Results of contact resistance distribution in ITER size conductor termination

JORDI (JOint Resistance DIstribution), a dedicated test facility for the measurement of contact resistance distribution in full-size, ITER type conductor terminations, has been successfully commissioned at CRPP. In contrast to earlier attempts, where the contact resistance in terminations was measured in current unbalanced condition, in JORDI the contact resistance is measured under imposed balanced current distribution among all current-carrying elements of the termination. The current from a 10 kA power supply is split by precision, low temperature shunt resistors into 98 parallel channels, each connected to the first cable stage of a full size ITER conductor. The voltage drop, in the range of few tens of nanovolt, is simultaneously sensed between each current carrying element (first cable stage) and the equipotential surface of the joint between the conductor termination and the facility current lead. We report first results of the contact resistance distribution in a prototype of typical ITER terminations, made of NbTi based cable-in-conduit conductor. The results of the measurements are analyzed based on a simple statistical model.