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Because rotating the heavy cryostat base during installation would be difficult, metrologists were on hand as the base entered the Assembly Hall to make sure the transporter positioned the component exactly as it must be lifted by the overhead cranes. The team managed to achieve a rotational tolerance of +/- 5 mm.
04 May 2020Download
The team anticipated the arrival of the cryostat base in the Assembly Hall by installing one instrument station high up on the nearest sector sub-assembly tool (you can see the instrument if you look closely) for a clear line of sight.
04 May 2020Download
In the Assembly Hall, the steel upending tool is lifted by increments of 5 degrees. A photogrammetric survey is performed between lifts in order to acquire baseline measurements and to monitor deformations.
02 March 2020Download
The upending tool is lifted off the floor so that metrologists can measure the planarity of its support pads.
24 February 2020Download
When two 340-tonne test loads were positioned on one of the sector sub-assembly tools in the Assembly Hall, the metrology team was there to help the operators align the loads vertical to gravity and within one millimetre. The team has established the Tokamak Complex Global Coordinate network for the alignment of components, as well as a local coordinate system in the Assembly Hall for vacuum vessel sector sub-assembly.
14 February 2020Download
ITER's Lionel Poncet (right) and Giacomo Calchi of the European Domestic Agency Fusion for Energy (F4E) perform a surface scan of a port opening inside the cryostat's lower cylinder. The ITER Organization and F4E enjoy an efficient resource-sharing collaboration in the area of metrology.
06 May 2019Download
A vast network of fiducial target nests installed on the concrete surfaces of the bioshield, port cells and galleries will enable installation contractors to align components to sub-millimetre accuracy. Advanced software was used to lay out the positions of each instrument station and simulate clear lines of sight to the fiducial nests. This simulated measurement geometry was used to predict the measurement uncertainty to be expected, which was subsequently qualified with real measurement data. (Pictured: one level of the Tokamak Complex)
12 November 2018Download
2,000 of these small fiducial tests will be placed by European building contractors in accessible areas of the Tokamak Complex. The nests are used to receive spherically mounted reflectors (SMRs), which are surveyed with laser trackers to establish their coordinate values and confirm their compliance with the simulation used during the network design process. Photo: F4E
15 October 2018Download
Before and after each component of the sector sub-assembly tool (SSAT) is preassembled and put into place, metrology engineers carry out a variety of measurements and computational analysis to verify that every component is assembled and positioned in accordance with its design requirements.
12 February 2018Download
Due to the size of the vacuum vessel sector sub-assembly tool (SSAT), several metrology instrument positions are needed to achieve the best precision measurements. A network of target nests embedded in the ground of the Assembly Building helps position the instruments around the SSAT. Photo: PES Metrology
25 January 2018Download
One of the optical metrology tools used to take measurements on the ITER site. As the buildings rise, metrology teams carry out the measurements that provide the "as built" footprint to ITER teams.
16 January 2017Download
Surveyors from the metrology consortium G2Métric & Arkadia use laser measurement equipment to verify the position and elevation of the 80 embedded steel plates used to anchor the drain tanks.
29 September 2014Download
Central to identifying the variances—and defining customization requirements—are sophisticated optical metrology techniques. Alignment of the ITER blanket will be achieved by customizing approximately 4,000 interfacing components.
07 October 2013Download
Metrology contractors (GDV) take GPS measurements as part of the primary survey network qualification survey. Photo: F4E
26 October 2011Download
Eleven survey monuments were positioned around the ITER site in 2010 as part of the ITER Primary Survey Network. Two additional temporary monuments were used during the surveys to shorten the measurement distance to improve the accuracy. On top of the monument is a Leica GPS Receiver. Photo: ITER Organization (Pictured: contractors from GDV Systems GmbH, Germany)Download
In this illustration, the field of view for each camera is modelled and used to identify measurable targets. This array of cameras is repeated 18 times toroidially around the ITER vacuum vessel.Download
The ITER pit survey network will consist of approximately 220 target nests mounted to the bioshield wall at the port cell openings. Metrology instruments mounted on dedicated stands, within the port cells, will extend through the cryostat ports into the pit to measure and align tokamak components with respect to this network. Lines of sight have been carefully studied to ensure that the network remains available throughout construction of the principle tokamak components.Download
Once assembly is complete, a survey will be carried out to determine the as-built position of the interfaces for in-vessel components. Using software tools developed specifically for ITER, a survey simulation was carried out to determine achievable accuracy. 9,000 measurement targets were simulated using the CAD file as a template, to represent targeting the complete vacuum vessel.Download
Measurement geometry for the survey of the interface components of an inboard blanket shield module. Photogrammetry simulation is used to predict the measurement uncertainty.Download
The first survey of the ITER Primary Survey Network, as well as subsequent monitoring surveys, was carried out using a combination of terrestrial measurements (pictured here with a Leica Total station) combined with differential GPS and levelling measurements. An accuracy of approximately 1 mm was achieved for these surveys.Download
The vacuum vessel sectors shall be aligned and welded as pairs and then triplets. The 3 triplets will then be aligned and simultaneously welded together. The as-built geometry of the various sectors shall be dimensionally controlled throughout this process to ensure that the required tolerances are maintained. This image, produced through a virtual assembly process, indicates how manufacturing and assembly variation can be visually represented as compared with the CAD model.Download
Alignment of the vacuum vessel sectors will require a survey from multiple instruments to measure their large volume and to minimize measurement uncertainty. This image shows measurements from five laser tracker stations with lines of sight indicated to both in-vessel and ex-vessel fiducial target points.Download
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