Standard Active Last Updated: Apr 16, 2020
ASTM C996-20

Standard Specification for Uranium Hexafluoride Enriched to Less Than 5 %  235U


This specification covers nuclear grade uranium hexafluoride (UF6) that has been processed through an enrichment plant or produced by blending highly enriched uranium with other uranium to produce a concentration suitable for nuclear fuel fabrication. This specification defines the impurity and uranium isotope limits for the enriched commercial grade UF6 and for enriched reprocessed UF6. All materials should conform to the specified chemical, physical, and isotopic requirements.


1.1 This specification covers nuclear grade uranium hexafluoride (UF6) that either has been processed through an enrichment plant or has been produced by the blending of Highly Enriched Uranium with other uranium to obtain uranium of any  235U concentration below 5 % and that is intended for fuel fabrication. The objectives of this specification are twofold: (1) to define the impurity and uranium isotope limits for Enriched Commercial Grade UF6 so that, with respect to fuel design and manufacture, it is essentially equivalent to enriched uranium made from natural UF6, and (2) to define limits for Enriched Reprocessed UF6 to be expected if Reprocessed UF6 is to be enriched without dilution with Commercial Natural UF6. For such UF6, special provisions, not defined herein, may be needed to ensure fuel performance and to protect the work force, process equipment, and the environment.

1.2 This specification is intended to provide the nuclear industry with a standard for enriched UF6 that is to be used in the production of sinterable UO2 powder for fuel fabrication. In addition to this specification, the parties concerned may agree to other appropriate conditions.

1.3 The scope of this specification does not comprehensively cover all provisions for preventing criticality accidents or requirements for health and safety or for shipping. Observance of this specification does not relieve the user of the obligation to conform to all applicable international, federal, state, and local regulations for processing, shipping, or in any other way using UF6 (see, for example, TID-7016, DP-532, and DOE O474.1).

1.4 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.

1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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Book of Standards Volume: 12.01
Developed by Subcommittee: C26.02
Pages: 4
DOI: 10.1520/C0996-20
ICS Code: 27.120.30