MECHANISM OF URANIUM DIOXIDE SODIUM EXPLOSIVE INTERACTIONS

The lack of nucleation sites in the liquid-liquid-like system results in the overheating of the liquid sodium until homogeneous nucleation occurs. When the superheat limit is reached, vaporization is rapid enough to produce shock waves. Large-scale coherent UO//2-Na vapor explosions would appear impossible in a reactor environment. In a real reactor system, fission gases and fragments, as well as solid materials and gas bubbles entrained in the liquid sodium, would be present and would promote boiling prior to reaching the threshold for homogeneous nucleation in sodium, therefore resulting in mild interactions of the type observed in the TREAT in-pile experiments.