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Latest ITER Newsline

  • Gravity supports | First production unit in China

    Bolted in a perfect circle to the pedestal ring of the cryostat base, 18 gravity supports will brace the curved outer edge of each toroidal field coil. These un [...]

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  • Conference | Fun-filled vacuum

    The science of ITER is not simple. But with a bit of imagination (and a dose of humour) a way can be found to convey the most complex physics notions to a publi [...]

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  • Naive question of the week | What happens to the car keys?

    We begin today a new series that aims to answer basic, even naive, questions about fusion and ITER. An image used often, when trying to convey the amount of e [...]

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  • Metrology | Facing the millimetre test

    In the realm of the very large at ITER, some of the biggest challenges are lurking down in the millimetre range. Within the Assembly Building a massive struct [...]

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  • Fusion research in Europe | Working it out together

    In Europe, fusion research is structured around a goal-oriented roadmap that closely involves universities, research laboratories and industry. Sibylle Günter, [...]

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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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