High temperature superconducting current lead test facility with heat pipe intercepts

A high temperature superconducting (HTS) current lead test facility using heat pipe thermal intercepts is under development at the Superconductivity Technology Center at Los Alamos National Laboratory. The facility can be configured for tests at currents up to 1000 A. Mechanical cryocoolers provide refrigeration to the leads. Electrical isolation is maintained by intercepting thermal energy from the leads through cryogenic heat pipes. HTS lead warm end temperature is variable from 65 K to over 90 K by controlling heat pipe evaporator temperature. Cold end temperature is variable up to 30 K. Performance predictions in terms of heat pipe evaporator temperature as a function of lead current are presented for the initial facility configuration, which supports testing up to 200 A. Measurements are to include temperature and voltage gradient in the conventional and HTS lead sections, temperature distribution and heat transfer rate in the heat pipes, as well as optimum and off-optimum performance of the conventional lead sections.