Modeling of the sedimentation of heterogeneous phases accompanying the vitrification of liquid radioactive wastes

Abstract

The precipitation of the dispersed phase on the bottom of a melter accompanying vitrification of model solutions of high-level wastes was analyzed and a procedure was proposed for determining the macroscopic parameter characterizing the diffusion of small inclusions of the dispersed phase. The maximum sizes of the conglomerates of the dispersed phase near the bottom of an EP-500 melter and the characteristic time over which the impurity is removed from the melt as a result of sedimentation of the heterogeneous phases were determined on the basis of the results. It was shown that these two characteristics of the dispersed phase have virtually no effect on the depth of the melt of the glass phase. For real furnaces used for vitrification with Joule heating, the results obtained could mean that in the hypothetical case when there is no convection and no temperature gradient in the melter, the precipitating dispersed phases based on fission products will settle almost entirely on the bottom of the melter in the form of a dense layer of precipitate.