Effects of gas velocity and break size on steam penetration depth using gas jet into water similarity experiments

A method is given to predict the steam penetration depth under an incidental Steam Generator Tube Rupture (SGTR) accident. Several similar experiments were performed by injecting gas into water to simulate the steam jetting into liquid Lead Bismuth Eutectic (LBE). The steam penetration behaviors including flow regimes and cavity phenomena were captured by visualization method and a semi-empirical correlation was modified for the penetration depth based on dimensional analysis and experimental data. The results showed that the penetration depth was proportional to the density ratio of gas jet to liquid coolant, gas velocity, and break size of tube. Further predictions with similarity theory have been conducted. The penetration depth was about 0.7 m during a large break (a double-ended break) of one SG cooling tubes under a postulated SGTR accident of lead-based reactor.