Improvement of probabilistic fracture mechanics analysis code PASCAL2 for reactor pressure vessel focusing on weld-overlay cladding

Nishikawa, Hiroyuki*; Onizawa, Kunio 

Probabilistic fracture mechanics analysis code PASCAL2 has been developed in JAEA to support the validation of the codes and standards which provide the structural integrity assessment method of reactor pressure vessels during pressurized thermal shock. In this study, the evaluation methods of flaw initiation and growth considering weld-overlay cladding in PASCAL2 and non-destructive inspection models have been improved. Using the improved PASCAL2 code, effects of the initiation and growth models of a cladding flaw and the non-destructive inspection model on the failure probability have been analyzed. The analysis results, indicating the application of the improved initiation model decreases the conditional probability of failure, suggested the most feasible models. The results also showed that only maximum detection probability affected the failure probability among the parameter of the improved non-destructive inspection model.