ITER Diagnostics building starting to take shape

Among the 39 buildings under construction in the vast 42-hectare ITER platform, where the equipment of the most ambitious fusion energy facility will be housed, the Tokamak complex is the one of critical importance because it holds the key to success.

Without a doubt it is the most emblematic construction area of the project. It consists of the Tokamak building, where the ITER machine will be located with two adjacent buildings where the fusion fuel will be stored and treated known as the Tritium building, and the Diagnostics building, where the information received by the instruments acting as the eyes and ears inside the machine will be interpreted, analysed and processed. The works are being carried out by the VFR consortium (Vinci Ferrovial Razel) as part of the contract that was awarded by F4E in December 2012.

Almost a year ago the ITER project celebrated an important milestone with the completion of the first floor of the Tokamak complex known as the B2 slab. Works on the site have further advanced and on June 23 the propping works for the level above, which measures 9 300 m2, have started. Today the Diagnostics building has started to take shape and it is estimated that 800 m3 of concrete and 110 tonnes of steel will be used for the construction of its slab. The concrete will be poured in three lots to cover its 1 600 m2 surface and works are expected to last three months mobilising 40 workers.

One of the biggest construction challenges of the Tokamak complex is the installation of the embedded plates. These are thick steel plates onto which several steel studs with rounded heads are welded. They are anchored deep into the concrete and positioned with accuracy to match the location of the ITER equipment that will be installed. More than 80 000 embedded plates will be installed in the Tokamak complex.

The installation of one type of embedded plates, known as the “shear lugs and skirts”, which are the finishing points of the Tokamak machine into the concrete structure, will be particularly challenging. They will have to be placed with an accuracy of 10 mm, which is remarkably tight considering that they weigh approximately 3 tonnes each. It would be like loading a truck into a container with a 5 mm margin.

Meanwhile, the reinforcement works on the 3.5 metre-thick bio-shield wall that will surround the Tokamak machine are ongoing.