Processes for dissolving uranium-zirconium and uranium-zirconium-niobium alloy fuels in ammonium fluoride solutions (Modified Zirflex processes) were developed in the laboratory. A non-aqueous process (Zircex process), in which high-zirconium alloys are hydrochlorinated at about 600°C, offers the possibility of zirconium separation prior to solvent extraction. Dissolvents consisting of mixtures of hydrofluoric acid and hydrogen peroxide or hydrofluoric acid, nitric acid, and aluminum nitrate are also attractive, but corrosion rates with common construction materials have proven excessively high at over 20 mils per month.