Design details of the current lead test facility Karlsruhe (CuLTKa)

The new current lead test facility CuLTKa was successfully commissioned in 2014 at the Karlsruhe Institute of Technology, Germany. Towards the end of the year the first pair of High Temperature Superconductor current leads (CL) for the Japanese tokamak JT-60SA was tested. These CL have to carry currents of up to 26 kA and are cooled with helium (He) at two different temperature levels, 4.5 K and 50 K, respectively. After commissioning and test of the first pair another 24 CL will be tested until 2017. The facility consists of five cryostats: The first cryostat distributes the He coming from the 2 kW refrigerator to the different experiments in the ITEP. In the second one, with an integrated He-bath, the forced flow He for the CL is cooled down to 4.4 K and the 50 K He is piped through. In a valve box the He at two temperature levels is distributed to two test cryostats housing each one pair of CL. This paper describes the design of the facility from a cryogenic point of view starting from the basic demands. The overall setup is derived and particular details are explained. Some design calculations will be opposed to measured data from its real performance. ... mehrIn addition one major safety aspect is described.