Aspects of the technical development for NET (Next European Torus)

NET is envisaged to form, in the European fusion development program, the link between the present-day NET and the following Fusion Demonstration Reactor. The main performance objectives are: the ignition margin, the burn pulse duration and the testing capabilities. The most important design parameters are listed. The operation schedule compromises different stages, e.g. one to maximize the physics capability and another to test two design iterations of a blanket concept. At the end of the operation the machine will have accumulated 105 cycles and 400 days of integrated operating time corresponding to 0,8 MWy/m2 of neutron fluence. Then selection of workable contenders for all DEMO components will be possible. Conceptually the machine is devided into 1) a relatively permanent structure, the support structure, the main vacuum containment and shielding and 2) removable and exchangeable parts such as divertor plates, blanket and first wall. The problems as seen from the present state of knowledge are outlined in connection with the particular parts. Finally, comments on the magnets, the blanket and the first wall/divertor are made. 3 figs. (qui)