Abstract The High Temperature Reactor HTR offers beside the production of electricity the potential of the production of secondary energy carriers for the fuel and heat market. Therefore the HTR can considerably contribute to solutions of future problems in the energy supply of the Federal Republic of Germany as well as of the world. On the basis of the experiences with the power plants AVR, Fort St. Vrain and THTR-300 new concepts of reactors have been proposed: the medium size reactor HTR 500 and the Modular HTR concept. The high temperature heat application is directed towards the refinement of fossil fuels, the long distance energy system and other applications as e.g. process steam for chemical industry, enhanced oil recovery and water splitting. The research and development program in the projects Prototype Plant Nuclear Process Heat (PNP) and Nuclear Long Distance Energy (NFE) has shown very promising results. These results show that nuclear process heat is technically feasibly and that it is possible to reach a commercial application in the next decades.