Quench tests analysis of the first JT-60SA Toroidal Field coils

Abstract

In order to check the performance of the JT-60SA Toroidal Field (TF) coils and hence mitigate their possible fabrication risks, a series of tests have been carried out in the Cold Test Facility (CTF) at CEA Saclay in nominal conditions at 5K and 25.7kA. One major test performed is the so called “temperature margin test” during which the inlet helium temperature of the Winding Pack (WP) is controlled to increase progressively to the calculated current sharing temperature of 7.3K in the high field region to launch the quench. The measurements of voltage, pressure and temperature signals allow us to study the thermo-hydraulic behavior of the JT-60SA coils during a quench. This paper will present the 6 quench tests on 5TF coils accomplished between February and September 2016, of which the first manufactured coil TFC10 has carried out two quench tests and two pure Fast Discharges without any quenches. It will analyze in particular the temperature and pressure rise in helium, the corresponding physical phenomena after each voltage variation, the four quench dynamic phases, the quench propagation velocity and the dissipated power in the coils.