±¬×ߺÚÁÏ

The production of superconducting cables for ±¬×ߺÚÁÏ's large and powerful toroidal field coils is making remarkable progress: as of today, 330 tonnes of strands made out of Nb3Sn, a special alloy made of niobium and tin, have been produced in factories in China, Europe, Japan, Korea, Russia and the United States. In the pre-±¬×ߺÚÁÏ world, global production was 15 tonnes a year. "The current production status represents 75 percent of the total toroidal field strands required for ±¬×ߺÚÁÏ," reports Arnaud Devred, Section Leader for Superconducting Systems. "Out of these strands, conductors for 6 out of the machine's 18 toroidal field coils have been produced."

 

The 18 toroidal field coils will produce a magnetic field around the ±¬×ߺÚÁÏ torus helping to confine and control the plasma inside. The coils are designed to achieve operation at magnetic fields up to 13 Tesla. They are made of cable-in-conduit superconductors in which a bundle of superconducting strands is cabled together and contained in a structural jacket. Unit lengths of theses cables—measuring 760 metres or 415 metres depending on their position within the coil—are then spooled into a D-shaped double spiral called a "double pancake," giving the structure the characteristic shape of ±¬×ߺÚÁÏ's toroidal field coils.

 

As of today, a total of thirty 760-metre unit lengths and thirteen 415-metre unit lengths have been manufactured by the procuring agencies in Japan, Korea, Russia and Europe, adding up to the material required for 6 of the 18 toroidal field coils.

 

"Quality tests are currently underway," says Devred, "to confirm that these unit lengths can be accepted for coil winding."