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Latest ITER Newsline

  • Cryolines | Another day, another spool

    Having wedged his body and equipment into the cramped space between the ceiling and the massive pipe, a worker is busy welding two cryolines spools. A few metre [...]

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  • Image of the week | Bearings unveiled

    The construction teams are in the last stages of preparing the Tokamak pit for the first major operation of ITER machine assembly: the lowering of the cryostat [...]

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  • Technology | Perfecting tritium breeding for DEMO and beyond

    While ITER will never breed tritium for its own consumption, it will test breeding blanket concepts—the tools and techniques that designers of future DEMO react [...]

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  • Fusion world | Japan and Europe complete the assembly of JT-60SA

    The JT-60SA fusion experiment in Naka, Japan, is designed to explore advanced plasma physics in support of the operation of ITER and next-phase devices. After s [...]

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  • Manufacturing | Thermal shield milestone in Korea

    Six years after the start of fabrication, Korean contractor SFA has completed the last 40° sector of vacuum vessel thermal shield. The stainless steel panels, c [...]

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Of Interest

See archived entries

Cryoplant

How to install a compressor

In order to properly install a helium compressor skid on its concrete pad, you need to start with a large push broom to sweep away the dust that inevitably accumulates on the pad's surface.

The last of the 18 skids will be safely and precisely installed atop their massive four-metre-high concrete pads this week. (Click to view larger version...)
The last of the 18 skids will be safely and precisely installed atop their massive four-metre-high concrete pads this week.
Then come sophisticated laser measurements; a set of steel plates, or shims, of different thicknesses; and, eventually, a powerful telescopic crane to delicately manoeuvre the 20-tonne compressor skid into place.

In the ITER cryoplant, the last of the 18 skids will be safely and precisely installed atop their massive four-metre-high concrete pads this week. Organized in three "compression station trains," each linked to a helium cold box, the compressors will supply the cold boxes with gaseous helium at 21.8 bars and eventually provide the necessary gas flow for the supercritical helium cooling needs of the Tokamak.

The 20-tonne skid comprises the compressor itself, its motor, and different auxiliaries. Perfect positioning is essential to avoid vibrations and difficulties in attaching the interconnections of the ''station trains.'' (Click to view larger version...)
The 20-tonne skid comprises the compressor itself, its motor, and different auxiliaries. Perfect positioning is essential to avoid vibrations and difficulties in attaching the interconnections of the ''station trains.''
Positioning the 20-tonne skid—which comprises the compressor itself, its motor, and different auxiliaries—onto the surface of the concrete pad is an operation that demands millimetric precision, as a slight misalignment could result in damaging vibrations and difficulties in attaching the interconnections of the "station trains."

A pad's concrete surface, however, cannot provide the perfect reference for such tight tolerances. Tiny differences in "altitude" or planarity brought to light by laser measurements need to be compensated by the stacking of shims upon which the skid will rest.

And then the final step: once the skid is in place and anchored deep into the pad's slots, a special grouting—part cement, part resin—is poured to federate the pad and the skid into a mechanically homogeneous structure—a monolith of concrete and steel.


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