CNIM unveils the manufacturing process of the radial plates

To best way to understand Europe’s contribution to ITER is to visit the companies producing the different components. This is where expertise, skills, high-tech machinery and trained workforces come together to manufacture the complex and strikingly massive components.

F4E together with CNIM organised a technical briefing for a team of journalists at their facility in Toulon, France. In 2013, a new 3000 m² building was constructed to house the machines for the manufacturing of the radial plates. CNIM and SIMIC will have to produce 35 radial plates each for the European contribution to ITER’s Toroidal Field (TF) coils. Each plate is manufactured in 316LN stainless steel to tolerances of less than a millimetre and weighs either 5.5 tonnes or 9.8 tonnes, depending on the type. One could think of the radial plates as cases where the superconducting conductor of the TF coils will be inserted within the grooves.

The components require machines of high precision and a lot of space. To fulfil these requirements, CNIM has developed a unique electron beam welding process which is ideally suited to large-scale high-precision items. Carried out under local vacuum, this innovative process was designed and tested by CNIM, before being deployed. CNIM’s new machining centre allows two plates to be machined simultaneously in the temperature controlled conditions required to guarantee thermal stability. The adjacent dock enables the finished product to be transported by sea.

During the visit, we also got a first glimpse of Europe’s first radial plate, which is expected to be ready in July. Then, it will be delivered to ASG Superconductors in La Spezia, Italy, to be fitted into the ITER TF coil winding packs. After producing a second plate five weeks later, CNIM expects to reach cruising speed and manufacture the remaining plates at a rate of one every four weeks. Fifty CNIM members of staff will work round the clock in three eight-hour shifts for the duration of the project, which is expected to last until 2017.