ASTM C996-20

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Designation: C996 − 15 C996 − 20
Standard Specification for
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Uranium Hexafluoride Enriched to Less Than 5 % U
This standard is issued under the fixed designation C996; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This specification covers nuclear grade uranium hexafluoride (UF ) that either has been processed through an enrichment
plant,plant or has been produced by the blending of Highly Enriched Uranium with other uranium to obtain uranium of any U
concentration below 5 % and that is intended for fuel fabrication. The objectives of this specification are twofold: (1) Toto define
the impurity and uranium isotope limits for Enriched Commercial Grade UF so that, with respect to fuel design and manufacture,
it is essentially equivalent to enriched uranium made from natural UF ;, and (2) Toto define limits for Enriched Reprocessed UF
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to be expected if Reprocessed UF is to be enriched without dilution with Commercial Natural UF . For such UF , special
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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 UF that is to be used in the
production of sinterable UO 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 UF
(see, for example, TID-7016, DP-532, and DOE O474.1).
1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.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.
2. Referenced Documents
2.1 ASTM Standards:
C761 Test Methods for Chemical, Mass Spectrometric, Spectrochemical, Nuclear, and Radiochemical Analysis of Uranium
Hexafluoride
C787 Specification for Uranium Hexafluoride for Enrichment
C859 Terminology Relating to Nuclear Materials
C1052 Practice for Bulk Sampling of Liquid Uranium Hexafluoride
C1703C1883 Practice for Sampling of Gaseous Enriched Uranium Hexafluoride for Enrichment
E29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
2.2 ANSI/ASME Standards:
ASME NQA-1 Quality Assurance Requirements for Nuclear Facility Applications
ANSI N14.1 Nuclear Materials—Uranium Hexafluoride—Packaging for Transport
This specification is under the jurisdiction of ASTM Committee C26 on Nuclear Fuel Cycle and is the direct responsibility of Subcommittee C26.02 on Fuel and Fertile
Material Specifications.
Current edition approved July 1, 2015March 1, 2020. Published July 2015April 2020. Originally approved in 1983. Last previous edition approved in 20102015 as
C996 – 10.C996 – 15. DOI: 10.1520/C0996-15.10.1520/C0996-20.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036.10036, http://www.ansi.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C996 − 20
2.3 U.S. Government Documents:
Inspection, Weighing, and Sampling of Uranium Hexafluoride Cylinders, Procedure for Handling and Analysis of Uranium
Hexafluoride, Vol. 1,ORO-671-1 DOE Report ORO-671-1, Inspection, Weighing, and Sampling of Uranium Hexafluoride
Cylinders, Procedure for Handling and Analysis of Uranium Hexafluoride, Vol 1, latest revision
Nuclear Safety Guide, U.S. NRC Report TID-7016,TID-7016 Rev. 2, 1978Nuclear Safety Guide, Rev. 2
Clarke, H. K., Handbook of Nuclear Safety, DOE Report DP-532 Handbook of Nuclear Safety
Code of Federal Regulations, Title 10,10 CFR 50 Code of Federal Regulations, Title 10, Part 50, (Appendix B)
2.4 Other Document:
The UFUSEC-651 Manual: Good Handling Practices for Uranium Hexafluoride, The UF Manual: Good Handling Practices
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for Uranium Hexafluoride United States Enrichment Corporation Report USEC-651, Report, latest revision
3. Terminology
3.1 Definitions:
3.1.1 Terms shall be defined in accordance with Terminology C859, except for the terms listed below.
3.2 Definitions of Terms Specific to This Standard:
3.1.1 Terms shall be defined in accordance with Terminology C859 except for the following:
3.2.1 Commercial Natural UF —, n—UF from natural unirradiated uranium (containing 0.711 6 0.004 g U per 100 g
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U).100 gU).
3.2.1.1 Discussion—
It is recognized that some contamination with reprocessed uranium may occur during routine processing. This is acceptable
provided that the UF meets the requirements for Commercial Natural UF as specified in Specification C787.
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3.2.2 Reprocessed Derived Enriched UF —, n—any UF made from uranium that has been exposed in a neutron irradiation
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facility and subsequently chemically separated from the fission products and transuranic isotopes so generated.obtained from the
blending of Highly Enriched Uranium with any other uranium.
3.1.4 Highly Enriched Uranium—any form of uranium having a U content of 20 % or greater.
3.2.3 Enriched Commercial Grade UF —, n—UF enriched from Commercial Natural UF or Derived Enriched UF that meets
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the specification limits for Enriched Commercial Grade UF .
3.2.4 Enriched Reprocessed UF —, n—UF enriched from Reprocessed UF , any mixture of Reprocessed UF and Commercial
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Natural UF or Derived Enriched UF , exceeding the applicable limits of Sections 4 and 5 for Enriched Commercial Grade UF .
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The wide range of irradiation levels, cooling times, reprocessing, conversion, and enrichment processes, and fuel cycle choices for
combination with unirradiated UF , together with the varying acceptance limits of different fuel fabrication facilities, make it not
practical to specify the exact radionuclide composition of Enriched Reprocessed UF .
3.2.5 Highly Enriched Uranium, n—any form of uranium having a U content of 20 % or greater.
3.2.6 Derived Enriched Reprocessed UF —, n—any UF obtained from the blending of Highly Enriched Uranium with any
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other uranium.made from uranium that has been exposed in a neutron irradiation facility and subsequently chemically separated
from the fission products and transuranic isotopes so generated.
3.3 For enriched UF transactions, “buyer” usually represents the electric power utility company or the fuel fabricator, and
“seller” usually represents the isotopic enrichment facility.
4. Safety, Health Physics, and Criticality Requirements
4.1 The UF concentration shall not be less than 99.5 g UF per 100 g of sample in order to limit the potential hydrogen content
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for nuclear criticality safety.
4.2 The total absolute vapor pressure shall not exceed the values given below:following values:
Available from U.S. U. S. Government Printing Office Superintendent of Documents, 732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401.Accountability
Office (GAO), 441 G St., NW, Washington, DC 20548, http://www.gao.gov.
Available from United States Enrichment Corporation, 6903Centrus Energy Corporation, 6901 Rockledge Drive, Bethesda, MD 20817.
C996 − 20
380 kPa at 80°C (55 psia at 176°F), or
517 kPa at 93°C (75 psia at 200°F), or
862 kPa at 112°C (125 psia at 235°F)
380 kPa at 80 °C (55 psia at 176 °F), or
517 kPa at 93 °C (75 psia at 200 °F), or
862 kPa at 112 °C (125 psia at 235 °F)
Additionally, if a measurement is taken over solid UF , the vapor pressure shall not exceed the values given following values:
50 kPa at 20 °C (7 psia at 68 °F), or
69 kPa at 35 °C (10 psia at 95 °F)
below:
50 kPa at 20°C (7 psia at 68°F), or
69 kPa at 35°C (10 psia at 95°F)
The purpose of the pressure check is to limit the hydrogen fluoride, air, or other volatile components that might cause
overpressure when heating the shipping container, such as to obtain a liquid sample or withdraw the contents.
4.2.1 If the temperature differs from 20°C20 or 35°C,35 °C, a temperature correction must be performed which takes the change
in vapor pressure of UF into account. For example, an acceptable correction would be that the pressure must remain below
P (T) + 39.3 kPa, where P (T) is the vapor pressure of pure UF over solid at temperature T and P (T) is given according
UF6 UF6 6 UF6
to in accordance with Log P = 12.77 – (2562.46/T), with P in Pascal and T in K. Other methods or equations to assure that
UF6
the pressure limits above are met are acceptable provided that validated temperature compensation is made.
4.3 The total hydrocarbon, chlorocarbon, and partially substituted halohydrocarbon content shall not exceed 0.01 mol % of the
UF . The reason for the exclusion of these materials is to prevent a vigorous reaction with UF upon heating. It is essential that
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contamination of the UF containers, such as by vacuum pump oil, be prevented since it is not practical to obtain a sample without
heating the UF . An alternative
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