Magnets

Have the last pancake!

After close to five years of intense activity, the winding table at the south end of the European poloidal field coil factory on site is now empty. Last week, the last circular conductor arrangement ("double pancake") required for the last ring-shaped coil still in fabrication was finalized and moved to the next workstation. Since production began in August 2017, 30 such double pancakes have been produced for the four poloidal field coils that Europe manufactured in the facility.

24 metres in diameter—that's about as wide as a six-lane highway. The last double pancake for poloidal field coil #3 is also the last double pancake required by the European Domestic Agency's ring-magnet procurement program.
With the finalization of this last double pancake, a formidable industrial venture is coming to an end. Like its predecessors on the production line, the last pancake will be moved from one workstation to another to be insulated, resin-impregnated, stacked and eventually compressed with seven other similar arrangements in order to form a 385-tonne, 24-metre-in-diameter ring magnet.

Manufacturing such large and massive high-tech components required bespoke tools and sophisticated techniques that had never before been implemented at that scale. The European Domestic Agency, Fusion for Energy, and its contractors went through a steep learning curve, with operators acquiring skills and experience on both manual operations and machine control. Tooling performance was improved through better preventive and corrective maintenance activities, thus reducing the number and duration of production stops. Time and energy was also saved through the constant progress achieved in the scheduling and sequencing of activities. Drawing from the lessons learned during the manufacturing of the first coil (PF5, 17 metres in diameter), operators reduced the fabrication time of the second, PF2, by a full year.

The informal celebration that took place in the winding facility on 23 June acknowledged the remarkable synergy between the many contractors involved in the venture. Coming from different worlds, the European contractors ASG Superconductors S.p.A., CNIM, Dalkia, Veolia, Mammoet, Criotec Impianti SpA, Elytt Energy, ALSYOM, SEA Alp, and SEIV all worked as one team, which decisively contributed to the success of the operations.

In August, the winding table will be dismantled by the very company, the Italian SEA Alp, who designed and manufactured it. The winding facility will feel a bit empty with the table removed.