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News & Media

Latest ITER Newsline

  • Men of measure

    'Neither snow nor rain nor heat nor gloom of night stays these couriers from the swift completion of their appointed rounds.' [From the Greek historian Herodotu [...]

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  • The end of a nine-year journey

    In December, as toroidal field conductor unit length #133 came off the production line, the ITER community celebrated a major milestone—the end of a nine-year p [...]

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  • The little coupler that could

    Concrete and steel met at the end of the 19th century, never to part again. From their encounter a new material was born that revolutionized construction techni [...]

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  • The radio power house

    The steel structurethat's being erected against the northeast side of the Assembly Hall is for a large building that will be densely packed with power supplies [...]

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  • Spaceport ITER

    At nightfall, when buildings, work areas, roads and parking lots light up, the ITER site looks like an alien spaceport. Drenched in the yellow glow of sodium l [...]

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Of Interest

See archived articles

Pouring the protective circle

-R.A.

Since construction of the ground support structure for the Tokamak Complex began in 2010, huge volumes of concrete have been poured to form the edifice's seismic foundations, retaining walls, and basemat. Since November 2014 work has been underway on the Complex's basement-level walls and pillars.

In the early hours of Wednesday, 21 October, workers poured the first 200° segment of the bioshield, in an all-day operation that took some 15 hours to complete. (Click to view larger version...)
In the early hours of Wednesday, 21 October, workers poured the first 200° segment of the bioshield, in an all-day operation that took some 15 hours to complete.
But concrete pouring in a nuclear building is never routine, with each pour day marking the end of months of calculations, modellization and painstaking preparation.

For the ITER bioshield—the 3.2-metre-thick "ring fortress" surrounding the machine, whose role is to protect workers and the environment from the radiation generated by the fusion reaction—preparations have been particularly complex. Realizing a "perfect pour" for such a massive and strategic structure is so important that it was practised in a specially constructed full-scale mockup on the platform.

The density of the lattice of steel reinforcement makes the use of traditional concrete vibrators—used to encourage the concrete to reach every recess—impractical. As a consequence, an extra-fluid, self-compacting concrete was selected by the contractors and trialled in the on-site mockup.

At the end of the day 600 m³ of concrete were in place (centre circle), filling over half of the bioshield's circumference. (Click to view larger version...)
At the end of the day 600 m³ of concrete were in place (centre circle), filling over half of the bioshield's circumference.
The conclusive results allowed pouring operations to begin. In the early hours of Wednesday, 21 October, workers poured the first 200° segment of the bioshield, in an all-day operation that took some 15 hours to complete.

As dusk settled on the ITER site 600 m³ of concrete were in place, filling over half of the bioshield's circumference. The pouring of the remaining 160° segment is scheduled in January 2016.


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