1、Designation: C 1413 05Standard Test Method forIsotopic Analysis of Hydrolyzed Uranium Hexafluoride andUranyl Nitrate Solutions by Thermal Ionization MassSpectrometry1This standard is issued under the fixed designation C 1413; 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 (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This method applies to the determination of isotopiccompositio
3、n in hydrolyzed nuclear grade uranium hexafluo-ride. It covers isotopic abundance of235U between 0.1 and5.0 % mass fraction, abundance of234U between 0.0055 and0.05 % mass fraction, and abundance of236U between 0.0003and 0.5 % mass fraction. This test method may be applicable toother isotopic abunda
4、nce providing that corresponding stan-dards are available.1.2 This test method can apply to uranyl nitrate solutions.This can be achieved either by transforming the uranyl nitratesolution to a uranyl fluoride solution prior to the deposition onthe filaments or directly by depositing the uranyl nitra
5、tesolution on the filaments. In the latter case, a calibration withuranyl nitrate standards must be performed.1.3 This test method can also apply to other nuclear gradematrices (for example, uranium oxides) by providing a chemi-cal transformation to uranyl fluoride or uranyl nitrate solution.1.4 Thi
6、s 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 practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Document
7、s2.1 ASTM Standards:2C 696 Test Methods for Chemical, Mass Spectrometric, andSpectrochemical Analysis of NuclearGrade Uranium Di-oxide Powders and PelletsC 753 Specification for Nuclear Grade, Sinterable UraniumDioxide PowderC 761 Test Methods for Chemical, Mass Spectrometric,Spectrochemical, Nuclea
8、r, and Radiochemical Analysis ofUranium HexafluorideC 776 Specification for Sintered Uranium Dioxide PelletsC 787 Specification for Uranium Hexafluoride for Enrich-mentC 788 Specification for NuclearGrade Uranyl Nitrate So-lutionC 996 Specification for Uranium Hexafluoride Enriched toLess Than 5 %23
9、5UC 1334 Specification for Uranium Oxides with a235UContent Less Than 5 % for Dissolution Prior to Conver-sion to NuclearGrade Uranium DioxideC 1346 Practice for Dissolution of UF6from P10 TubesC 1347 Practice for Preparation and Dissolution of UraniumMaterials for AnalysisC 1348 Specification for B
10、lended Uranium Oxides with a235U Content of Less Than 5 % for Direct HydrogenReduction to NuclearGrade Uranium Dioxide3. Summary of Test Method3.1 After dilution of uranyl fluoride or uranyl nitrate solu-tion, approximatively 2 g of uranium are deposited on arhenium filament.Analysis is performed in
11、 a thermal ionizationmass spectrometer (TIMS), uranium is vaporized and ionizedthrough electrons emitted by a second filament; ions areextracted by an electric field, separated by a magnetic field, andcollected by four collectors on mass 234, 235, 236, 238. Thecollectors are either faraday cups or e
12、lectron multiplierscollectors (ion counting).3.2 Evaporation sequence and ion counting time are ad-justed with the analysis of standard solutions of certifiedisotopic content. Nitrate and fluoride solutions lead to twodifferent calibrations.4. Significance and Use4.1 Uranium hexafluoride used to pro
13、duce nuclear fuel mustmeet certain criteria for its isotopic composition as described inSpecifications C 787 and C 996.1This 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 appr
14、oved June 1, 2005. Published June 2005. Originallyapproved in 1999. Last previous edition approved in 1999 as C 1413 99.2For 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
15、 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.5. Interferences5.1 This test method only applies to nuclear grade uraniummatrices (as defined in Specification C 753, C 776,
16、C 787,C 788, C 1334,orC 1348). Large amount of impurities, whichare found, for example, in uranium ore concentrates, may biasresults. A purification step may be necessary, as described inSpecification C 696.5.2 The type of acid used (HF or HNO3) and its concentra-tion will strongly influence the obt
17、ained isotopic results (see9.2).6. Apparatus6.1 Thermal Ionization Mass Spectrometer (TIMS)Configured with four detectors.36.1.1 This test method requires a mass spectrometer with aresolution greater than 400 (full width at 1 % of peak height)and an abundance sensitivity of less than 105(contributio
18、n ofmass 238 on the mass 237). A typical instrument would have230 mm radius of curvature, single or double focussing, andsingle or multiple filament design. The pressure in the ioniza-tion chamber should be below 3 3 106torr (typically 107torr).6.2 Preconditioning Unit for the TIMSTo dry filamentaft
19、er deposition of uranyl solution.6.3 Rhenium Filament Loading Assembly for the TIMSInthis test method, a double filament set up is used.6.4 PipetsAutomatic or equivalent, 1, 20, 50, and 100 L.6.5 Pipets TipsIn accordance with 6.4.6.6 Liquid Dispenser2.5 mL.6.7 Disposable Polypropylene Vials.7. Reage
20、nts and Materials7.1 Purity of MaterialsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents conform to the specification of the Committee onAnalytical Reagents of the American Chemical Society wheresuch specifications are available.4Other gr
21、ades may be usedprovided it is first ascertained that the reagent is of sufficientlyhigh priority to permit its use without lessening the accuracy ofthe determination.7.2 Purity of WaterDemineralized or distilled water isfound acceptable for this uranium isotopic analysis.7.3 High Purity Rhenium Fil
22、aments ( 99.95 %), withgeometrical characteristics in accordance with the TIMS manu-facturers recommendations (typically thickness is 0.04 mmand width is 0.70 mm). Some equipment may accept tungstenfilaments.7.4 Isotopic Uranium Standards7.4.1 UF6of certified236U,235U isotopic composition,such as CO
23、G 006, 008, 009, 010, 013, 014, 015.57.4.2 U3O8of certified isotopic composition, such as NBLCRM U-010, U-020, U-030, U-050, CEA 014.67.4.3 U3O8from reprocessed origin and of certified236Ucomposition, such as MIR 1.67.5 Hydrofluoric Acid (0.05 M)Dilute 173 L of HFsolution (sp gr 1.18, 28.9 M) to 100
24、 mL with water.7.6 Nitric Acid (0.1 M)Dilute 0.6 mL of concentratedHNO3(sp gr 1.42, 16 M) to 100 mL with water.8. Preparation of Apparatus8.1 Prepare the thermal ionization mass spectrometer inaccordance with the manufacturers recommendations. A veri-fication of collector yield and an optimisation o
25、f the ion beammay be necessary on a daily basis. This can be achieved byheating the ionizing filament, locating the187Re peak andfocusing for maximum intensity. The187Re signal is normallyabove 0.1 to 0.2 3 1011A.8.2 A verification of mass calibration is usually performedon a weekly basis in order t
26、o optimize the value for themagnetic field.9. Calibration and Standardization9.1 Because of mass segregation during the evaporation ofuranium, it is necessary to adjust the ion acquisition timeprogram with the analysis of uranium standards. The numberof standards and the range covered will depend on
27、 theinstrument used, the evaporation sequence, and the accuracywhich is required.9.1.1 For the analysis of235U in the 0.1 to 5.0 mass % rangeand of234U in the 0.0055 to 0.05 mass % range, four to sevenstandards should be used (see Table 1). For analysis of236Uinthe 0.0003 to 0.5 mass % range, only t
28、wo standards were used.9.2 Preparation of the StandardsSeparate calibrations arerequired for uranyl fluoride solutions and uranyl nitrate solu-tions.9.2.1 Uranyl Fluoride Calibration:9.2.1.1 UF6StandardsGeneral principles for hydrolysisof UF6are described in Test Methods C 761 and PracticeC 1346. Hy
29、drolysis should be done in pure water (no HNO3added). Final concentration is for example 266 g uranium perlitre (20 % mass U).NOTE 1Other concentrations may be used (for example, 10 % massU), provided that volumes in 10.2 are adapted to deposit the same uraniumamount on the rhenium filament.NOTE 22
30、g of uranium are deposited on the filaments. In case ofother filament geometries (see 7.3), other uranium amounts may be moreadapted (up to 10 g U).9.2.1.2 In a polypropylene vial, pour 2.5 mL of water andadd 20 L of solution prepared in 9.2.1.1. Mix the vial contentby inverting vigorously to obtain
31、 a solution containing approxi-mately 2 g/L uranium.9.2.1.3 Other StandardsUranium standard solutions, ifnot from hydrolyzed UF6origin, must be transformed to a pure3Areduced number of detectors may be used which will correspond to a reducednumber of isotopes analyzed. For single collector instrumen
32、ts, refer to SpecificationC 696.4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K.,
33、and the United States Pharmacopeiaand National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,MD.5COGEMA/Service Laboratoire, BP 16, 26701 Pierrelatte Cedex, France.6CEA/CETAMA, BP 171, 30 207 Bagnols sur Cze, France.C1413052uranyl fluoride solution prior to the analysis. Dissolut
34、ion of theuranic material can be performed in accordance with PracticeC 1347. The solution is then transferred in a platinum crucibleto be carefully dried on a heated plate to be transformed toUO3. The residue is then dissolved with diluted HF (0.05 M) toobtain an uranyl fluoride solution with an ur
35、anium concentra-tion of 2 g/L and a fluoride concentration 1 g/L.9.2.2 Uranyl Nitrate Calibration:9.2.2.1 U3O8StandardsThe standards are dissolved inaccordance with Practice C 1347. The solutions are evaporatedto dryness and the residue is transformed by calcination toU3O8. It is then dissolved in 0
36、.1 M HNO3to give a solutioncontaining 2 g/L uranium.9.2.2.2 Hydrolyzed UF6StandardsUranyl fluoride solu-tions with an uranium concentration of 2 g/L are evaporated todryness and dissolved in 0.1 M HNO3to give an uranyl nitratesolution containing 2 g/L uranium.9.3 Analysis of the uranyl fluoride or u
37、ranyl nitrate standardsolutions is performed in accordance with 10.2-10.4.9.3.1 Calibrate the TIMS in accordance with the manufac-turers recommendations to achieve the users performance andquality assurance criteria.9.3.2 The235U/238U mass discrimination factor, B, is cal-culated as follows:B 51/ DM
38、! R/Rs! 1 (1)where:B = mass discrimination factor,DM = mass difference = (238-235) = 3,Rs= certified value of235U/238U of standard, andR= average measured value of235U/238U for n differentanalyses.9.3.2.1 B should be below 2 3 104.9.4 For each batch of routine samples to be analyzed, averification o
39、f the calibration of the acquisition program isrecommended. This is done by inserting in the batch a standardwith isotopic composition close to that of the samples.10. Procedure10.1 Prepare the solution to be analyzed in accordance with9.2 to obtain either a fluoride or nitrate solution with anurani
40、um concentration of approximately 2 g/L.10.2 Load 1 L of solution 10.1 on the filament. Dry andbake the filament with the TIMS preconditioning unit. Theheating sequence (electrical current, time applied) must beperformed in accordance with the manufacturers recommen-dation or users experience.NOTE 3
41、For uranyl fluoride solutions, temperatures significantlygreater than 600C must be avoided. The temperature of the filamentduring the final stages of sample mounting is a critical parameter and canproduce a significant bias between runs if not carefully controlled.10.3 Insert the filaments assembly
42、into the mass spectrom-eter and obtain a pressure of less than 3 3 106torr.10.4 Analysis in accordance with the users standard oper-ating procedure for TIMS analysis.NOTE 4The heating pattern for the filaments and the mass spectrom-eter ratio measurements may slightly vary depending on the instrumen
43、t.10.4.1 Heat the ionization filament to 5 A.10.4.2 Heat the evaporation filament to 1 A.10.4.3 Heat the ionization filament until a signal of 0.08 31011A is obtained, locate the187Re peak and adjust the focusfor maximum intensity. Heat the ionization filament until asignal of 0.2 3 1011A is obtaine
44、d on the187Re peak.10.4.4 Heat the evaporation filament until a signal of 1011A is obtained on the238U peak, focus for maximum intensity.Heat the evaporation filament until a signal of 7 3 1011Aisobtained.10.4.5 Start the ratio measurement (this should correspondto approximately 30 minutes after ste
45、p 10.4.1).10.4.5.1 Determine the baseline at mass 233.5.10.4.5.2 During a 32second scan, acquire the234U,235U,236U,238U signal on the four collectors. Calculate the ratio234U/238U,235U/238U,236U/238U, corrected from baseline.10.4.5.3 Repeat step 10.4.5.2 ten times. Calculate the aver-age ratio toget
46、her with the estimated standard deviation.Perform a Dixon test to eliminate anomalous points.10.4.5.4 Repeat steps 10.4.5.1-10.4.5.3 so that the totalacquisition time corresponds to that obtained during thecalibration (see 9.1).TABLE 1 Mass Ratios to Total Uranium235U/U (mass fraction, %)Reference C
47、ertified ValuesASummary Statistics of MeasuredValuesx 6 sxxsnCOG 006 0.7112 6 0.0002 0.7110 0.0004 5COG 008 0.8676 6 0.0008 0.8670 0.0004 20NBL CRM U010 0.9911 6 0.0005 0.9918 0.0009 50COG 009 1.0705 6 0.0010 1.0696 0.0005 5COG 010 1.3006 6 0.0012 1.2995 0.0004 10NBL U020 2.0130 6 0.001 2.0131 0.000
48、9 18COG 013 2.5959 6 0.0026 2.5969 0.0005 10NBL U030 3.0032 6 0.0008 3.0042 0.0014 26COG 014 3.3678 6 0.0034 3.3663 0.0006 20CEA 014 3.3678 6 0.0034 3.3699 0.0010 84COG 015 4.2960 6 0.0042 4.2940 0.0011 10NBL U050 4.9490 6 0.0025 4.9449 0.0025 10234U/U (mass fraction, %)Reference Certified ValuesASu
49、mmary Statistics of MeasuredValuesx 6 sxxsnNBL CRM U010 0.0053 6 0.00002 0.0054 0.0001 50COG 006 0.0054 6 0.0001 0.0052 0.0001 5COG 008 0.0069 6 0.0001 0.0067 0.0001 20COG 010 0.0070 6 0.0001 0.0069 0.0001 10COG 009 0.0088 6 0.0001 0.0087 0.0001 5NBL U020 0.0123 6 0.00005 0.0123 0.0001 18COG 013 0.0224 6 0.0002 0.0223 0.0001 10NBL U050 0.0275 6 0.00005 0.0273 0.0001 9CEA 014 0.0288 6 0.0006 0.0290 0.0001 84COG 014 0.0325 6 0.0003 0.0327 0.0002 20COG 015 0.0378 6 0.0004 0.0382 0.0001 10236U/U (mass fraction in %)Re
