The reinforced concrete foundations of the Tokamak Complex will isolate the Tokamak, Diagnostic and Tritium Buildings from the surrounding rock on which they are built and protect them against the effect of possible seismic activity.

The first level of reinforcement is the 1.5-metre-thick basemat that now completely covers the floor of the Seismic Isolation Pit.

Work continues to shape 493 concrete plinths on top of this basemat: these are the 1,7-metre-high pillars that will be topped with anti-seismic bearings. The flexible structure of these bearings, made alternately of layers of metal and rubber, is capable of filtering and absorbing the accelerations linked to ground motion. As the floor of the Tokamak Complex will rest on top of these plinths, the height of each plinth is verified precisely: each plinth must bear an equal amount of load.

The retaining walls of the Tokamak Complex will completely cover the rock face of the Seismic Pit. One-and-a-half metres thick at their base, they taper to 0.5 metres at their top height of 15 metres. In total, the Seismic Pit basemat, the reinforced concrete walls and the Tokamak Complex basemat will require the casting of approximately 100,000 tons of concrete. A dedicated batching plant with two mixing machines and eight holding tanks was built on the ITER platform to limit transportation in the area of the ITER construction site and to secure supply.

By early February 2012, the Seismic basemat was completed; 481 concrete pillars had been cast; and 304 seismic bearings installed. Workers will finish the retaining walls in March 2012. Formwork and reinforcement work for the Tokamak Complex basemat (the actual floor of the installation) will be carried out early in the year before concrete pouring begins in July (July 2012 - October 2012). Civil works on the three buildings that make up the Tokamak Complex will begin in 2012 (projected completion date: mid-2015).

Work began in December 2011 to excavate the Assembly Hall (adjacent to the Tokamak Complex) down to 1.5 metres, which will require the removal of 7,500 cubic metres of soil.

Click here to view recent videos of construction progress.