1.1 ,This specification covers uranium hexafluoride (UF₆) intended for feeding to an enrichment plant. Included are specifications for UF₆ derived from unirradiated natural uranium and UF₆ derived from irradiated uranium that has been reprocessed and converted to UF₆ for enrichment and subsequent reuse. The objectives of this specification are twofold: (1) to define the impurity and uranium isotope limits for Commercial Natural UF₆ feedstock, and (2) to define additional limits for Reprocessed UF₆ (or any mixture of Reprocessed UF₆ and Commercial Natural UF₆). For such UF₆, special provisions may be needed to ensure that no extra hazard arises to the work force, process equipment, or the environment.