1、Designation: C 1474 00 (Reapproved 2006)e1Standard 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 C 1474; the number immediately following the desi
2、gnation 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 (e) indicates an editorial change since the last revision or reapproval.e1NOTEEditorial changes were made in July
3、 2006.1. Scope1.1 This test method is applicable to 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, and2
4、38U.The analysis can be performed on various material 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 in
5、this test method focuses on fuel product material but 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
6、 test methods such as radiochemistry and thermal ioniza-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 normal
7、ly found present inmaterials. The example data presented 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. Optimal
8、accuracy (or a low bias) is achieved through the use 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
9、-taining a low bias for the high-abundance isotopes, 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 bymea
10、suring the intensity ratios of each low-abundance isotopeto 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 instrume
11、nt is calibrated and the samples measured inunits of 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 uran
12、ium concentration of a solution is notimportant when 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
13、 the user of this standard to establish appro-priate 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:3C 753 Specification for Nuclear-Grade, Sinter
14、able UraniumDioxide PowderC 776 Specification for Sintered Uranium Dioxide PelletsC 778 Specification for Standard SandC 833 Specification for Sintered (Uranium-Plutonium) Di-oxide Pellets1This test method is under the jurisdiction ofASTM Committee C26 on NuclearFuel Cycle and is the direct responsi
15、bility of Subcommittee C26.05 on Methods ofTest.Current edition approved July 1, 2006. Published September 2006. Originallyapproved in 2000. Last previous edition approved in 2000 as C 147400.2Policke, T.A., Bolin, R. N., and Harris, T. L., “Uranium Isotope Measurementsby Quqdrupole ICP-MS for Proce
16、ss 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, www.astm.org, orcontact ASTM Customer Service at serviceastm.or
17、g. 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 19428-2959, United States.C 859 Terminology Relating to Nuclear Materials4C 1347 Practice f
18、or Preparation and Dissolution of UraniumMaterials for AnalysisD 1193 Specification for Reagent WaterE 135 Terminology Relating to Analytical Chemistry forMetals, Ores, and Related MaterialsE 456 Terminology Relating to Quality and StatisticsE 882 Guide for Accountability and Quality Control in theC
19、hemical Analysis Laboratory3. Terminology3.1 Definitions:3.1.1 For definitions of terms relating to analytical atomicspectroscopy, refer to Terminology E 135.3.1.2 For definitions of terms relating to statistics, refer toTerminology E 456.3.1.3 For definitions of terms relating to nuclear materials,
20、refer to Terminology C 859.3.1.4 For definitions of terms specifically related toQ-ICP-MS in addition to those found in 3.2, refer to Appendix3 of Jarvis et al.53.2 Definitions of Terms Specific to This Standard:3.2.1 dead time, nthe interval during which the detectorand its associated counting elec
21、tronics 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 ratio from the true ratio as afunction of the
22、 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 lighter isotopes. The result is anunder estim
23、ation of the lighter isotopes which can be signifi-cant.6“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
24、 more significant.64. 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 ug of uraniumper gram of solution (ug U/g solution or ppm of U). Otherdissolution methods may
25、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 precision and a reduced biasfor all sample, sta
26、ndard, 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,236U, and238U. Mass biascorrection factors, w
27、hich 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 intensity/U isotope intensity sumequals the234
28、U 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 C 753, C 776,C 778, and C 833. Included in these criteria is t
29、he 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 Isotopic Peak EffectsInterferences can o
30、ccurfrom 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 method, the Q-ICP-MS peak resolutionfor235
31、U 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. Followthe instrument manufacturers instruc
32、tions 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.The biasfrom the UH+interference only b
33、ecomes 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 beused to test the significance of thi
34、s 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 range, it can show that the glassware and
35、uptakesystem 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 are random between the repeat trials orwhether they drift toward increasing or decreasing inten
36、sity.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 are4Withdrawn.5Jarvis, K.E., Gray, A.L., and Houk, R.S., Handbook of Inductively CoupledPlasma Mass Spectrometry, Bl
37、ackie and Son Ltd., Glasgow and London, orChapman and Hall, New York, 1992.6Date, 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.C 1474 00 (2006)e12higher, then it may be an indication of
38、 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 0.00001 g.7.2 Polytetrafluoroethylene (PTFE) Oak Ridge Tubes7,30mL, or equiv
39、alent.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 Caps7,14 mL, or equivalent.7.6 Q-ICP-MS Instrument, controlled by computer andfitted with the associated software and peripherals.7.7 Peristaltic Pump.
40、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 specifications are available.8
41、Other 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, as definedby Type
42、I of Specification D 1193.8.3 Hydrofluoric Acid (sp gr 1.18)49 % w/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
43、, and dilute to approximately 84.7g with water.8.5 Isotopic Control 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 concentr
44、ation 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 intensity sum was esta
45、blished 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 continues to ope
46、rate 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 ug of U3O8per g of solution (42
47、35 ug 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 Stock Solu-tions, 84.7 ug of U per g
48、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 analysis control mate-rials should be within 1.0
49、 Wt % of the235U enrichment to be analyzed inunknown sample materials. 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 sep
