ASTM C1474-00(2011)
(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
SIGNIFICANCE AND USE
Nuclear-grade reactor fuel material must meet certain criteria, such as those described in Specifications C 753, C 776, C 778, and C 833. Included in these criteria is the uranium isotopic composition. This test method is designed to demonstrate whether or not a given material meets an isotopic requirement and whether the effective fissile content is in compliance with the purchaser’specifications.
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 8, 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.
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 precautionary statements are given in Section 9.
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: C1474 − 00 (Reapproved 2011)
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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope countingprecisionforthelow-abundanceisotopeswhilemain-
taining a low bias for the high-abundance isotopes, resulting
1.1 This test method is applicable to the determination of
from high-intensity dead time effects. No blank subtraction or
the isotopic composition of uranium (U) in nuclear-grade fuel
background correction is utilized. Depending upon the stan-
material. The following isotopic weight percentages are deter-
dards chosen, enrichments between depleted and 97% can be
mined using a quadrupole inductively coupled plasma-mass
233 234 235 236 238 quantified. The calibration and measurements are made by
spectrometer (Q-ICP-MS): U, U, U, U, and U.
measuring the intensity ratios of each low-abundance isotope
The analysis can be performed on various material matrices
233 234 235 236 238
to the intensity sum of U, U, U, U, and U. The
after acid dissolution and sample dilution into water or dilute
high-abundance isotope is obtained by difference.
nitric (HNO ) acid. These materials include: fuel product,
uranium oxide, uranium oxide alloys, uranyl nitrate (UNH) 1.4 The values stated in SI units are to be regarded as the
crystals, and solutions. The sample preparation discussed in standard. The values given in parentheses are for information
this test method focuses on fuel product material but may be only.Theinstrumentiscalibratedandthesamplesmeasuredin
used for uranium oxide or a uranium oxide alloy. Other unitsofisotopicweightpercent(Wt%).Forexample,the U
235 235
preparation techniques may be used and some references are enrichment may be stated as Wt% Uorasg U/100 g of
given. Purification of the uranium by anion-exchange extrac- U. Statements regarding dilutions, particularly for ug/g con-
tion is not required for this test method, as it is required by centrations or lower, are given assuming a solution density of
other test methods such as radiochemistry and thermal ioniza- 1.0 since the uranium concentration of a solution is not
tion mass spectroscopy (TIMS). This test method is also importantwhenmakingisotopicratiomeasurementsotherthan
described in ASTM STP 1344 . tomaintainareasonablyconsistentintensitywithinatolerance
233 range.
1.2 The U isotope is primarily measured as a qualitative
1.5 This standard does not purport to address all of the
measure of its presence by comparing the U peak intensity
safety concerns, if any, associated with its use. It is the
to a background point since it is not normally found present in
responsibility of the user of this standard to establish appro-
materials. The example data presented in this test method do
233 233
priate safety and health practices and determine the applica-
notcontainany Udata.A Uenrichedstandardisgivenin
bility of regulatory limitations prior to use. Specific precau-
Section 8, and it may be used as a quantitative spike addition
tionary statements are given in Section 9.
to the other standard materials listed.
1.6 This international standard was developed in accor-
1.3 Asingle standard calibration technique is used. Optimal
dance with internationally recognized principles on standard-
accuracy(oralowbias)isachievedthroughtheuseofasingle
ization established in the Decision on Principles for the
standard that is closely matched to the enrichment of the
Development of International Standards, Guides and Recom-
samples. The intensity or concentration is also adjusted to
mendations issued by the World Trade Organization Technical
within a certain tolerance range to provide good statistical
Barriers to Trade (TBT) Committee.
ThistestmethodisunderthejurisdictionofASTMCommitteeC26onNuclear
2. Referenced Documents
Fuel Cycle and is the direct responsibility of Subcommittee C26.05 on Methods of
2.1 ASTM Standards:
Test.
Current edition approved June 1, 2011. Published June 2011. Originally
ε1
approved in 2000. Last previous edition approved in 2006 as C1474–00(2006) .
DOI: 10.1520/C1474-00R11.
2 3
Policke,T.A.,Bolin,R.N.,andHarris,T.L.,“UraniumIsotopeMeasurements For referenced ASTM standards, visit the ASTM website, www.astm.org, or
by Quqdrupole ICP-MS for Process Monitoring of Enrichment,” Symposium on contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Applications of Inductively Coupled Plasma-Mass Spectrometry to Radionuclide Standards volume information, refer to the standard’s Document Summary page on
Determinations: Second Volume, ASTM STP 1344, ASTM, 1998, p. 3. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1474 − 00 (Reapproved 2011)
C753Specification for Nuclear-Grade, Sinterable Uranium per gram of solution (ug U/g solution or ppm of U). Other
Dioxide Powder dissolution methods may be used.Astandard peristaltic pump
C776Specification for Sintered Uranium Dioxide Pellets is used as the means of sample introduction into the plasma.
C778Specification for Standard Sand The uranium intensity (that is, concentration), as initially
C833Specification for Sintered (Uranium-Plutonium) Diox- indicatedbyaratemeterreading,isadjustedtowithinacertain
ide Pellets for Light Water Reactors tolerance range to provide good precision and a reduced bias
C859Terminology Relating to Nuclear Materials for all sample, standard, and control measurements.Acalibra-
C1347Practice for Preparation and Dissolution of Uranium tion standard is run and all sample analyses are bracketed by
Materials for Analysis theanalysisofcontrols.Calculationsareperformedtomeasure
D1193Specification for Reagent Water the intensity ratios of each low-abundance isotope to the
233 234 235 236 238
E135Terminology Relating to Analytical Chemistry for intensity sum of U, U, U, U, and U. Mass bias
Metals, Ores, and Related Materials correction factors, which are established using the instrument
E456Terminology Relating to Quality and Statistics software and the calibration standard data, are then applied to
E882Guide for Accountability and Quality Control in the the sample and control data. The corrected ratio measurement
Chemical Analysis Laboratory for a low abundance isotope is equal to the abundance of that
isotope(forexamplethe Uintensity/Uisotopeintensitysum
3. Terminology
equals the U abundance). The high abundance isotope is
determined by subtracting the low-abundance isotopes from
3.1 Definitions:
100%.
3.1.1 For definitions of terms relating to analytical atomic
spectroscopy, refer to Terminology E135.
5. Significance and Use
3.1.2 For definitions of terms relating to statistics, refer to
5.1 Nuclear-grade reactor fuel material must meet certain
Terminology E456.
criteria, such as those described in Specifications C753, C776,
3.1.3 For definitions of terms relating to nuclear materials,
C778, and C833. Included in these criteria is the uranium
refer to Terminology C859.
isotopic composition. This test method is designed to demon-
3.1.4 For definitions of terms specifically related to
strate whether or not a given material meets an isotopic
Q-ICP-MS in addition to those found in 3.2, refer toAppendix
requirement and whether the effective fissile content is in
3 of Jarvis et al.
compliance with the purchaser’s specifications.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 dead time, n—the interval during which the detector
6. Interferences
and its associated counting electronics are unable to record
6.1 Adjacent Isotopic Peak Effects—Interferences can occur
another event or resolve successive pulses. The instrument
from adjacent isotopes of high concentration, such as an
signal response becomes nonlinear above a certain count rate
235 234
intense U peak interfering with the measurement of U
due to dead time effects.
and U. This is particularly the case for instruments that
3.2.2 mass bias or fractionation, n—the deviation of the
provide only nominal unit mass resolution at 10% of the peak
observed or measured isotope ratio from the true ratio as a
height. For this test method, the Q-ICP-MS peak resolution
function of the difference in mass between the two isotopes. 235
for U was set to within 0.70 6 0.15 daltons (Atomic Mass
Thisdeviationistheresultofseveraldifferentprocesses.Ithas
Units-AMU) full-width-tenth-maximum (FWTM) peak height
been suggested that the Q-ICP-MS ion transmission and
to reduce adjacent peak interference effects.
focusing device create a dense space charge effect, which can
6.2 Isobaric Molecular Ion Interferences— U could inter-
cause a preferential loss of lighter isotopes. The result is an
236 +
fere with U determinations by forming a UH ion. Follow
under estimation of the lighter isotopes which can be signifi-
5 the instrument manufacturer’s instructions to minimize these
cant. “Rayleigh fractionation associated with sample evapo-
molecular ion formations, for example by optimizing the
rationinwhichlighterisotopesarecarriedawaypreferentially”
nebulizer gas flow rate. The use of a calibration standard that
is insignificant with solution nebulization, but with other
is similar in isotopic composition and intensity to the samples
methods of introduction such as electrothermal vaporization,
5 reducesthepotentialbiasfromthisinterferenceeffect.Thebias
can be more significant.
+
from the UH interference only becomes significant for the
integrated peak intensity of U when the sample intensity
4. Summary of Test Method
deviates from the calibration standard intensity and it is very
4.1 A sample of the nuclear-grade material (nominally 0.2
low, that is, near the background intensity contribution. A
g) is digested in HNO or a HNO /HF mixture and diluted in
3 3
naturally enriched standard, which contains no U, can be
series to a concentration of approximately 0.10 ug of uranium
used to test the significance of this interference.
6.3 Memory Interference Effects—Memory effects or
sample carryover can occur from previously run samples.
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
Theseeffectscanbedetectedinseveralways.Firstofall,ifthe
Chapman and Hall, New York, 1992 .
bias factors from the calibration standard are outside of a
Date,A. R., and Gray,A.L., Applications of Inductively Coupled Plasma Mass
normaltendedrange,itcanshowthattheglasswareanduptake
Spectrometry, Blackie and Son Ltd., Glasgow and London, or Chapman and Hall,
NewYork, 1989. system is contaminated with another enrichment. Secondly, it
C1474 − 00 (Reapproved 2011)
can be detected by looking at the standard deviation of the standard secondary stock solution (see 8.7) to a 125-mL
repeat trials from a sample analysis and whether the peak polypropylene sample bottle, and dilute to approximately 84.7
intensitymeasurementsarerandombetweentherepeattrialsor g with water.
whether they drift toward increasing or decreasing intensity.
NOTE 1—The concentration of the calibration and control standard
Also, the percent standard deviation (% SD) of the intensity
solutions are adjusted or remade for a given sample batch analysis to
ratios should be less than or on the same order of the % SD of
achieve a maximum established uranium intensity measurement. Refer to
the peak intensities. If the peak intensity measurements are 13.1.5 for directions on how this intensity level of the uranium isotope
sumisdetermined.Theintensitysumwasestablishedat2.0 60.2million
higher, then it may be an indication of a memory effect from a
counts per second (cps) for the data presented. The sensitivity, and
sample of a different enrichment level. It could also be
therefore this concentration, is dependent upon the user’s own instrumen-
indicative of general instrument instability or problems with
tation.The2.0-millioncpsintensitylevelisestablishedbasedonanupper
sample uptake and delivery to the plasma.
intensity level at which the instrument continues to operate in a linear
intensity versus concentration range, and is therefore also instrument
dependent. Intensity levels above this range can become nonlinear as a
7. Apparatus
function of concentration due to dead time effects.
7.1 Balance, with precision of 0.00001 g.
8.6 Isotopic Enrichment Standard Primary Stock Solutions,
7.2 Polytetrafluoroethylene (PTFE) Oak Ridge Tubes,30
5000 ug of U O per g of solution (4235 ug of U per g of
3 8
mL, or equivalent.
solution)—0.250 g of the appropriate NBL U O isotopic
3 8
standard heated to dissolve with 5 mL of water and 10 mL of
7.3 Drying Oven, controlled at 108 6 5°C.
concentrated HNO , then diluted to 50.0 g of water in a
7.4 Polypropylene Sample Bottle, 125 mL, or equivalent.
125-mL polypropylene sample bottle.
7.5 Disposable Polypropylene Tubes With Snap-on Caps ,
8.7 Isotopic Enrichment Standard Secondary Stock
14 mL, or equivalent.
Solutions, 84.7 ug of U per g of solution—Add 2.0 mL of the
7.6 Q-ICP-MS Instrument, controlled by computer and
appropriate isotopic enrichment standard primary stock solu-
fitted with the associated software and peripherals.
tion (see 8.6) to a 125-mLpolypropylene sample bottle, add 5
mL of concentrated HNO , then dilute to 100.0 g with water.
7.7 Peristaltic Pump. 3
NOTE 2—The isotopic calibration standard and analysis control mate-
8. Reagents and Materials
rials should be within 1.0 Wt % of the U enrichment to be analyzed in
unknown sample materials. Likewise, the low-abundance isotopes ( U
8.1 Purity of Reagents—Reagent grade chemicals shall be 236
and U)shouldbeincloseagreementbetweenstandardsandsamples.It
used in all tests. Unless otherwise indicated, it is intended that
is recommended that separate primary and secondary stock solutions be
all reagents conform to the specifications of the Committee on made from a separate and preferably an independent source of isotopic
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 specifications are available. Other grades may be used
such standards, the primary and secondary stock solutions may be made
provided it is first ascertained that th
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