Summary: "The problem of evaporation of secondary radioactive wastes resulting from waste disposal studies at Mound Laboratoy has been studied experimentally to determine the fundamental design characteristics of a plant size unit. Emphasis, of course, was on decontamination, but the factors affecting foaming and scaling also had to be investigated and evaluated. Generally speaking, the final design is a standard type of evaporator, the only unique feature being the relation of the two effects. Where critical, as affecting performance, the particular design features have been specified."