ASTM_C_1413_-_05_2011.pdf

Designation:C141305(Reapproved 2011)Standard Test Method forIsotopic Analysis of Hydrolyzed Uranium Hexafluoride andUranyl Nitrate Solutions by Thermal Ionization MassSpectrometry1This standard is issued under the fixed designation C1413;the number immediately following the designation 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 method applies to the determination of isotopiccomposition 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 abundance 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 nitratesolution 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 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 practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2C696 Test Methods for Chemical,Mass Spectrometric,andSpectrochemical Analysis of Nuclear-Grade Uranium Di-oxide Powders and PelletsC753 Specification for Nuclear-Grade,Sinterable UraniumDioxide PowderC761 Test Methods for Chemical,Mass Spectrometric,Spectrochemical,Nuclear,and Radiochemical Analysis ofUranium HexafluorideC776 Specification for Sintered Uranium Dioxide PelletsC787 Specification for Uranium Hexafluoride for Enrich-mentC788 Specification for Nuclear-Grade Uranyl Nitrate Solu-tion or CrystalsC996 Specification for Uranium Hexafluoride Enriched toLess Than 5%235UC1334 Specification for Uranium Oxides with a235U Con-tent of Less Than 5%for Dissolution Prior to Conversionto Nuclear-Grade Uranium DioxideC1346 Practice for Dissolution of UF6from P-10 Tubes,C1347 Practice for Preparation and Dissolution of UraniumMaterials for AnalysisC1348 Specification for Blended Uranium Oxides with235UContent of Less Than 5%for Direct Hydrogen Reductionto Nuclear Grade 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 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 electron 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 produce nuclear fuel mustmeet certain criteria for its isotopic composition as described inSpecifications C787 and C996.1This test method is under the jurisdiction ofASTM Committee C26 on NuclearFuel Cycle and is the direct responsibility of Subcommittee C26.05 on Methods ofTest.Current edition approved June 1,2011.Published June 2011.Originallyapproved in 1999.Last previous edition approved in 2005 as C1413 05.DOI:10.1520/C1413-05R11.2For 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 website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 5.Interferences5.1 This test method only applies to nuclear grade uraniummatrices(as defined in Specification C753,C776,C787,C788,C1334,or C1348).Large amount of impurities,which arefound,for example,in uranium ore concentrates,may biasresults.A purification step may be necessary,as described inSpecification C696.5.2 The type of acid used(HF or HNO3)and its concentra-tion will strongly influence the obtained 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 abu