Big muscle for a huge load

November 2018: At the Larsen & Tourbo's Hazira manufacturing complex on the northwestern coast of India, work is underway on the "ribs," "flanges," "knuckles," and "crown" that make up a top lid segment.

June 2020: Upon completion of the segments for the fourth and last section of the ITER cryostat in India, ITER India contractor Larsen & Toubro marks the end of an eight-year industrial adventure to manufacture the world's largest steel vacuum chamber (16,000 m³).

February 2021: The major elements of the cryostat top lid are aligned on the workshop floor, waiting to be positioned inside the supporting frame to be assembled and welded.

June 2021: Two welders from MAN Energy Solutions, working in parallel on opposite sides of the top lid's skin, produce the ''first arc'' of a welding campaign scheduled to last four to five months. The cryostat top lid is made of twelve 30-degree sections that require approximately 300 metres of deep welds (50 millimetres deep on average, but up to 280 millimetres at the flange levels) and more than 4 tonnes of filler metal.

March 2022: In the onsite Cryostat Workshop, the finalized top lid is being prepared for a long hibernation. Because it seals the cryostat, the 665-tonne, circular structure will be the last machine component to be lowered into the assembly pit.

Wrapping operations for the cryostat top lid begin in January 2023, close to one year after the massive component was finalized. Sealed in an environment saturated with corrosion inhibitor molecules and wrapped in a succession of protective layers, the top lid will remain in outdoor storage until installation at the end of core machine assembly.

Coordination and anticipation are key for a successful, smooth and safe operation. As the transport trailer power packs warm up, a last briefing brings together the operators and responsible officers from the dozen companies and organizations involved in the top lid transfer.

As it sat at the far end of the Cryostat Workshop, the top lid certainly felt like a large component. But as it slowly came out of the building amidst the roar of the power packs, it seemed to have dramatically grown in size. The 30-metre-in-diameter, 10-metre-tall load dwarfed everything around it.

On its way to the storage location, some 50 metres away from the Cryostat Workshop, the flying saucer-shaped component passes the Cleaning Facility and adjacent Assembly Hall, whose architectural design add a futuristic touch to the scene.

A heavy duty, 50-centimetre-thick reinforced slab was recently constructed to accommodate the combined load of the top lid, support frame and transport platforms in the last phase of the operation. At approximately 900 tonnes, their total weight is equivalent to that of three Airbus A380s.

Success was achieved through the close collaboration and coordination of the ITER Organization, global logistics provider DAHER, and transport platform operator Mammoet; Cegelec played an important role in designing systems and processes to synchronize the movements of the six individual transport platforms, and risk manager Apave was responsible for the safety of the transfer.