1、Designation: C1474 19Standard 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 designation indicates the
2、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 the determination
3、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 material matricesafter ac
4、id 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 but may beused for u
5、ranium 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 ioniza-tion mass spec
6、troscopy (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 presented in this test
7、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 of a singlestanda
8、rd 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, resultingfrom hig
9、h-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 isotopeto the intens
10、ity 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 isotopic weight p
11、ercent (Wt %). For example, the235Uenrichment may be stated as Wt %235Uorasg235U/100 g ofU. Statements regarding dilutions, particularly for g/g con-centrations or lower, are given assuming a solution density of1.0 since the uranium concentration of a solution is notimportant when making isotopic ra
12、tio 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 safety, health, an
13、d environmental practices and deter-mine the applicability of regulatory limitations prior to use.Specific precautionary statements are given in Section 9.1.6 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the De
14、cision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:31This test method is under the jurisdiction ofASTM Committee C26 on NuclearFuel
15、 Cycle and is the direct responsibility of Subcommittee C26.05 on Methods ofTest.Current edition approved Feb. 1, 2019. Published February 2019. Originallyapproved in 2000. Last previous edition approved in 2011 as C1474 00 (2011).DOI: 10.1520/C1474-19.2Policke, T.A., Bolin, R. N., and Harris, T. L.
16、, “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, visit the ASTM website, ww
17、w.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.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis i
18、nternational standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT)
19、 Committee.1C753 Specification for Nuclear-Grade, Sinterable UraniumDioxide PowderC776 Specification for Sintered Uranium Dioxide Pellets forLight Water ReactorsC778 Specification for Standard SandC833 Specification for Sintered (Uranium-Plutonium) Diox-ide Pellets for Light Water ReactorsC859 Termi
20、nology Relating to Nuclear MaterialsC1347 Practice for Preparation and Dissolution of UraniumMaterials for AnalysisD1193 Specification for Reagent WaterE135 Terminology Relating to Analytical Chemistry forMetals, Ores, and Related MaterialsE456 Terminology Relating to Quality and StatisticsE882 Guid
21、e for Accountability and Quality Control in theChemical Analysis Laboratory3. Terminology3.1 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 defin
22、itions of terms relating to nuclear materials,refer to Terminology C859.3.1.4 For definitions 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
23、 the detectorand its associated counting electronics are unable to recordanother event or resolve 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
24、ratio from the true ratio as afunction of the difference in mass between the two isotopes.This 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
25、lighter isotopes. The result is anunder estimation of the lighter isotopes which can be signifi-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 introducti
26、on such as electrothermal vaporization,can be more significant.54. Summary of Test Method4.1 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 g of uraniumper gram of solution (g U/g solution
27、or ppm of U). Otherdissolution methods may be used. A standard peristaltic pumpis used as 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 prec
28、ision and a reduced biasfor all sample, standard, and control measurements. A calibra-tion 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,23
29、6U, and238U. Mass biascorrection factors, which are established using the instrumentsoftware 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 int
30、ensity/U isotope intensity sumequals the234U abundance). The high abundance isotope isdetermined 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, an
31、d C833. Included in these criteria is the uraniumisotopic composition. This test method is 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 I
32、sotopic Peak EffectsInterferences can occurfrom adjacent isotopes of high concentration, such 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 met
33、hod, the Q-ICP-MS peak resolutionfor235U was set to within 0.70 6 0.15 daltons (Atomic MassUnits-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. Fol
34、lowthe instrument manufacturers instructions to minimize thesemolecular ion formations, for 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.
35、The biasfrom the UH+interference only becomes significant for theintegrated peak intensity 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
36、 beused to test the significance of this interference.6.3 Memory Interference EffectsMemory 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 ran
37、ge, it can show that the glassware and uptake4Jarvis, K. E., Gray, A. L., and Houk, R. S., Handbook 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 Mas
38、sSpectrometry, Blackie and Son Ltd., Glasgow and London, or Chapman and Hall,New York, 1989.C1474 192system is contaminated with another enrichment. Secondly, itcan be detected by looking at the standard deviation of therepeat trials from a sample analysis and whether the peakintensity measurements
39、are random between the repeat trials orwhether they drift toward increasing or decreasing intensity.Also, the percent standard deviation (% SD) of 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 ma
40、y be an indication of a memory effect from asample of a different enrichment level. It could also beindicative of general instrument instability or problems withsample uptake and delivery to the plasma.7. Apparatus7.1 Balance, with precision of 0.0001 g.7.2 Polytetrafluoroethylene (PTFE) Oak Ridge T
41、ubes6,30mL, or equivalent.7.3 Drying Oven, controlled at 108 6 5C.7.4 Polypropylene Sample 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
42、.7 Peristaltic Pump.8. Reagents and Materials8.1 Purity of ReagentsReagent grade chemicals 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 specificat
43、ions are available.7Other grades may be usedprovided it is first ascertained that the 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
44、, as definedby Type I of Specification D1193.8.3 Hydrofluoric Acid (sp gr 1.18)49 % w/w concentratedhydrofluoric acid (HF).8.4 Isotopic Calibration Standard, 0.10 g of U per g ofsolutionAdd 100 uL of the appropriate isotopic calibrationstandard secondary stock solution (see 8.7) to a 125-mLpolypropy
45、lene sample bottle, and dilute to approximately 84.7g with water.8.5 Isotopic Control Standard, 0.10 g 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.N
46、OTE 1The concentration of the calibration and control standardsolutions are adjusted 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 inten
47、sity sum was established at 2.0 6 0.2 millioncounts per second (cps) for the data presented. 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
48、 continues to operate in a linearintensity versus concentration range, and is therefore 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 g of U3O8per g
49、 of solution (4235 g of U per g ofsolution)0.250 g of the appropriate NBL U3O8isotopicstandard 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 StockSolutions, 84.7 g of U per g of solutionAdd 2.0 mL of theappropriate isotopic enrichment standard 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
