ASTM C1429-21

Standard Test Method for Isotopic Analysis of Uranium Hexafluoride by Double-Standard Multi-Collector Gas Mass Spectrometer

SIGNIFICANCE AND USE
5.1 Uranium hexafluoride used to produce nuclear-reactor fuel must meet certain criteria for its isotopic composition. This test method may be used to help determine if sample materials meet the criteria described in Specifications C787 and C996.
SCOPE
1.1 This test method covers a quantitative test method applicable to determining the mass percent of uranium isotopes in uranium hexafluoride (UF6) samples. This method as described is for concentrations of  235U between 0.1 and 10 mass %, and  234U and  236U between 0.0001 and 0.1 mass %.  
1.2 This test method is for laboratory analysis by a gas mass spectrometer with a multi-collector.  
1.3 This standard complements Test Methods C761, the double-standard method for gas mass spectrometers using a single collector, by providing a method for spectrometers using a multi-collector.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
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.

General Information

• Status: Published
• Publication Date: 30-Sep-2021
• ICS: 27.120.30 - Fissile materials and nuclear fuel technology
• Technical Committee: C26 - Nuclear Fuel Cycle
• Drafting Committee: C26.05 - Methods of Test

Relations

• Refers: ASTM C859-24 - Standard Terminology Relating to Nuclear Materials
• Effective Date: 01-Jan-2024
• Refers: ASTM C787-20 - Standard Specification for Uranium Hexafluoride for Enrichment
• Effective Date: 01-Mar-2020
• Refers: ASTM C996-20 - Standard Specification for Uranium Hexafluoride Enriched to Less Than 5&#x2009;%&#x2009;<sup > 235</sup>U
• Effective Date: 01-Mar-2020
• Refers: ASTM C1215-18 - Standard Guide for Preparing and Interpreting Precision and Bias Statements in Test Method Standards Used in the Nuclear Industry
• Effective Date: 01-Jul-2018
• Refers: ASTM C761-18 - Standard Test Methods for Chemical, Mass Spectrometric, Spectrochemical, Nuclear, and Radiochemical Analysis of Uranium Hexafluoride
• Effective Date: 01-Feb-2018
• Refers: ASTM C996-15 - Standard Specification for Uranium Hexafluoride Enriched to Less Than 5 % ²³⁵U
• Effective Date: 01-Jul-2015
• Refers: ASTM C787-15 - Standard Specification for Uranium Hexafluoride for Enrichment
• Effective Date: 01-Jul-2015
• Refers: ASTM C859-14a - Standard Terminology Relating to Nuclear Materials
• Effective Date: 15-Jun-2014
• Refers: ASTM C859-14 - Standard Terminology Relating to Nuclear Materials
• Effective Date: 15-Jan-2014
• Refers: ASTM C859-13a - Standard Terminology Relating to Nuclear Materials
• Effective Date: 01-Jun-2013
• Refers: ASTM C859-13 - Standard Terminology Relating to Nuclear Materials
• Effective Date: 01-May-2013
• Refers: ASTM C1215-92(2012)e1 - Standard Guide for Preparing and Interpreting Precision and Bias Statements in Test Method Standards Used in the Nuclear Industry
• Effective Date: 01-Jun-2012
• Refers: ASTM C787-11 - Standard Specification for Uranium Hexafluoride for Enrichment
• Effective Date: 01-Jun-2011
• Refers: ASTM C761-11 - Standard Test Methods for Chemical, Mass Spectrometric, Spectrochemical, Nuclear, and Radiochemical Analysis of Uranium Hexafluoride
• Effective Date: 15-May-2011
• Refers: ASTM C859-10b - Standard Terminology Relating to Nuclear Materials
• Effective Date: 01-Nov-2010

Overview

ASTM C1429-21, titled Standard Test Method for Isotopic Analysis of Uranium Hexafluoride by Double-Standard Multi-Collector Gas Mass Spectrometer, provides a laboratory method for determining the precise isotopic composition of uranium hexafluoride (UF₆). This standard is critical for supporting uranium enrichment and nuclear fuel production, ensuring that materials meet the isotopic criteria specified in ASTM C787 and C996. The method described uses a multi-collector gas mass spectrometer and is specifically applicable to measuring mass percentages of uranium-235 between 0.1 and 10%, and uranium-234 and uranium-236 between 0.0001 and 0.1%.

Key Topics

• Quantitative isotopic analysis: The test method provides procedures for measuring the mass percent of uranium isotopes (U-234, U-235, U-236, and by deduction, U-238) in UF₆ samples.
• Instrument requirements: Utilizes a gas mass spectrometer equipped with a multi-collector system, capable of simultaneously detecting ions corresponding to UF₆ isotopologues.
• Double-standard method: Employs a low-value and high-value pair of standards bracketing the sample, enhancing analytical precision through symmetrical sequence measurements and Lagrange interpolation.
• Precision and accuracy: Repeatability and reproducibility of results are validated using traceable reference materials and pairs of standards, with methodologies to calculate and report precision and bias.
• Safety: Provides important guidance regarding the safe handling of radioactive, toxic, and reactive UF₆ gas in laboratory environments. Adherence to best practices and applicable safety data sheets is mandatory.

Applications

• Nuclear fuel fabrication: Ensures uranium hexafluoride used in fuel production complies with strict isotopic requirements, supporting reactor safety and efficiency.
• Uranium enrichment processes: Used in enrichment facilities to confirm product quality and compliance with international specifications.
• Regulatory compliance: Helps demonstrate conformity with contractual, regulatory, and international requirements for uranium isotopic composition.
• Research and quality control: Supports research programs and continuous quality assurance in nuclear materials laboratories.

The standard is particularly suited for laboratories performing high-precision isotopic analysis on UF₆ for the nuclear industry. By employing a double-standard method and leveraging multi-collector technology, laboratories can achieve reliable and accurate isotope ratio measurements essential for downstream nuclear applications.

Related Standards

For comprehensive quality assurance and alignment with nuclear industry best practices, consider the following related ASTM standards:

• ASTM C761 - Test Methods for Chemical, Mass Spectrometric, Spectrochemical, Nuclear, and Radiochemical Analysis of Uranium Hexafluoride
• ASTM C787 - Specification for Uranium Hexafluoride for Enrichment
• ASTM C996 - Specification for Uranium Hexafluoride Enriched to Less Than 5% U-235
• ASTM C859 - Terminology Relating to Nuclear Materials
• ASTM C1215 - Guide for Preparing and Interpreting Precision and Bias Statements in Test Method Standards Used in the Nuclear Industry

These standards collectively support robust nuclear fuel cycle management, consistent uranium isotopic analysis, terminology alignment, and high-quality laboratory practices.

Keywords: ASTM C1429-21, isotopic analysis, uranium hexafluoride, multi-collector gas mass spectrometer, uranium isotopes, nuclear fuel production, uranium enrichment, uranium analysis standard.

Standards Content (Sample)

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:C1429 −21
Standard Test Method for
Isotopic Analysis of Uranium Hexafluoride by Double-
Standard Multi-Collector Gas Mass Spectrometer
This standard is issued under the fixed designation C1429; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* C859Terminology Relating to Nuclear Materials
C996Specification for Uranium Hexafluoride Enriched to
1.1 This test method covers a quantitative test method
Less Than 5% U
applicabletodeterminingthemasspercentofuraniumisotopes
C1215Guide for Preparing and Interpreting Precision and
in uranium hexafluoride (UF ) samples. This method as de-
235 Bias Statements in Test Method Standards Used in the
scribed is for concentrations of U between 0.1 and
234 236 Nuclear Industry
10mass%, and U and U between 0.0001 and 0.1
2.2 Other Documents:
mass%.
USEC 651Good Handling Practices for Uranium Hexafluo-
1.2 Thistestmethodisforlaboratoryanalysisbyagasmass 3
ride
spectrometer with a multi-collector.
3. Terminology
1.3 This standard complements Test Methods C761, the
double-standard method for gas mass spectrometers using a 3.1 Definitions:
singlecollector,byprovidingamethodforspectrometersusing
3.1.1 Except as otherwise defined herein, definitions of
a multi-collector. terms are as given in Terminology C859.
3.2 Definitions of Terms Specific to This Standard:
1.4 This standard does not purport to address all of the
3.2.1 A standard, n—the low-value standard of a standard
safety concerns, if any, associated with its use. It is the
pair that brackets the sample.
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter- 3.2.2 B standard, n—the high-value standard of a standard
mine the applicability of regulatory limitations prior to use.
pair that brackets the sample.
1.5 This international standard was developed in accor-
3.2.3 determination, n—a single isotopic value, calculated
dance with internationally recognized principles on standard-
from a sequence of ratios; the most basic isotopic value
ization established in the Decision on Principles for the
calculated.
Development of International Standards, Guides and Recom-
3.2.4 Lagrange’s interpolation formula, n—a mathematical
mendations issued by the World Trade Organization Technical
equation designed to estimate values between two or more
Barriers to Trade (TBT) Committee.
known values.
2. Referenced Documents
3.2.5 run, n—a completed, six-entry symmetrical sequence
consisting of A standard, sample, B standard, B standard,
2.1 ASTM Standards:
sample, and A standard from which a determination can be
C761Test Methods for Chemical, Mass Spectrometric,
calculated for one or more isotopes.
Spectrochemical,Nuclear,andRadiochemicalAnalysisof
Uranium Hexafluoride 3.2.6 standard spread, n—the difference between the high
C787Specification for Uranium Hexafluoride for Enrich- and low standards; sometimes called standard range.
ment
3.2.7 test result, n—a reported value; the mean of two or
more determinations.
This test method is under the jurisdiction ofASTM CommitteeC26 on Nuclear
4. Summary of Test Method
Fuel Cycle and is the direct responsibility of Subcommittee C26.05 on Methods of
Test.
4.1 Uranium hexafluoride gas is introduced into an ioniza-
Current edition approved Oct. 1, 2021. Published November 2021. Originally
tion source. The resulting ions are accelerated down the flight
approved in 1999. Last previous edition approved in 2014 as C1429–99 (2014).
tube into the magnetic field. The magnetic field separates the
DOI: 10.1520/C1429-21.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on Available from Centrus Energy Corp., 6901 Rockledge Drive, Suite 800
the ASTM website. Bethesda, Maryland 20817, https://www.centrusenergy.com.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1429−21
ions into ion beams in accordance with the m/e ratio. Four to avoid breathing fumes. Use appropriate personal protective
234 + 235 + 236 +
collectors are stationed so the UF , UF , UF , equipment such as gloves, eye, and face protection.
5 5 5
238 +
and UF ion beams strike individual collectors.
8. Procedure
4.2 Two standards are chosen whose values bracket the
8.1 Select standards:
desired isotope of the sample. The sample and two standards
8.1.1 Choose high and low standards that bracket the
are introduced in a six-entry, symmetrical sequence. Then,
sample isotope(s) being evaluated. If the mass percent
measurements are taken that give the mole ratio of the desired
234 235 236
238 of U, U, and U are all desired, then the two standards
isotope to U.
mustbracketeachofthethreeisotopestopermitcalculationof
4.3 Through Lagrange’s interpolation formula, these mea-
all isotopes for every run.
surements are used to calculate the mass percent of the desired
8.1.2 If standards that bracket all isotopes are unavailable,
isotope.Ifstandardsareavailablethatbracketallisotopes,then
analyze the isotope(s) bracketed by the originally selected
234 235 236
the U, U, and U mass percents are calculated from the
standards, then select other standards to run the remaining
same six-entry run.
isotope(s).
4.4 The results of two six-entry, symmetrical-sequence runs
8.2 Prepare Sample and Standards:
areaveragedtofindtestresultsforeachisotope.The Umass
8.2.1 Attach sample and standard containers to the spec-
percent is obtained by subtraction.
trometer.
8.2.2 Open and close the appropriate valves to evacuate the
5. Significance and Use
air from the inlet system.
5.1 Uranium hexafluoride used to produce nuclear-reactor
8.2.3 Open the sample and standard containers individually
fuel must meet certain criteria for its isotopic composition.
and vent the gas phase to the cold trap. This is to remove
This test method may be used to help determine if sample
impurities that may bias the results or interfere with the
materials meet the criteria described in Specifications C787
ionization. If necessary, freeze the UF with ice water or a
and C996.
mixture of crushed dry ice and isopropyl alcohol to permit
longer venting without losing large amounts of UF .
6. Apparatus
8.2.4 Permit exhaust system pressure to recover.
6.1 Mass spectrometer with the following features and
8.2.5 Check to see if impurities have been sufficiently
capabilities:
removed by introducing UF into the ion source and observing
6.1.1 Anionsourcewithanacceleratingvoltageofapproxi-
pressure, or exhausting through the cold trap and observing
mately 8 kV,
pressure on the other side, or any other suitable means.
6.1.2 A resolving power of greater than or equal to 500,
8.2.6 If necessary, repeat 8.2.3 – 8.2.5 until samples are
6.1.3 A minimum of three points of attachment for stan-
clean.
dards or samples,
8.3 Prepare Instrument:
6.1.4 An ion collection system consisting of four collector
8.3.1 Adjust instrument parameters to focus ion beams in
234 + 235 + 236 +
cups stationed to collect UF , UF , UF , and
238 +
5 5 5
proper collectors and maximize the UF current reading.
238 +
UF ions,
8.3.2 Enter standard values and other information if needed
6.1.5 An ion-current amplifier for each collector cup,
for calculations performed by computer.
6.1.6 A voltage-to-frequency (V-to-F) converter for each
8.3.3 Program the spectrometer to run two of the following
amplifier,
six-entry, symmetrical sequences: low standard, sample, high
6.1.7 A counter for each V-to-F converter, and
standard, high standard, sample, low standard.
6.1.8 Computercontroloveropeningandclosingvalves,the
8.4 Run the Analysis:
timing, and the integration of analytical sequences.
8.4.1 Obtain measurements from all four collectors during
7. Hazards
each entry.
7.1 Uranium hexafluoride (UF ) is radioactive, toxic, and
9. Calculation
highly reactive, especially with reducing substances and mois-
9.1 Perform the following operations for each of the U,
ture. Appropriate laboratory facilities, materials of
235 236
U, and U isotopes:
construction, and techniques shall be utilized when handling
+
9.1.1 Foreachentry,obtainaratiobydividingtheUF ion
UF (see, for example, USEC-651).
238 +
count of the desired isotope by the UF ion count.
7.2 Follow all safety procedures for handling UF provided
9.1.2 Find the mean of the two low standard ratios and
by the facility. Familiarization and compliance with the Safety
designate this A.
Data Sheet is essential.
9.1.3 Find the mean of the two sample ratios and designate
7.3 When released to atmosphere, gaseous UF reacts with this X.
moisture to produce hexafluoride (HF) gas and toxic UO F
9.1.4 Find th
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: C1429 − 99 (Reapproved 2014) C1429 − 21
Standard Test Method for
Isotopic Analysis of Uranium Hexafluoride by Double-
Standard Multi-Collector Gas Mass Spectrometer
This standard is issued under the fixed designation C1429; 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 Scope*
1.1 This test method covers a quantitative test method applicable to determining the mass percent of uranium isotopes in uranium
hexafluoride (UF ) samples. This method as described is for concentrations of U between 0.1 and 10 mass %, 10 mass %, and
234 236
U and U between 0.0001 and 0.1 mass %.
1.2 This test method is for laboratory analysis by a gas mass spectrometer with a multi-collector.
1.3 This standard complements Test Methods C761, the double-standard method for gas mass spectrometers using a single
collector, by providing a method for spectrometers using a multi-collector.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
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
C996 Specification for Uranium Hexafluoride Enriched to Less Than 5 % U
C1215 Guide for Preparing and Interpreting Precision and Bias Statements in Test Method Standards Used in the Nuclear
Industry
2.2 Other Documents:
USEC 651 Good Handling Practices for Uranium Hexafluoride
3. Terminology
3.1 Definitions:
This test method is under the jurisdiction of ASTM CommitteeC26 on Nuclear Fuel Cycle and is the direct responsibility of Subcommittee C26.05 on Methods of Test.
Current edition approved June 1, 2014Oct. 1, 2021. Published June 2014November 2021. Originally approved in 1999. Last previous edition approved in 20092014 as
ε1
C1429 – 99 (2009)(2014). . DOI: 10.1520/C1429-99R14.10.1520/C1429-21.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from Centrus Energy Corp., 6901 Rockledge Drive, Suite 800 Bethesda, Maryland 20817, https://www.centrusenergy.com.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1429 − 21
3.1.1 Except as otherwise defined herein, definitions of terms are as given in Terminology C859.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 A standard, n—the low-value standard of a standard pair that brackets the sample.
3.2.2 B standard, n—the high-value standard of a standard pair that brackets the sample.
3.2.3 determination, n—a single isotopic value, calculated from a sequence of ratios; the most basic isotopic value calculated.
3.2.4 Lagrange’s interpolation formula, n—a mathematical equation designed to estimate values between two or more known
values.
3.2.5 run, n—a completed, six-entry symmetrical sequence consisting of A standard, sample, B standard, B standard, sample, and
A standard from which a determination can be calculated for one or more isotopes.
3.2.6 standard spread, n—the difference between the high and low standards; sometimes called standard range.
3.2.7 test result, n—a reported value; the mean of two or more determinations.
4. Summary of Test Method
4.1 Uranium hexafluoride gas is introduced into an ionization source. The resulting ions are accelerated down the flight tube into
the magnetic field. The magnetic field separates the ions into ion beams in accordance with the m/e ratio. Four collectors are
234 + 235 + 236 + 238 +
stationed so the UF , UF , UF , and UF ion beams strike individual collectors.
5 5 5 5
4.2 Two standards are chosen whose values bracket the desired isotope of the sample. The sample and two standards are
introduced in a six-entry, symmetrical sequence. Then, measurements are taken that give the mole ratio of the desired isotope to
U.
4.3 Through Lagrange’s interpolation formula, these measurements are used to calculate the mass percent of the desired isotope.
234 235 236
If standards are available that bracket all isotopes, then the U, U, and U mass percents are calculated from the same
six-entry run.
4.4 The results of two six-entry, symmetrical-sequence runs are averaged to find test results for each isotope. The U mass
percent is obtained by subtraction.
5. Significance and Use
5.1 Uranium hexafluoride used to produce nuclear-reactor fuel must meet certain criteria for its isotopic composition. This test
method may be used to help determine if sample materials meet the criteria described in Specifications C787 and C996.
6. Apparatus
6.1 Mass spectrometer with the following features and capabilities:
6.1.1 An ion source with an accelerating voltage of approximately 8 kV,
6.1.2 A resolving power of greater than or equal to 500,
6.1.3 A minimum of three points of attachment for standards or samples,
234 + 235 + 236 + 238 +
6.1.4 An ion collection system consisting of four collector cups stationed to collect UF , UF , UF , and UF
5 5 5 5
ions,
6.1.5 An ion-current amplifier for each collector cup,
C1429 − 21
6.1.6 A voltage-to-frequency (V-to-F) converter for each amplifier,
6.1.7 A counter for each V-to-F converter, and
6.1.8 Computer control over opening and closing valves, the timing, and the integration of analytical sequences.
7. Hazards
7.1 Uranium hexafluoride (UF ) is radioactive, toxic, and highly reactive, especially with reducing substances and moisture.
Appropriate laboratory facilities, materials of construction, and techniques shall be utilized when handling UF (see, for example,
USEC-651).
7.2 Follow all safety procedures for handling UF provided by the facility. Familiarization and compliance with the Safety Data
Sheet is essential.
7.3 When released to atmosphere, gaseous UF reacts with moisture to produce hexafluoride (HF) gas and toxic UO F
6 2 2
particulates. Use sufficient ventilation or respiratory protection to avoid breathing fumes. Use appropriate personal protective
equipment such as gloves, eye, and face protection.
8. Procedure
8.1 Select standards:
234 235
8.1.1 Choose high and low standards that bracket the sample isotope(s) being evaluated. If the mass percent of U, U, and
U are all desired, then the two standards must bracket each of the three isotopes to permit calculation of all isotopes for every
run.
8.1.2 If standards that bracket all isotopes are unavailable, analyze the isotope(s) bracketed by the originally selected standards,
then select other standards to run the remaining isotope(s).
8.2 Prepare Sample and Standards:
8.2.1 Attach sample and standard containers to the spectrometer.
8.2.2 Open and close the appropriate valves to evacuate the air from the inlet system.
8.2.3 Open the sample and standard containers individually and vent the gas phase to the cold trap. This is to remove impurities
that may bias the results or interfere with the ionization. If necessary, freeze the UF with ice water or a mixture of crushed dry
ice and isopropyl alcohol to permit longer venting without losing large amounts of UF .
8.2.4 Permit exhaust system pressure to recover.
8.2.5 Check to see if impurities have been sufficiently removed by introducing UF into the ion source and observing pressure,
or exhausting through the cold trap and observing pressure on the other side, or any other suitable means.
8.2.6 If necessary, repeat 7.2.38.2.3 – 7.2.58.2.5 until samples are clean.
8.3 Prepare Instrument:
238 +
8.3.1 Adjust instrument parameters to focus ion beams in proper collectors and maximize the UF current reading.
8.3.2 Enter standard values and other information if needed for calculations performed by computer.
8.3.3 Program the spectrometer to run two of the following six-entry, symmetrical sequences: low standard, sample, high standard,
high standard, sample, low standard.
C1429 − 21
8.4 Run the Analysis:
8.4.1 Obtain measurements from all four collectors during each entry.
9. Calculation
234 235 236
9.1 Perform the following operations for each of the U, U, and U isotopes:
+ 238 +
9.1.1 For each entry, obtain a ratio by dividing the UF ion count of the desired isotope by
...