Application of the 4C code to the thermal-hydraulic analysis of the CS superconducting magnets in EAST

The thermal-hydraulic transient, driven in the EAST Central Solenoid by two successive sinusoidal current pulses of different amplitude and frequency, forced in the CS1 coil alone, is studied with the 4C code. The sensitivity of the evolution of the computed transient to the uncertainty of the conductor void fraction and of the inter-turn inter-pancake heat transfer is studied parametrically. The coupling time constant (~ 36 ms), needed to reproduce with the simulations the measured evolution of the temperature of the supercritical He coolant at the coil outlet, turns out to be much longer than that of the corresponding short sample (~ 5 ms).