Simulation of thermal-hydraulic transients in the KSTAR PF1 coil using the 4C code

KSTAR is a fully superconducting tokamak, in operation since 2008 at the National Fusion Research Institute in Korea. All coils are wound using cable-in-conduit conductors and cooled with forced-flow supercritical helium (SHe) at 4.5 K and 5.5 bar. We consider here the central pair, PF1U/L, of the central solenoid coils; during operation these coils are subjected to sharp current transients, which induce AC losses in the coil. The thermal hydraulic transient following a trapezoidal current pulse, with ramp up to 10 kA at a rate of 1 kA/s and ramp down to 0 kA at a rate of 10 kA/s, is simulated here using the 4C code, and the results are compared with the measurements.