Numerical simulation of bubble migration characteristics and distribution probability under lead-cooled fast reactor during SGTR accident

Abstract

The phenomena of lead–bismuth fast reactors may lead to steam generator tube rupture (SGTR) accident. This accident results in heat exchange between high-pressure supercooled water and high-temperature liquid lead–bismuth metal (LBE), generating large number of bubbles. Some bubbles enter the core leading to local heat transfer deterioration and power transients. This study focuses on the European Lead-cooled System and utilizes a drag coefficient model based on bubble-LBE two-phase flow. It combines with the Porous Media Model and the Discrete Phase Model to simulate the migration of bubbles during SGTR accident. The study concludes that the smaller the bubble diameters, the easier it is carried into the core. As the LBE velocity increases, more bubbles can be carried into the core. The temperature change of LBE does not affect the entrainment ability of LBE. Additionally, when the rupture occurs at the bottom of the SG, there is a higher likelihood of bubbles accumulating in the core.