1、Designation: C 1380 04Standard Test Method forthe Determination of Uranium Content and IsotopicComposition by Isotope Dilution Mass Spectrometry1This standard is issued under the fixed designation C 1380; the number immediately following the designation indicates the year oforiginal adoption or, in
2、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 test method covers a method for the determinationof the uranium concentration
3、in uranium oxides by isotopedilution mass spectrometry (IDMS). The isotopic compositionof the oxide is measured simultaneously.1.2 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 a
4、ppro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:D 1193 Specification for Reagent Water23. Summary of Test Method3.1 For measurement of the elemental uranium concentra-tion of uranium oxides by I
5、DMS, a representative and accu-rately measured aliquot of the sample is prepared. A knownquantity of233U (“spike”) is added to an aliquot of the sample.The sample aliquot and spike are taken to dryness, redissolvedin dilute nitric acid, and loaded on a filament for analysis in athermal ionization ma
6、ss spectrometer (TIMS). After measure-ment of the isotopic ratios in the spiked sample, the uraniumcontent and isotopic composition of sample are calculated.4. Significance and Use4.1 Determination of percent uranium content and235Uabundance in oxides and other materials containing highconcentration
7、s of uranium is required for special nuclearmaterials accountability, regulatory requirements, and processcontrol.5. Interferences5.1 The calculations assume any233U in the sample isnegligible. If the sample contains significant233U, the samplemust be analyzed for isotopic composition with and witho
8、utadded spike, and the calculations adjusted accordingly.6. Apparatus6.1 Thermal ionization mass spectrometer (TIMS) config-ured with Faraday cup detectors and an automated operatingsystem.6.2 Preconditioning unit for the TIMS.6.3 Filament loading assembly for the TIMS.6.4 Balance, analytical, with
9、five-place range.6.5 Vials, glass, disposable with plastic caps.6.6 Pipet, automatic, Ranin or equivalent, variable to 1000L.6.7 Pipet tips, disposable plastic, 1001000 L.6.8 Liquid dispenser, Repipettey or equivalent.7. Reagents and Materials7.1 Purity of MaterialsReagent grade chemicals shall beus
10、ed 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.3Other grades may be usedprovided it is first ascertained that the reagent is of su
11、fficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.7.2 Purity of WaterUnless otherwise indicated, referencesto water shall mean reagent water in conformance withSpecification D 1193.7.3 Nitric Acid, HNO3, concentrated (70 %).7.4 Nitric Acid, 0.8 M (5 % v/v)Cau
12、tiously add 50 mL ofconcentrated nitric acid to 950 mL of water.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 approved June 1, 2004. Published July 2004. Originally appr
13、ovedin 1997. Last previous edition approved in 1997 as C 1380 97.2For 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 the standards Document Summary page onthe ASTM webs
14、ite.3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, D. C. For suggestions on the testing of reagents notlisted by the American Chemical Society, Washington, D. C. For suggestions on thetesting of reagents not listed by the American Chemical Society
15、, see AnalarStandards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U. K., and theUnited States Pharmacopeia and National Formulary, U.S. Pharmaceutical Con-vention (USPC), Rockville, MD.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United
16、States.7.5 Nitric Acid, 0.1 MAdd 6.5 mL concentrated nitric acidto 900 mL of water, mix, and bring to 1000 mL with water.7.6 Hydrogen Peroxide H2O2,30%.7.7 Elemental and Isotopic Uranium Standards (New Brun-swick Laboratory CRM 114, CRM 116, CRM 129, or equiva-lent4).7.8 Uranium-233 spike assay and
17、isotopic standard (NBLCRM 111A4or equivalent)Dilute NBL CRM 111A 1:50by weight with a 5 % nitric acid to give a233U concentration ofapproximately 10 g233U/g solution.NOTE 1An exact 1:50 dilution is not required. The requirement is forprecise and accurate weights of standard and diluent. Calculate th
18、e exactconcentration of each isotope in the diluted spike standard in accordancewith 11.2. Other dilutions of CRM 111-A may be used if accurate weightsare known, and the aliquot of CRM 111A used in the measurement of testsamples yields a233U/23XU ratio of at least 0.02, where X is the majoruranium i
19、sotope.8. Preparation of Apparatus8.1 Prepare the thermal ionization mass spectrometer(TIMS) in accordance with manufacturers recommendations.9. Calibration and Standardization9.1 Standardization of233U Spike Solution:9.1.1 Prior to using a new diluted spike solution, verify theconcentration of the
20、solution with CRM 129 uranium oxide orits equivalent. If the new spike solution does not give resultswithin control limits, its standardized concentration must beverified with another NBL certified reference material forelemental uranium, such as CRM 114 or equivalent.9.2 Calibration of TIMS:9.2.1 C
21、alibrate the TIMS in accordance with manufacturersrecommendations to achieve the users performance and qual-ity assurance criteria.10. Procedure10.1 Weigh, to the nearest 0.01 mg, a labeled vial and capfor each sample; record the weight.10.2 Tare the balance and weigh, to the nearest 0.01 mg, a0.350
22、.45 g aliquot of the sample into the vial. Record theweight.NOTE 2Smaller or larger aliquots of sample may be used. However,the sample size should be sufficient to obtain a representative sample ofthe material and the ratio of the measured233U to major uranium isotopein the material must be greater
23、than 0.02. It is recommended that samplesbe prepared in duplicate.10.3 Cautiously add 5 mL concentrated HNO3to the sampleand heat slowly on a hot plate to dissolve the sample.10.4 Heat the sample/HNO3to dryness.10.5 Remove the sample from the hot plate and examine theresidue.NOTE 3If conversion of t
24、he sample to orange/red uranium nitrate/oxide was incomplete, repeat Steps 10.3-10.5.10.6 After conversion is complete and the sample is dry,cool the vial, add 40 mL 0.8 M HNO3, and cap with theappropriate plastic lined cap.10.7 Mix the vial contents thoroughly by inverting vigor-ously.10.8 Weigh th
25、e vial and its contents to the nearest 0.1 mgand record the weight.10.9 Label a new 20mL vial with sample identificationnumber and “Dil 1.”10.10 Place the labeled vial and a plastic lined cap on thebalance, and zero the balance.10.11 Add 0.5 mL of the original dilution (from step 10.8),set the cap o
26、n the vial, and record the weight to the nearest 0.01mg.10.12 Tare the balance, add 20 mL of 0.8 M HNO3, andrecord the weight to the nearest 0.01 mg.10.13 Cap the vial and mix the contents thoroughly byinverting vigorously.10.14 Label a third vial with sample identification and “Dil2,” place the via
27、l and a plastic lined cap on the balance, andzero the balance.10.15 Add 0.5 mL of Dilution 1, set the cap on the vial, andrecord the weight to the nearest 0.01 mg.10.16 Tare the balance, add 0.5 mL of233U spike solution tothe vial, and record the weight to the nearest 0.01 mg.10.17 Add five drops of
28、 30 % H2O2and 1 mL of concen-trated HNO3to the vial, set it on the hot plate, and heat todryness.10.18 Remove from the hot plate, cool, and add 0.02 mL 0.1M HNO3.10.19 Swirl or agitate the vial to dissolve the sample.10.20 Load 4 L of the dissolved sample (Step 10.19) on afilament for analysis in th
29、e TIMS.10.21 Analyze in accordance with the users standard oper-ating procedure for TIMS analysis.NOTE 4Follow the requirements for analysis of duplicate samples,standards, or controls as recommended in the users quality control plan.11. Calculation11.1 From the certified reference values of the233U
30、 spikestandard (obtained from the certificate of analysis) and anystandardization performed per Step 9.1, calculate the exactconcentration of each isotope (in g/g) in the spike solution.g isotopeg certified solution5moles U total!g certified solution3at fractn isotope 3 at mass isotope (1)where the
31、atomic mass for each isotope5is as follows:233U = 233.039627 g/mol,234U = 234.040945 g/mol,235U = 235.043922 g/mol,236U = 236.045561 g/mol, and238U = 238.050784 g/mol.11.2 Using the weights obtained during standard dilution inStep 7.8, calculate the exact concentrations of each isotopepresent in the
32、 working spike solution:4Available from the US Department of Energy, New Brunswick Laboratory, D350, 9800 South Cass Avenue, Argonne, IL 60439. CRM 114 and CRM 129 havebeen replaced by CRM 129A.5CRC Handbook of Chemistry g* is from Step 10.11;g+is weight from Step 10.8tare of vial and cap Step 10.1;
33、g+is from Steps 10.11 and 10.12; andgis from Step 10.15.11.6 Using the individual ratios from the sample analysis for234U,235U, and236U, calculate the amount of each isotopepresent in the sample. The individual values are corrected forthe amount of each isotope present in the spiking solutions ascal
34、culated in Step 11.2:g isotopeg sample5RX 3 g233U added 3 AX 2 g23XU added#g sample(5)where:R2 =23XU/238U atomic ratio,RX = R2/R1 (see Step 11.5), andAX = atomic mass23XU/atomic mass233U.11.7 To calculate the concentration of total uranium, add upthe concentrations calculated for each isotope in Ste
35、ps 11.5 and11.6.12. Precision and Bias12.1 One hundred aliquants of CRM 114, a normal oxidewith certified value of 0.847396 g U/g, were analyzed by fouranalysts on two Thermal Ionization Mass Spectrometers over aperiod of several months. The average measured uraniumcontent was 0.847689 gU/g, with a
36、relative standard deviationof 0.18 %. In the same time period, analysis of 80 aliquants ofCRM 129, certified value 0.847726, gave a measured uraniumcontent of 0.847906, with a relative standard deviation of0.17 %. For CRM 116, a highly enriched metal uraniumstandard containing 0.999673 gU/g, 53 aliq
37、uants were ana-lyzed over the same time period. The average measured valuewas 0.999422 gU/g with a relative standard deviation of0.15 %. The average measured percentage of U-235 for CRM116 was 93.124, with a relative standard deviation of 0.004 %.The certified value for this standard is 93.1215 wt %
38、235U. Thet-test for bias showed no significant bias in this data at the 95 %confidence level.12.2 For each attribute being measured, the measurementdata set was tested for bias. The test calculates the t statistic:t 5?Meas 2 Ref?=U2Meas ! 1 U2Ref!(6)where:Meas = mean of the measured attribute value
39、data set,Ref = reference value,U(Meas) = standard uncertainty of the measured value,which is the standard deviation of the data setdivided by the square root of the number ofobservations in the data set; that is, the standarderror of the data set, andU(Ref) = standard uncertainty of the reference va
40、lue,which is half of the 95 % confidence intervalradius associated with the reference value; forexample, if the reference value and its associ-ated 95 % confidence interval of an attribute is10 6 1, its standard uncertainty would be halfof 1, or 0.5.This statistic is compared to values for a two-sid
41、ed t-statisticwith degrees of freedom (df) determined by the followingformula:df 5U2Meas! 1 U2Ref!2U4Meas!N 2 11U4Ref!60(7)which is a particular application of Satterthwaites approxi-mation for effective degrees of freedom, with an assignment of60 degrees of freedom to the reference value uncertaint
42、y.13. Keywords13.1 isotope dilution mass spectrometry (IDMS); uraniumconcentration; uranium isotopesC1380043ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised t
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