ASTM C1413-99
(Test Method)Standard Test Method for Isotopic Analysis of Hydrolyzed Uranium Hexafluoride and Uranyl Nitrate Solutions by Thermal Ionization Mass Spectrometry
Standard Test Method for Isotopic Analysis of Hydrolyzed Uranium Hexafluoride and Uranyl Nitrate Solutions by Thermal Ionization Mass Spectrometry
SCOPE
1.1 This method applies to the determinations of isotopic composition in hydrolyzed nuclear grade uranium hexafluoride. It covers isotopic abundance of 235U between 0.1 and 5.0% mass fraction, abundance of 234U between 0.0055 and 0.05% mass fraction, and abundance of 236U between 0.0003 and 0.5% mass fraction. This test method may be applicable to other isotopic abundance providing that corresponding standards are available.
1.2 This test method can apply to uranyl nitrate solutions. This can be achieved either by transforming the uranyl nitrate solution to a uranyl fluoride solution prior to the deposition on the filaments or directly by depositing the uranyl nitrate solution on the filaments. In the latter case, a calibration with uranyl nitrate standards must be performed.
1.3 This test method can also apply to other nuclear grade matrices (for example, uranium oxides) by providing a chemical transformation to uranyl fluoride or uranyl nitrate solution.
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 and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: C 1413 – 99
Standard Test Method for
Isotopic Analysis of Hydrolyzed Uranium Hexafluoride and
Uranyl Nitrate Solutions by Thermal Ionization Mass
Spectrometry
This standard is issued under the fixed designation C 1413; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope Spectrochemical, Nuclear, and Radiochemical Analysis of
Uranium Hexafluoride
1.1 This method applies to the determination of isotopic
C 776 Specification for Sintered Uranium Dioxide Pellets
composition in hydrolyzed nuclear grade uranium hexafluo-
C 787 Specification for Uranium Hexafluoride for Enrich-
ride. It covers isotopic abundance of U between 0.1 and
ment
5.0 % mass fraction, abundance of U between 0.0055 and
C 788 Specification for Nuclear–Grade Uranyl Nitrate So-
0.05 % mass fraction, and abundance of U between 0.0003
lution
and 0.5 % mass fraction.This test method may be applicable to
C 996 Specification for Uranium Hexafluoride Enriched to
other isotopic abundance providing that corresponding stan-
235 2
Less Than 5 % U
dards are available.
C 1334 Specification for Uranium Oxides with a U
1.2 This test method can apply to uranyl nitrate solutions.
Content Less Than 5 % for Dissolution Prior to Conver-
This can be achieved either by transforming the uranyl nitrate
sion to Nuclear–Grade Uranium Dioxide
solution to a uranyl fluoride solution prior to the deposition on
C 1346 Practice for Dissolution of UF from P–10 Tubes
the filaments or directly by depositing the uranyl nitrate
C 1347 PracticeforPreparationandDissolutionofUranium
solution on the filaments. In the latter case, a calibration with
Materials for Analysis
uranyl nitrate standards must be performed.
C 1348 Specification for Blended Uranium Oxides with a
1.3 This test method can also apply to other nuclear grade
U Content of Less Than 5 % for Direct Hydrogen
matrices (for example, uranium oxides) by providing a chemi-
Reduction to Nuclear–Grade Uranium Dioxide
cal transformation to uranyl fluoride or uranyl nitrate solution.
1.4 This standard does not purport to address all of the
3. Summary of Test Method
safety concerns, if any, associated with its use. It is the
3.1 After dilution of uranyl fluoride or uranyl nitrate solu-
responsibility of the user of this standard to establish appro-
tion, approximatively 2 µg of uranium are deposited on a
priate safety and health practices and determine the applica-
rheniumfilament.Analysisisperformedinathermalionization
bility of regulatory limitations prior to use.
mass spectrometer (TIMS), uranium is vaporized and ionized
2. Referenced Documents through electrons emitted by a second filament; ions are
extractedbyanelectricfield,separatedbyamagneticfield,and
2.1 ASTM Standards:
collected by four collectors on mass 234, 235, 236, 238. The
C 696 Test Methods for Chemical, Mass Spectrometric, and
collectors are either faraday cups or electron multipliers
Spectrochemical Analysis of Nuclear–Grade Uranium Di-
collectors (ion counting).
oxide Powders and Pellets
3.2 Evaporation sequence and ion counting time are ad-
C 753 Specification for Nuclear Grade, Sinterable Uranium
justed with the analysis of standard solutions of certified
Dioxide Powder
isotopic content. Nitrate and fluoride solutions lead to two
C 761 Test Methods for Chemical, Mass Spectrometric,
different calibrations.
4. Significance and Use
This test method is under the jurisdiction of ASTM Committee C–26 on
4.1 Uranium hexafluoride used to produce nuclear fuel must
Nuclear Fuel Cycle and is the direct responsibility of Subcommittee C26.05 on
meetcertaincriteriaforitsisotopiccompositionasdescribedin
Methods of Test.
Specifications C 787 and C 996.
Current edition approved Jan. 10, 1999. Published March 1999.
Annual Book of ASTM Standards, Vol 12.01.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C 1413
236 235
5. Interferences 7.4.1 UF of certified U, U isotopic composition,
such as COG 006, 008, 009, 010, 013, 014, 015.
5.1 This test method only applies to nuclear grade uranium
7.4.2 U O of certified isotopic composition, such as NBL
matrices (as defined in Specification C 753, C 776, C 787, 3 8
CRM U-010, U-020, U-030, U-050, CEA 014.
C 788, C 1334, or C 1348). Large amount of impurities, which
7.4.3 U O from reprocessed origin and of certified U
3 8
are found, for example, in uranium ore concentrates, may bias
composition, such as MIR 1.
results. A purification step may be necessary, as described in
7.5 Hydrofluoric Acid (0.05 M)—Dilute 173 µL of HF
Specification C 696.
solution (sp gr 1.18, 28.9 M) to 100 mL with water.
5.2 The type of acid used (HF or HNO ) and its concentra-
7.6 Nitric acid (0.1 M)—Dilute 0.6 mL of concentrated
tion will strongly influence the obtained isotopic results (see
HNO (sp gr 1.42, 16 M) to 100 mL with water.
9.2).
8. Preparation of Apparatus
6. Apparatus
8.1 Prepare the thermal ionization mass spectrometer in
6.1 Thermal Ionization Mass Spectrometer (TIMS)—
accordance with the manufacturer’s recommendations. A veri-
Configured with four detectors.
fication of collector yield and an optimisation of the ion beam
6.1.1 This test method requires a mass spectrometer with a
may be necessary on a daily basis. This can be achieved by
resolution greater than 400 (full width at 1 % of peak height)
heating the ionizing filament, locating the Re peak and
–5
and an abundance sensitivity of less than 10 (contribution of
focusing for maximum intensity. The Re signal is normally
mass 238 on the mass 237). A typical instrument would have
–11
above 0.1 to 0.2 3 10 A.
230 mm radius of curvature, single or double focussing, and
8.2 A verification of mass calibration is usually performed
single or multiple filament design. The pressure in the ioniza-
on a weekly basis in order to optimize the value for the
–6 –7
tion chamber should be below 3 3 10 torr (typically 10
magnetic field.
torr).
6.2 Preconditioning Unit for the TIMS—To dry filament
9. Calibration and Standardization
after deposition of uranyl solution.
9.1 Because of mass segregation during the evaporation of
6.3 Rhenium Filament Loading Assembly for the TIMS.In
uranium, it is necessary to adjust the ion acquisition time
this test method, a double filament set up is used.
program with the analysis of uranium standards. The number
6.4 Pipets—Automatic or equivalent, 1, 20, 50, and 100 µL.
of standards and the range covered will depend on the
6.5 Pipets Tips—In accordance with 6.4.
instrument used, the evaporation sequence, and the accuracy
6.6 Liquid Dispenser—2.5 mL.
which is required.
6.7 Disposable Polypropylene Vials.
9.1.1 Fortheanalysisof Uinthe0.1to5.0mass%range
and of U in the 0.0055 to 0.05 mass % range, four to seven
7. Reagents and Materials
standards should be used (see Table 1). For analysis of Uin
7.1 Purity of Materials—Reagent grade chemicals shall be
the 0.0003 to 0.5 mass % range, only two standards were used.
used in all tests. Unless otherwise indicated, it is intended that
9.2 Preparation of the standards—Separate calibrations are
all reagents conform to the specification of the Committee on
required for uranyl fluoride solutions and uranyl nitrate solu-
Analytical Reagents of the American Chemical Society where
tions.
such specifications are available. Other grades may be used
9.2.1 Uranyl Fluoride Calibration
provided it is first ascertained that the reagent is of sufficiently
9.2.1.1 UF Standards—Generalprinciplesforhydrolysisof
high priority to permit its use without lessening the accuracy of
UF are described in Test Methods C 761 and Practice C 1346.
the determination.
Hydrolysis should be done in pure water (no HNO added).
7.2 Purity of Water—Demineralized or distilled water is
Final concentration is for example 266 g uranium per litre
found acceptable for this uranium isotopic analysis.
(20 % mass U).
7.3 High Purity Rhenium Filaments (> 99.95 %), with
NOTE 1—Other concentrations may be used (for example, 10 % mass
geometricalcharacteristicsinaccordancewiththeTIMSmanu-
U),providedthatvolumesin10.2areadaptedtodepositthesameuranium
facturer’s recommendations (typically thickness is 0.04 mm
amount on the rhenium filament.
and width is 0.70 mm). Some equipment may accept tungsten
NOTE 2—2 µg of uranium are deposited on the filaments. In case of
filaments.
other filament geometries (see 7.3), other uranium amounts may be more
7.4 Isotopic Uranium Standards adapted (up to 10 µg U).
9.2.1.2 In a polypropylene vial, pour 2.5 mL of water and
add 20 µL of solution prepared in 9.2.1.1. Mix the vial content
byinvertingvigorouslytoobtainasolutioncontainingapproxi-
Areduced number of detectors may be used which will correspond to a reduced
mately 2
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