1、Designation: C1474 00 (Reapproved 2011)Standard Test Method forAnalysis of Isotopic Composition of Uranium in Nuclear-Grade Fuel Material by Quadrupole Inductively CoupledPlasma-Mass Spectrometry1This standard is issued under the fixed designation C1474; the number immediately following the designat
2、ion indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method is applicable to
3、the determination ofthe isotopic composition of uranium (U) in nuclear-grade fuelmaterial. The following isotopic weight percentages are deter-mined using a quadrupole inductively coupled plasma-massspectrometer (Q-ICP-MS):233U,234U,235U,236U, and238U.The analysis can be performed on various materia
4、l matricesafter acid dissolution and sample dilution into water or dilutenitric (HNO3) acid. These materials include: fuel product,uranium oxide, uranium oxide alloys, uranyl nitrate (UNH)crystals, and solutions. The sample preparation discussed inthis test method focuses on fuel product material bu
5、t may beused for uranium oxide or a uranium oxide alloy. Otherpreparation techniques may be used and some references aregiven. Purification of the uranium by anion-exchange extrac-tion is not required for this test method, as it is required byother test methods such as radiochemistry and thermal ion
6、iza-tion mass spectroscopy (TIMS). This test method is alsodescribed in ASTM STP 13442.1.2 The233U isotope is primarily measured as a qualitativemeasure of its presence by comparing the233U peak intensityto a background point since it is not normally found present inmaterials. The example data prese
7、nted in this test method donot contain any233U data.A233U enriched standard is given inSection 8, and it may be used as a quantitative spike additionto the other standard materials listed.1.3 A single standard calibration technique is used. Optimalaccuracy (or a low bias) is achieved through the use
8、 of a singlestandard that is closely matched to the enrichment of thesamples. The intensity or concentration is also adjusted towithin a certain tolerance range to provide good statisticalcounting precision for the low-abundance isotopes while main-taining a low bias for the high-abundance isotopes,
9、 resultingfrom high-intensity dead time effects. No blank subtraction orbackground correction is utilized. Depending upon the stan-dards chosen, enrichments between depleted and 97 % can bequantified. The calibration and measurements are made bymeasuring the intensity ratios of each low-abundance is
10、otopeto the intensity sum of233U,234U,235U,236U, and238U. Thehigh-abundance isotope is obtained by difference.1.4 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly. The instrument is calibrated and the samples measured inunits of
11、 isotopic weight percent (Wt %). For example, the235Uenrichment may be stated as Wt %235Uorasg235U/100 g ofU. Statements regarding dilutions, particularly for ug/g con-centrations or lower, are given assuming a solution density of1.0 since the uranium concentration of a solution is notimportant when
12、 making isotopic ratio measurements other thanto maintain a reasonably consistent intensity within a tolerancerange.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate
13、 safety and health practices and determine the applica-bility of regulatory limitations prior to use. Specific precau-tionary statements are given in Section 9.2. Referenced Documents2.1 ASTM Standards:3C753 Specification for Nuclear-Grade, Sinterable UraniumDioxide PowderC776 Specification for Sint
14、ered Uranium Dioxide PelletsC778 Specification for SandC833 Specification for Sintered (Uranium-Plutonium) Di-oxide PelletsC859 Terminology Relating to Nuclear MaterialsC1347 Practice for Preparation and Dissolution of UraniumMaterials for Analysis1This test method is under the jurisdiction ofASTM C
15、ommittee C26 on NuclearFuel Cycle and is the direct responsibility of Subcommittee C26.05 on Methods ofTest.Current edition approved June 1, 2011. Published June 2011. Originallyapproved in 2000. Last previous edition approved in 2006 as C1474 00(2006)e1.DOI: 10.1520/C1474-00R11.2Policke, T.A., Boli
16、n, R. N., and Harris, T. L., “Uranium Isotope Measurementsby Quqdrupole ICP-MS for Process Monitoring of Enrichment,” Symposium onApplications of Inductively Coupled Plasma-Mass Spectrometry to RadionuclideDeterminations: Second Volume, ASTM STP 1344, ASTM, 1998, p. 3.3For referenced ASTM standards,
17、 visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 194
18、28-2959, United States.D1193 Specification for Reagent WaterE135 Terminology Relating to Analytical Chemistry forMetals, Ores, and Related MaterialsE456 Terminology Relating to Quality and StatisticsE882 Guide for Accountability and Quality Control in theChemical Analysis Laboratory3. Terminology3.1
19、 Definitions:3.1.1 For definitions of terms relating to analytical atomicspectroscopy, refer to Terminology E135.3.1.2 For definitions of terms relating to statistics, refer toTerminology E456.3.1.3 For definitions of terms relating to nuclear materials,refer to Terminology C859.3.1.4 For definition
20、s of terms specifically related toQ-ICP-MS in addition to those found in 3.2, refer to Appendix3 of Jarvis et al.43.2 Definitions of Terms Specific to This Standard:3.2.1 dead time, nthe interval during which the detectorand its associated counting electronics are unable to recordanother event or re
21、solve successive pulses. The instrumentsignal response becomes nonlinear above a certain count ratedue to dead time effects.3.2.2 mass bias or fractionation, nthe deviation of theobserved or measured isotope ratio from the true ratio as afunction of the difference in mass between the two isotopes.Th
22、is deviation is the result of several different processes. It hasbeen suggested that the Q-ICP-MS ion transmission andfocusing device create a dense space charge effect, which cancause a preferential loss of lighter isotopes. The result is anunder estimation of the lighter isotopes which can be sign
23、ifi-cant.5“Rayleigh fractionation associated with sample evapo-ration in which lighter isotopes are carried away preferentially”is insignificant with solution nebulization, but with othermethods of introduction such as electrothermal vaporization,can be more significant.54. Summary of Test Method4.1
24、 A sample of the nuclear-grade material (nominally 0.2g) is digested in HNO3or a HNO3/HF mixture and diluted inseries to a concentration of approximately 0.10 ug of uraniumper gram of solution (ug U/g solution or ppm of U). Otherdissolution methods may be used. A standard peristaltic pumpis used as
25、the means of sample introduction into the plasma.The uranium intensity (that is, concentration), as initiallyindicated by a ratemeter reading, is adjusted to within a certaintolerance range to provide good precision and a reduced biasfor all sample, standard, and control measurements. A calibra-tion
26、 standard is run and all sample analyses are bracketed bythe analysis of controls. Calculations are performed to measurethe intensity ratios of each low-abundance isotope to theintensity sum of233U,234U,235U,236U, and238U. Mass biascorrection factors, which are established using the instrumentsoftwa
27、re and the calibration standard data, are then applied tothe sample and control data. The corrected ratio measurementfor a low abundance isotope is equal to the abundance of thatisotope (for example the234U intensity/U isotope intensity sumequals the234U abundance). The high abundance isotope isdete
28、rmined by subtracting the low-abundance isotopes from100 %.5. Significance and Use5.1 Nuclear-grade reactor fuel material must meet certaincriteria, such as those described in Specifications C753, C776,C778, and C833. Included in these criteria is the uraniumisotopic composition. This test method is
29、 designed to demon-strate whether or not a given material meets an isotopicrequirement and whether the effective fissile content is incompliance with the purchasers specifications.6. Interferences6.1 Adjacent Isotopic Peak EffectsInterferences can occurfrom adjacent isotopes of high concentration, s
30、uch as anintense235U peak interfering with the measurement of234Uand236U. This is particularly the case for instruments thatprovide only nominal unit mass resolution at 10 % of the peakheight. For this test method, the Q-ICP-MS peak resolutionfor235U was set to within 0.70 6 0.15 daltons (Atomic Mas
31、sUnits-AMU) full-width-tenth-maximum (FWTM) peak heightto reduce adjacent peak interference effects.6.2 Isobaric Molecular Ion Interferences235U could inter-fere with236U determinations by forming a UH+ion. Followthe instrument manufacturers instructions to minimize thesemolecular ion formations, fo
32、r example by optimizing thenebulizer gas flow rate. The use of a calibration standard thatis similar in isotopic composition and intensity to the samplesreduces the potential bias from this interference effect.The biasfrom the UH+interference only becomes significant for theintegrated peak intensity
33、 of236U when the sample intensitydeviates from the calibration standard intensity and it is verylow, that is, near the background intensity contribution. Anaturally enriched standard, which contains no236U, can beused to test the significance of this interference.6.3 Memory Interference EffectsMemor
34、y effects orsample carryover can occur from previously run samples.These effects can be detected in several ways. First of all, if thebias factors from the calibration standard are outside of anormal tended range, it can show that the glassware and uptakesystem is contaminated with another enrichmen
35、t. Secondly, itcan be detected by looking at the standard deviation of therepeat trials from a sample analysis and whether the peakintensity measurements are random between the repeat trials orwhether they drift toward increasing or decreasing intensity.Also, the percent standard deviation (% SD) of
36、 the intensityratios should be less than or on the same order of the % SD ofthe peak intensities. If the peak intensity measurements arehigher, then it may be an indication of a memory effect from asample of a different enrichment level. It could also be4Jarvis, K.E., Gray, A.L., and Houk, R.S., Han
37、dbook of Inductively CoupledPlasma Mass Spectrometry, Blackie and Son Ltd., Glasgow and London, orChapman and Hall, New York, 1992 .5Date,A. R., and Gray,A.L., Applications of Inductively Coupled Plasma MassSpectrometry, Blackie and Son Ltd., Glasgow and London, or Chapman and Hall,New York, 1989.C1
38、474 00 (2011)2indicative of general instrument instability or problems withsample uptake and delivery to the plasma.7. Apparatus7.1 Balance, with precision of 0.00001 g.7.2 Polytetrafluoroethylene (PTFE) Oak Ridge Tubes6,30mL, or equivalent.7.3 Drying Oven, controlled at 108 6 5C.7.4 Polypropylene S
39、ample Bottle, 125 mL, or equivalent.7.5 Disposable Polypropylene Tubes With Snap-on Caps6,14 mL, or equivalent.7.6 Q-ICP-MS Instrument, controlled by computer andfitted with the associated software and peripherals.7.7 Peristaltic Pump.8. Reagents and Materials8.1 Purity of ReagentsReagent grade chem
40、icals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents conform to the specifications of the Committee onAnalytical Reagents of the American Chemical Society wheresuch specifications are available.7Other grades may be usedprovided it is first ascertained that the
41、 reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.8.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water, as definedby Type I of Specification D1193.8.3 Hydrofluoric Acid (sp gr 1.18)49 % w
42、/w concentratedhydrofluoric acid (HF).8.4 Isotopic Calibration Standard, 0.10 ug of U per g ofsolutionAdd 100 uL of the appropriate isotopic calibrationstandard secondary stock solution (see 8.7) to a 125-mLpolypropylene sample bottle, and dilute to approximately 84.7g with water.8.5 Isotopic Contro
43、l Standard, 0.10 ug of U per g ofsolutionAdd 100 uL of the appropriate isotopic controlstandard secondary stock solution (see 8.7) to a 125-mLpolypropylene sample bottle, and dilute to approximately 84.7g with water.NOTE 1The concentration of the calibration and control standardsolutions are adjuste
44、d or remade for a given sample batch analysis toachieve a maximum established uranium intensity measurement. Refer to13.1.5 for directions on how this intensity level of the uranium isotopesum is determined. The intensity sum was established at 2.0 6 0.2 millioncounts per second (cps) for the data p
45、resented. The sensitivity, andtherefore this concentration, is dependent upon the users own instrumen-tation. The 2.0-million cps intensity level is established based on an upperintensity level at which the instrument continues to operate in a linearintensity versus concentration range, and is there
46、fore also instrumentdependent. Intensity levels above this range can become nonlinear as afunction of concentration due to dead time effects.8.6 Isotopic Enrichment Standard Primary Stock Solutions,5000 ug of U3O8per g of solution (4235 ug of U per g ofsolution)0.250 g of the appropriate NBL U3O8iso
47、topicstandard heated to dissolve with 5 mL of water and 10 mL ofconcentrated HNO3, then diluted to 50.0 g of water in a125-mL polypropylene sample bottle.8.7 Isotopic Enrichment Standard Secondary Stock Solu-tions, 84.7 ug of U per g of solutionAdd 2.0 mL of theappropriate isotopic enrichment standa
48、rd primary stock solu-tion (see 8.6) to a 125-mL polypropylene sample bottle, add 5mL of concentrated HNO3, then dilute to 100.0 g with water.NOTE 2The isotopic calibration standard and analysis control mate-rials should be within 1.0 Wt % of the235U enrichment to be analyzed inunknown sample materi
49、als. Likewise, the low-abundance isotopes (234Uand236U) should be in close agreement between standards and samples. Itis recommended that separate primary and secondary stock solutions bemade from a separate and preferably an independent source of isotopicenrichment standard (to serve as standard and control stock solutions) ifsuch a source can be found. However, given the limited availability ofsuch standards, the primary and secondary stock solutions may be madefrom the same enrichment CRM, with separate dissolutions and bottlesbeing designated as standard and co
