A Probabilistic Physics-of-Failure Approach for Assessing the Frequency of Steam Generator Tube Ruptures

摘要

In probabilistic safety assessments (PSA) of pressurized water reactors (PWR), it is imperative to assess the potential and frequency of steam generator tube ruptures (SGTR). Estimation of frequency of SGTRs has traditionally been based on historical occurrences, which are not applicable to new designs of steam generators (SG) with different geometries, material properties, degradation mechanisms and thermal-hydraulic behaviors. This paper presents a Probabilistic Physics of Failure (PPoF) based approach for estimating SGTR frequency. PPoF models have been developed in this research to simulate primary failure mechanisms in SG tubes. An example application of this proposed PPoF-based approach has been presented for a new design of small modular reactor (SMR) SGs consisting of helically-coiled tubes and fabricated with advanced tube materials. Sensitivity analysis has been performed to study the effect of input variables to SGTR frequency values.