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Pre-compression rings

Six packed and stacked

In a factory not far from ITER, French equipment manufacturer CNIM (Toulon) is working under a contract with Europe's Fusion for Energy to manufacture a set of nine composite rings. These high-tech components—with exceptional tensile strength—will have an important role to play in protecting ITER's toroidal field coils.
The completed pre-compression rings at CNIM, stacked and ready for transport.
During the estimated 30,000 pulses of the ITER machine, the ITER toroidal field coils and coil structures will be subjected to huge electromagnetic forces, on the order of several hundred meganewtons (MN). Caused by electromagnetic interaction between the toroidal field coil current and the magnetic field generated by the poloidal field coils, these out-of-plane forces will cause stress to the toroidal field coils and, over time, fatigue.
 
Six pre-compression rings—three at the top and three at the bottom—will hold tightly to the coils with a radial force of 7,000 tonnes per coil, pulling the coils into contact and reducing toroidal tension in the outercoil structures. Three other composite rings will be manufactured as spares.
 
Six pre-compression rings have been handed over to the ITER Organization and three others are in fabrication at CNIM.
 
Read the full story on the Fusion for Energy website.