ASTM C1428-18(2023)

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.
Designation: C1428 − 18 (Reapproved 2023)
Standard Test Method for
Isotopic Analysis of Uranium Hexafluoride by
Single–Standard Gas Source Multiple Collector Mass
Spectrometer Method
This standard is issued under the fixed designation C1428; 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 2.2 Other Document:
USEC-651 Uranium Hexafluoride: A Manual of Good Han-
1.1 This test method is applicable to the isotopic analysis of
dling Practices
uranium hexafluoride (UF ) with U concentrations less than
234 236
or equal to 5 % and U, U concentrations of 0.0002 to
3. Terminology
0.1 %.
3.1 For definitions of terms relating to the nuclear fuel
1.2 This test method may be applicable to the analysis of the cycle, refer to Terminology C859.
entire range of U isotopic compositions providing that
4. Summary of Test Method
adequate Certified Reference Materials (CRMs or traceable
standards) are available. 4.1 The unknown sample and a CRM or traceable standard
whose isotopic composition is close to that of the sample are
1.3 This standard does not purport to address all of the
introduced in sequence into the mass spectrometer, and U,
safety concerns, if any, associated with its use. It is the
235 236 238
U, U, and U ions are focused through corresponding
responsibility of the user of this standard to establish appro-
collector slits to the four separate collectors. Measurements are
priate safety, health, and environmental practices and deter-
234 235 236
made that are proportional to the ratios of U, U, or U
mine the applicability of regulatory limitations prior to use.
to U. With the known composition of the CRM or traceable
1.4 This international standard was developed in accor-
standard, these ratios of molar ratios permit calculation of the
234 235 236
dance with internationally recognized principles on standard-
U, U, and U contents. Memory corrections are ap-
ization established in the Decision on Principles for the
plied based on the periodic measurement of two CRMs or
Development of International Standards, Guides and Recom-
traceable standards.
mendations issued by the World Trade Organization Technical
5. Significance and Use
Barriers to Trade (TBT) Committee.
5.1 Uranium hexafluoride is a basic material used to pro-
2. Referenced Documents
duce nuclear reactor fuel. To be suitable for this purpose, the
material must meet criteria for isotopic composition. This test
2.1 ASTM Standards:
method is designed to determine whether the material meets
C787 Specification for Uranium Hexafluoride for Enrich-
the requirements described in Specifications C787 and C996.
ment
C859 Terminology Relating to Nuclear Materials
6. Apparatus
C996 Specification for Uranium Hexafluoride Enriched to
235 6.1 A gas source multiple collector mass spectrometer with
Less Than 5 % U
the following attributes:
6.1.1 The resolving power of the mass spectrometer is not
less than 500. The resolving power (R) is calculated from the
1 235 + 238 +
This test method is under the jurisdiction of ASTM Committee C26 on Nuclear
registered mass spectrum of both the UF and UF
5 5
Fuel Cycle and is the direct responsibility of Subcommittee C26.05 on Methods of
isotopes as follows:
Test.
Current edition approved June 1, 2023. Published June 2023. Originally
a·M
approved in 1999. Last previous edition approved in 2018 as C1428 – 18. DOI: R 5 (1)
b·ΔM
10.1520/C1428-18R23.
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 Available from United States Enrichment Corporation, 6903 Rockledge Drive,
the ASTM website. Bethesda, MD 20817.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1428 − 18 (2023)
SH X X SL
where: 0.0002 to 0.01 C /C #4,C /C #4; in concen-
234~236! 234~236! 234~236! 234~236!
SH X X SL
235 + 238 +
tration range 0.01 to 0.1 C /C #3,C /C #3.
a = distance between centers of the UF and UF
234~236! 234~236! 234~236! 234~236!
5 5
peaks,
238 +
b = peak width of the UF isotope (10 % valley), 9. Procedure
238 +
M = 333 − mass(u) UF , and
A typical sequence for the analytical determination is X, S,
235 +
ΔM = 3 = 333 − 330, 330 − mass(u) UF .
5 X, S, where X and S mean the introduction of the sample
and the CRM or traceable standard, respectively. Each intro-
6.1.2 The abundance sensitivity of the mass spectrometer is
−5
duction is followed by ion source evacuation before the next
specified as less than 1×10 as contribution of mass 333
238 + 236 +
( UF ) to mass 331 ( UF ). introduction. During each introduction, a simultaneous mea-
5 5
6.1.3 The four collectors have collector slits adjusted for surement of the four uranium isotopes occurs.
238 +
ions of masses 329, 330, 331, and 333. Ion currents are
The intensities of the UF ion beam for both sample and
amplified by four amplifiers, having noise level less than
CRM or traceable standard introduction shall not differ more
0.5 mV.
than 3 %. Adjustment is performed by pressure equalization
6.1.4 The ion beams are kept within the slits by an auto-
of the sample and standard in the inlet system.
matic beam positioner circuit.
The number of introductions per analytical sequence is de-
6.1.5 The pumping system of the mass spectrometer analy-
pendent on the precision required.
−8
ser tube shall maintain a pressure less than 5×10 torr with a
9.1 Attach sample containers containing the appropriate
sample flowing into the ion source.
sample, X, and standard, S, to the inlet system, and prepare
6.1.6 The memory correction factor of the mass spectrom-
eter as defined in 10.1 shall be consistent with the required both materials for introduction into the ion source as follows:
accuracy and precision, and shall not exceed 1.005.
9.1.1 Operate the appropriate valves to remove air en-
6.1.7 The sample inlet system shall be equipped with a
trapped in the connectors and to check that there are no leaks
manifold, including adjustable leak, and valves for introducing
in inlet system.
the sample and CRM or traceable standard in sequence and for
9.1.2 Freeze the UF by immersing the sample container
evacuating corresponding lines. The pumping system of the
(the unknown sample) into a mixture of water and ice.
−2
inlet system must maintain a pressure less than 2×10 torr by
9.1.3 Open the valve on the container to permit evacuation
evacuating.
of volatile impurities, and then close the valve.
7. Hazards
9.1.4 Remove the coolant from around the container and
allow the UF to return to room temperature.
7.1 Uranium hexafluoride (UF ) is radioactive, toxic, and 6
highly reactive especially with reducing substances and mois- 9.1.5 Repeat 9.1.2 – 9.1.4 for the CRM or traceable stan-
ture. Appropriate laboratory facilities, materials of dard.
construction, and techniques shall be utilized when handling
9.2 Operation of the Mass Spectrometer:
UF (see for example USEC-651).
9.2.1 Operate appropriate valves to admit the CRM or
7.2 When released to atmosphere, gaseous UF reacts with
traceable standard into the ion source.
moisture to produce HF gas and toxic UO F particulates. Use
2 2
9.2.2 Adjust the accelerating voltage or magnet current to
sufficient ventilation or respiratory protection to avoid breath-
234 + 235 + 236 + 238 +
focus the ion beams UF , UF , UF , and UF
ing fumes. Use appropriate personal protective equipment such 5 5 5 5
to their corresponding collectors. Adjust the mass spectrometer
as gloves, eye, and face protection. Consult the Safety Data
238 +
parameters to obtain the maximum UF ion current and
Sheet (SDS) for additional information.
maximum resolution.
238 +
8. Calibration and Standardization
9.2.3 Regulate the adjustable leak to obtai
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