Besides the production of electricity, the high-temperature reactor (HTR) offers the potential for producing secondary energy carriers for the fuel and heat market. Therefore, the HTR can make a considerable contribution to solving future problems in the energy supply of the Federal Republic of Germany, as well as of the whole world. On the basis of experience with the power plants Arbeitsgemeinschaft Versuchsreaktor, Fort St. Vrain, and THTR-300, new concepts of reactors have been proposed: the medium-sized reactor HTR 500 and the modular HTR concept. The high-temperature heat application is directed toward the refinement of fossil fuels, the long-distance energy system, and other applications, such as process steam for the chemical industry, enhanced oil recovery, and energy for steel production. The research and development program in the Prototype Plant Nuclear Process Heat and Nuclear Long-Distance Energy projects has shown very promising results. These results show that nuclear process heat is technically feasible and that it is possible to reach a commercial application in the next few decades.