1、Designation:C142899 (Reapproved 2005) Designation: C1428 11Standard Test Method forIsotopic Analysis of Uranium Hexafluoride bySingleStandard Gas Source Multiple Collector MassSpectrometer Method1This standard is issued under the fixed designation C1428; the number immediately following the designat
2、ion 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 () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method is applicable to
3、the isotopic analysis of uranium hexafluoride (UF6) with235U concentrations less than orequal to 5 % and234U,236U concentrations of 0.0010.0002 to 0.1 %.1.2 This test method may be applicable to the analysis of the entire range of235U isotopic compositions providing that adequatestandards are availa
4、ble. U isotopic compositions providing that adequate Certified Reference Materials (CRMs or traceablestandards) are available.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish a
5、ppropriate safety health practices and determine the applicability of regulatory limitationsprior to use.2. Referenced Documents2.1 ASTM Standards:2C787 Specification for Uranium Hexafluoride for EnrichmentC996 Specification for Uranium Hexafluoride Enriched to Less Than 5 %235U2.2 Other Document:US
6、EC-651 Uranium Hexafluoride: A Manual of Good Handling Practices33. Summary of Test Method3.1 The unknown sample and a CRM or traceable standard whose isotopic composition is close to that of the sample areintroduced in sequence into the mass spectrometer, and234U,235U,236U, and238U ions are focused
7、 through correspondingcollector slits to the four separate collectors. Measurements are made that are proportional to the ratios of234U,235U, or236Uto238U. With the known composition of the CRM or traceable standard, these ratios of molar ratios permit calculation of the234U,235U, and236U contents.
8、Memory corrections are applied based on the periodic measurement of two CRMs or traceable standards.4. Significance and Use4.1 Uranium hexafluoride is a basic material used to produce nuclear reactor fuel. To be suitable for this purpose, the materialmust meet criteria for isotopic composition. This
9、 test method is designed to determine whether the material meets the requirementsdescribed in Specifications C787 and C996.5. Apparatus5.1 A gas source multiple collector mass spectrometer with the following attributes:5.1.1 The resolving power of the mass spectrometer is not less than 500. The reso
10、lving power (R) is calculated from theregistered mass spectrum of both the235UF5+and238UF5+isotopes as follows:R 5a Mb DM(1)1This test method is under the jurisdiction of ASTM Committee C26 on Nuclear Fuel Cycle and is the direct responsibility of Subcommittee C26.05 on Methods of Test.Current editi
11、on approved JuneMarch 1, 2005.2011. Published December 2005.April 2011. Originally approved in 1999. Last previous edition approved in 19992005 asC142899(2005). DOI: 10.1520/C1428-99R05.10.1520/C1428-11.2For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Servi
12、ce at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3Available from Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402.3Available from United States Enrichment Corporation, 6903
13、 Rockledge Drive, Bethesda, MD 20817.1This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM r
14、ecommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.wherea = d
15、istance between centers of the235UF5+and238UF5+peaks,b = peak width of the238UF5+isotope (10 % valley),M = 333 mass(u)238UF5+, andDM = 3 = 333 330, 330 mass(u)235UF5+5.1.2 The abundance sensitivity of the mass spectrometer is specified as less than 13105as contribution of mass 333 (238UF5+)to mass 3
16、31 (236UF5+).5.1.3 The four collectors have collector slits adjusted for ions of masses 329, 330, 331, and 333. Ion currents are amplified byfour amplifiers, having noise level less than 0.5 mV.5.1.4 The ion beams are kept within the slits by an automatic beam positioner circuit.5.1.5 The pumping sy
17、stem of the mass spectrometer analyser tube shall maintain a pressure less than 53108torr with a sampleflowing into the ion source.5.1.6 The memory correction factor of the mass spectrometer as defined in 9.1 shall be consistent with the required accuracyand precision, and shall not exceed 1.01.1.00
18、5.5.1.7 The sample inlet system shall be equipped with a manifold, including adjustable leak, and valves for introducing thesample and CRM or traceable standard in sequence and for evacuating corresponding lines. The pumping system of the inletsystem must maintain a pressure less than 23102torr by e
19、vacuating.6. Hazards6.1 Since UF6is radioactive, toxic, and highly reactive, especially with reducing substances and moisture (see USEC-651),appropriate facilities and practices for analysis shall be provided.7. Calibration and Standardization7.1 Uranium Hexafluoride Isotopic7.1.1 Two CRMs or tracea
20、ble standards are used to determine the memory correction factor. The relative235U concentrationdifference of these standards shall not be more than 20%.7.1.2For memory correction factor determination forU concentration ratio of upper CRM or traceable standard ( C235SH)to235U of lower CRM ortraceabl
21、e standard ( C235SL) shall not be more than three ( C235SH/ C235SL# 3).7.1.2 For memory correction factor determination for234U and236U isotopes in concentration range 0.01 to 0.1%, twostandards are used which differ inU isotopes, two CRMs or traceable standards are used which differ in234U(236U) co
22、ncentration. The relativedifference shall not exceed two times; in concentration range 0.001 to 0.01%, the relative difference shall not exceed four times.7.1.3The standards used for measurements may differ inU) concentration. In concentration range 0.0002 to 0.01, C234 236!SH/ C234 236!SL# 8; in co
23、ncentrationrange 0.01 to 0.1, C234 236!SH/ C234 236!SL# 6.7.1.3 The CRMs or traceable standards used for measurements may differ in235U concentration from a sample, but the relativedifference shall not be more than 10%. The relative difference inU concentration from a sample. ( C235X) on condition t
24、hat C235SH/ C235X# 1.5 and C235X/ C235SL# 1.5. For234U(236U) concentration shall not exceed two times for the concentration range 0.001 to 0.01%, and shall not bemore than 50% for the concentration range 0.01 to 0.1%. U) isotopes, the following range limitations shall be used: 0.0002 to 0.01C234236!
25、SH/ C234236!X# 4, C234236!X/ C234236!SL# 4; in concentration range 0.01 to 0.1 C234236!SH/ C234236!X# 3, C234236!X/ C234236!SL#3.8. ProcedureA typical sequence for the analytical determination is X, S, X, S, where X and S mean the introduction of the sample and theCRM or traceable standard, respecti
26、vely. Each introduction is followed by ion source evacuation before the next introduction.During each introduction, a simultaneous measurement of the four uranium isotopes occurs.The intensities of the238UUF5+ion beam for both sample and CRM or traceable standard introduction shall not differ more t
27、han3 %. Adjustment is performed by pressure equalization of the sample and standard in the inlet system.The number of introductions per analytical sequence is dependent on the precision required.8.1 Attach sample containers containing the appropriate sample, X, and standard, S, to the inlet system,
28、and prepare bothmaterials for introduction into the ion source as follows:8.1.1 Operate the appropriate valves to remove air entrapped in the connectors and to check that there are no leaks in inletsystem.8.1.2 Freeze the UF6by immersing the sample container (the unknown sample) into a mixture of wa
29、ter and ice.8.1.3 Open the valve on the container to permit evacuation of volatile impurities, and then close the valve.8.1.4 Remove the coolant from around the container and allow the UF6to return to room temperature.8.1.5 Repeat 8.1.2-8.1.4 for the standard. for the CRM or traceable standard.8.2 O
30、peration of the Mass Spectrometer8.2.1 Operate appropriate valves to admit the CRM or traceable standard into the ion source.8.2.2 Adjust the accelerating voltage or magnet current to focus the ion beams234UF5+,235UF5+,236UF5+, and238UF5+toC1428 112their corresponding collectors.Adjust the mass spec
31、trometer parameters to obtain the maximum 238UF5+ion current and maximum resolution.8.2.3 Regulate the adjustable leak to obtain a238UF5+ion current of about 109A.8.2.4 Measure the ion current ratio of234U,235U, and236Uto238U.8.2.5 Terminate the flow of the CRM or traceable standard and evacuate the
32、 ion source.8.2.6 Repeat 8.2.1, 8.2.4, and 8.2.5 for the sample.9. Calculation9.1 The memory correction factor M is calculated by the formula:Mi5EiS12 EiS2EiS2riS12 riS2riS2(2)where:Mi= memory correction factor,EiS1, EiS2= molar ratios of isotope of interest to238U is calculated from certified data
33、of the two CRMs or traceable standards taken for memory determination,riS1= measured ion current ratio of isotope of interest to238U for Standard 1, and U for CRM or traceable standard 1, andriS2= measured ion current ratio of isotope of interest to238U for Standard 2.U for CRM or traceable standard
34、 2.9.2 The ratio of molar ratios for the CRMs or traceable standards is calculated as follows:RiS5riS1riS2(3)9.3 The ratio of molar ratios for the sample is calculated as follows:RiX5riXriS(4)where:riX= measured ion current ratio of isotope of interest to238U for the sample, andriS= measured ion cur
35、rent ratio of isotope of interest to238U for the working standard.U for the working CRM or traceablestandard.9.4 The corrected molar ratio EiXis calculated for the sample using the memory correction factor, Mi, and certified data of theCRM or traceable standard:EiX5 1 1 Mi RiX2 1!# EiS(5)where:EiS=
36、ratio of certified molar concentrations of isotope of interest to238U for the working standard.U for the working CRMor traceable standard.9.5 Calculate the molar concentration of isotope of interest for the sample:CiX5EiX 1001 1(EjX(6)where:EjX= corrected molar ratios for234U,235U, and236U (see 9.4)
37、.9.6 Calculate the weight percent for234U,235U, and236U as follows:Ci5CiX Ai(CjX Aj(7)where:CjX= molar concentration of the isotope j,Ai= atomic mass of the isotope i of interest, andAj= atomic masses of the isotope j.10. Precision and Bias10.1 Isotopic uranium standardsCRMs have been analysed from
38、1995 to 1996.analyzed in 2009. The measurements wereconducted in one laboratory on two mass spectrometers by various operators.10.2 PrecisionFor each standard, the average measured value, X, is given together with the standard deviation, Sr, obtainedfor n experiments. Results are listed in For each
39、CRM, the average measured value, CiX, is given together with the relativestandard uncertainty, obtained for n experiments under repeatability. Results are listed in Table 1.The standards used for measurements differed in isotopic composition from the analyzed standards. The relative difference inC14
40、28 113TABLE1UraniumIsotopicStandardCRMsResultsMass-spectrometerAMass-spectrometerBCRMsusedfordeterminationofthememorycorrectionfactorReg.No.RM,Lotnumber,Certifiedvalues,IsotopeMassFraction,%CRM7533-99,207-05(WorkingCRM)CRM7523-99,210-06CRM7533-99,207-05(WorkingCRM)CRM7520-99,3-79C235U(atom%)SRMCerti
41、fiedValues6absoluteerrorC235S=1.204760.0005C235S=4.951260.0024C235S=0.504060.0003SRMCertifiedValues=4.951260.0024C235S=1.204760.0005C235S=4.951260.0024C235S=0.504060.0003C234S=0.0461260.00015C234S=0.0074760.00002C234S=0.0461260.00015C234S=0.003560.0001C236S=0.0152160.00010C236S=0.0023160.00002C236S=
42、0.0152160.00010C236S=0.006060.0001CRMeasuredValues,IsotopeMassFraction,%CRM7530-99,186-01CRM7530-99,186-01CRMsusedasasampleReg.No.RM,Lotnumber,Certifiedvalues,IsotopeMassFraction,%CRM7530-99,186-01CRM7530-99,186-01C235XC234XC236XC235XC234XC236X4.003260.00190.036060.00020.013360.00024.003260.00190.03
43、6060.00020.013360.0002XS!4.00240.035900.013244.00350.035950.01328MeanCiX!4.00240.035900.013244.00350.035950.01328Quantityofdeternationsunderrepeatability(n)999101010Quantityofdeterminationsunderrepeatability(n)99910101095Relativestandarduncertainty,%0.14890060.71978620.430006050.719830.000282Relativ
44、estandarduncertainty,%0.0060.120.430.006050.09830.000282595.1629BiasCiX2CiX!02.437760.00122.437380.000520BiasCiX2CiX!0.000122.437380.00052095.167903.143460.00153.14280060.00032095.0000595.100.00153.14280060.00030.000050.00005CRMsusedfordeterminationofthememorycorrectionfactorReg.No.RM,Lotnumber,Cert
45、ifiedvalues,IsotopeMassFraction,%CRM7533-99,207-05(WorkingCRM)CRM7523-99,210-06CRM73907-05CRM7520-99,3-79(WorkingCRM)CRMsusedfordeterminationofthememorycorrectionfactorReg.No.RM,Lotnumber,Certifiedvalues,IsotopeMassFraction,%CRM7533-99,207-05(WorkingCRM)CRM7523-99,210-06CRM7533-99,207-05CRM7520-99,3
46、-79(WorkingCRM)C235S=4.25260.0024.25110.0005C235S=420.0024C235S=0.504060.0C235S=4.951260.0024C235S=11.204760.0005C235S=4.951260.0024C235S=0.504060.0C234U(S=0.0461260.00015C234S=0.0074760.00002C234S=0.0461260.00015C234S=0.003560.0001C234S=0.0461260.00015C234S=0.0074760.00002C234S=0.0461260.00015C234S
47、=0.003560.0001C236S=0.0152160.00010C236S=0.0023160.00002C236S0.0152160.00010C236S=0.006060.0001CRMsusedatom%)CRM7527-99,219-08CRM7527-99,219-08CRMsusedasasampleReg.No.RM,Lotnumber,Certifiedvalues,IsotopeMassFraction,%CRM7527-99,219-08CRM7527-99,219-08C235XC234XC236XC235XC234XC236X2.825060.00110.0254
48、560.00010.0007060.000032.825060.00110.0254560.00010.0007060.0000395MeanCiX!2.148900.005336420.000722.8243050.005325440.00001420MeanCiX!2.82480.025420.000722.8243050.025440.00001420679Quantityofdeterminationsunderrepeatability(n)101010101010Quantityofdeterminationsunderrepeatability(n)101010101010Rel
49、ativestandarduncertainty,%0.005.1735.20.0090.147.2Relativestandarduncertainty,%0.0050.135.20.0090.147.2BiasCiX2CiX!0.00020.0000320.00070.000010.00003BiasCiX2CiX!0.00020.000030.000020.00070.000010.00003CRMsusedfordeterminationofthememorycorrectionfactorRegNoRMLotnumberCRM7520-99,3-79CRM7523-99,210-06(WorkingCRM)CRM7520-99,3-79CRM7523-99,210-06(WorkingCRM)C235S=0.504060.0003C20.0005C235S=0.504060.0003C270.0005C1428 114235U concentration was equal close to 10%, and one in234U and236U concentrations was equal close to 50%.10.3 BiasI
