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

The entrainment of droplets containing solid or soluble fission product sim ulants from the surface of a boiling water pool into a gas atmosphere was i nvestigated at conditions, which are relevant to a severe core melt scenari o. Different air-steam ratios and at pressures (2-6 bar) were considered in the model containment. Measurements carried out far above the air-liquid i nterface are compared with the predictions of existing correlations. Favora ble agreement is obtained with the correlation of Kataoka and Ishii [Int. J . Heat Mass Transf. 27 (1984)] for the entrainment of soluble fission produ cts into an air-steam atmosphere. Results from integral measurements howeve r suggest that improved correlations should be based on the Froude, Weber a nd Rayleigh numbers, and separate between entrainment and sedimentation. (C ) 2001 Elsevier Science B.V. All rights reserved.