After the steam generator tube rupture accident (SGTR) in the lead-based reactor, water will jet into the molten pool with a lot of steam generated, and bubbles may enter the reactor core affecting the safe operation of the reactor.

This study aims to observe the penetration depth of water jet into high-temperature liquid pool by visualization technique for the evaluation of this process.

Firstly, a novel experimental system was designed for injecting subcooled water jets into a high-temperature silicone oil pool, and a high-speed video-camera was employed to capture the dynamic process of water jets into the oil pool. Then, a series of visualization experiments were conducted to analyze the penetration behavior of the jets in the pool by manipulating the pressure and nozzle diameter.

A new correlation for dimensionless penetration depth is developed based on the form of model analysis. The discrepancy between predicted results and present experiment results is within ±30%. It is also found that the spatiotemporal inhomogeneity of momentum change and boiling heat transfer has an important effect on the penetration depth.

This study contributes to a deeper understanding of CCI (Coolant-Coolant Interaction) type jets and can be further applied to studying the phenomena when water jets into molten heavy metals.