Pre-assembly

Prepping the first coil pair

Since their delivery to ITER, in April and July of last year, toroidal field coils #12 and #13 from Japan have been slowly and steadily gaining weight. As the 320-tonne components are prepped for pre-assembly, close to 10 tonnes of equipment, some of it temporary, are being added to their already considerable mass.
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In a vast storage/workshop facility on site, a pair of Japanese toroidal field coils is being prepped for the first pre-assembly operation on the sector sub-assembly tools. The process adds approximately 10 tonnes of equipment, some of it temporary, to their already considerable mass.
"Some of the equipment is added at ITER because it is too fragile to be exposed to the long sea journey, or because it depends on the reverse engineering assessment carried out after arrival to match the coil with neighbouring components," explains Sebastien Koczorowski, the responsible officer for the toroidal field coil preparation activities. "Other equipment—like the interface clamps or the inter-coil structures—need to be installed and customized on site."

The largest part of the added weight, however, consists of equipment necessary for the lifting and subsequent installation of the coils on pre-assembly tooling in the Assembly Hall—for example a set of massive lifting lugs required for transport by the overhead cranes, or components that will interface with the giant sector sub-assembly tool.

Standing on the scaffolding or crouching under the coils, several teams are at work. Members of the DYNAMIC SNC consortium (one of two machine assembly contractors) they are busy installing the delicate network of the external cooling circuit (130 metres of thin piping), connecting the low-voltage wires for the diagnostics systems, or match-drilling for various interface elements.

It will take another few months to finalize the equipment work and transfer the coils to the sector sub-assembly tool. Once associated to vacuum vessel sector #6 and corresponding thermal shield panels, they will form the first of the nine pre-assemblies required for the ITER Tokamak.

In the vast storage/workshop facility, a second pair of coils will soon undergo a similar preparation process, which will be repeated until all nine pre-assemblies are complete and the machine torus finalized.