Inside the pit
From dizzying volume to cramped environment
There was a time when the assembly pit felt like a huge arena, with toy-like tools scattered on the floor and workers reduced to Playmobil-size figures. Progressively, over the past year, the perception has changed dramatically. As successive components are installed, the place seems to be shrinking—a dizzying volume turning into a cramped environment.
In a spectacular operation, the 1,250-tonne cryostat base was first to enter the pit in May 2020. Resting on a set of 18 chrome-plated spherical bearings anchored in the massive concrete crown, the soup-dish-shaped component reduced the visible diameter of the pit by more than one metre but without altering the feeling of space. The pit still felt big and empty.
At ITER, you can hardly blink before the scene in the Tokamak pit changes. This photo from 13 April 2021 will be supplanted as soon as poloidal field coil #6 is installed. (Click to download the image.)
The installation of the lower cylinder, the following August, and of the silver-plated lower cryostat thermal shield in January of 2021, also did not change this perception.
Beginning in February, when the first gravity supports for the 18 toroidal field coils were installed on the base pedestal and the temporary supports for poloidal field coil #6 (PF6) were arranged in a circle in the centre of the pit, the place began to feel small and crowded.
And when the bottom cylinder of the central column (the first segment of a 20-metre-tall assembly tool) was lowered into the pit on 27 March, it was as if the vast arena had shrunk to the dimensions of a small outdoor swimming pool—with room for a very limited number of swimmers.
The present view, as reflected in this image, will soon be a thing of the past as PF6 (10 metres in diameter) is inserted this week. Enjoy it while it lasts ...
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