Electrical and thermal designs and analyses of joints for the ITER PF coils

The Poloidal Field (PF) coils of the International Thermonuclear Experimental Reactor (ITER) are designed with NbTi cable-in-conduit conductors wound in double pancakes which are connected in series by joints. The electrical analysis of these joints includes estimation of the dc resistance, calculation of ac loss power, of loop currents and local Joule heating during the whole plasma scenario. The effect of a plasma disruption is also considered. The thermal analysis is performed using a transient thermohydraulic two-fluid code, modeling the two-channel structure of the cable as well as the counter-flow heat exchanger created in the joint. We show that the CEA twin-box concept using compressed cables inside independent copper-steel boxes is quite usable in all the ITER PF coils. A discussion about possible options (copper RRR) is also presented.