1、Designation:C153908(Reapproved 2014)Standard Test Method forDetermination of Technetium-99 in Uranium Hexafluoride byLiquid Scintillation Counting1This standard is issued under the fixed designation C1539;the number immediately following the designation indicates the year oforiginal adoption or,in t
2、he 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 a quantitative method used todetermine technetium-99(99Tc)in uranium he
3、xafluoride(UF6)by liquid scintillation counting.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of
4、 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:2C787 Specification for Uranium Hexafluoride for Enrich-mentC996 Specification for Uranium Hexafluoride En
5、riched toLess Than 5%235UC1215 Guide for Preparing and Interpreting Precision andBias Statements in Test Method Standards Used in theNuclear Industry2.2 Other Document:USEC-651Uranium Hexafluoride:A Manual of GoodHandling Practices33.Terminology3.1 Definitions:3.1.1 quench standard curvea relationsh
6、ip betweensample quench and detection efficiency.A quench curve for anisotope in a given cocktail and vial combination is developedby counting a series of standards containing the same activityof that isotope,but each with different quench.Sample quenchis typically quantified by a variety of paramet
7、ers.4.Summary of Test Method4.1 Ameasured portion of hydrolyzed uranium hexafluoride(UF6)containing approximately 0.8 to 1.2 g of uranium or avolume of sample less than or equal to 30 mL is transferred toa centrifuge tube.The uranium is precipitated using ammo-nium hydroxide.After centrifuging,the d
8、ecanted supernatant isacidified with sulfuric acid and extracted with tributyl phos-phate.An aliquot of the extract is transferred to a scintillationvial,where stannous chloride in hydrochloric acid and liquidscintillation cocktail are added.The99Tc beta activity is thendetermined by liquid scintill
9、ation counting.5.Significance and Use5.1 Uranium hexafluoride is a basic material used to preparenuclear reactor fuel.To be suitable for this purpose,thematerial must meet the criteria for technetium composition.This test method is designed to determine whether the materialmeets the requirements des
10、cribed in Specifications C787 andC996.5.2 Using the specified instrumentation and parameters,thismethod has a lower detection limit of 0.0004 gTc/gU.NOTE1Different instrumentation or parameters may provide varyingdetection limits,as calculated in 11.4.6.Apparatus6.1 Liquid Scintillation Counter,4wit
11、h alpha/beta discrimi-nation and enhanced low level discrimination over the entireenergy range of 0 to 2000 keV.6.2 Centrifuge.6.3 Analytical Balance,1 mg sensitivity.6.4 Separatory Funnel,125 mL volume.1This test method is under the jurisdiction ofASTM Committee C26 on NuclearFuel Cycle and is the
12、direct responsibility of Subcommittee C26.05 on Methods ofTest.Current edition approved June 1,2014.Published June 2014.Originallyapproved in 2002.Last previous edition approved in 2008 as C1539 08.DOI:10.1520/C1539-08R14.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact A
13、STM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3Available from U.S.Enrichment Corporation,6903 Rockledge Drive,Bethesda,MD 20817.4The sole source of supply of the apparatus known to the commi
14、ttee at this timeis Packard Tri-Carb Model 1905 AB/LA.If you are aware of alternative suppliers,please provide this information to ASTM International Headquarters.Your com-ments will receive careful consideration at a meeting of the responsible technicalcommittee,1which you may attend.Copyright ASTM
15、 International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 6.5 Liquid Scintillation Vials,20 mL.6.6 Centrifuge Tubes with Caps,50 mL.6.7 Laboratory Wipes,lint free disposable.7.Reagents and Materials7.1 Purity of ReagentsReagent grade chemicals shall beused in al
16、l tests.Unless otherwise indicated,it is intended thatall reagents conform to the specifications of the Committee ofAnalytical Reagents of the American Chemical Society wherespecifications are available.57.2 Purity of WaterUnless otherwise indicated,referencesto water shall be understood to mean laboratory accepteddeionized water.7.3 Ammonium Hydroxide(NH4OH),concentrated(14.5M).7.4 Hydrochloric Acid(HCl),concentrated(12M).7.5 Hydrochloric Acid(HCl),(1M).Add 82 mL of concen-trated(12 M)HCl to 90
