Assembly Hall

An ever-changing landscape

11 Apr 2022

The view from the gangway, 55 metres above the floor of the Assembly Hall, is an ever-changing landscape. The 6,000-square-metre staging area accommodates only two permanent features: the twin sector sub-assembly tools (SSAT1 and SSAT2) designed to assemble the massive vacuum vessel sectors, toroidal field coils and thermal shield segments into sector modules. All around them, the movement of workers, elevated platforms, forklifts, rigging elements and giant components composes a slow-motion spectacle—half mechanical ballet, half construction game.

Close to 100 metres from door to wall: the Assembly Hall povides a 6,000-square-metre shop floor to receive, equip and pre-assemble the massive components required for the ITER machine.

The latest arrival (1) in this view taken on 8 April 2022 is vacuum vessel sector #8, manufactured in Korea and delivered to ITER on 1 April. Like a fossilized alien life form, the component has shed its protective cocoon (2), which now stands empty at the lower left of the image.

Close to the newly arrived sector, a toroidal field coil (#9 from Europe), lies in the upending tool (3). Soon, the tool will be moved to its vertical orientation and the magnet coil will be transferred to SSAT1 to be assembled with the second vacuum vessel sector, which has already been equipped with a thermal shield segment (4). A few metres away, SSAT2 holds a close-to-finalized sector module (5), scheduled to be installed in the assembly pit (6) in the coming weeks.

To the right of the twin assembly tools, an area (7) is dedicated to the assembly of the US-procured central solenoid modules. Of the three cylindrical elements, the greenish one is the first module, delivered to ITER in September 2021. The yellow tool to the left is the lifting fixture that will used to move the modules to the assembly platform (grey) and stack them one atop the other in order to form the 18-metre tall, 1,000-tonne central solenoid.

The structure along the wall, on the right side of the Hall (8) is part of the support system for the waveguides that will connect the gyrotron sources in the Radio Frequency Building to the tokamak machine.

As these lines are being written, the scene in the Assembly Hall has already been transformed, with the house-like cocoon for vacuum vessel sector #8 moved to temporary storage and readied for dismantlement.

All it takes ...

A vacuum vessel sector, two toroidal field coils, thermal shield segments... that's all it takes to assemble a 1,250-tonne "sector module." In the Assembly Hall, barely visible in the background, sector module #6 is ready to be installed in the Tokamak pit; in the foreground, sector module # 1(7) has entered the pre-assembly process.

A sense of scale

Workers standing on a sector sub-assembly tool beam provide a sense of scale. A fully assembled sector module represents only one-ninth of the ITER vacuum vessel.

Nine sectors for a doughnut

Of the nine 40° vacuum vessel sectors required to close the ITER doughnut-shaped plasma chamber, four are procured by Korea (here #8) and five by Europe. The last of the Korean sectors and the first sector from Europe are scheduled for delivery before the end of the year.

Six modules to stack

Delivered in September 2021, the first of the six modules required for the central solenoid magnet sits between the lifting fixture (holding an orange mockup) and the assembly platform (grey). The six modules will be stacked one atop the other in order to form the 18-metre tall, 1,000-tonne magnet.

The view from above

At 55 metres above the floor, the gangway offers a spectacular view of the Assembly Hall's ever-changing landscape. In this 6,000-square-metre building, components are unloaded, received, equipped, and handled prior to being lifted into the Tokamak assembly pit.