1、Designation:C134497(Reapproved 2013)Standard Test Method forIsotopic Analysis of Uranium Hexafluoride by Single-Standard Gas Source Mass Spectrometer Method1This standard is issued under the fixed designation C1344;the number immediately following the designation indicates the year oforiginal adopti
2、on 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 covers the isotopic analysis of uraniumhexafluoride(UF6)and may
3、be used for the entire range of235U isotopic compositions for which standards are available.1.2 This test method is applicable to the determination ofthe isotopic relationship between two UF6samples.If theabundance of a specific isotope of one sample(the standard)isknown,its abundance in the other c
4、an be determined.This testmethod is flexible in that the number of times a given materialis admitted to the ion source may be adjusted to the minimumrequired for a specified precision level.1.3 The sensitivity with which differences between twomaterials can be detected depends on the measuring syste
5、mused,but ratio-measuring devices can generally read ratio-of-mol ratio differences as small as 0.0001.1.4 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.5 This standard does not purport to address all of thesafety concerns,if
6、 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.Specific hazardsstatements are given in Section 7.2.Referenced Documents2.1 ASTM Standards:2
7、C787 Specification for Uranium Hexafluoride for Enrich-mentC996 Specification for Uranium Hexafluoride Enriched toLess Than 5%235U2.2 Other Document:USEC-651,Uranium Hexafluoride:A Manual of GoodHandling Practices33.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 drop through,na
8、measurement of the amount of the238UF5+ion beam that can be passed through the235UF5+collector slit and measured on the235UF5+collector,stated asa percentage of the total238UF5+signal.3.1.2 memory corrections,ncorrections applied to thesample analysis results for memory effects.3.1.3 memory effect,n
9、the inability of the mass spectrom-eter to omit completely the isotopic composition of the sampleanalyzed previously from attributing to the results of furthersamples analyzed.3.1.4 normal isotopic abundance material,nUF6having avalue of 0.711 weight percent(wt%)235U.3.1.5 ratio-of-mol-ratios,nthe m
10、ol ratio(235U/238U)ofthe sample divided by the mol ratio of the standard,or theinverse condition of the mol ratio of the standard divided by themol ratio of the sample.4.Summary of Test Method4.1 Test MethodThe unknown sample and a standard withan isotopic composition close to that of the sample are
11、introduced in sequence into the Neir mass spectrometer.UF5+ions of the isotopes are focused through a mass-resolvingcollector slit and onto a faraday cup collector.Measurementsare made of235UF5+to the total of the other UF5+isotopes.With the known composition of the standard,calculation of the235U c
12、omposition of the sample can be determined.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 isotopic composition.This1This test method is under the jurisdiction ofASTM Committ
13、ee C26 on NuclearFuel Cycle and is the direct responsibility of Subcommittee C26.05 on Methods ofTest.Current edition approved July 1,2013.Published July 2013.Originally approvedin 1997.Last previous edition approved in 2008 as C1344 97(2008)1.DOI:10.1520/C1344-97R13.2For referenced ASTM standards,v
14、isit 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.3Available from U.S.Enrichment Corporation,6903 Rockledge Dr.,Bethesda,MD 20817,http:/.Copyright A
15、STM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 test method is designed to determine whether the materialmeets the requirements described in Specifications C787 andC996.5.2 ASTM Committee C-26 Safeguards Statement:5.2.1 The material(uranium hexafluo
16、ride)to which this testmethod applies is subject to the nuclear safeguards regulationsgoverning its possession and use.The analytical procedure inthis test method has been designated as technically acceptablefor generating safeguards accountability data.5.2.2 When used in conjunction with appropriate certifiedreference materials(CRMs),this procedure can demonstratetraceability to the national measurement base.However,adher-ence to this procedure does not automatically guarantee regu-latory accep