule heating in the joint, heat exchange through the joint between P1.2 and the slightly colder P1.1, and helium propagation from the heater to the peak field region in the conductor.