Development of RPV Reliability Analysis Code Based on Probabilistic Fracture Mechanics Methodology.

In order to improve the accuracy and applicability in probabilistic fracture mechanics (PFM) code for evaluating the failure probability of a reactor pressure vessel, a new PFM code PASCAL (PFM Analysis of Structural Components in Aging LWR), which incorporates some improved fracture mechanics analysis models and computational procedure such as Monte Carlo simulation procedure, elasto-plastic fracture criterion, semi-elliptical crack extension models and model for overlay cladding, has been developed. Basic performance and functions of the code were confirmed based on the verification analyses. The effect of influence parameters on failure probability was investigated by some case studies using the relevant functions introduced in PASCAL. Based on the results of case studies, the influence of fracture criterion, warm pre-stress (WPS), semi-elliptical crack extension models and overlay cladding on failure probability are discussed