''The data accumulated during the first part of WEST's Phase II campaign will contribute to the optimization of the lifespan of the tungsten divertor in ITER and in future industrial power plants,'' says IRFM director Jérôme Bucalossi.
The divertor is a crucial component whose role in a tokamak is to control the exhaust of waste gas and impurities from the plasma. During operation, the heat loads on the divertor's plasma-facing elements can be as high as 10-20 MW per square metre, equivalent to those that a space shuttle or capsule encounter when re-entering the Earth's atmosphere. The manufacturing of a divertor is in itself a major industrial challenge: in WEST's case, the divertor comprises 456 actively cooled elements that are not all identical—some equipped with instrumentation, others not. Combining tungsten and copper, two metals that are particularly difficult to weld together, the elements need to be positioned within tolerances of 0.3 millimetres.
In 2013, the quarter-century-old tokamak Tore Supra decided to reinvent itself and, under the name WEST (for W Environment in Steady-state Tokamak), head for new horizons and objectives.
"With the first part of the Phase II campaign now over—and with the second planned this autumn—we will have accumulated a considerable amount of data to model and optimize the lifespan of the divertor in ITER and in future industrial power plants," says Jérôme Bucalossi, head of the CEA institute IRFM (Institute for Magnetic Fusion Research) that operates WEST.
