Council milestone #50
The way to assembly is open
30 Mar 2020
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R.A.
Passing an ITER Council milestone is always an achievement. Passing this milestone at this moment is much more than that: it is a demonstration that, despite the constraints imposed by the public health context, the ITER Organization, the European Domestic Agency and their contractors are determined to keep moving forward and to remain on schedule.
The main load has just passed the protruding lid that closes the assembly pit. The full theatre of future assembly operations is fully visible ...
ITER Council milestone #50, which was successfully achieved two days ahead of schedule late on 28 March, is of considerable significance for the project, as it opens the way for the launch of the machine assembly phase.
The milestone consisted in demonstrating that the heavy lift cranes could successfully travel between the Assembly Hall and the Tokamak Building in order to deliver components to the Tokamak pit.
Three actions were required: first, the completion of the crane hall structure; second, the removal of the temporary wall separating the buildings; and finally, the verification of the overhead crane load path in the Tokamak Building.
The last operation, both spectacular and delicate, required validating the full 170-metre-long runway of the double bridge crane—from the entrance of the Assembly Hall, all the way to the opposite end of the newly created crane hall and back.
It was a display of Titans, with no less than 1,000 tonnes of steel and concrete test loads attached to the giant hoists of the bridge crane (more details in the image gallery below).
Totalling approximately 1,000 tonnes, the loads are ready to undertake their 170-metre-long journey from the entrance of the Assembly Hall all the way to the opposite end of the newly created crane hall.
Initiated at 8:00 a.m., the operation lasted well into the night and was only considered completed when the crane and its loads had returned to the Assembly Hall and were secured. By then Saturday had turned into Sunday, but 31 March—the official target for ITER Council milestone #50*—was still 48 hours away.
The crane and its loads moved slowly, taking long pauses at strategic locations: at the "seismic link" between the two buildings, at the threshold of the Tokamak Building, over the protruding lid of the assembly pit ...
All the while, metrology systems were monitoring the deflections that the loads were causing to the runway beams and steel pillars—essential information for validating the crane hall's structure and achieving the milestone.
With the temporary wall between the Assembly Hall and Tokamak Building removed, one could take in, for the first time, the full theatre of future assembly operations—a huge open space that even dwarfs the 20-metre-high vacuum vessel sector sub-assembly tools.
It was an awesome view that conveyed the unique size, complexity and beauty of ITER.
* Since early 2016, the ITER Organization has been tracking project progress against high-level milestones agreed by the ITER Council. Whether related to construction, manufacturing or deliveries—or rather to programmatic milestones like recruitment and contract signatures—these milestones are underpinned in the schedule by the many thousands of activities that make up progress to First Plasma.
See the Fusion for Energy website for a related article.
As heavy as a fully loaded jetliner, the test loads that were used to test the full range of sector sub-assembly tool functions last September are now back to work. Thick steel plaques have been affixed to their sides to bring the total weight of each load to approximately 420 tonnes.
The 840-tonne double load on the "north bridge" (right) is complemented by a 156-tonne load on the "south bridge," bringing the total to a little more than 1,000 tonnes. Calculations and modelling are used to extrapolate the effect the actual 1,500-tonne loads will have on the building's structure.
A delicate threshold
The loads have now reached the threshold of the Tokamak Building. In a few moments they will be moved back and forth along the crane's beams to monitor the deflection of the runway and that of the crane hall pillars.
Very little clearance
The threshold has been passed and the cranes have entered the Tokamak Building. Now comes another delicate phase as the two 420-tonne loads need to pass over the protruding lid of the assembly pit, with a clearance of a few centimetres only. The removal of the lid—another delicate operation—is scheduled in the coming days.
A big beam for a heavy load
The double overhead bridge crane comprises four such 47-metre-long, 155-tonne steel girders, or beams. Arranged in two pairs and working in tandem, they can lift up to 1,500 tonnes. The double overhead bridge crane was tested at 125 percent of its capacity (1,870 tonnes) in December 2017.
The numbers on the scale
The weight of the loads appears in real time on the small screens just above the rails. Figures vary slightly depending on the load positions along the beam.
The overseers
The load path operation was overseen by Roberto Lanza (left, ITER Responsible Officer for cranes and crane operations) and Duco Jensen (ITER site planning coordinator), with strong support from construction coordinator Stéphane Herpin. The operation involved personnel from the Buildings Infrastructure & Power Supplies (BIPS) Project Team; Fusion for Energy contractors VFR (Vinci, Ferrovial, Razel-Bec), REEL (cranes), Dalkia, GDES, Martifer (manufacturing and installation of the crane hall), SAMT, and Nuvia; and contractors supporting both the ITER Organization and Fusion for Energy (Engage, Apave, Energhia, Tiresia, and MOMENTUM).
Coming next ...
The side wall of the circular lid that closes the assembly pit has already been taken down, allowing a dizzying view into the 30-metre-deep concrete cylinder. The removal of the 11 segments that make up the lid is scheduled to begin on Thursday 2 April and last through the end of the work week.