May 30, 2020

On Tuesday 26 May, the 1250-ton soup-bowl-shaped base of the ITER cryostat was gradually lifted from its frame, carried across the Assembly Hall to the Tokamak Building and eventually lowered into the Tokamak assembly pit at the ITER facility near Cadarache in southeastern France.
The operation in the machine assembly theatre marked the culmination of a ten-year effort to design, manufacture, deliver, assemble and weld one of the most crucial components of the ITER machine—the 30-metre-high, 30-metre-in-diameter ITER cryostat (of which the base is only one part)—which will act as a thermos, insulating the magnetic system at cryogenic temperature from the outside environment.
Procured by India, manufactured in segments by Larsen & Toubro Ltd at its Hazira factory, the cryostat is assembled and welded on site.
One of the most delicate phases of the operation slowly unfolded as the cryostat base descended into the deep concrete cylinder, almost brushing its inner walls, to be positioned within millimetre accuracy into its support system.
At the start of the operation, ITER Director-General Bernard Bigot had stressed the unique importance of the moment and expressed his confidence in the operation’s success. “The coming moments will stand out in the minds and memories of us all,” he said. “What you will accomplish today, as a team, is something that has never been done before in history—and although you have rehearsed it many times, it will be a first-of-a-kind operation. We trust the engineering calculations, strategy and control. We trust the materials science. We trust the metrology. But my confidence today is because I trust you to work as one committed and highly professional team, convinced as we all are that failure is not an option.”
And fail it did not. By Wednesday afternoon, the first and heaviest component of the ITER machine was positioned at its final altitude a few centimetres above the hydraulic jacks that will support its weight until final metrology and adjustments are performed and the load can be transferred to the cryostat support.
With this spectacular achievement, a new chapter has opened in the long history of ITER, one of the most ambitious energy projects in the world today.
In southern France, 35 nations are collaborating to build the world’s largest tokamak, a magnetic fusion device that has been designed to prove the feasibility of fusion as a large-scale and carbon-free source of energy based on the same principle that powers our Sun and stars.
The experimental campaign that will be carried out at ITER is crucial to advancing fusion science and preparing the way for the fusion power plants of tomorrow.
The tokamak is an experimental machine designed to harness the energy of fusion. Inside a tokamak, the energy produced through the fusion of atoms is absorbed as heat in the walls of the vessel. Just like a conventional power plant, a fusion power plant will use this heat to produce steam and then electricity by way of turbines and generators.
First developed by Soviet research in the late 1960s, the tokamak has been adopted around the world as the most promising configuration of magnetic fusion device. ITER will be the world’s largest tokamak—twice the size of the largest machine currently in operation, with ten times the plasma chamber volume.
(Source and image: ITER)