ASTM C1474-00
(Test Method)Standard Test Method for Analysis of Isotopic Composition of Uranium in Nuclear-Grade Fuel Material by Quadrupole Inductively Coupled Plasma-Mass Spectrometry
Standard Test Method for Analysis of Isotopic Composition of Uranium in Nuclear-Grade Fuel Material by Quadrupole Inductively Coupled Plasma-Mass Spectrometry
SCOPE
1.1 This test method is applicable to the determination of the isotopic composition of uranium (U) in nuclear-grade fuel material. The following isotopic weight percentages are determined using a quadrupole inductively coupled plasma-mass spectrometer (Q-ICP-MS): 233U, 234U, 235U, 236U, and 238U. The analysis can be performed on various material matrices after acid dissolution and sample dilution into water or dilute nitric (HNO3) acid. These materials include: fuel product, uranium oxide, uranium oxide alloys, uranyl nitrate (UNH) crystals, and solutions. The sample preparation discussed in this test method focuses on fuel product material but may be used for uranium oxide or a uranium oxide alloy. Other preparation techniques may be used and some references are given. Purification of the uranium by anion-exchange extraction is not required for this test method, as it is required by other test methods such as radiochemistry and thermal ionization mass spectroscopy (TIMS). This test method is also described in ASTM STP 1344.
1.2 The 233U isotope is primarily measured as a qualitative measure of its presence by comparing the 233U peak intensity to a background point since it is not normally found present in materials. The example data presented in this test method do not contain any 233U data. A 233U enriched standard is given in Section , and it may be used as a quantitative spike addition to the other standard materials listed.
1.3 A single standard calibration technique is used. Optimal accuracy (or a low bias) is achieved through the use of a single standard that is closely matched to the enrichment of the samples. The intensity or concentration is also adjusted to within a certain tolerance range to provide good statistical counting precision for the low-abundance isotopes while maintaining a low bias for the high-abundance isotopes, resulting from high-intensity dead time effects. No blank subtraction or background correction is utilized. Depending upon the standards chosen, enrichments between depleted and 97 % can be quantified. The calibration and measurements are made by measuring the intensity ratios of each low-abundance isotope to the intensity sum of 233U, 234U, 235U, 236U, and 238U. The high-abundance isotope is obtained by difference.
1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. The instrument is calibrated and the samples measured in units of isotopic weight percent (Wt %). For example, the 235U enrichment may be stated as Wt % 235U or as g 235U/100 g of U. Statements regarding dilutions, particularly for ug/g concentrations or lower, are given assuming a solution density of 1.0 since the uranium concentration of a solution is not important when making isotopic ratio measurements other than to maintain a reasonably consistent intensity within a tolerance range.
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 precautionary statements are given in Section 9.
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Designation: C 1474 – 00
Standard Test Method for
Analysis of Isotopic Composition of Uranium in Nuclear-
Grade Fuel Material by Quadrupole Inductively Coupled
Plasma-Mass Spectrometry
This standard is issued under the fixed designation C1474; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope from high-intensity dead time effects. No blank subtraction or
background correction is utilized. Depending upon the stan-
1.1 This test method is applicable to the determination of
dards chosen, enrichments between depleted and 97% can be
the isotopic composition of uranium (U) in nuclear-grade fuel
quantified. The calibration and measurements are made by
material. The following isotopic weight percentages are deter-
measuring the intensity ratios of each low-abundance isotope
mined using a quadrupole inductively coupled plasma-mass
233 234 235 236 238
233 234 235 236 238
to the intensity sum of U, U, U, U, and U. The
spectrometer (Q-ICP-MS): U, U, U, U, and U.
high-abundance isotope is obtained by difference.
The analysis can be performed on various material matrices
1.4 The values stated in SI units are to be regarded as the
after acid dissolution and sample dilution into water or dilute
standard. The values given in parentheses are for information
nitric (HNO ) acid. These materials include: fuel product,
only.Theinstrumentiscalibratedandthesamplesmeasuredin
uranium oxide, uranium oxide alloys, uranyl nitrate (UNH)
unitsofisotopicweightpercent(Wt%).Forexample,the U
crystals, and solutions. The sample preparation discussed in
235 235
enrichment may be stated as Wt% Uorasg U/100 g of
this test method focuses on fuel product material but may be
U. Statements regarding dilutions, particularly for ug/g con-
used for uranium oxide or a uranium oxide alloy. Other
centrations or lower, are given assuming a solution density of
preparation techniques may be used and some references are
1.0 since the uranium concentration of a solution is not
given. Purification of the uranium by anion-exchange extrac-
importantwhenmakingisotopicratiomeasurementsotherthan
tion is not required for this test method, as it is required by
tomaintainareasonablyconsistentintensitywithinatolerance
other test methods such as radiochemistry and thermal ioniza-
range.
tion mass spectroscopy (TIMS). This test method is also
1.5 This standard does not purport to address all of the
described in ASTM STP 1344 .
safety concerns, if any, associated with its use. It is the
1.2 The U isotope is primarily measured as a qualitative
responsibility of the user of this standard to establish appro-
measure of its presence by comparing the U peak intensity
priate safety and health practices and determine the applica-
to a background point since it is not normally found present in
bility of regulatory limitations prior to use. Specific precau-
materials. The example data presented in this test method do
233 233
tionary statements are given in Section 9.
notcontainany Udata.A Uenrichedstandardisgivenin
Section 8, and it may be used as a quantitative spike addition
2. Referenced Documents
to the other standard materials listed.
2.1 ASTM Standards:
1.3 Asingle standard calibration technique is used. Optimal
C753 Specification for Nuclear-Grade, Sinterable Uranium
accuracy(oralowbias)isachievedthroughtheuseofasingle
Dioxide Powder
standard that is closely matched to the enrichment of the
C776 Specification for Sintered Uranium Dioxide Pellets
samples. The intensity or concentration is also adjusted to
C788 Specification for Nuclear-Grade Uranyl Nitrate So-
within a certain tolerance range to provide good statistical
lution
countingprecisionforthelow-abundanceisotopeswhilemain-
C833 Specification for Sintered (Uranium-Plutonium) Di-
taining a low bias for the high-abundance isotopes, resulting
oxide Pellets
C859 Terminology Relating to Nuclear Materials
C1347 PracticeforPreparationandDissolutionofUranium
ThistestmethodisunderthejurisdictionofASTMCommitteeC26onNuclear
Materials for Analysis
Fuel Cycle and is the direct responsibility of Subcommittee C26.05 on Methods of 4
D1193 Specification for Reagent Water
Test.
Current edition approved June 10, 2000. Published August 2000.
Policke,T.A.,Bolin,R.N.,andHarris,T.L.,“UraniumIsotopeMeasurements
by Quqdrupole ICP-MS for Process Monitoring of Enrichment,” Symposium on
Applications of Inductively Coupled Plasma-Mass Spectrometry to Radionuclide Annual Book of ASTM Standards, Vol 12.01.
Determinations: Second Volume, ASTM STP 1344, ASTM, 1998, p. 3. Annual Book of ASTM Standards, Vol 11.01.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C 1474
E135 Terminology Relating to Analytical Chemistry for theanalysisofcontrols.Calculationsareperformedtomeasure
Metals, Ores, and Related Materials the intensity ratios of each low-abundance isotope to the
233 234 235 236 238
E456 Terminology Relating to Quality and Statistics intensity sum of U, U, U, U, and U. Mass bias
E882 Guide for Accountability and Quality Control in the correction factors, which are established using the instrument
Chemical Analysis Laboratory software and the calibration standard data, are then applied to
the sample and control data. The corrected ratio measurement
3. Terminology
for a low abundance isotope is equal to the abundance of that
isotope(forexamplethe Uintensity/Uisotopeintensitysum
3.1 Definitions:
equals the U abundance). The high abundance isotope is
3.1.1 For definitions of terms relating to analytical atomic
determined by subtracting the low-abundance isotopes from
spectroscopy, refer to Terminology E135.
100%.
3.1.2 For definitions of terms relating to statistics, refer to
Terminology E456.
5. Significance and Use
3.1.3 For definitions of terms relating to nuclear materials,
5.1 Nuclear-grade reactor fuel material must meet certain
refer to Terminology C859.
criteria,suchasthosedescribedinSpecificationsC753,C776,
3.1.4 For definitions of terms specifically related to
C788, and C833. Included in these criteria is the uranium
Q-IPC-MS in addition to those found in 3.2, refer toAppendix
isotopic composition. This test method is designed to demon-
3 of Jarvis et al.
strate whether or not a given material meets an isotopic
3.2 Definitions of Terms Specific to This Standard:
requirement and whether the effective fissile content is in
3.2.1 dead time, n—the interval during which the detector
compliance with the purchaser’s specifications.
and its associated counting electronics are unable to record
another event or resolve successive pulses. The instrument
6. Interferences
signal response becomes nonlinear above a certain count rate
6.1 Adjacent Isotopic Peak Effects—Interferencescanoccur
due to dead time effects.
from adjacent isotopes of high concentration, such as an
3.2.2 mass bias or fractionation, n—the deviation of the
235 234
intense U peak interfering with the measurement of U
observed or measured isotope ratio from the true ratio as a
and U. This is particularly the case for instruments that
function of the difference in mass between the two isotopes.
provide only nominal unit mass resolution at 10% of the peak
Thisdeviationistheresultofseveraldifferentprocesses.Ithas
height.Forthistestmethod,theQ-ICP-MSpeakresolutionfor
been suggested that the Q-ICP-MS ion transmission and
235U was set to within 0.70 6 0.15 daltons (Atomic Mass
focusing device create a dense space charge effect, which can
Units-AMU) fill-width-tenth-maximum (FWTM) peak height
cause a preferential loss of lighter isotopes. The result is an
to reduce adjacent peak interference effects.
under estimation of the lighter isotopes which can be signifi-
9 6.2 Isobaric Molecular Ion Interferences— Ucouldinter-
cant. “Rayleigh fractionation associated with sample evapo-
fere with U determinations by forming a UH + ion. Follow
rationinwhichlighterisotopesarecarriedawaypreferentially”
the instrument manufacturer’s instructions to minimize these
is insignificant with solution nebulization, but with other
molecular ion formations, for example by optimizing the
methods of introduction such as electrothermal vaporization,
9 nebulizer gas flow rate. The use of a calibration standard that
can be more significant.
is similar in isotopic composition and intensity to the samples
reducesthepotentialbiasfromthisinterferenceeffect.Thebias
4. Summary of Test Method
+
from the UH interference only becomes significant for the
4.1 A sample of the nuclear-grade material (nominally 0.2
integrated peak intensity of U when the sample intensity
g) is digested in HNO or a HNO /HF mixture and diluted in
3 3
deviates from the calibration standard intensity and it is very
series to a concentration of approximately 0.10 ug of uranium
low, that is, near the background intensity contribution. A
per gram of solution (ug U/g solution or ppm of U). Other
naturally enriched standard, which contains no U, can be
dissolution methods may be used.Astandard peristaltic pump
used to test the significance of this interference.
is used as the means of sample introduction into the plasma.
6.3 Memory Interference Effects—Memory effects or
The uranium intensity (that is, concentration), as initially
sample carryover can occur from previously run samples.
indicatedbyaratemeterreading,isadjustedtowithinacertain
Theseeffectscanbedetectedinseveralways.Firstofall,ifthe
tolerance range to provide good precision and a reduced bias
bias factors from the calibration standard are outside of a
for all sample, standard, and control measurements.Acalibra-
normaltendedrange,itcanshowthattheglasswareanduptake
tion standard is run and all sample analyses are bracketed by
system is contaminated with another enrichment. Secondly, it
can be detected by looking at the standard deviation of the
repeat trials from a sample analysis and whether the peak
Annual Book of ASTM Standards, Vol 03.05
intensitymeasurementsarerandombetweentherepeattrialsor
Annual Book of ASTM Standards, Vol 14.02.
7 whether they drift toward increasing or decreasing intensity.
Annual Book of ASTM Standards, Vol 03.06.
Also, the percent standard deviation (% SD) of the intensity
Jarvis, K.E., Gray, A.L., and Houk, R.S., Handbook of Inductively Coupled
Plasma Mass Spectrometry, Blackie and Son Ltd., Glasgow and London, or
ratios should be less than or on the same order of the % SD of
Chapman and Hall, New York, 1992.
the peak intensities. If the peak intensity measurements are
Date,A.R., and Gray,A.L., Applications of Inductively Coupled Plasma Mass
higher, then it may be an indication of a memory effect from a
Spectrometry, Blackie and Son Ltd., Glasgow and London, or Chapman and Hall,
New York, 1989. sample of a different enrichment level. It could also be
C 1474
dependent. Intensity levels above this range can become nonlinear as a
indicative of general instrument instability or problems with
function of concentration due to dead time effects.
sample uptake and delivery to the plasma.
8.6 Isotopic Enrichment Standard Primary Stock Solutions,
7. Apparatus
5000 ug of U O per g of solution (4235 ug of U per g of
3 8
solution)—0.250 g of the appropriate NBL U O isotopic
7.1 Balance, with precision of 0.00001 g. 3 8
standard heated to dissolution with 5 mL of water and 10 mL
7.2 Polytetrafluoroethylene (PTFE) Oak Ridge Tubes ,30
of concentrated HNO , then diluted to 50.0 g of water in a
mL, or equivalent. 3
125-mL polypropylene sample bottle.
7.3 Drying Oven, controlled at 108 6 5°C.
8.7 Isotopic Enrichment Standard Secondary Stock Solu-
7.4 Polypropylene Sample Bottle, 125 mL, or equivalent.
tions, 84.7 ug of U per g of solution—Add 2.0 mL of the
7.5 Disposable Polypropylene Tubes With Snap-on Caps ,
appropriate isotopic enrichment standard primary stock solu-
14 mL, or equivalent.
tion (see 8.6) to a 125-mLpolypropylene sample bottle, add 5
7.6 Q-ICP-MS Instrument, controlled by computer and
mL of concentrated HNO , then dilute to 100.0 g with water.
fitted with the associated software and peripherals. 3
7.7 Peristaltic Pump.
NOTE 2—The isotopic calibration standard and analysis control mate-
rials should be within 1.0 Wt % of the U enrichment to be analyzed in
8. Reagents and Materials unknown sample materials. Likewise, the low-abundance isotopes ( U
and U) should be in close agreement between standards and samples. It
8.1 Purity of Reagents—Reagent grade chemicals shall be
is recommended that separate primary and secondary stock solutions be
used in all tests. Unless otherwise indicated, it is intended that
made from a separate and preferably an independent source of isotopic
all reagents conform to the specifications of the Committee on
enrichment standard (to serve as standard and control stock solutions) if
Analytical Reagents of theAmerican Chemical Society where such a source can be found. However, given the limited availability of
such standards, the primary and secondary stock solutions may be made
such specifications are available. Other grades may be used
from the same enrichment CRM, with separate dissolutions and bottles
provided it is first ascertained that the reagent is of sufficiently
being designated as standard and control stock solutions.
high purity to permit its use without lessening the accuracy of
8.8 Isotopic Enrichment U O Standards—New Brunswick
the determination.
3 8
8.2 Purity of Water—Unlessotherwiseindicated,references Laboratory (NBL) Certified Reference Materials (CRMs),
dependingontheenrichmentleveltobeanalyzed:forexample,
to water shall be understood to mean reagent water, as defined
by Type I of Specification D1193. CRM U-010, CRM U-030, CRM U-030A, CRM U-050, CRM
U-200, CRM U-350, CRM U-500, CRM U-750, CRM U-850,
8.3 Hydrofluoric Acid(spgr1.18)—49%w/wconcentrated
hydrofluoric acid (HF). CRM U-900, CRM U-930, and CRM U-970.
8.9 Nitric Acid (sp gr 1.42)—70% w/w concentrated nitric
8.4 Isotopic Calibration Standard, 0.10 ug of U per g of
solution—Add 100 uL of the appropriate isotopic calibration acid (HNO ).
8.10 U Isotopic Enrichment Spike Standard—NewBrun-
standard secondary stock solution (see 8.7) to a 125-mL
polypropylene sample bottle, and dilute to approximately 84.7 swick Laboratory (NBL) CRM 111A, used as a spike addition.
This standard is listed for optional use by the user as a spike
g with water.
8.5 Isotopic Control Standard, 0.10 ug of U per g of addition to the ot
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