Posted on: 11th September 2008

The ITER Organization, the Japanese and European Domestic Agencies, represented by Japan Atomic Energy Agency (JAEA) and Fusion for Energy (F4E) with the support of the European Commission, respectively, have jointly tested a prototype Niobium(Nb)-Titanium(Ti) superconductor for the ITER Poloidal Field (PF) coils. The test coil using the Nb-Ti conductor achieved stable operation at 52 kA and 6.4 Tesla, emulating the operating conditions of the PF coils in the ITER tokamak.

Extremely powerful superconducting magnets will be used to maintain the fusion plasma equilibrium and shape inside ITER. Demonstrating that the superconducting strands for these magnets would perform to design specification was one of the most important technological milestones for the project.

The test coil with an outer diameter of 1.5 m and weighing 6 tons was manufactured by an international collaboration: the Russian Domestic Agency produced the 0.73-mm diameter Nb-Ti superconducting strands and bundled them into a cable consisting of 1,440 strands; the European Domestic Agency assembled the cable into a steel jacket to make the final conductor. Winding of the conductor, insulating the turns and bonding them together to form a coil was also performed in Europe. The testing took place at the JAEA site in Naka, Japan, selected for the tests because of its technical characteristics and the availability of world class expertise. A team, consisting of experts from JAEA, F4E and the ITER Organization, performed the tests with participation from Russian and United States Domestic Agencies.