This specification provides the chemical and physical properties and requirements for nuclear-grade aluminum oxide powder intended for fabrication into shapes for nuclear applications. The materials shall conform to physical requirements as to particle size distribution, and specific surface area, and chemical requirements as to loss-on-ignition, and total and elemental concentrations of all impurities. Impurities may include silicaon, iron-chromium-nickel, magnesium, sodium, calcium, hafnium, fluorine, fluorine-chlorine-iodine-bromine, gadolinium, samarium, europium, and dysprosium.