Entrainment of soluble and non soluble tracers from a boiling water surface

The entrainment of droplets containing solid or soluble fission product simulants from the surface of a boiling water pool into a gas atmosphere was investigated at conditions, which are relevant to a severe core melt scenario. Different air-steam ratios and at pressures (2-6 bar) were considered in the model containment. Measurements carried out far above the air-liquid interface are compared with the predictions of existing correlations. Favorable agreement is obtained with the correlation of Kataoka and Ishii [Int. J. Heat Mass Transf. 27 (1984)] for the entrainment of soluble fission products into an air-steam atmosphere. Results from integral measurements however suggest that improved correlations should be based on the Froude, Weber and Rayleigh numbers, and separate between entrainment and sedimentation.