Publisher Summary This chapter deals with the state of nuclear power today. Many countries are working to improve the economics, safety, and proliferation resistance of advanced reactor–fuel cycle systems. Efforts are focused on making plants simpler to operate, inspect, maintain and repair. In the near term, most new nuclear power plants (NPPs) are likely to be evolutionary designs building on proven systems while incorporating technological advances and often economies of scale. For the longer term, the focus is on innovative designs, several of which are in the small-to-medium range (up to 700 MWe). Complementing the many initiatives above are two major international efforts to promote innovation—the US-initiated GIF and the IAEA's International Project on Innovative Nuclear Reactors and Fuel Cycles (INPRO). The former is currently geared towards specific technology development for reactors intended to come online around 2030. The latter is focused more on the establishment of user requirements to guide fuel cycle and reactor R&D programs targeted on prospective global midcentury energy markets.