ASTM_C_1219_-_05_2009.pdf

Designation:C121905(Reapproved2009)Standard Test Methods forArsenic in Uranium Hexafluoride1This standard is issued under the fixed designation C1219;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 These test methods are applicable to the determinationof total arsenic in uranium hexafluoride(UF6)by atomicabsorption spectrometry.Two test methods are given:TestMethod AArsine Generation-Atomic Absorption(Sections5-10),and Test Method BGraphite Furnace Atomic Absorp-tion(Appendix X1).1.2 The test methods are equivalent.The limit of detectionfor each test method is 0.1 g As/g U when using a samplecontaining 0.5 to 1.0 g U.Test Method B does not have thecomplete collection details for precision and bias data thus themethod appears as an appendix.1.3 Test Method A covers the measurement of arsenic inuranyl fluoride(UO2F2)solutions by converting arsenic toarsine and measuring the arsine vapor by flame atomic absorp-tion spectrometry.1.4 Test Method B utilizes a solvent extraction to removethe uranium from the UO2F2solution prior to measurement ofthe arsenic by graphite furnace atomic absorption spectrom-etry.1.5 Both insoluble and soluble arsenic are measured whenUF6is prepared according to Test Method C761.1.6 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.7 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:2C761 Test Methods for Chemical,Mass Spectrometric,Spectrochemical,Nuclear,and Radiochemical Analysis ofUranium HexafluorideC787 Specification for Uranium Hexafluoride for Enrich-mentD1193 Specification for Reagent Water3.Summary of Test Method3.1 Arsine Generation-Atomic Absorption SpectrometryMethodThe sample of UF6is hydrolyzed and the UO2F2solution is fumed with sulfuric acid in the presence of boricacid to complex the fluoride.Potassium iodide is used toreduce arsenic(V)to arsenic(III).Sodium borohydride is usedto generate arsine vapor in a hydride generator with subsequentmeasurement by flame atomic absorption spectrometry.3.2 Graphite Furnace Atomic Absorption SpectrometryMethodThe sample of UF6is hydrolyzed,and the uranium inthe UO2F2solution is removed by extraction with tri(2-ethyl-hexyl)phosphate/heptane.The aqueous phase containing thearsenic is analyzed by graphite furnace atomic absorption.4.Significance and Use4.1 Arsenic compounds are suspected to cause corrosion insome materials used in UF6handling equipment.Arsenicoriginates as a contaminant in fluorspar(CaF2)used to produceanhydrous hydrogen fluoride which is used subsequently in theproduction of UF6.1This test methods are under the jurisdiction of ASTM Committee C26 onNuclear Fuel Cycle and are the direct responsibility of Subcommittee C26.05 onMethods of Test.Current edition approved July 1,2009.Published August 2009.Originallyapproved in 1992.Last previous edition approved in 2005 as C1219 05.DOI:10.1520/C1219-05R09.2For 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 StatesNOTICE:This standard has either been superseded and replaced by a new version or withdrawn.Contact ASTM International(www.astm.org)for the latest information1 4.2 These test methods are used to measure the arseniccontent in UO2F2solutions prepared from the hydrolysis ofUF6for determination of conformance to Specification C787.TEST METHOD AARSINE GENERATION-ATOMICABSORPTION SPECTROMETRY5.Interferences5.1 The presence of hydrofluoric acid in the sample sup-presses arsine generation when using sodium borohydride.Boric acid is added to complex the fluoride present at a molarexcess of 250%.35.2 Arsenic(V)must be reduced to arsenic(III)otherwisearsine will not be generated using sodium borohydride andhydrochloric acid.5.3 The reduction of arsenic(V)by potassium iodide is timedependent at room temperature requiring strict adherence to theprocedure.5.4 Do not use platinum labware.6.Apparatus6.1 Atomic Absorption Spectrometer,equipped with an air-acetylene burner,arsenic hollow cathode lamp and hydridegenerator,gas/liquid separator,and hydride absorption cell.6.2 Hot Plate,capable of reaching a surface temperature of500C.7.Reagents and Materials7.1 Reagents:7.1.1 Purity of ReagentsReagent grade chemicals shall beu