Steam expansion and pressure fluctuation model based on steam generator tube rupture accident of lead-cooled faster reactor

作者：Ruiqi Bao, Li Liu, Junjie Yuan, Hanyang Gu · 发表于：The Physics of Fluids · 年份：2025 · DOI：10.1063/5.0268743

In the steam generator tube rupture (SGTR) accident in lead-cooled fast reactor (LFR), high-pressure water from secondary circuit interacts with high-temperature liquid lead-bismuth eutectic (LBE) in the primary circuit. The rapid flash evaporation and heat transfer cause the injected water to expand into a water–steam mixture, which then fragments into dispersed droplets, inducing pressure fluctuations in the LBE field. This study categorizes the water expansion process into two stages based on the SGTR progression: the flash-expansion stage and the heat transfer-expansion stage. The theoretical models for both stages are developed based on fluid dynamics and heat transfer principles. A quantitative investigation is conducted to examine the effects of jet pressure, jet size, LBE pressure, and droplet size on the dynamic characteristics of steam cavity expansion and parameter distributions in the LBE field. The study further compares the similarities and differences between two models. Through numerical solution, it is found that the steam cavity parameters fluctuate during the expansion process. Increasing the jet size or steam cavity radius, or decreasing the droplet size amplifies the fluctuation amplitude, whereas increasing the LBE pressure enhances the fluctuation frequency. Moreover, the parameter distribution in LBE field features “positive pressure zone” and “negative pressure zone,” with notable differences in their respective distributions. The proposed theoretical...