Thermal-hydraulic analysis of transients in the HELIOS loop including a CICC section representative of the JT-60SA Central Solenoid

The HELIOS facility at CEA Grenoble is a supercritical helium (SHe) loop which is being used to investigate the effects on the cryogenic cooling system of the pulsed heat loads which are typical of superconducting tokamak operation. In the standard configuration, the magnet heat load is simulated by electrical heaters wrapped around a section of cryoline. In the present work, the resistively heated section is substituted in the HELIOS model of the 4C code, already validated for the standard configuration of HELIOS, by a sub-size winding structure made of JT-60SA Cable-In-Conduit Conductors (CICCs). The new model is then used to highlight the differences in the circuit behaviour when the heated pipe is substituted by an actual magnet wound with CICCs, checking the representativeness of the control strategies developed for the present HELIOS configuration. The use of CICCs will be shown to produce an intrinsic smoothing of the temperature profiles which is not affecting the capability of the control strategies to smooth the heat loads to the cryoplant.