A PROCESS FOR TREATING RADIOACTIVE WATER-REACTIVE WASTES

摘要

A process was developed at Los Alamos National Laboratory to treat mixed, reactive wastes. An experimental program was the first step of process development. The chosen method was hydration by water at controlled reaction rate. At first, the use of humid nitrogen was investigated. Nitrogen was passed through a humidifier to gain appropriate humidity and then directed to the reactor with a reactive compound. It has been demonstrated that the reaction follows the Unreacted Shrinking Core Model, which has become a classic model for heterogeneous fluid-solid reactions. The reaction rate proved to be appropriate for finely divided powders but too slow for larger chunks of water-reactive reactants. Another set of experiments was conducted with direct contact of the reactive species with water at controlled conditions. Use of Li{sub}2SO{sub}4 or other sulfate solutions at different concentrations rather than pure water was investigated as a means to slow the reaction rate. Applying polyvinyl alcohol water-soluble bags was used to contain fine powders, prevent elutriation, and slow down the reaction rate. The results of the experimental program were used in the design of full-scale equipment.