Stress and strain considerations in the design of mechanical components in nuclear power plants

Abstract

The design of mechanical components in nuclear power plants must consider a series of loading conditions according to legal requirements. The quality of the design must be demonstrated to the authorized expert predominantly with the help of analyses. The basic approach for analyzing mechanical components is discussed, with emphasis on stress and strain limitation, using piping systems other than primary as an example. The KWU concept includes strain limitation for all postulated loading conditions of low probability, beyond stress limitation required for all operational loading conditions. This makes it possible to take a more balanced view of operational and accident loads, to take advantage of ductile material behavior, and to further improve upon piping systems and their supports with respect to operational conditions. Current design methods, including their effect on the required hardware configuration, and the role of strain limitation in the case of accident loads are described.