Phenomenological study of the pre-mixing step of sodium-water explosive interaction

The present experimental study aims at better understanding sodium-water explosive interaction in a hypothetical situation. Various experiments were performed in the past, but they still lead to large uncertainties in both interpreting experimental results and predicting accident-scale processes. From the moment it was considered that the explosive nature of the reaction could be due to a very fast water vaporization, sodium-water explosive interaction is studied by addressing the influence of the pre-mixing step (i.e. time between contact and explosion) on its consequences. A better understanding of the phenomena, and especially of the quantity and the rate of energy release, is needed to estimate the consequences of large term source accidents. The experimental measurements and their analytical discussion demonstrate that bubble destabilization is at the origin of pressure wave emission in the surroundings. Under the studied mixing conditions, sodium-water interaction severity depends mainly on the liquid sodium into water penetration limits (kinematic and thermodynamic). Only a fraction of the initial available reaction energy is likely to produce explosive effects, in accordance with the phenomenological model based on the steam explosion assumption.