Leak-before-break analyses of PWR and BWR piping concerning size effects

In this article, typical components of pressure water reactor (PWR) and boiling water reactor (BWR) primary circuits are examined, and their LBB behavior is investigated. The German standard (KTA) and the US approach (U.S.NRC) are compared. The quantitative results are obtained with the GRS codes PROST and WinLeck, which include different methods for fracture assessment and leak rate calculation. A clear trend concerning the pipe size is found, resulting in large safety margins for large-diameter piping.