Winding is over for ITER’s sixth Poloidal Field coil

Group photo of ASIPP team celebrating the completion of the conductor winding for Poloidal Field coil six

Six massive superconducting magnets, known as Poloidal Field (PF) coils, will embrace the ITER machine from top to bottom to shape and contribute to the stability of the superhot plasma. Europe is responsible for the production of five of these coils. One of Europe’s coils, however, the heaviest and lowest of all PF coils, is manufactured in China. Following an agreement between F4E and The Institute of Plasma Physics of the Chinese Academy of Sciences (ASIPP), and in line with the ITER project’s spirit of collaboration, ASIPP and F4E have joined forces to manufacture the sixth PF coil, in Hefei (China).

At the end of June, ASIPP celebrated a major milestone by completing the winding of the conductor lengths needed for the coil. The sixth PF coil consists of nine pairs of windings, known as Double Pancakes (DPs). It has been a long journey since the fabrication of the first pre-dummy DP in February 2016, followed by a dummy Double Pancake, before going ahead with the production of the first DP in February 2017.

The winding of each DP took around one month. Basically, it involved winding two superconducting cable lengths which eventually take the form of a spiral. Each turn of superconductor had to be electrically insulated from the adjacent turn with a combination of Kapton and fibre glass tapes.

Wrapping and insulating with Kapton and fiber and glass tapes the conductor of the sixth Poloidal Field coil

Furthermore two helium inlets had to be carefully fabricated to allow cold helium to flow inside the coil. The whole process was rigorously controlled to ensure the DP is fabricated in line with the technical requirements by a dedicated team of specialist technicians and engineers.

“ASIPP have been very collaborative with F4E and have reached this milestone due to the hard work, professionalism and attention to detail of their teams” explain Carlo Sborchia and Peter Readman, F4E Technical Officers following the production in China.

Welding the helium inlet of the Poloidal Filed coil’s first double pancake

It is expected that by the end of September all nine DPs will be fully impregnated paving the way for stacking, an activity where they will be placed one of top of each other, connected electrically and hydraulically. Then the nine DPs will become one solid component, known as the “Winding Pack” (WP), it will be ground insulated and impregnated. The final assembly of the WP will take place before shipment to the ITER site in France, which is expected before mid-2019.

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