Sodium pool combustion phenomena under natural convection airflow

Sodium pool fire is a design basis accident of sodium-cooled fast reactor. In this study, a numerical method for multi-dimensional modeling of sodium pool fire has been developed. It considers coupling of thermal-hydraulics, chemical reaction and aerosol dynamics equations. From the present multi-dimensional computation, phenomena of sodium pool fire are understood such as flow and temperature fields and aerosol mass distribution of various sizes. It has been found that the burning rate varies along the radial direction and the mass and heat transfer around the pool peripheral is maximum and most influential. The thermal-hydraulic phenomena in the near-surface region are very important to determine the sodium pool fire consequence such as the burning rate and aerosol emission. The area-averaged burning rate and aerosol release fraction calculated by the present numerical method are in agreement with experimental data.