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  • Neutral Beam Test Facility | After upgrades, SPIDER testbed set to restart

    After a two-year shutdown for upgrades, the SPIDER testbed at the ITER Neutral Beam Test Facility in Padua, Italy, is preparing for commissioning and operation. [...]

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  • ITER Research Plan | Jointly preparing a new blueprint

    As part of work underway to update the ITER Project Baseline, a group of experts nominated by the Members met in February to evaluate the new blueprint for achi [...]

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  • On site | Component transfer goes electric

    On Friday 16 February, a toroidal field coil was moved from the Assembly Hall to a storage place a few hundred metres away. Quite a routine operation at ITER, a [...]

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  • Image of the Week | Director-General Barabaschi visits India

    Following his visit to China, Japan and Korea last autumn, ITER Director-General Pietro Barabaschi continued his tour of ITER stakeholders w [...]

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  • Science | Increasing fusion performance with energetic-particle-driven instabilities

    New results published in Physical Review Letters suggest that instabilities driven by energetic particles can have a positive impact on fusion performance. In t [...]

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Of Interest

See archived entries

How to make a radial plate in 150 days

A radial plate is but a part of an ITER toroidal field coil; still, it is huge. And size and mass (16 metres tall, 5.5 to 9.8 metric tons) are not its only awe-inspiring characteristics ...

Before welding, grooves are pre-machined into both faces of the ''rough shape'' stainless steel plate. (Click to view larger version...)
Before welding, grooves are pre-machined into both faces of the ''rough shape'' stainless steel plate.
What impresses most is the high-precision manufacturing that the radial plates require. Once the six "rough shapes" that form a radial plate have been pre-machined and welded together (see video below), tolerances cannot exceed one millimetre. At each stage of fabrication, the plate's measurements are verified by laser.

A pre-machined radial plate ready for electron beam welding operations in the CNIM welding shop (Toulon, France). (Click to view larger version...)
A pre-machined radial plate ready for electron beam welding operations in the CNIM welding shop (Toulon, France).
Precision is paramount: 750 metre of jacketed superconducting cable have to fit into the grooves that are machined into the plate's steel. "The trajectory of the conductor must perfectly match that of the grooves," explains an expert at CNIM, the French company responsible for the fabrication of 35 radial plates out of a total of 70 (consortium partner SIMIC, in Italy, is responsible for the others). "If we deviate from the required measurements even by a few tenth of a millimetre, we can throw the plate away. And that would mean several million euros..."

Dimensional checks are performed at every stage of the manufacturing process. (Click to view larger version...)
Dimensional checks are performed at every stage of the manufacturing process.
At CNIM, like at SIMIC, the manufacturing process is long and painstaking. From the pre-machining of the rough shapes, it takes close to 150 days before a radial plate is finalized and ready to be sent to ASG Superconductors SpA, in La Spezia, Italy, where the conductor lengths will be inserted. Seven radial plates are needed for the assembly of each toroidal field coil.

"Another main challenge is the tight schedule," explains the CNIM management. "The expected delivery rate is one radial plate every four weeks. To achieve this, our teams must work around the clock in three 8-hour shifts."

The radial plate is now in the final stage of fabrication. All in all the manufacturing process takes about 150 days. (Click to view larger version...)
The radial plate is now in the final stage of fabrication. All in all the manufacturing process takes about 150 days.
Winning the EUR 160 million European contract for radial plate manufacturing translated into heavy investment for the company. It built a dedicated, 3,000 m² facility, acquired highly sophisticated tools (machining, welding, handling) and hired a specialized workforce of 50.

Read more on the European Domestic Agency website.
Watch this video on the radial plate manufacturing process (courtesy of CNIM).



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