Most complex lift to date completed at ITER

ITER's plasma chamber, or vacuum vessel, houses the fusion reactions and acts as a first safety containment barrier. It will be formed from nine wedge-shaped steel sectors that measure over 14 metres in height and weigh 440 tonnes. The sector sub-assembly tools - each about 22 metres in height and weighing around 860 tonnes - are designed to support the weight of one vacuum vessel sector, two toroidal field coils and silver-coated thermal shields, which together weigh some 1200 tonnes.

Following a full pre-lift test, the first full sector subassembly - consisting of the double-walled vacuum vessel sector, a tightly fitted thermal shield and two D-shaped vertical superconducting electromagnets called toroidal field coils - has now been transferred from the assembly hall into the tokamak pit.

The component is currently suspended only 50cm above its supports in the assembly pit, as the assembly team carries out the final positional operations. It will then be lowered to its supports.

"Many project actors have had a part in today's successful milestone," the ITER Organisation noted. "Vacuum vessel sector No.6, at the centre of the assembly, and associated thermal shielding was manufactured and delivered by the Korean Domestic Agency. India fabricated the in-wall shielding inside the double walls of the sector and Russia supplied the upper port. The toroidal field coils (TF12 and TF13) were procured by the Japanese Domestic Agency.

"Korea designed and built the upending tool, the giant sector sub-assembly tools, the lift attachment closest to the load, and the column tool in the pit that will support the vacuum vessel during welding, while the European Domestic Agency supplied the overhead bridge cranes and the next-in-line rigging attachment that allows the cranes to work together."

The ITER vacuum vessel - with an interior volume of 1400 cubic metres - is unique: the volume of plasma it can contain (840 cubic metres) is fully ten times larger than that of the largest operating tokamak in the world today. The ITER vacuum vessel, once assembled, will have an outer diameter of 19.4 metres, a height of 11.4 metres, and weigh approximately 5200 tonnes. With the subsequent installation of in-vessel components such as the blanket and the divertor, the vacuum vessel will weigh 8500 tonnes.

ITER is a major international project to build a tokamak fusion device designed to prove the feasibility of fusion as a large-scale and carbon-free source of energy. The goal of ITER is to operate at 500 MW (for at least 400 seconds continuously) with 50 MW of plasma heating power input. It appears that an additional 300 MWe of electricity input may be required in operation. No electricity will be generated at ITER. First plasma is planned for 2025, with deuterium-tritium fusion experiments commencing in 2035.

The European Union is contributing almost half of the cost of its construction, while the other six members (China, India, Japan, South Korea, Russia and the USA) are contributing equally to the rest.