Radioactive defense waste currently stored at the Savannah River Plant in liquid form is to be immobilized by incorporation into a borosilicate glass. The glass melter for this process will consist of a refractory lined tank enclosed in a water-cooled, steel vessel and fed by an aqueous slurry of glass frit plus radioactive waste. As an aid to understanding the melting process and scaling data from small melters, conservation principles were used to develop equations for predicting the melt rate for a feedpile of arbitrary radius plus additional information regarding feedpile behavior and energy consumption.