Development of Probabilistic Fracture Mechanics Analysis Code for Chinese Reactor Pressure Vessel: PET‐CR

ABSTRACT Probabilistic fracture mechanics (PFM), which integrates statistical analysis techniques with the conventional deterministic approach, has emerged as a promising methodology for assessing the structural integrity of reactor pressure vessels (RPVs). By leveraging PFM, numerical metrics including failure probability and failure frequency are calculated to quantify the integrity of an RPV and conduct safety comparisons among different RPVs. To strengthen the practical use of PFM in the Chinese nuclear industry, a new PFM analysis tool PET‐CR (Probabilistic fracture mechanics Evaluation Tool for Chinese Reactor pressure vessel) has been recently developed for probabilistic integrity assessment of Chinese embrittled RPVs in Generation II and III pressurized water reactors (PWRs). In this paper, the progress on the development of Python‐based PET‐CR is elaborated. In PET‐CR, irradiation embrittlement prediction models applicable to Chinese RPVs have been incorporated. Additionally, PET‐CR also has the capability to calculate transient stress intensity factors for both surface and embedded cracks in an RPV. Besides the code development, multi‐stage verifications have been implemented for PET‐CR to enable the reliability and accuracy of the computational results. Currently, PFM analysis for embrittled RPVs containing a single crack can be conducted by PET‐CR, and the conditional probabilities of crack initiation and vessel failure are efficiently computed. By employing PET‐CR, several PFM analysis examples for a Chinese typical PWR‐type RPV subjected to thermal transients are presented.