Tokamak assembly
Preparing for the Big Lift
9 May 2022
The distance was short but the challenge daunting: on Thursday last week, the first section of the plasma chamber was lifted 50 centimetres above its supports. What made this first-of-a-kind operation particularly delicate was the nature of the load (a 1,380-tonne, 18-metre-tall assembly) and the extreme precision its handling required.
The pre-lift operation on Thursday 5 May was a partial rehearsal for the big lift to come, testing the tools, sequences, and coordination. For the ITER Organization and DYNAMIC teams that participated, it was a success.
A restricted area most of the time, the space at the base of the giant SSAT2 pre-assembly tool was exceptionally crowded. Specialists sat facing rows of computers, checking the numbers and graphs flashing on the screens. Crane operators delicately manoeuvred the joysticks on their control boxes. Once all movement had ceased, metrology experts pointed laser beams all over the steely surface of the component, measuring the most minute dimensional deviations to ensure that they remained within tolerance.
The "pre-lift" operation on Thursday 5 May was only the first sequence of the long-expected installation of the first vacuum vessel module in the assembly pit. In both height and distance it represented only a fraction of what the actual operation, scheduled in the coming days, will require. But for the teams involved, it was an indispensable step—permitting the thorough testing of every instrument involved before the big move to come.
Click here to watch a short video of the pre-lift operation.
The sector module has now been lifted 50 centimetres above its supports. This small distance is visible below the rectangular structure illuminated by the green pointer's beam at the centre of the image.
The math is easy to do: each of the bridge crane's four hooks supports a load of approximately 345 tonnes (the totals for two hooks are visible in this image). The total weight of the sector module plus its rigging apparatus is in the range of 1,380 tonnes—the equivalent of four fully loaded Boeing 747s.
Although it represented only a fraction of what the actual operation will require, the "pre-lifting" of the sector assembly on Thursday 5 May permitted the thorough testing of every instrument that will be involved in the major move to come.
Lifting the 1,380-tonne sector sub-assembly a mere 50 centimetres required the participation of dozens of specialists from the ITER Organization and the DYNAMIC SNC consortium (in charge of the TAC2 machine assembly contract covering the main vessel and ports, sector sub-assembly with toroidal field coils and vacuum vessel thermal shielding, and welding: more information at https://www.iter.org/construction/TokamakAssembly).