Stability Estimate for CICC with Cooling Channel Using One- and Two-Fluid Codes

Abstract

Cable-In-Conduit Conductors (CICC) with central cooling channel have been recently tested in the QUench Experiment on Long Length (QUELL) at the Sultan facility, and are foreseen for the Toroidal Field (TF) and the Central Solenoid (CS) superconducting magnets of ITER (International Thermonuclear Experimental Reactor). A careful thermal-hydraulic analysis of this type of cables is needed in the design of magnets with a reasonable safety margin.

To the purpose of a more accurate description of the physics in the 2-channel topology, the 2-fluid code Mithrandir1 was recently developed from the 1-fluid code Gandalf.2 Mithrandir allows different thermodynamic state of the helium that flows in the cable bundle region and of the helium in the central channel. On the contrary, the homogenization intrinsic in a 1-fluid model can result, among others, in a significant overestimation of the stability margin.

Both Gandalf and Mithrandir have been very recently benchmarked against quench propagation data from QUELL. Here, we analyze the stability of QUELL, and a first comparison with experimental stability data for this type of conductor is presented, using a few measurements performed on QUELL.

Some stability calculations for an ITER CS conductor are then performed with the Mithrandir code, considering the influence of the 2-fluid coupling on the stability margin.