Numerical prediction and optimization of depressurized sodium-water reaction experiment with counterflow diffusion flame

Sodium-water reaction (SWR) is a design basis accident of a sodium-cooled fast reactor (SFR). A breach of the heat transfer tube in a steam generator results in contact of liquid sodium with water. Typical phenomenon is that the pressurized water blows off, vaporizes, and mixes with the liquid sodium. It is necessary to quantify the SWR phenomena in the safety evaluation of the SFR system. In this paper, a new computer program has been developed and the SWR in a counterflow diffusion flame is studied by a numerical simulation and an experiment. The experiment is designed based on the numerical simulation so that the stable reaction flame is maintained for a long time and physical and chemical quantities are measured. From the comparison of the analysis and the experiment, there exist discrepancies that may be caused by the assumptions of the chemical reaction. Hence, a new experiment is proposed to enhance the measurement accuracy and to investigate the reason of the disagreement. The authors propose a depressurized experiment and show the preliminary result of the experiment. It is found that a stable chemical reaction flame is formed. With the depressurization, it is expected that the flame location can be controlled and the reaction region becomes thicker because of decrease in the reactant gas density.