Integration of an advanced He-cooled divertor in a DEMO-relevant tokamak geometry

Strong impulses to the development of in-vessel components for near-term fusion reactors like DEMO were given by the recent EU power plant conceptual study (PPCS). Within the PPCS reactor models were developed based on the EU Helium cooled pebble bed blanket (HCPB) concept (reactor model B) and the dual coolant blanket (DC) concept (reactor model C). As a consequence of the study, a design review was carried out in the EU to create a modular HCPB blanket, followed by an effort at Forschungszentrum Karlsruhe (FZK) of a complete in-vessel integration. Also, the development of a gas cooled divertor was launched within the PPCS, with the aim of increasing both safety and the overall plant efficiency. The latest and most advanced divertor concept, which was developed at FZK, is based on a feasible and effective heat transfer enhancement technique, namely the multiple jet impingement cooling technology, while helium was chosen as a gaseous coolant due to its good safety characteristics when used with a Be-containing blanket. A brief description of the divertor design is given with the focus is on reactor integration and target layout.