Probabilistic fracture mechanics of nuclear pressure vessels

An approach has been developed to predict the probability that a fabrication flaw in a reactor pressure vessel will extend by fatigue crack growth mechanisms and become a through-wall flaw. The fracture mechanics model treats the size of the flaw, the location of the flaw, and the parameters governing the fatigue crack growth rates as stochastic variables that are described by histograms that represent their statistical distributions. A Latin Hypercube approach forms the basis for efficient numerical calculations of vessel failure probabilities. A second aspect of the vessel failure model evaluates the benefits of inservice inspections at prescribed inspection time intervals and with prescribed nondestructive examination capabilities.