ASTM C1456-2008 Standard Test Method for the Determination of Uranium or Gadolinium or Both in Gadolinium Oxide-Uranium Oxide Pellets or by X-Ray Fluorescence (XRF)《用X射线荧光法(XRF)测定氧.pdf

1、Designation: C 1456 08Standard Test Method forDetermination of Uranium or Gadolinium (or both) inGadolinium Oxide-Uranium Oxide Pellets or by X-RayFluorescence (XRF)1This standard is issued under the fixed designation C 1456; the number immediately following the designation indicates the year oforig

2、inal 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 describes the steps necessary for thepreparati

3、on and analysis by X-ray fluorescence (XRF) ofgadolinium or uranium (or both) in gadolinium oxide-uraniumoxide pellets or powders.1.2 This test method requires the use of appropriate internalstandard(s). Care must be taken to ascertain that samplesanalyzed by this method do not contain the internal

4、standardelement(s) or that this contamination has been corrected formathematically whenever present. Such corrections are notaddressed in this test method.1.3 This standard contains notes that are explanatory and arenot part of the mandatory requirements of the standard.1.4 The values stated in SI u

5、nits are to be regarded asstandard. No other units of measurement are included in thisstandard.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 and health pr

6、actices and determine the applica-bility of regulatory limitations prior to use. Specific precau-tions are given in Section 8 and various notes throughout themethod.2. Referenced Documents2.1 ASTM Standards:2C 1118 Guide for Selecting Components for Wavelength-Dispersive X-Ray Fluorescence (XRF) Sys

7、temsD 1193 Specification for Reagent WaterE 135 Terminology Relating to Analytical Chemistry forMetals, Ores, and Related Materials2.2 Other DocumentANSI/HPS N43.2-2001 Radiation Safety for X-ray Diffrac-tion and X-ray Fluorescence Analysis Equipment33. Terminology3.1 DefinitionsFor definitions of t

8、erms used in this guide,see Terminology E 135.3.2 Symbol:LiTB = lithium tetraborate (see 7.4).4. Summary of Test Method4.1 Solution or pellet standards containing the equivalent of110 % gadolinium oxide and 9099 % uranium oxide andappropriate internal standards are placed in the sample holderof an X

9、-ray spectrometer and exposed to an X-ray beamcapable of exciting the uranium and gadolinium L-a emissionlines and the appropriate emission line for the internal stan-dard. The intensities generated are measured by an appropriatedetector. The intensity ratio values obtained from this data areused to

10、 calibrate the X-ray analyzer.4.2 Samples are prepared in the same manner as thestandards and analyzed using conditions and curves generatedfrom those standards.NOTE 1Yttrium and strontium have been used successfully as internalstandards for uranium and samarium for gadolinium. Scatter lines alsohav

11、e been used as internal standard lines.4An explanation of internalstandard method is found in several sources.5,61This test method is under the jurisdiction of ASTM Committee C26 on NuclearFuel Cycle and is the direct responsibility of Subcommittee C26.05 on Methods ofTest.Current edition approved D

12、ec. 1, 2008. Published January 2009. Originallyapproved in 2000. Last previous edition approved in 2000 as C 1456 00.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to

13、 the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.4Andermann, G, and Kemp, J.W., “Scattered X-Rays as Internal Standards inX-Ray Spectroscopy,” Analytical Chemistry, V

14、ol 20 (8), 1958.5Bertin, E.P., Introduction to X-Ray Spectrometric Analysis, Plenum Press, NewYork and London, 1978.6Tertian, R. and Claisse, F., Principles of Quantitative X-Ray FluorescenceAnalysis , Heyden and Son, London, Philadelphia and Rheine, 1982.1Copyright ASTM International, 100 Barr Harb

15、or Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5. Significance and Use5.1 This test method is applicable to samples containing 2 to10 % gadolinium oxide and 90 to 98 % uranium oxide on the“as received” basis. The method may be used to determineconcentration of either uranium,

16、 gadolinium, or both.5.2 Either wavelength-dispersive or energy-dispersiveX-ray fluorescence systems may be used provided the softwareaccompanying the system is able to accommodate the use ofinternal standards.6. Apparatus6.1 X-Ray SpectrometerSee Guide C 1118 or the manu-facturers operating manuals

17、 for the selection of the X-rayspectrometer. The method is valid for either energy-dispersiveor wavelength-dispersive systems.6.2 Sample Cups/HoldersPrepare liquid sample cups forthe X-ray spectrometer as described by the manufacturer.Vented, disposable sample cups with snap-on caps are satis-factor

18、y for most such analyses; such cups decrease the likeli-hood of contamination between samples. Sample holders forfused pellets should keep any pellet chips from getting into themoving parts of the instrument.6.3 Window FilmPolyester, polyethylene, and polypropy-lene films have been used successfully

19、 as the film window forcups or holders, or both. Tests should be performed todetermine the serviceability of any film chosen before insertioninto the instrument.6.4 Solution Dispenser (optional)The dispenser for theinternal standard solution, if used, should be capable ofreproducibly dispensing the

20、internal standard solution to a levelof 0.1 % relative standard deviation of the volume dispensed.6.5 Muffle Furnace, 1100C capacity.7. Reagents and Materials7.1 Purity of MaterialsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents conform

21、to the specifications of the Committee ofAnalytical Reagents of the American Chemical Society wheresuch specifications 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 determi

22、nation.7.2 Purity of WaterUnless otherwise indicated, referencesto water shall mean reagent water conforming to SpecificationD 1193.7.3 Gadolinium Oxide, Gd2O3It is recommended that thestandards be prepared using same batch as in pellets/powder.7.4 Lithium Tetraborate, Li2B4O7, fusion grade.7.5 Nitr

23、ic Acid, HNO3, concentrated (70 %).7.6 Samarium Oxide, Sm2O3, or other suitable internalstandard for gadolinium (see Note 1).7.7 Uranium Oxide, U3O8, NBL CRM-129 (or equivalent).8NOTE 2High purity UO2may be used if certification of uraniumanalysis is not required.7.8 Yttrium Oxide, Y2O3, or other su

24、itable internal standardfor uranium (see Note 1).8. Technical Precautions8.1 XRF equipment analyzes by the interaction of ionizingradiation with the sample. Applicable safety regulations andstandard operating procedures must be reviewed prior to theuse of such equipment. All modern XRF spectrometers

25、 areequipped with safety interlocks to prevent accidental penetra-tion of the X-ray beam by the user. Do NOT override theseinterlocks without proper training (See ANSI/HPS N43.2-2001).8.2 Instrument performance may be influenced by environ-mental factors such as heat, vibration, humidity, dust, stra

26、yelectronic noise and line voltage stability. These factors andperformance characteristics should be reviewed prior to use ofthis test method.9. Preparation of Apparatus9.1 Chamber EnvironmentThe liquid standards andsamples used in this method are corrosive. Some fumes will beemitted from the sample

27、 cups. These fumes may be detrimentalto the spectrometer chamber. It is desirable to flush thischamber with an inert gas (usually helium) before and duringanalysis. Some X-ray spectrometers control the change ofsample chamber atmosphere (air, vacuum, helium) automati-cally through the software; in o

28、thers, it must be done manually.Follow the instrument manufacturers recommendations toachieve the inert gas environment. Allow sufficient stabiliza-tion time before analysis. Fused pellet standards and samplesmay be analyzed using either a vacuum or helium environment.Line intensities will be slight

29、ly higher using a vacuum envi-ronment. WarningCare must be taken to assure that avacuum environment is not chosen with liquid samples. Ana-lyze standards and samples under the same environment.9.2 X-Ray Power SupplyIf the power to the X-ray tube isnot controlled by the instrument software, set the p

30、ropercombination of voltage and current for the instrument in use.These settings must be determined by the user for his instru-ment and choice of X-ray tube. Allow sufficient stabilizationtime prior to analysis.10. Calibration and Standardization10.1 Internal Standard Solution:10.1.1 Weigh 45 g of t

31、he internal standard compoundchosen for uranium and5goftheinternal standard compoundchosen for gadolinium into a beaker. Cover with a minimumamount of water. Add concentrated nitric acid slowly.7Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. Fo

32、r Suggestions on the testing of reagents notlisted by the American Chemical Society, see Annual Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.8The sole source of sup

33、ply of the apparatus known to the committee at this timeis U.S. Department of Energy, New Brunswick Laboratory, D 350, 9800 South CassAvenue, Argonne, IL 60439, ATTN: Reference Material Sales. If you are aware ofalternative suppliers, please provide this information to ASTM InternationalHeadquarters

34、. Your comments will receive careful consideration at a meeting of theresponsible technical committee,1which you may attend.C1456082NOTE 3For yttrium oxide and samarium oxide, the reaction will beslow and may require heating. If strontium carbonate is used for uranium,the reaction will be vigorous.

35、The strength of the internal standard solutionmay be changed to achieve optimum excitation with the equipment beingused. The exact concentration of the internal standard solution is notcritical; however, it is critical that the internal standard solution added tostandards and samples be the same.10.

36、1.2 Heat on a hot plate if necessary to complete thedissolution.10.1.3 Cool the solution to room temperature, and transferto a 1000-mL volumetric flask. Filter the solution if necessary.Dilute to volume with water and mix thoroughly.10.2 Calibration Standards:10.2.1 Liquid Standards:10.2.1.1 Prepare

37、 a calibration standard for each concentra-tion level by weighing into a beaker the amounts of uraniumoxide and gadolinium oxide (which have been ignited accord-ing to directions on analysis certificate), given in Table 1.10.2.1.2 Dissolve the oxide in 25 mL of water and 25 mLconcentrated nitric aci

38、d. Heat on a hot plate, if necessary tocomplete the dissolution. Reduce volume to 15 mL.10.2.1.3 When cool, transfer each solution to a properlylabeled 25-mL volumetric flask containing the amount ofinternal standard solution indicated in Table 1.NOTE 4The internal standard solution may be added usi

39、ng a dispens-ing pipette if desired; however, care must be taken to assure that noadjustment to the dispenser is made between use for standards and use forsamples.10.2.1.4 Dilute to volume with water and mix thoroughly.10.2.2 Pellet Standards:10.2.2.1 For each standard, weigh 15 g lithium tetraborat

40、einto a labeled crucible suitable for the fusion technique.NOTE 5Explanation of the fusion technique is beyond the scope ofthis guide. Description of the technique may be found in severalsoucres.5,6Platinum, platinum-gold or graphite crucibles have been foundacceptable.10.2.2.2 Add the amounts of ur

41、anium oxide and gadoliniumoxide indicated in Table 1.10.2.2.3 Add the amount of internal standard solution (see10.1) indicated in Table 1.NOTE 6The dry-weight equivalent amount of internal standard com-pounds may be weighed directly into each crucible in place of internalstandard solution. If the so

42、lution is used with graphite crucibles, pipetteinto the center of the crucible. Do not allow the solution to touch the sidesof crucible.10.2.2.4 Fuse in a muffle furnace set at 10001100C untilall materials are in solution. (The pellet will be clear andwithout streaks. Mixing while melting is recomme

43、nded).NOTE 7Automatic fusers are available and may be substituted, ifdesired. Follow the manufacturers operating instruction. Fusion inplatinum crucibles may also be done over an air-gas burner. If the pelletcracks or recrystallizes while cooling, remelting in the same crucible willnot invalidate an

44、alysis.10.3 Instrument Calibration:10.3.1 Follow the manufacturers instructions for the instru-ment in use to obtain intensity data for the uranium L-a,gadolinium L-a and the internal standard lines for eachstandard.10.3.2 Care must be exercised that the analytical conditionsdetermined appropriate f

45、or the instrument in use are docu-mented, or recorded, in sufficient detail that these may bereproduced in subsequent runs and when analyzing thesamples.10.3.3 Calculate the analyte/internal standard ratios fromthe data obtained in 10.3.1. Calculate a calibration curve usingthese ratios. The calibra

46、tion curve will normally be a straightline of form:Y 5 mX 1 b (1)where:Y = concentration of analyte (U or Gd),X = analyte/internal standard ratio,m = slope of line, andb = intercept of straight line.11. Procedure11.1 Sample Preparation (Liquid):11.1.1 Mix the powder or grind pellet to ensure homogen

47、e-ity. Weigh, to the nearest 0.1 mg, a 1.00-g portion of the sampleinto a beaker or flask. (Duplicate aliquots may be required tomeet site or customer quality assurance requirements.)11.1.2 Dissolve in 1+1 (volume/volume) HNO3. Heat on hotplate, if necessary, to achieve complete dissolution.11.1.3 C

48、ool and transfer into a 25-mL volumetric flaskcontaining the internal standard solution.11.1.4 Dilute to volume with water and mix thoroughly.11.2 Sample Preparation (Fusion):11.2.1 Mix the powder or grind pellet to ensure homogene-ity.11.2.2 Weigh, to the nearest 0.1 mg, a 1.00-g portion of thesamp

49、le into fusion crucible containing 15 g LiTB. (Duplicatealiquots may be required to meet site or customer qualityassurance requirements.)11.2.3 Add the internal standard(s) for the analytes (seeNote 5 above).11.2.4 Place the crucibles in a muffle furnace set at 1100Cand fuse until all materials are in solution (see Note 6 above).11.2.5 When cool, label the pellets or place in labeled boxesfor identification.11.3 Counting the Sample:11.3.1 Set the X-ray spectrometer to the conditions noted in10.3.2. If the analytical conditions are controlled by computer,