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Effect of LWR Coolant Environments on the Fatigue Life of Reactor Materials (NUREG/CR-6909) - Final ReportOn this page: Download complete document The following links on this page are to documents in Adobe Portable Document Format (PDF). See our Plugins, Viewers, and Other Tools page for more information. For successful viewing of PDF documents on our site please be sure to use the latest version of Adobe. Publication InformationManuscript Completed: November 2006 Prepared by Argonne National Laboratory H. J. Gonzalez, NRC Project Manager Prepared for AbstractThe ASME Boiler and Pressure Vessel Code provides rules for the design of Class 1 components ofnuclear power plants. Figures I–9.1 through I–9.6 of Appendix I to Section III of the Code specify design curves for applicable structural materials. However, the effects of light water reactor (LWR) coolant environments are not explicitly addressed by the Code design curves. The existing fatigue strain–vs.–life (ε–N) data illustrate potentially significant effects of LWR coolant environments on the fatigue resistance of pressure vessel and piping steels. Under certain environmental and loading conditions, fatigue lives in water relative to those in air can be a factor of ≈12 lower for austenitic stainless steels, ≈3 lower for Ni-Cr-Fe alloys, and ≈17 lower for carbon and low-alloy steels. This report summarizes the work performed at Argonne National Laboratory on the fatigue of piping and pressure vessel steels in LWR environments. The existing fatigue ε–N data have been evaluated to identify the various material, environmental, and loading parameters that influence fatigue crack initiation, and to establish the effects of key parameters on the fatigue life of these steels. Fatigue life models are presented for estimating fatigue life as a function of material, loading, and environmental conditions. The environmental fatigue correction factor for incorporating the effects of LWR environments into ASME Section III fatigue evaluations is described. The report also presents a critical review of the ASME Code fatigue design margins of 2 on stress (or strain) and 20 on life and assesses the possible conservatism in the current choice of design margins. |
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