ASTM C1344-97(2008)
(Test Method)Standard Test Method for Isotopic Analysis of Uranium Hexafluoride by Single-Standard Gas Source Mass Spectrometer Method
Standard Test Method for Isotopic Analysis of Uranium Hexafluoride by Single-Standard Gas Source Mass Spectrometer Method
SIGNIFICANCE AND USE
Uranium hexafluoride is a basic material used to prepare nuclear reactor fuel. To be suitable for this purpose, the material must meet the criteria for isotopic composition. This test method is designed to determine whether the material meets the requirements described in Specifications C 787 and C 996.
ASTM Committee C-26 Safeguards Statement:
The material (uranium hexafluoride) to which this test method applies is subject to the nuclear safeguards regulations governing its possession and use. The analytical procedure in this test method has been designated as technically acceptable for generating safeguards accountability data.
When used in conjunction with appropriate certified reference materials (CRMs), this procedure can demonstrate traceability to the national measurement base. However, adherence to this procedure does not automatically guarantee regulatory acceptance of the regulatory safeguards measurements. It remains the sole responsibility of the user of this test method to ensure that its application to safeguards has the approval of the proper regulatory authorities.
SCOPE
1.1 This test method covers the isotopic analysis of uranium hexafluoride (UF6) and may be used for the entire range of 235U isotopic compositions for which standards are available.
1.2 This test method is applicable to the determination of the isotopic relationship between two UF6 samples. If the abundance of a specific isotope of one sample (the standard) is known, its abundance in the other can be determined. This test method is flexible in that the number of times a given material is admitted to the ion source may be adjusted to the minimum required for a specified precision level.
1.3 The sensitivity with which differences between two materials can be detected depends on the measuring system used, but ratio-measuring devices can generally read ratio-of-mol ratio differences as small as 0.0001.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5 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 determine the applicability of regulatory limitations prior to use. Specific hazards statements are given in Section 7.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: C 1344 – 97 (Reapproved 2008)
Standard Test Method for
Isotopic Analysis of Uranium Hexafluoride by Single-
Standard Gas Source Mass Spectrometer Method
This standard is issued under the fixed designation C1344; 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 USEC-651, Uranium Hexafluoride: A Manual of Good
Handling Practices
1.1 Thistestmethodcoverstheisotopicanalysisofuranium
hexafluoride (UF ) and may be used for the entire range of
3. Terminology
U isotopic compositions for which standards are available.
3.1 Definitions of Terms Specific to This Standard:
1.2 This test method is applicable to the determination of
3.1.1 drop through, n—a measurement of the amount of the
the isotopic relationship between two UF samples. If the
238 + 235 +
UF ion beam that can be passed through the UF
5 5
abundance of a specific isotope of one sample (the standard) is
235 +
collector slit and measured on the UF collector, stated as
known, its abundance in the other can be determined.This test
238 +
a percentage of the total UF signal.
method is flexible in that the number of times a given material
3.1.2 memory corrections, n—corrections applied to the
is admitted to the ion source may be adjusted to the minimum
sample analysis results for memory effects.
required for a specified precision level.
3.1.3 memory effect, n—the inability of the mass spectrom-
1.3 The sensitivity with which differences between two
eter to omit completely the isotopic composition of the sample
materials can be detected depends on the measuring system
analyzed previously from attributing to the results of further
used, but ratio-measuring devices can generally read ratio-of-
samples analyzed.
mol ratio differences as small as 0.0001.
3.1.4 normal isotopic abundance material, n—UF havinga
1.4 The values stated in SI units are to be regarded as
value of 0.711 weight percent (wt%) U.
standard. No other units of measurement are included in this
235 238
3.1.5 ratio-of-mol-ratios, n—the mol ratio ( U/ U) of
standard.
the sample divided by the mol ratio of the standard, or the
1.5 This standard does not purport to address all of the
inverseconditionofthemolratioofthestandarddividedbythe
safety concerns, if any, associated with its use. It is the
mol ratio of the sample.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
4. Summary of Test Method
bility of regulatory limitations prior to use. Specific hazards
4.1 Test Method—Theunknownsampleandastandardwith
statements are given in Section 7.
an isotopic composition close to that of the sample are
+
2. Referenced Documents introduced in sequence into the Neir mass spectrometer. UF
2 ions of the isotopes are focused through a mass-resolving
2.1 ASTM Standards:
collector slit and onto a faraday cup collector. Measurements
C787 Specification for Uranium Hexafluoride for Enrich-
235 + +
are made of UF to the total of the other UF isotopes.
5 5
ment
Withtheknowncompositionofthestandard,calculationofthe
C996 Specification for Uranium Hexafluoride Enriched to
U composition of the sample can be determined.
Less Than 5 % U
2.2 Other Document:
5. Significance and Use
5.1 Uraniumhexafluorideisabasicmaterialusedtoprepare
nuclear reactor fuel. To be suitable for this purpose, the
ThistestmethodisunderthejurisdictionofASTMCommitteeC26onNuclear
material must meet the criteria for isotopic composition. This
Fuel Cycle and is the direct responsibility of Subcommittee C26.05 on Methods of
test method is designed to determine whether the material
Test.
meets the requirements described in Specifications C787 and
Current edition approved Dec. 1, 2008. Published January 2009. Originally
approved in 1997. Last previous edition approved in 2003 as C1344–97 (2003). C996.
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 U.S. Enrichment Corporation, 6903 Rockledge Dr., Bethesda,
the ASTM website. MD 20817, http://www.usec.com.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C 1344 – 97 (2008)
5.2 ASTM Committee C-26 Safeguards Statement: replaced, repairs are made on the sample inlet system, or the
5.2.1 The material (uranium hexafluoride) to which this test instrument is refocused so the flow rate of UF is altered
significantly.
method applies is subject to the nuclear safeguards regulations
governing its possession and use. The analytical procedure in 6.1.1.8 Thecomputercontrolofthemassspectrometermust
allow the operator to monitor parameters of the spectrometer
this test method has been designated as technically acceptable
for generating safeguards accountability data. and check other operating conditions. The development of an
interactive program allows input of sample information, per-
5.2.2 When used in conjunction with appropriate certified
forms necessary calculations, makes memory corrections, and
reference materials (CRMs), this procedure can demonstrate
records data. Flexibility of the interactive program allows
traceabilitytothenationalmeasurementbase.However,adher-
pausing of the instrument for adjustment or restart capability,
ence to this procedure does not automatically guarantee regu-
or both. Suggested methods of analysis checks include the
latory acceptance of the regulatory safeguards measurements.
standard deviation (SD) on individual data points, linearity of
Itremainsthesoleresponsibilityoftheuserofthistestmethod
thedataset,andacheckofsourcepressuredifferencesbetween
to ensure that its application to safeguards has the approval of
thestandardandsamplethatcanbemonitoredbythecomputer
the proper regulatory authorities.
program. Manifold valve actuation, conditioning time, and
pump-out time are features of the computer control program.
6. Apparatus
6.1 Neir Mass Spectrometer,withthefollowingfeaturesand
7. Hazards
capabilities:
7.1 Since UF is radioactive, toxic, and highly reactive,
6.1.1 Asingle-focusing spectrometer, with a 127-mm mini-
especially with reducing substances and moisture (see USEC-
mum deflection radius, is satisfactory when equipped and
651), appropriate facilities and practices for analysis must be
focused as follows:
provided.
6.1.1.1 The sample inlet system must have two sample
holders, to which UF containers can be attached, and the
8. Procedure
necessary valves to evacuate the sample lines through which
the sample and standard are introduced. The sample inlet
8.1 Calibration of Isotopic Standards:
systemshouldbenickelorMonelforusewithcorrosivegases,
8.1.1 One working standard is required for the analysis of a
and should have minimum volume.
sample at any specific concentration of any isotope. Two
6.1.1.2 A single adjustable leak, operated by an automatic
working standards are required to determine memory correc-
leak control mechanism for admitting the sample into the
tions. Memory can be measured more precisely with a large
spectrometer ion source, is preferred.
difference between two working standards, but the adverse
6.1.1.3 The pumping system of the spectrometer analyzer effect of introducing wide concentration ranges into the mass
−8
tubemustmaintainapressurebelow5 310 torrwithsample
spectrometer must be considered. Ideally, the values obtained
flowing into the ion source. from the high- and low-memory standards should symmetri-
6.1.1.4 Focus the instrument for resolution consistent with cally bracket those of the sample to be corrected. Working
−10
precision requirements. A high-current ion beam of 5 310 standards approximately 5% apart (having a ratio of ratios of
−9
to 1 310 amps is necessary, with a signal-to-noise ratio 1.05) are suitable for most applications.
greater than 3000 in the low-current amplifier system. 8.1.2 A reasonable limit for the relative e between the
6.1.1.5 Adual collector must be used, so that ions from one unknown sample and the working standard to which it is
compared is 2.5%. A series of working standards prepared at
isotope are passed through a resolving slit and focused on a
low-current collector, and ions from all other isotopes are 5% intervals and used for sample comparisons thus enables
this 2.5% limit.
focused on a high-current collector. The preferred method of
maintaining the low-current ion beam within the collector slit 8.1.3 Prepare a working standard, and standardize against
isbyanautomaticbeampositionercircuit.Aresolvingslitwith an oxide blend of CRM standards that is within 0.02% of the
adjustable width features enhances the measurement of all value of the working standard.
isotopes but is not mandatory for isotopic measurements. 8.2 Sample Preparation:
6.1.1.6 The amplified high- and low-current signals are fed 8.2.1 Attach tubes containing the appropriate working stan-
into a multimeter or other device capable of ratioing high- and dard, S, and the sample, X, to the spectrometer inlet system,
and prepare the materials for introduction into the ion source,
low-current signals. If a multimeter is used, the multimeter
must have a minimum of 5.5 digits of resolution, a means of as follows:
ratioing the high- and low-current signals, and interactive 8.2.1.1 If adequate sample and working standard are avail-
communication capability with the controller. able,openallvalvesbetweenthesampleandworkingstandard
6.1.1.7 The memory effect of the spectrometer must be containers and the pumping system, except the valves on the
sample and working standard containers. If the amount of
consistent with the precision required since a high memory
level is usually more variable than a low one. Memory values sample or working standard is limited, proceed to 8.2.2.
8.2.1.2 Open the valve on the sample container, and then
of 2 to 3% are typical, but up to 10% memory can be
tolerated. The memory characteristics of a spectrometer must close it quickly to vent gases to the pumping system.
be established from periodic measurement of the effect. Cur- 8.2.1.3 After the pumping system has evacuated the ve
...
This document is not anASTM standard and is intended only to provide the user of anASTM 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:C1344–97 (Reapproved 2003) Designation: C 1344 – 97 (Reapproved 2008)
Standard Test Method for
Isotopic Analysis of Uranium Hexafluoride by Single-
Standard Gas Source Mass Spectrometer Method
This standard is issued under the fixed designation C1344; 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
1.1 This test method covers the isotopic analysis of uranium hexafluoride (UF ) and may be used for the entire range of U
isotopic compositions for which standards are available.
1.2 This test method is applicable to the determination of the isotopic relationship between two UF samples. If the abundance
of a specific isotope of one sample (the standard) is known, its abundance in the other can be determined. This test method is
flexible in that the number of times a given material is admitted to the ion source may be adjusted to the minimum required for
a specified precision level.
1.3 The sensitivity with which differences between two materials can be detected depends on the measuring system used, but
ratio-measuring devices can generally read ratio-of-mol ratio differences as small as 0.0001.
1.4The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5 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 determine the applicability of regulatory
limitations prior to use. Specific hazards statements are given in Section 7.
2. Referenced Documents
2.1 ASTM Standards:
C787 Specification for Uranium Hexafluoride for Enrichment
C996 Specification for Uranium Hexafluoride Enriched to Less Than 5 % U
2.2 Other Document:
USEC-651, Uranium Hexafluoride: A Manual of Good Handling Practices
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
238 + 235 +
3.1.1 drop through, n—a measurement of the amount of the UF ion beam that can be passed through the UF collector
5 5
235 + 238 +
slit and measured on the UF collector, stated as a percentage of the total UF signal.
5 5
3.1.2 memory corrections, n—corrections applied to the sample analysis results for memory effects.
3.1.3 memory effect, n—the inability of the mass spectrometer to omit completely the isotopic composition of the sample
analyzed previously from attributing to the results of further samples analyzed.
3.1.4 normal isotopic abundance material, n—UF having a value of 0.711 weight percent (wt%) U.
235 238
3.1.5 ratio-of-mol-ratios, n—the mol ratio ( U/ U) of the sample divided by the mol ratio of the standard, or the inverse
condition of the mol ratio of the standard divided by the mol ratio of the sample.
4. Summary of Test Method
4.1 Test Method—The unknown sample and a standard with an isotopic composition close to that of the sample are introduced
+
insequenceintotheNeirmassspectrometer.UF ionsoftheisotopesarefocusedthroughamass-resolvingcollectorslitandonto
235 + +
a faraday cup collector. Measurements are made of UF to the total of the other UF isotopes. With the known composition
5 5
of the standard, calculation of the
U composition of the sample can be determined.
This test method is under the jurisdiction ofASTM Committee C26 on Nuclear Fuel Cycle and is the direct responsibility of Subcommittee C26.05 on Methods ofTest.
Current edition approved Aug. 10, 1997. Published May 1997.
Current edition approved Dec. 1, 2008. Published January 2009. Originally approved in 1997. Last previous edition approved in 2003 as C1344–97 (2003).
ForreferencedASTMstandards,visittheASTMwebsite,www.astm.org,orcontactASTMCustomerServiceatservice@astm.org.For Annual Book of ASTM Standards
, Vol 12.01.volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from U.S. Enrichment Corporation, 6903 Rockledge Dr., Bethesda, MD 20817, http://www.usec.com.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C 1344 – 97 (2008)
5. Significance and Use
5.1 Uranium hexafluoride is a basic material used to prepare nuclear reactor fuel. To be suitable for this purpose, the material
must meet the criteria for isotopic composition. This test method is designed to determine whether the material meets the
requirements described in Specifications C787 and C996.
5.2 ASTM Committee C-26 Safeguards Statement:
5.2.1 The material (uranium hexafluoride) to which this test method applies is subject to the nuclear safeguards regulations
governing its possession and use. The analytical procedure in this test method has been designated as technically acceptable for
generating safeguards accountability data.
5.2.2 When used in conjunction with appropriate certified reference materials (CRMs), this procedure can demonstrate
traceability to the national measurement base. However, adherence to this procedure does not automatically guarantee regulatory
acceptance of the regulatory safeguards measurements. It remains the sole responsibility of the user of this test method to ensure
that its application to safeguards has the approval of the proper regulatory authorities.
6. Apparatus
6.1 Neir Mass Spectrometer, with the following features and capabilities:
6.1.1 Asingle-focusing spectrometer, with a 127-mm minimum deflection radius, is satisfactory when equipped and focused as
follows:
6.1.1.1 The sample inlet system must have two sample holders, to which UF containers can be attached, and the necessary
valves to evacuate the sample lines through which the sample and standard are introduced. The sample inlet system should be
nickel or Monel for use with corrosive gases, and should have minimum volume.
6.1.1.2 A single adjustable leak, operated by an automatic leak control mechanism for admitting the sample into the
spectrometer ion source, is preferred.
−8
6.1.1.3 The pumping system of the spectrometer analyzer tube must maintain a pressure below 5 310 torr with sample
flowing into the ion source.
−10
6.1.1.4 Focus the instrument for resolution consistent with precision requirements. A high-current ion beam of 5 310 to
−9
1 310 amps is necessary, with a signal-to-noise ratio greater than 3000 in the low-current amplifier system.
6.1.1.5 A dual collector must be used, so that ions from one isotope are passed through a resolving slit and focused on a
low-currentcollector,andionsfromallotherisotopesarefocusedonahigh-currentcollector.Thepreferredmethodofmaintaining
thelow-currentionbeamwithinthecollectorslitisbyanautomaticbeampositionercircuit.Aresolvingslitwithadjustablewidth
features enhances the measurement of all isotopes but is not mandatory for isotopic measurements.
6.1.1.6 The amplified high- and low-current signals are fed into a multimeter or other device capable of ratioing high- and
low-current signals. If a multimeter is used, the multimeter must have a minimum of 5.5 digits of resolution, a means of ratioing
the high- and low-current signals, and interactive communication capability with the controller.
6.1.1.7 The memory effect of the spectrometer must be consistent with the precision required since a high memory level is
usuallymorevariablethanalowone.Memoryvaluesof2to3%aretypical,butupto10%memorycanbetolerated.Thememory
characteristicsofaspectrometermustbeestablishedfromperiodicmeasurementoftheeffect.Currentmemoryvaluesusuallywill
apply until the ion source is replaced, repairs are made on the sample inlet system, or the instrument is refocused so the flow rate
of UF is altered significantly.
6.1.1.8 The computer control of the mass spectrometer must allow the operator to monitor parameters of the spectrometer and
check other operating conditions. The development of an interactive program allows input of sample information, performs
necessary calculations, makes memory corrections, and records data. Flexibility of the interactive program allows pausing of the
instrument for adjustment or restart capability, or both. Suggested methods of analysis checks include the standard deviation (SD)
onindividualdatapoints,linearityofthedataset,andacheckofsourcepressuredifferencesbetweenthestandardandsamplethat
can be monitored by the computer program. Manifold valve actuation, conditioning time, and pump-out time are features of the
computer control program.
7. Hazards
7.1 Since UF is radioactive, toxic, and highly reactive, especially with reducing substances and moisture (see USEC-651),
appropriate facilities and practices for analysis must be provided.
8. Procedure
8.1 Calibration of Isotopic Standards:
8.1.1 One working standard is required for the analysis of a sample at any specific concentration of any isotope. Two working
standardsarerequiredtodeterminememorycorrections.Memorycanbemeasuredmorepreciselywithalargedifferencebetween
two working standards, but the adverse effect of introducing wide concentration ranges into the mass spectrometer must be
considered. Ideally, the values obtained from the high- and low-memory standards should symmetrically bracket those of the
sample to be corrected. Working standards approximately 5% apart (having a ratio of ratios of 1.05) are suitable for most
applications.
8.1.2 A reasonable limit for the relative e between the unknown sample and the working standard to which it is compared is
C 1344 – 97 (2008)
2.5%. A series of working standards prepared at 5% intervals and used for sample comparisons thus enables this 2.5% limit.
8.1.3 Prepare a working standard, and standardize against an oxide blend of CRM standards that is within 0.02% of the value
of the working standard.
8.2 Sample Preparation:
8.2.1 Attach tubes containing the appropriate working standard, S, and the sample, X, to the spectrometer inlet system, and
prepare the materials for introduction into the ion source, as follows:
8.2.1.1 If adequate sample and working standa
...
This document is not anASTM standard and is intended only to provide the user of anASTM 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:C1344–97 (Reapproved 2003) Designation: C 1344 – 97 (Reapproved 2008)
Standard Test Method for
Isotopic Analysis of Uranium Hexafluoride by Single-
Standard Gas Source Mass Spectrometer Method
This standard is issued under the fixed designation C1344; 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
1.1 This test method covers the isotopic analysis of uranium hexafluoride (UF ) and may be used for the entire range of U
isotopic compositions for which standards are available.
1.2 This test method is applicable to the determination of the isotopic relationship between two UF samples. If the abundance
of a specific isotope of one sample (the standard) is known, its abundance in the other can be determined. This test method is
flexible in that the number of times a given material is admitted to the ion source may be adjusted to the minimum required for
a specified precision level.
1.3 The sensitivity with which differences between two materials can be detected depends on the measuring system used, but
ratio-measuring devices can generally read ratio-of-mol ratio differences as small as 0.0001.
1.4The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5 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 determine the applicability of regulatory
limitations prior to use. Specific hazards statements are given in Section 7.
2. Referenced Documents
2.1 ASTM Standards:
C787 Specification for Uranium Hexafluoride for Enrichment
C996 Specification for Uranium Hexafluoride Enriched to Less Than 5 % U
2.2 Other Document:
USEC-651, Uranium Hexafluoride: A Manual of Good Handling Practices
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
238 + 235 +
3.1.1 drop through, n—a measurement of the amount of the UF ion beam that can be passed through the UF collector
5 5
235 + 238 +
slit and measured on the UF collector, stated as a percentage of the total UF signal.
5 5
3.1.2 memory corrections, n—corrections applied to the sample analysis results for memory effects.
3.1.3 memory effect, n—the inability of the mass spectrometer to omit completely the isotopic composition of the sample
analyzed previously from attributing to the results of further samples analyzed.
3.1.4 normal isotopic abundance material, n—UF having a value of 0.711 weight percent (wt%) U.
235 238
3.1.5 ratio-of-mol-ratios, n—the mol ratio ( U/ U) of the sample divided by the mol ratio of the standard, or the inverse
condition of the mol ratio of the standard divided by the mol ratio of the sample.
4. Summary of Test Method
4.1 Test Method—The unknown sample and a standard with an isotopic composition close to that of the sample are introduced
+
insequenceintotheNeirmassspectrometer.UF ionsoftheisotopesarefocusedthroughamass-resolvingcollectorslitandonto
235 + +
a faraday cup collector. Measurements are made of UF to the total of the other UF isotopes. With the known composition
5 5
of the standard, calculation of the
U composition of the sample can be determined.
This test method is under the jurisdiction ofASTM Committee C26 on Nuclear Fuel Cycle and is the direct responsibility of Subcommittee C26.05 on Methods ofTest.
Current edition approved Aug. 10, 1997. Published May 1997.
Current edition approved Dec. 1, 2008. Published January 2009. Originally approved in 1997. Last previous edition approved in 2003 as C1344–97 (2003).
ForreferencedASTMstandards,visittheASTMwebsite,www.astm.org,orcontactASTMCustomerServiceatservice@astm.org.For Annual Book of ASTM Standards
, Vol 12.01.volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from U.S. Enrichment Corporation, 6903 Rockledge Dr., Bethesda, MD 20817, http://www.usec.com.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C 1344 – 97 (2008)
5. Significance and Use
5.1 Uranium hexafluoride is a basic material used to prepare nuclear reactor fuel. To be suitable for this purpose, the material
must meet the criteria for isotopic composition. This test method is designed to determine whether the material meets the
requirements described in Specifications C787 and C996.
5.2 ASTM Committee C-26 Safeguards Statement:
5.2.1 The material (uranium hexafluoride) to which this test method applies is subject to the nuclear safeguards regulations
governing its possession and use. The analytical procedure in this test method has been designated as technically acceptable for
generating safeguards accountability data.
5.2.2 When used in conjunction with appropriate certified reference materials (CRMs), this procedure can demonstrate
traceability to the national measurement base. However, adherence to this procedure does not automatically guarantee regulatory
acceptance of the regulatory safeguards measurements. It remains the sole responsibility of the user of this test method to ensure
that its application to safeguards has the approval of the proper regulatory authorities.
6. Apparatus
6.1 Neir Mass Spectrometer, with the following features and capabilities:
6.1.1 Asingle-focusing spectrometer, with a 127-mm minimum deflection radius, is satisfactory when equipped and focused as
follows:
6.1.1.1 The sample inlet system must have two sample holders, to which UF containers can be attached, and the necessary
valves to evacuate the sample lines through which the sample and standard are introduced. The sample inlet system should be
nickel or Monel for use with corrosive gases, and should have minimum volume.
6.1.1.2 A single adjustable leak, operated by an automatic leak control mechanism for admitting the sample into the
spectrometer ion source, is preferred.
−8
6.1.1.3 The pumping system of the spectrometer analyzer tube must maintain a pressure below 5 310 torr with sample
flowing into the ion source.
−10
6.1.1.4 Focus the instrument for resolution consistent with precision requirements. A high-current ion beam of 5 310 to
−9
1 310 amps is necessary, with a signal-to-noise ratio greater than 3000 in the low-current amplifier system.
6.1.1.5 A dual collector must be used, so that ions from one isotope are passed through a resolving slit and focused on a
low-currentcollector,andionsfromallotherisotopesarefocusedonahigh-currentcollector.Thepreferredmethodofmaintaining
thelow-currentionbeamwithinthecollectorslitisbyanautomaticbeampositionercircuit.Aresolvingslitwithadjustablewidth
features enhances the measurement of all isotopes but is not mandatory for isotopic measurements.
6.1.1.6 The amplified high- and low-current signals are fed into a multimeter or other device capable of ratioing high- and
low-current signals. If a multimeter is used, the multimeter must have a minimum of 5.5 digits of resolution, a means of ratioing
the high- and low-current signals, and interactive communication capability with the controller.
6.1.1.7 The memory effect of the spectrometer must be consistent with the precision required since a high memory level is
usuallymorevariablethanalowone.Memoryvaluesof2to3%aretypical,butupto10%memorycanbetolerated.Thememory
characteristicsofaspectrometermustbeestablishedfromperiodicmeasurementoftheeffect.Currentmemoryvaluesusuallywill
apply until the ion source is replaced, repairs are made on the sample inlet system, or the instrument is refocused so the flow rate
of UF is altered significantly.
6.1.1.8 The computer control of the mass spectrometer must allow the operator to monitor parameters of the spectrometer and
check other operating conditions. The development of an interactive program allows input of sample information, performs
necessary calculations, makes memory corrections, and records data. Flexibility of the interactive program allows pausing of the
instrument for adjustment or restart capability, or both. Suggested methods of analysis checks include the standard deviation (SD)
onindividualdatapoints,linearityofthedataset,andacheckofsourcepressuredifferencesbetweenthestandardandsamplethat
can be monitored by the computer program. Manifold valve actuation, conditioning time, and pump-out time are features of the
computer control program.
7. Hazards
7.1 Since UF is radioactive, toxic, and highly reactive, especially with reducing substances and moisture (see USEC-651),
appropriate facilities and practices for analysis must be provided.
8. Procedure
8.1 Calibration of Isotopic Standards :
8.1.1 One working standard is required for the analysis of a sample at any specific concentration of any isotope. Two working
standardsarerequiredtodeterminememorycorrections.Memorycanbemeasuredmorepreciselywithalargedifferencebetween
two working standards, but the adverse effect of introducing wide concentration ranges into the mass spectrometer must be
considered. Ideally, the values obtained from the high- and low-memory standards should symmetrically bracket those of the
sample to be corrected. Working standards approximately 5% apart (having a ratio of ratios of 1.05) are suitable for most
applications.
8.1.2 A reasonable limit for the relative e between the unknown sample and the working standard to which it is compared is
C 1344 – 97 (2008)
2.5%. A series of working standards prepared at 5% intervals and used for sample comparisons thus enables this 2.5% limit.
8.1.3 Prepare a working standard, and standardize against an oxide blend of CRM standards that is within 0.02% of the value
of the working standard.
8.2 Sample Preparation:
8.2.1 Attach tubes containing the appropriate working standard, S, and the sample, X, to the spectrometer inlet system, and
prepare the materials for introduction into the ion source, as follows:
8.2.1.1 If adequate sample and working stand
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