THE PROJECT

Tokamak assembly

Dessin au trait du tokamak ITER, un réacteur de fusion nucléaire.

The size and weight of the major components, the tiny tolerances and careful handling required for the assembly of huge and unique systems, the diversity of manufacturers, the tight schedule, complex interfaces ... all of these elements combine to make the assembly of the ITER tokamak an engineering and logistics challenge of enormous proportions.

Core machine assembly is proceeding from bottom to top. Beginning with the heaviest single component—the 1,250-tonne cryostat base, installed in May 2020—assembly contractors are executing the sequence as planned: lower poloidal field coils, cryostat lower cylinder and thermal shield and, over the next years, the nine vacuum vessel modules, subsequent ring coils, components at the top of the machine, central solenoid and, finally, the cryostat lid.

Detailed line drawing of the inside of the ITER Tokamak, a nuclear fusion reactor.

1

Components enter the Assembly Hall through the Cleaning Facility, where they are unpacked and cleaned with compressed air, pressurized demineralized water, or specialty detergents. The Cleaning Facility operates as an airlock between the Hall and the outside environment.

2

The overhead crane system transfers the newly arrived loads to temporary laydown areas, or zones reserved for sub-assembly activities. Then, in the order determined by assembly sequences, the components or assemblies are transported to the Tokamak pit, a 30-metre-deep concrete cylinder in the centre of the Tokamak Building.

3

The ITER Organization is using a number of other warehouse spaces on site to receive, inspect and prepare the largest components for handling in the Assembly Hall. Each ITER component is absolutely unique—and in many cases has required ten years to design, prototype and manufacture. Every possible precaution is taken in their unloading and transport.

4

Contractors working under the supervision of the ITER Organization are carrying out the thousands of complex lifting, positioning, joining, and inspection activities of ITER machine assembly. 

These contractors are carrying out the day-to-day work of machine assembly under the oversight of the ITER Organization:

CNPE Consortium

The CNPE Consortium (China Nuclear Power Engineering; China Nuclear Industry 23 Construction Company Ltd.; Southwestern Institute of Physics; Institute of Plasma Physics, Chinese Academy of Sciences ASIPP; and Framatome) is responsible for Tokamak Machine Assembly (assembly of the cryostat and cryostat thermal shield; magnet feeders; the central solenoid, poloidal field and correction coil magnets; and cooling structures and instrumentation) and for Sector Module Sub-Assembly (assembly of the main vessel, sector sub-assembly with toroidal field coils and vacuum vessel thermal shielding). 

ENSA

ENSA (Equipos Nucleares SA) is responsible for Vacuum Vessel Welding—the in-pit welding of the nine sectors of the vacuum vessel. Work will take place inside of the restricted space of the Tokamak pit, after the sub-assemblies are successively lowered into place by the machine assembly contractor and temporarily braced. 

Repair

Following the discovery of issues in 2022, these companies have been carrying out the repair/refurbishment of the ITER thermal shield and vacuum vessel sectors. Thermal shield repair: In India, INOX CVA is removing thermal shield cooling piping, machining the panels' surface, and welding new piping. Thermal shield replacement: SamHong Heavy Machinery (Korea) is manufacturing two replacement sets of vacuum vessel thermal shield. Vacuum vessel bevel repair: The SIMANN consortium (comprising the Italian firms SIMIC S.p.A. and Ansaldo Nucleare) is carrying out the repair of vacuum vessel bevel joints on site at ITER.

23000

tonnes

1000000

components

1200

engineering packages

10

years