Worksite progress
The visible and the barely noticeable
12 Sep 2022
Progress in ITER can be highly visible—like the spectacular addition of the first bridge spanning the construction platform's main boulevard (see article in this issue)—or nearly unnoticeable, like the final alignment of toroidal field coils on the vacuum vessel section inside the Tokamak pit. Whether perceptible or not, whether occurring in the intense heat of the ITER platform during the months of July and August or in the more clement temperature of the Assembly Hall, progress on the ITER site this summer was observable in every corner. To take its full measure, embark on a visual tour through the gallery below.
On 12 September, vacuum vessel sector #8, from Korea, was transferred from the upending tool (left) to the available sector sub-assembly tool on the other side of the Assembly Hall. The twin assembly tools are now both occupied, one with sector #1(7) and one with sector #8.
Massive works for ultra-high voltage
Massive construction work is underway to erect the High Voltage (HV) Supply Building for neutral beam injection at the foot of the Tokamak Complex. The building will house HV decks and HV deck bushings for the two heating and one diagnostic neutral beam injectors. All galleries and trenches are now done, and concrete slabs have been poured for Level 1 and the transformers supports. Work on the building's superstructure will begin soon.
It's not routine and will never be. But the delicate process of extracting a 440-tonne vacuum vessel sector from the upending tool and of lifting it and transporting it into the arms of the sub-assembly tool is now "stabilized." With this modest formulation, experts mean that, having lifted and installed three vacuum vessels since April 2021 (the last one, pictured here, on Monday this week) they are treading on familiar territory.
In the ITER cryoplant, the commissioning and dynamic testing of the nitrogen vaporization system have been successfully initiated to support the startup of the liquid helium plant system. Other activities underway include oil filling (some 60,000 litres) and cleaning procedures to prepare for operation.
For years, workers laying rebar and pouring concrete were a familiar sight on the ITER site. They are now back, bent on building a set of new structures that all have to do with electrical power. In this photo, blinding concrete is being poured for the slab of one of the Neutral Beam Power Supply buildings.
ITER's assembly theatre
The ITER Assembly Hall, just a few days before vacuum vessel sector #8 (standing vertically in the upending tool at right) is transferred over to one of the giant standing assembly tools on the left. At 440 tonnes, a vacuum vessel sector is heavier than a commercial jetliner loaded with passengers, baggage and fuel.
Six independent modules make up the 1,000-tonne, 18-metre-tall central solenoid. This summer, the first module was positioned with millimetric precision on the bespoke assembly platform (centre) in the Hall in order to assemble the extensions that will later connect to the magnet feeders. (Positioning accuracy is +/-1mm in plane.)
The shinier a thermal shield's silver coating, the better its thermal radiation performance. Here, the right-hand outboard segment for vacuum vessel sector #8 is hand polished before being moved into position on the vacuum vessel sub-assembly tool.
Since we last reported on sector module #6, a major milestone has been achieved: the toroidal field coils have been aligned to their final position in the pit and are ready to be bolted to the toroidal field coil gravity supports. (More on gravity supports at https://www.iter.org/newsline/-/2916.)
On 6 September, the second central solenoid module, which had been delivered in October 2021, joined the first in the dedicated assembly zone at the far end of the Assembly Hall. The remaining five modules (including one spare) are in the final stages of fabrication at General Atomics in California and expected at ITER by mid-2023.
For the first time in its existence, vacuum vessel sector #8 is in a vertical position. (At the factory, during D-shape assembly, and during transport, the ITER vacuum vessel sectors are always horizontal.) Sector #8 is the third section of the vacuum vessel to be delivered. Six more sectors are expected, one from Korea and five from Europe. This image also features, in the background, the second central solenoid module (wrapped in pink plastic) being lifted to its assembly zone at the far end of the Assembly Hall.
The steel and concrete structural works for the Control Building are complete and the installation of exterior cladding is advancing well. The team is finalizing roofing, windows and doors and installing cable trays. The control room will be staffed 7 days a week, 24 hours a day, by 60-80 operators during the operational phases of the ITER machine.