ASTM C1672-23
(Test Method)Standard Test Method for Determination of the Uranium, Plutonium or Americium Isotopic Composition or Concentration by the Total Evaporation Method Using a Thermal Ionization Mass Spectrometer
Standard Test Method for Determination of the Uranium, Plutonium or Americium Isotopic Composition or Concentration by the Total Evaporation Method Using a Thermal Ionization Mass Spectrometer
SIGNIFICANCE AND USE
5.1 The total evaporation method is used to measure the isotopic composition of uranium, plutonium, and americium materials, and may be used to measure the elemental concentrations of these elements when employing the IDMS technique.
5.2 Uranium and plutonium compounds are used as nuclear reactor fuels. In order to be suitable for use as a nuclear fuel the starting material must meet certain criteria, such as found in Specifications C757, C833, C753, C776, C787, C967, C996, or as specified by the purchaser. The uranium concentration, plutonium concentration, or both, and isotope abundances are measured by TIMS following this method.
5.3 Americium-241 is the decay product of 241Pu isotope. The abundance of the 241Am isotope together with the abundance of the 241Pu parent isotope can be used to estimate radio-chronometric age of the Pu material for nuclear forensic applications Ref (6). The americium concentration and isotope abundances are measured by TIMS following this method.
5.4 The total evaporation method allows for a wide range of sample loading with no significant change in precision or accuracy. The method is also suitable for trace-level loadings with some loss of precision and accuracy. The total evaporation method and modern instrumentation allow for the measurement of minor isotopes using ion counting detectors, while the major isotope(s) is(are) simultaneously measured using Faraday cup detectors.
5.5 The new generation of miniaturized ion counters allow extremely small samples, in the picogram range, to be measured via the total evaporation method. The method may be employed for measuring environmental or safeguards inspection samples containing nanogram quantities of uranium or plutonium. Very small loadings require special sample handling and careful evaluation of measurement uncertainties.
5.6 Typical uranium analyses are conducted using sample loadings between 50 nanograms and 800 nanograms. For uranium isotope ratios the total evapo...
SCOPE
1.1 This method describes the determination of the isotopic composition, or the concentration, or both, of uranium, plutonium, and americium as nitrate solutions by the total evaporation method using a thermal ionization mass spectrometer (TIMS) instrument. Purified uranium, plutonium, or americium nitrate solutions are deposited onto a metal filament and placed in the mass spectrometer. Under computer control, ion currents are generated by heating of the filament(s). The ion currents are continually measured until the whole deposited solution sample is exhausted. The measured ion currents are integrated over the course of the measurement and normalized to a reference isotope ion current to yield isotope ratios.
1.2 In principle, the total evaporation method should yield isotope ratios that do not require mass bias correction. In practice, samples may require this bias correction. Compared to the conventional TIMS method described in Test Method C1625, the total evaporation method is approximately two times faster, improves precision of the isotope ratio measurements by a factor of two to four, and utilizes smaller sample sizes. Compared to the C1625 method, the total evaporation method provides “major” isotope ratios 235U/238U, 240Pu/239Pu, and 241Am/243Am with improved accuracy.
1.3 The total evaporation method is prone to biases in the “minor” isotope ratios (233U/238U, 234U/238U, and 236U/238U ratios for uranium materials and 238Pu/239Pu, 241Pu/239Pu, 242Pu/239Pu, and 244Pu/239Pu ratios for plutonium materials) due to peak tailing from adjacent major isotopes. The magnitude of the absolute bias is dependent on measurement and instrumental characteristics. The relative bias, however, depends on the relative isotopic abundances of the sample. The use of an electron multiplier equipped with an energy filter may eliminate or diminish peak tailing effects. Measurement of the abundance sensitivity of the instrument m...
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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: C1672 − 23
Standard Test Method for
Determination of the Uranium, Plutonium or Americium
Isotopic Composition or Concentration by the Total
Evaporation Method Using a Thermal Ionization Mass
1
Spectrometer
This standard is issued under the fixed designation C1672; 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 eliminate or diminish peak tailing effects. Measurement of the
abundance sensitivity of the instrument may be used to ensure
1.1 This method describes the determination of the isotopic
that such biases are negligible, or may be used to bias correct
composition, or the concentration, or both, of uranium,
the minor isotope ratios.
plutonium, and americium as nitrate solutions by the total
evaporation method using a thermal ionization mass spectrom- 1.4 The values stated in SI units are to be regarded as
eter (TIMS) instrument. Purified uranium, plutonium, or am- standard. When non-SI units are provided in parentheses, they
ericium nitrate solutions are deposited onto a metal filament are for information only.
and placed in the mass spectrometer. Under computer control,
1.5 This standard may involve the use of hazardous mate-
ion currents are generated by heating of the filament(s). The ion
rials and equipment. This standard does not purport to address
currents are continually measured until the whole deposited
all the safety concerns, if any, associated with its use. It is the
solution sample is exhausted. The measured ion currents are
responsibility of the user of this standard to establish appro-
integrated over the course of the measurement and normalized
priate safety, health, and environmental practices and to
to a reference isotope ion current to yield isotope ratios.
determine the applicability of regulatory limitations prior to
use.
1.2 In principle, the total evaporation method should yield
1.6 This international standard was developed in accor-
isotope ratios that do not require mass bias correction. In
dance with internationally recognized principles on standard-
practice, samples may require this bias correction. Compared
ization established in the Decision on Principles for the
to the conventional TIMS method described in Test Method
Development of International Standards, Guides and Recom-
C1625, the total evaporation method is approximately two
mendations issued by the World Trade Organization Technical
times faster, improves precision of the isotope ratio measure-
Barriers to Trade (TBT) Committee.
ments by a factor of two to four, and utilizes smaller sample
sizes. Compared to the C1625 method, the total evaporation
235 238 240
2. Referenced Documents
method provides “major” isotope ratios U/ U, Pu/
239 241 243
2
Pu, and Am/ Am with improved accuracy.
2.1 ASTM Standards:
C753 Specification for Nuclear-Grade, Sinterable Uranium
1.3 The total evaporation method is prone to biases in the
233 238 234 238 236 238
Dioxide Powder
“minor” isotope ratios ( U/ U, U/ U, and U/ U
238 239 241 239
C757 Specification for Nuclear-Grade Plutonium Dioxide
ratios for uranium materials and Pu/ Pu, Pu/ Pu,
242 239 244 239
Powder for Light Water Reactors
Pu/ Pu, and Pu/ Pu ratios for plutonium materials)
C776 Specification for Sintered Uranium Dioxide Pellets for
due to peak tailing from adjacent major isotopes. The magni-
Light Water Reactors
tude of the absolute bias is dependent on measurement and
C787 Specification for Uranium Hexafluoride for Enrich-
instrumental characteristics. The relative bias, however, de-
ment
pends on the relative isotopic abundances of the sample. The
C833 Specification for Sintered (Uranium-Plutonium) Diox-
use of an electron multiplier equipped with an energy filter may
ide Pellets for Light Water Reactors
C859 Terminology Relating to Nuclear Materials
1
This test method is under the jurisdiction of ASTM Committee C26 on Nuclear
Fuel Cycle and is the direct responsibility of Subcommittee C26.05 on Methods of
2
Test. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Dec. 1, 2023. Published January 2024. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 2007. Last previous edition approved in 2017 as C1672 – 17. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/C1672-23. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshoho
...
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: C1672 − 17 C1672 − 23
Standard Test Method for
Determination of Uranium or Plutoniumthe Uranium,
Plutonium or Americium Isotopic Composition or
Concentration by the Total Evaporation Method Using a
1
Thermal Ionization Mass Spectrometer
This standard is issued under the fixed designation C1672; 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 method describes the determination of the isotopic composition, or the concentration, or both, of uranium and
plutoniumuranium, plutonium, and americium as nitrate solutions by the total evaporation method using a thermal ionization mass
spectrometer (TIMS) instrument. Purified uranium or plutoniumuranium, plutonium, or americium nitrate solutions are deposited
onto a metal filament and placed in the mass spectrometer. Under computer control, ion currents are generated by heating of the
filament(s). The ion currents are continually measured until the whole deposited solution sample is exhausted. The measured ion
currents are integrated over the course of the measurement and normalized to a reference isotope ion current to yield isotope ratios.
1.2 In principle, the total evaporation method should yield isotope ratios that do not require mass bias correction. In practice,
samples may require this bias correction. Compared to the conventional TIMS method described in Test Method C1625, the total
evaporation method is approximately two times faster, improves precision of the isotope ratio measurements by a factor of two
to four, and utilizes smaller sample sizes. Compared to the C1625 method, the total evaporation method provides “major” isotope
235 238 240 239 241 243
ratios U/ U and U, Pu/ Pu Pu, and Am/ Am with improved accuracy.
233 238 234 238 236 238
1.3 The total evaporation method is prone to biases in the “minor” isotope ratios ( U/ U, U/ U, and U/ U ratios for
238 239 241 239 242 239 244 239
uranium materials and Pu/ Pu, Pu/ Pu, Pu/ Pu, and Pu/ Pu ratios for plutonium materials) due to peak tailing
from adjacent major isotopes. The magnitude of the absolute bias is dependent on measurement and instrumental characteristics.
The relative bias, however, depends on the relative isotopic abundances of the sample. The use of an electron multiplier equipped
with an energy filter may eliminate or diminish peak tailing effects. Measurement of the abundance sensitivity of the instrument
may be used to ensure that such biases are negligible, or may be used to bias correct the minor isotope ratios.
1.4 The values stated in SI units are to be regarded as standard. When non-SI units are provided in parentheses, they are for
information only.
1.5 This standard may involve the use of hazardous materials and equipment. 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
and health practices and safety, health, and environmental practices and to determine the applicability of regulatory limitations
prior to use.
1.6 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.
1
This test method is under the jurisdiction of ASTM Committee C26 on Nuclear Fuel Cycle and is the direct responsibility of Subcommittee C26.05 on Methods of Test.
Current edition approved Jan. 1, 2017Dec. 1, 2023. Published January 2017January 2024. Originally approved in 2007. Last previous edition approved in 20142017 as
C1672 – 07 (2014).C1672 – 17. DOI: 10.1520/C1672-17.10.1520/C1672-23.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
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C1672 − 23
2. Referenced Documents
2
2.1 ASTM Standards:
C753 Specification for Nuclear-Grade, Sinterable Uranium Dioxide Powder
C757 Specification for Nuclear-Grade Plutonium Dioxide Powder for Light Water Reactors
C776 Specification for Sintered Uranium Dioxide Pellets for Light Water Reactors
C787 Specification for Uranium Hexafluoride for Enrichment
C8
...
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