Foaming in slurries and sludges is of immediate concern because of the environmental hazards posed during the safe disposal of radioactive wastes. The present research studied foaminess in simulated radioactive waste, which is a highly alkaline sludge, during dynamic conditions (i.e. boiling). A maximum in foaminess is observed which is due to two competing effects: Amphiphilic particles promoting foaminess by attachment to the bubble surfaces and foam inhibition due to clustering of particles. The maximum in foaminess was of the order of 400 vol% which is detrimental for the working of the commercial evaporator. The antifoaming action of a commercial antifoam agent was investigated as well as an improved antifoamer recently developed by IIT in conjunction with researchers at SRNL.