API laser trackers are used in nuclear research centers in the construction of nuclear fusion reactors for assembly and geometric control tasks. In addition, API laser measurement technology and measuring systems support the construction and assembly of fusion research facilities.

Nuclear fusion: Laser-based 3D metrology from API

For some time now, API’s laser-based measuring systems have been firmly established in basic research on nuclear fusion.

Fusion research facility Wendelstein 7-X

The fusion experiment of the Max Planck Institute Greifswald is based on the stellarator principle. The plasma vessel that holds the up to 100 million degrees hot plasma, reminds of a twisted, half empty bicycle inner tube. During production, the individual plasma vessel modules are also accessible from the outside. At the manufacturer, their complex contours can already be checked from the outside with API RADIAN laser trackers.

The ultra-compact API RADIAN laser trackers can also be brought into the plasma vessel itself and be set up through the narrow access openings. Compared to photogrammetry, the use of RADIAN saves process time and delivers equivalent or more accurate measurement results.

Application of an API laser tracker in the plasma
vessel of a fusion reactor.

Use of API laser trackers in the construction of fusion reactors

Today, RADIAN laser trackers are also used in the construction and assembly of nuclear fusion
reactors. The goal of nuclear fusion research is to reproduce the fusion processes we observe in the heart of the stars and in the sun. ITER is a nuclear fusion reactor under construction and an international research project with the goal of producing electricity from fusion energy.

The reactor is based on the tokamak principle and has been under construction at the
Cadarache nuclear research center in southern France since 2007. The API team is proud to be a supplier of 3D measurement solutions for this ambitious project. RADIAN tracker lasers are used daily for demanding
assembly and geometric control tasks.

ITER Cryostat: measurements with API laser tracker (mounted on 29-meter-high support) and vProbe.

500 MW fusion power

ITER is expected to generate 500 MW of fusion power with an input power of 50 MW. According to current plans (as of January 2020), the facility is scheduled to generate hydrogen plasma for the first time in December 2025.

Measurements with API laser tracker and vProbe on pipes and nozzles of the cryostat, which are cut and aligned on site.

Around 2035 the experiments will become more realistic by using tritium, but also more difficult due to the neutron radiation.

ITER fusion reactor und ITER Kryostat

Part of the ITER reactor is a vacuum vessel, an empty toroidal chamber in which plasma is confined. Superconducting electromagnets provide the magnetic fields necessary to keep the plasma rotating inside the vessel without touching the inner walls. The tokamak is enclosed in a cryostat that isolates the inner hot parts from the superconducting magnets, which are cryogenically cooled.

The ITER cryostat is welded together from thick-walled stainless-steel sheets with a thickness of 40 to 180 millimetres. It is the largest stainless-steel high vacuum chamber in the world. Its weight is 3,400 tons. The outer diameter is 28 meters, the height is 30 meters. Without laser-based measuring technology, assembly and installation would not be possible.

Easy Relocation

Small and compact measuring systems such as RADIAN laser tracker and vProbe no longer have to be moved by crane when changing location and therefore no longer need to be disconnected from the power supply when moving. The calibration of a hall coordinate system – essential for the construction of nuclear fusion reactors and the assembly of their components – is made much easier by simply mounting RADIAN laser tracker on a 29-meter special support.

Further Information:

Here you can see the API laser at ITER in
action Please select 2019 and the month October 10, then go to the large building in the second picture “in the blue dot”. With the ‘right arrow’ you can reach Tokamak 3 after 10 clicks.

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