Conceptual design for a bulk tungsten divertor tile in JET

The ITER-like Wall project (ILW) for JET aims at providing the plasma chamber of the tokamak with an environment of mixed materials which will be relevant for the actual first wall construction on ITER. Tungsten plays a key role in the divertor cladding. For the central tile, also called LB-SRP for “load-bearing septum replacement plate”, bulk tungsten is envisaged in order to cope with the high heat loads expected (up to 10 MW/m2 for 10 s). The outer strike-point in the divertor will be positioned on this tile for the most relevant configurations. Forschungszentrum Jülich (FZJ) has developed a conceptual design based on an assembly of tungsten blades or lamellae. An appropriate interface with the base carrier of JET, on which modules of two tiles are positioned and fixed by remote handling procedures, is a substantial part of the integral design. Important issues are the electromagnetic forces and expected temperature distributions. Material choices combine tungsten, TZM™, Inconel® and ceramic parts. The completed design has been finalised in a proposal to the ILW project, with utmost ITER-relevance.