The roof of the ITER Assembly Hall building has been lifted

An imposing steel structure standing like a giant has risen from the ground overlooking the Tokamak complex. It is no other than the Assembly Hall building where the high-tech components of the biggest-ever fusion device will be assembled. It has taken approximately seven months to erect the 22 columns that weigh 6 000 tonnes upon which the 800 tonne roof relies. The operation had to be carefully planned in order to lift the load bit by bit and cope with the wind to position the roof exactly. The teams of F4E, ITER IO, the VFR consortium, Martifer, VSL and Apave have been preparing for this moment for some time which took nearly 36 hours to be completed. Under the watchful eye of 25 engineers and support staff, 22 hydraulic jacks all connected to six hydraulic pumps, carefully lifted the roof from the ground.

Bernard Bigot, ITER Director-General, was also there to witness parts of the operation and highlighted the importance of the work stating that “without this building there would be no assembly, and without assembly there would be no machine and no project”. For Laurent Schmieder, Head of Buildings Infrastructure and Power Supplies, and his team this has been an important milestone. “The challenge was to agree on a date with all parties taking also into consideration the weather forecast. Once this was agreed there was no turning back. Our goal was to coordinate the different contractors during the multiple stages of this operation in a seamless manner” he explains. We spoke to Gaël Nocenti working for VSL, the company responsible for the heavy lifting, to get some insight on the logistics. “First we started lifting the roof 20 cm from the ground to check the jacks and tooling. Then we had to wait for the topographical surveys that lasted approximately 12 hours. The following day we continued lifting the roof, an operation that lasted 16 hours, until it reached 60 meters high. We were proud be a part of the ITER project and see it taking off”.

The Assembly Hall building stands out due to its impressive size: 100 metres long, 60 metres wide and 60 metres high. Its construction started seven months ago with a workforce of 50 people who had to erect its steel structure. There was, however, a tricky challenge in all this: where would they assemble the massive roof? The decision was taken to erect the facades of the Assembly Hall and build the roof on the ground from where it would be eventually lifted. The team of engineers had to work round the clock so they could lift the roof and the facades on the same day, but not at the same time. To give you an example, the days and nights before they had to fix the more than 65 000 bolts. Thanks to this creative planning, the task has been completed three months earlier.

As the roof was lifted and installed, there was sign of relief and satisfaction. This was an achievement that deserved a small symbolic celebration: 500 yellow and blue balloons, reflecting the colours of ITER and the EU, were released in the steel structure to reach the sun. The same source of energy that ITER aims to bring to earth.

If you want to view the operation, click here.