Civil engineering works officially over in ITER Tokamak building

Without any doubt the ITER Tokamak complex is the most fascinating of the 39 facilities on-site. With a footprint bigger than that of a football stadium, this is the home of the biggest fusion device of our time. Inside its walls, one of the most anticipated experiments will be carried out. Standing 60 m high on the construction site, with a foundation nearly 20 m below the ground, this fortress of 100 000 m³ of concrete symbolises the promise of unlimited energy. It is where the ITER device will be located, weighing 23 000 tonnes, almost three times the Eiffel Tower. For some this is a sophisticated civil engineering project of sheer mastery. For others, this is the legendary Camelot of the fusion community.

The F4E teams in collaboration with the Vinci, Ferrovial, Razel-Bec (VFR) consortium have been racing against time to hand over the edifice in order to move forward with the ITER assembly. For the last ten years, more than 900 people have been working at times in three shifts, amounting to 7 000 000 hours. As part of the contract, the teams were also responsible for the construction of the impressive Assembly Hall, the Cleaning Facility, other surrounding buildings. In 2020, the temporary partition between the Tokamak building and the Assembly Hall was dismantled to kick start the assembly phase of the device by allowing the transfer of heavy components between the two facilities. In parallel, the design, manufacturing, and installation of 249 nuclear doors, of which 195 used for shielding, carried on as planned. The VFR consortium, together with their subcontractors Cegelec, Sommer, and Baumert were also entrusted with this task. In June 2023, with the last piece of door equipment in place, a chapter was closed. Following a thorough process of checks of the sensors and instrumentation of all doors, amongst other things, the papers certifying the official completion of the civil engineering works marked the end of an era.

Representatives of F4E, Engage, Apave, Vinci, Ferrovial and Razel (VFR) during the ceremony making the completion of the civil engineering works of ITER Tokamak building, Cadarache, France. ©F4E

In a small ceremony, held in the offices of F4E, the representatives of all parties celebrated the successful teamwork and its outcome. Following a series of exchanges, highlighting the collaboration of all those years, the parties signed certificates confirming the completion of the works.

Laurent Schmieder, Programme Manager of F4E's Buildings, Infrastructure and Power Supplies (BIPS) shared some thoughts. "The construction of mega-projects represents human progress and leaves a mark on history. I have led the F4E team managing this this contract from the start and I'm proud of what we have achieved together. The result is more than the sum of different parts. It's a collective endeavour resulting from strong engagement, professionalism, and enthusiasm. You may recall that "ITER" in Latin means "the way". Together with the VFR consortium we found the way to deliver."

Romaric Darbour, Deputy Programme Manager of F4E's BIPS, looked back on some of the key moments in time. "I still remember the pouring of the first concrete for the foundation of the Tokamak building, walking between the anti-seismic bearings or seeing the cranes lifting the beams of the Assembly Hall. None of this would have been possible without the commitment of the F4E and ITER Organization teams, our long-standing partnership with Engage consortium, acting as Architect-Engineer, the support to the owner provided by Jacobs, Capgemini and IDOM, and without any doubt the VFR consortium, their subcontractors and the staff located here on-site and remotely. In many respects, the Tokamak building is a first-of-a-kind facility. We have learnt a great deal for the future homes of fusion reactors by delivering the one for ITER."

Marc Lachaise, F4E Director, thanked all F4E staff having contributed to the project. "This success is above your success-the people involved from the start of the civil engineering works. As a team, you can be proud of what you have accomplished, in spite of the numerous difficulties linked to the requirements of the Tokamak Complex. The people who managed, designed, and built this infrastructure have collectively grown and have become a high-performance team. They bring together a diverse set of competences and skills, which have been necessary to meet the high-quality needs and safety standards. Congratulations to all for this landmark achievement."

View of the ITER Tokamak Building and of the busbar bridge construction in progress, ITER site, Cadarache, France, August 2023. ©ITER Organization

Meanwhile, there has been more progress with other buildings and facilities. For example, the Neutral Beam Power Supply Building and its High Voltage Power Supply Building are now weatherproof, and works are advancing with in the installation of HVAC and electrical equipment. The ITER Control building and that of the Fast Discharge Resistor are nearly finished.

Busbar and Cryoline bridges erected on-site, Cadarache, France, August 2023. ©ITER Organization

Works, however, have become more noticeable in that part of the platform where the cryoline and busbar bridges are located. They result from a contact signed between F4E and Demathieu Bard in 2019 for a period of five years.

View inside of the Cryoline bridge, ITER site, Cadarache, France, August 2023. ©ITER Organization

The cryolines, starting from the coldbox of Cryoplant, will run along bridge to be connected to the ITER machine to carry cryogenic fluids. The 440-tonne bridge, supported by two 4.5 m high pillars, was lifted in 2022 and is now ready for the installation of equipment. Its length is impressive because it runs for approximately 70 metres perpendicular to the Cryoplant and then runs parallel to the Assembly Hall for another 60m to reach the Tokamak Complex.

View inside of the Busbar bridge, ITER site, Cadarache, France, August 2023. ©F4E

Similarly, the steel frame of the busbar bridge has been completed. Its purpose will be to deliver power from the Magnet Power Conversion building to the magnets in the device. The aluminium busbars will carry 7 000 times the current of a heavy-duty electrical cable and will be actively cooled. The steel structures and part of the civil engineering works were carried out by Blocotelha. With respect to services, tests and commissioning, Bouygues Energies or Valiance were also involved for the electrical part, and Spie batignolles for the mechanical part.

With nearly 90% of the civil engineering works completed for operations during the first phase of the experiment, the teams on the ground have every reason to be satisfied. They have surely come a long way and delivered efficiently. This said, there is no pause in their daily routine because their goal is to literally pave the way for fusion energy.

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