Nuclear fusion: Inside the construction of the world’s largest tokamak

By James Cutmore

Published: Monday, 28 March 2022 at 12:00 am

Nuclear fusion, the physical reaction that powers the stars, is a potentially unlimited source of energy that could end our energy worries and dependence on fossil fuels. The construction of industrial plants to produce electricity from fusion is one of the greatest scientific challenges of our time.

In Saint-Paul-lès-Durance in the south of France, 35 nations are collaborating to build ITER, the largest nuclear fusion reactor of its kind in the world in the world. ITER is a type of magnetic fusion reactor called a tokamak, designed to demonstrate the feasibility of fusion as a large-scale energy source with no carbon emissions. Construction of the entire plant has been underway since 2010 on a 42-hectare site in the countryside of Provence.

Meanwhile in Italy, the National Research Council of Padua are building two prototype experiments for the external heating of the ITER plasma, called the ‘MITICA’ and ‘SPIDER’ experiments. These two testbeds will help scientists further improve and perfect systems that will then be installed on ITER.

Once completed, ITER will be used to conduct scientific research into fusion power, with the hope of being able to demonstrate the viability of building a nuclear fusion reactor. The facility is scheduled for completion in 2025, and the hope is that the first plasma generation will be achieved by the end of that year.

If successful, nuclear fusion could well help countries reduce their reliance on fossil fuels, leading to much-reduced carbon emissions, and thus helping us tackle the climate crisis.

Photographer Luigi Avantaggiato was granted access to the ITER construction site, and we bring you his recent images in our online gallery.

Find out more about nuclear fusion:

Cryostat assembly

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Technicians assemble the sections of the cryostat at ITER construction site at Saint-Paul-lez-Durance, France. Cryostat is a huge vacuum containment vessel and provides the high vacuum, ultra-cool environment for the vacuum vessel and the superconducting magnets. Photo by Luigi Avantaggiato

Tourist attraction

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Tourists visiting ITER workspaces take pictures of the construction of the poloidal field coils, an important component that helps generate a magnetic field in a tokamak. Photo by Luigi Avantaggiato

Assembly building

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The assembly building is the location for pre-assembly activities on the massive components of the ITER device before they are transported to the Tokamak complex for installation. Photo by Luigi Avantaggiato

Vacuum assembly

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In the assembly hall engineers work on the second vacuum vessel sub-assembly. The vessel provides a high-vacuum environment for the plasma, improves radiation shielding and plasma stability, acts as the primary confinement barrier for radioactivity. Photo by Luigi Avantaggiato

High voltage

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An electrical substation on the ITER site. The entire ITER site is independently powered from an electrical substation that draws power directly from the 400 kilovolt national electrical grid. Electricity requirements for the ITER plant and facilities will range from 110MW up to 620MW for peak periods of 30 seconds during plasma operation. Photo by Luigi Avantaggiato

Welding it together

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In a workshop, a technician performs a weld on the external shield of the cryostat during construction. Photo by Luigi Avantaggiato

The tokamak pit

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The reactor will be contained within this seismic isolation pit, a 17-metre deep cavity in the ITER platform excavated to house the concrete base, retaining walls and seismic plates that will protect the buildings and equipment in the event of an earthquake. Photo by Luigi Avantaggiato

Fine tuning

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Isabella Mario, a physicist at Italian National Institute of Nuclear Physics (INFN), makes an adjustment to the SPIDER experiment at the Neutral Beam Test Facility in Padua, Italy. Photo by Luigi Avantaggiato

Keeping their cool

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The cooling system of the SPIDER and MITICA projects is located in an entire building of the NBTF in Padua and is capable of dissipating up to 70MW of power. Photo by Luigi Avantaggiato

How it will look

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This illustration shows the tokamak and its plant systems housed in their concrete home. An estimated one million parts will be assembled in the machine alone. Photo by ITER organisation

Harnessing the power of the Sun

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The Sun sets on the construction site of the ITER project in Saint-Paul-lès-Durance, France. Photo by Luigi Avantaggiato

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