A comparison of fracture mechanics methodologies for postulated flaws embedded in the wall of a nuclear reactor pressure vessel

摘要

This study continues an investigation of a computational methodology for calculating the Mode I stress intensity factor, K{sub}I, for flaws embedded in the wall of a nuclear reactor pressure vessel (RPV). The results generated by a model published by Electricite de France (EdF) for calculating linear-elastic fracture mechanics (LEFM) K{sub}I solutions for embedded flaws were compared against solutions previously generated using the EPRI NP-1181 embedded-flaw model (which provides an analytical interpretation of the ASME Boiler and Pressure Vessel Code, Section XI, Appendix A, procedure) and solutions generated using the ABAQUS finite-element computer code. For the flaw geometries examined in the current study, the EPRI / ASME LEFM peak-value K{sub}I solutions were in slightly better agreement with ABAQUS LEFM peak-value K{sub}I solutions than those generated by the EdF model. The EdF and the EPRI/ASME LEFM K{sub}I solutions, corrected to account for plasticity, were benchmarked for three embedded flaw geometries by comparing them with ABAQUS three-dimensional fully elastic-plastic fracture mechanics (EPFM) K{sub}J solutions. The ABAQUS EPFM K{sub}J solutions were significantly higher in magnitude than the ABAQUS LEFM K{sub}I solutions. For the limited number of flaws examined, both plasticity-correction methods significantly underpredicted the ABAQUS EPFM peak-value K{sub}J solutions.