Simplification: the key to improved safety and reliability in advanced light water reactors

The first step of the research and development program for future nuclear electric power generation through the Electric Power Research Institute (EPRI) was the survey of the interests of utilities. The message obtained was that light water technology is a valid base for the future expansion, but the future systems must be simpler. The us program develops advanced PWR and BWR options for future at basic unit power output of 1300 and 600 MWe. The Utility Requirement Document has set the goals in safety, reliability and economy. In this paper, the simplification features of the 600 MWe unit design are reported. The primary elements of the simplification are natural safety features, fewer systems and components, forgiving systems and components, forgiving man-machine interfaces, and standardization. The most important element is the utilization of passive safety features for reactivity control, emergency core cooling and emergency containment cooling. Consequently, the numbers of systems and components are reduced. Also the operation and maintenance are simplified. The policy of standardization was established. (K.I.)