The foundations of the Tokamak Complex

The 1.5-metre-thick reinforced basemat, the B2 slab, is ready to receive the first walls of the Tokamak Complex. September 2014 (Click to view larger version...)
The 1.5-metre-thick reinforced basemat, the B2 slab, is ready to receive the first walls of the Tokamak Complex. September 2014
Building begins in 2014 on the Tokamak Complex, the 360,000-ton edifice that will house the ITER Tokamak and supporting diagnostic and tritium systems.

Eighty metres tall, 120 metres long and 80 metres wide, the Tokamak Complex will dominate the ITER scientific installation when it is completed in 2016. Its construction will require 16,000 tons of rebar, 150,000 m³ of concrete and 7,500 tons of steel for the building structures. A dedicated batching plant on site, with two mixing machines and eight holding tanks, will supply the concrete in order to limit the amount of construction vehicles travelling on the roads in the area of the ITER construction site.

The Tokamak Complex will be built in a 90 x 130 metre area on the ITER platform, the Seismic Pit, which was excavated and reinforced with a ground support structure between 2010 and 2012. A 1.5-metre basemat and thick retaining walls are now in place to protect the future buildings and their equipment from ground motion in the case of an earthquake.

On the level surface of the Seismic Pit basemat, 493 columns were cast and topped with 20 cm-thick anti-seismic bearing made of alternate layers of metal and rubber. With a capacity for lateral movement of 10 cm, these bearings—which will support the foundation of the Tokamak Complex—are capable of filtering and absorbing the accelerations linked to ground motion.

The last step before Tokamak Complex construction was the realization of 1.5-metre-thick reinforced basemat, the B2 slab. Propping and reinforcement works for the B2 slab were carried out in 2013. The basemat was poured in 15 segments over a nine-month period, from December 2013 to August 2014.

With the B2 basemat slab in place, construction can begin on the buildings of the Tokamak Complex.

Click here to view recent videos of construction progress.
Foundation Facts
Tokamak Complex ground support structure:
  • Construction: 18 months (completed April 2012)
  • Amount of steel reinforcement: 3,400 tons
  • Concrete required: 110,000 cubic metres
  • Thickness of Seismic Pit basemat: 1.5 metres
  • Thickness of retaining walls: from 1.5 metres (bottom) to 0.5 metres (top)
  • Number of seismic pads supporting the Tokamak Complex: 493
  • Tokamak Complex basemat:
  • Construction: 9 months (December 2013 - August 2014)
  • Amount of steel reinforcement: 3,600 tons
  • Concrete required: 14,000 cubic metres
  • Thickness of Tokamak Complex basemat: 1.5 metres