Safety aspects of advanced LWR designs

Advanced reactor designs are now being actively pursued in many centres throughout the world for both economic and safety reasons. The Safety and Reliability Directorate of AEA Technology has reviewed these designs to see if they pose any new issues for safety analysis, which will require new methods or data to resolve. In order to identify potential accident sequences in new designs, a generic logical tool for accident sequence identification has been developed. Also, the safety of these designs has been found to rest more on analysis of such natural processes as natural convection. This may call for more detailed models and experimental verification. These apart, no fundamental difficulties have been found. Simplified designs should make it easier to demonstrate the required degree of safety more transparently, and many of the new designs can retain the benefit gained from operating experience with existing plant if the departures from current practice are not too radical. (author). 1 fig