Survey on design rationarization and fracture assessment methods for light water reactor piping

Based on the assumption of the large-scale break at various locations in piping systems, many pipe whip restraints are installed in the presently designed light water reactors. However, requirement of this installation recently began to be relaxed in West Germany and the United States, which resulted in the rationalization of the plant. In this report, it is intended to grasp the present status on the changes in design requirement and to make clear the research and development items required in the future evaluation. In the first place, the present status and the background of the changeds of the design guides are shown. At the next part, relating researches performed at various organizations are summarized. At last, two fracture criteria, i.e. J-integral approach and the net-section stress criterion are examined in some detail and the required researches on each approach are clarified for the future application. (author)