Detailed electromagnetic analysis for design optimization of a tungsten divertor plate for JET

The ITER-like Wall Project (ILW) at JET aims at replacing carbon fiber composite (CFC) on plasma-facing surfaces by tungsten and beryllium, which are relevant to the ITER design. The original design of the JET divertor, with CFC tiles, has quite high eddy current-related loads. Tungsten has a much higher electrical conductivity than CFC, and this does not allow a simple replacement of the CFC with solid tungsten in the original design. So-called fishbone- or tree-like shapes, avoiding large loops of eddy currents, have been proposed for the tungsten components and supporting structures. These shapes reduce the eddy current loads drastically and provide well-defined paths for the Halo current. This report describes how the design of the supporting structures is driven by electromagnetic considerations. Analytical and numerical techniques are combined and cross-checked. A study has undertaken for two variable orthogonal magnetic fields, for two cases of Halo current, with three orthogonal background magnetic fields. Then the worst load combinations were identified and used for the calculation of the forces and stresses in fixtures. (C) 2007 Elsevier B.V. All rights reserved.