Meeting the energy challenge through innovations in passive nuclear power technology

Abstract

A large fraction of the world's nuclear power stations are currently expected to retire during the first quarter of the twenty-first century. Whilst the replacement of these older stations with new nuclear capacity is highly desirable from the standpoint of emissions abatement and resource conservation, this option has hitherto been regarded as expensive compared with fossil fuel alternatives, and it has been hindered by the difficulties of demonstrating safety in ways which can be appreciated by the general public. This paper shows how both of these key obstacles can be overcome through the application of passive safety technology to the well proven and widely deployed PWR concept. The US NRC licensed Westinghouse AP600 system is used to illustrate how unequalled levels of safety and reliability have been achieved using considerably simplified safety systems which rely on natural phenomena such as gravity, evaporation, and condensation. These simplified systems employ far fewer components (pumps, pipes, valves, and so on) than conventional plants, and hence require only around half the conventional building volume. The consequent savings in capital cost, construction time and cost, and operation and maintenance costs deliver generation economics which, for the AP600, are superior to those of currently available nuclear plant and are competitive with oil and coal. A larger unit currently under development at Westinghouse, the AP1000, promises to be directly competitive with natural gas. Finally, the international IRIS reactor project is used to illustrate how the PWR concept can be integrated within a single pressure vessel to deliver an economic, inherently safe, and proliferation resistant design of around 300 MW(e). It is concluded that passive safety system technology provides nuclear power with the potential to compete economically with all other alternative forms of generation, and delivers high levels of safety in a way which can be more readily understood and accepted by the public.