International PFM Round Robin analyses by Japanese participants on reactor pressure vessel integrity during pressurized thermal shock

Onizawa, Kunio ; Kanto, Yasuhiro*; Yoshimura, Shinobu*

The international Round Robin (RR) activity was established in PFM sub-committee in the Japan Welding Engineering Society. This paper summarizes the results from six Japanese participants in the international RR on probabilistic fracture mechanics (PFM) analyses on reactor pressure vessel integrity during pressurized thermal shock (PTS). The RR activity consists of two parts; deterministic analysis on temperature and stress during PTS, and probabilistic analysis on vessel fracture probability. The results from deterministic analysis by five participants were agreed well with among others. One exceptional case was calculation results based on a newly-developed finite difference method. For probabilistic analysis all participants used the same PFM analysis code PASCAL2. Results from five participants were compared with regard to the effects of inspection performance, Cu content and initial reference temperature on fracture probability. The results gave a reasonable agreement although slight differences among participants were found. The differences caused by the selection of some inputs and simulation method are discussed.