Preliminary Design of 30 KA Current Leads for the Enea Cicc Upgraded Test Facility

An upgrade of the CICC facility at the ENEA Superconductivity laboratories for the characterization of superconducting long length wound conductors in forced He flow cooling, has begun. In this framework a considerable effort has been spent for the design of two appropriate gas-cooled current leads for a 30 kA insert. Indeed, several geometrical and operational constraints have been considered due to the re-use of the pre-existing cryogenic plant and background magnet. In particular, to limit the overall length of the leads and the amount of cooling gas to be employed, a hybrid resistive/HTS configuration has been conceived. It consists of a copper bar, with an adequate heat exchanger, from room temperature down to 40 K and an HTS BSCCO part from 40 K down to 5 K. Two helium inlets are foreseen for the lead cooling: one at 5 K at the bottom edge, in parallel to the background magnet refrigerant line, and one at 16 K in the joint between the resistive and the HTS parts. In this paper the description of the numerical analyses performed for the optimal design of the leads are discussed.