PWRs with passive safety systems

The development activities in the area of nuclear plant design in recent years have caused widespread interest in the plants incorporating passive safety features and simplified system designs. In recent years, design studies were undertaken to use passive phenomena such as natural circulation and gravity to provide safety functions, rather than to rely on the active systems requiring power supply and control systems. The resulting simplification leads to reduced capital costs and shortened construction period. Westinghouse developed the AP600 plant, which is a 600 MWe PWR and features passive safety systems, simplified plant design and the decreased reliance on operator interface. In 1988, the program was initiated to investigate the application of AP600 technology to the use in Japan with more appropriate design features. This plant with 960 MWe rating is designated 'Simplified pressurized water reactor' (SPWR). The key objectives of the SPWR design are shown. The reactor cooling system, the plant instrumentation and control, the passive engineered safety features, the testing program, the plant arrangement and seismic consideration, the safety analysis and the plant simplification and economics of the SPWR are reported. (K.I.)