Development of the Coil Terminal Boxes for the ITER Magnet Feeder Systems

The nuclear radiation levels, magnetic fields and general access restrictions in the ITER Tokamak are such that it is undesirable to place remote control helium supply valves close to the coils. The Coil Terminal Boxes (CTB), which are further away from the coils, are therefore designed for easy access and contain as much as possible the components needing maintenance, such as the cryo-valves. The CTBs also house the electrical cold-warm transitions with the HTS current leads and the NbTi feeder busbars. Also most of the feeder instrumentation is located in the CTB. Based on the functional specification by ITER, ASIPP has manufactured and tested a prototype CTB for the ITER magnet system. This test allowed for the verification of the mechanical design of the cryostat and the thermal shield design. Following a discussion of the ITER CTB design, with particular emphasis on the concepts of flow distribution for the large ITER magnet system, considering safety and maintenance, this paper will also present the results of the prototype CTB development.