Experimental results of ITER cold circulators towards the performance demonstration

Abstract

The cold circulators, the most challenging component of ITER cryo-distribution system, have been designed, manufactured and tested successfully at factory. The design point for the cold circulator has been specified as 2.21 kg/s at 4.3 K inlet temperature having 0.155 MPa pressure head, dedicated for the nominal operation of toroidal field (TF) superconducting magnet of ITER. The expected isentropic efficiency has been defined as 70 % or more suitable to cater the demands of the cryo-distribution system. Two cold circulators for TF superconducting magnet have been installed in the Test Auxiliary Cold Box (TACB) followed by the integration of TACB system with the 5.0 kW at 4.5 K class cryogenic test facility at Japan. Final cold acceptance test of the complete system has been performed in order to validate the design conditions of TACB and cold circulators. Qualification tests of two cold circulators have been executed at closed loop operating condition. The cool-down of cold circulators down to 4.6 K temperature level and normal operating results as well as the experimental validation of performance along with the obtained isentropic efficiencies at the operating conditions have been demonstrated meeting the system level requirements of ITER cryo-distribution.