ITER's
poloidal field system consists of six horizontal coils. Coils #2-6 will be procured by Europe in a dedicated 250 metre-long coil winding facility on the ITER site. Coil #1— the smallest of the poloidal field coils (although it weighs a full 293 tonnes)—will be manufactured in Russia under the leadership of the Efremov Institute in St. Petersburg and delivered to Cadarache by boat.
The second Procurement Arrangement signed in Moscow with the Russian Domestic Agency this week, number 50, was for the fast discharge units, switching networks, and the high-current, water-cooled busbars. The fast discharge units are used to protect ITER's superconducting coils in case of a quench. To allay the consequences of such an event, large resistor banks are inserted in the circuits to dissipate the energy stored in the coils that can reach values up to 50 GJ.
The switching networks are used at every pulse for plasma initiation in each of the central solenoid coil packs, and in the circuits of the poloidal field coils #1 and #6. The high-current, water-cooled busbars connect the AC/DC power converters to the switching networks, the fast discharge units and finally to the superconducting coils. The total length of the busbars on ITER will be 10 km for the 21 power supply circuits.