Design and manufacture of a prototype NbTi full-size joint sample for the ITER poloidal field coils

The design of the poloidal field (PF) coils of the International Thermonuclear Experimental Reactor (ITER) relies on the use of 45 kA NbTi cable-in-conduit conductors. An R&D programme is carried out jointly between CEA and ENEA to acquire knowledge on the behaviour of such conductors. In addition to the manufacture and tests of two subsize joint samples at CEA Cadarache, the design of a poloidal field full-size-joint sample (PF-FSJS) has been carried out. This sample is composed of two conductor legs made of stainless steel-jacketed NbTi full size cables, of a lower joint built according to the “twin box” concept developed at CEA, and of two upper terminals to be connected to the facility current leads. A description of the sample design, the techniques used for the different manufacturing steps of the conductor legs, the terminations and the assembly is related. This prototype sample will be tested in the Sultan test facility at Villigen (Switzerland) and will be a model for the manufacture of joints for the PF coils.