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News & Media

Latest ITER Newsline

  • Real-time collaboration delivers for fusion computing

    A key computing system for ITER is now being trialled at the European tokamak JET, following collaboration betweenteams at the UK's Culham Centre for Fusion Ene [...]

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  • The balance of power

    It comes as no surprise that the French railway operator SNCF is the largest consumer of electricity in the country—it takes a lot of megawatts to power 500 sup [...]

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  • "Dummy" winding takes shape

    As orange lights flash and machines softly hum, layer one of a 'dummy' pancake winding (the building block of a poloidal field coil) is taking shape on the wind [...]

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  • As big (and heavy) as a whale

    It was pouring when the two 35-metre-long quench tanks were delivered to the ITER site at 2:12 a.m. on Thursday 24 November. And it was still raining heavily on [...]

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  • A passage to India

    108 days, 10,200 kilometres, 16 countries, and only two flat tires. These are the remarkable statistics of a no-less-remarkable journey: a father and son who tr [...]

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Of Interest

See archived articles

How to make a radial plate in 150 days

-R.A.

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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