The tokamak systems monitor (TSM) will provide an integrated view of the machine's condition in near real time, with delays generally under 1 second, so operators can see what is going on inside the machine—and if necessary, react immediately. The system, under development by the Port Plugs & Diagnostics Division team, will also provide an even fuller set of information within minutes to help engineers and scientists make adjustments between pulses. While its primarily role will be to follow the use of the machine against design limits as the tokamak progresses though its lifetime, a happy by-product of the way it is being developed is that it can also be used to refine engineering models during the design phase.
Prototype control room interface for the tokamak systems monitor, using red/amber/green light to show the overall status of systems and components. A 3D representation of the machine allows zoom-in, zoom-out and rotation—and includes a more fine-graded scale indicating the effect of a detected event on each of the tokamak systems.
The methodology has already been developed and used in various industries and other tokamaks—but none as complex as ITER. The approach used at ITER differs in two ways. "First, as far as we know, the level of multi-physics in our algorithms and models has never been done before in fusion," says Daniel Iglesias, Tokamak Systems Monitor Coordinator. "In a tokamak you have several events that are really fast and that involve a whole lot of different phenomena. Typically, the different impacts—for example, heat transfer phenomena, static and transient electromagnetics, dynamic (inertial) phenomena, and the stress fields—are analyzed in isolation. But of course in reality, these things happen at the same time and their effects overlap. In a tokamak the overlaps are more substantial and involve a larger variety of engineering disciplines than in common industries, so we need to reconstruct and then simulate many of them all together in order to get a complete picture of what is happening inside the machine. This multi-physics, or multi-disciplinary engineering, is one of our big challenges."
Prototype of the operator interface provided by the tokamak systems monitor, allowing a comparison of the expected behaviour with what is reconstructed by the TSM diagnostic through direct measurements. In this example, a screen shows transient displacement parameters, which can be plotted as time-dependent graphs for locations requiring attention and fine analysis, or as 3D color-coded contours over a specified interval.