Some components of the ITER machine are referred to as "captive" because, once installed, they become boxed-in by other components or by a built structure and cannot easily be removed. Quite a few diagnostic systems have parts that fall into this category, including systems that have only just passed the conceptual or preliminary design review phase. Because these systems rely on rapidly evolving technology, it does not make sense to freeze their entire design years before the diagnostics will be used. But their "captive" elements must be completed and installed much earlier than the rest of the system.
Support elements for diagnostic pipes, cables and lines are received at the workshop of the installation contractor on the ITER site, before they are assembled into full supports.
"Installing interfaces for diagnostics systems as captive components takes a great deal of planning," says Kempenaars. "We've produced hundreds of documents and drawings, and spent thousands of man hours for something that probably appears quite simple to someone on the outside."
Recently installed supports at the L1 level of the Tokamak Building, showing some of the detail of how the supports are bolted to the ceiling by first welding threaded studs to steel plates embedded in the ceiling concrete. This allows for high accuracy in the installation of the optical beamlines.
"Because my systems are the first to be installed, I was the first to have to raise engineering work packages, to get them into the system, to get them approved, to get them manufactured and get the ball rolling," says Kempenaars. "This is how I ended up setting the example."
Supports installed on the ceiling in the B1 level of the Tokamak Building, showing the ''ceiling hugging'' nature, which keeps the diagnostic systems very close to the ceiling and above other installed equipment.