1、Designation:C140816Standard Test Method forCarbon(Total)in Uranium Oxide Powders and Pellets ByDirect Combustion-Infrared Detection Method1This standard is issued under the fixed designation C1408;the number immediately following the designation indicates the year oforiginal adoption or,in the case
2、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 determination of carbon innuclear-grade uranium oxide powders and pelle
3、ts to determinecompliance with specifications.1.2 Gadolinium oxide(Gd2O3)and gadolinium oxide-uranium oxide powders and pellets may also be analyzed usingthis test method.1.3 This test method covers the determination of 5 to 500 gof residual carbon.1.4 This test method describes an induction furnace
4、 carriergas combustion system equipped with an infrared detector.Itmay also be applied to a similar instrument equipped with athermal conductivity detector.1.5 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.5.1 The preferred s
5、ystem of units is micrograms carbonper gram of sample(g/g sample)or micrograms carbon pergram of uranium(g/g U).1.6 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
6、 and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2C753 Specification for Nuclear-Grade,Sinterable UraniumDioxide PowderC776 Specification for Sintered Uranium Dioxide PelletsC859 Terminology Relating to Nuclear Mat
7、erialsC888 Specification for Nuclear-Grade Gadolinium Oxide(Gd2O3)PowderC922 Specification for Sintered Gadolinium Oxide-UraniumDioxide Pellets2.2 NIST Standard:3NIST SRM 101G Standard Reference MaterialsStainlessSteel3.Terminology3.1 DefinitionsExcept as otherwise defined herein,defini-tions of ter
8、ms are given in Terminology C859.3.2 Definitions of Terms Specific to This Standard:3.2.1 acceleratoran igniter and a flux which promotesboth combustion and a fluid melt by effectively lowering themelting point of the sample.4.Summary of Test Method4.1 The powered or crushed test specimen and an app
9、ropri-ate accelerator(metal flux)are added to a crucible,placedwithin an induction-heated furnace and burned at a nominaltemperature of 1600 to 1700C in a stream of oxygen.Thecarbon in the sample is oxidized to primarily carbon dioxide(CO2)with some carbon monoxide(CO)formed.A catalystconverts the C
10、O to CO2and the products of combustion arescavenged free of sulfur compounds,halogens,and watervapor.The CO2is swept into an infrared cell detector.Theamount of carbon is automatically determined from storedcalibration data,and is displayed or printed out,or both,by thecarbon analyzer.4.2 The actual
11、 configuration of the system may vary withvendor and model.Typical systems include columns of mate-rials such as copper oxide,platinized silica gel,magnesiumperchlorate,sodium hydroxide,and cellulose to purify the CO2stream.5.Significance and Use5.1 Uranium dioxide is used as a nuclear-reactor fuel.
12、Gadolinium oxide is used as an additive to uranium dioxide.In1This 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 March 1,2016.Published March 2016.Originallyapproved i
13、n 1998.Last previous edition approved in 2009 as C1408 09.DOI:10.1520/C1408-16.2For 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
14、ASTM website.3Available from National Institute of Standards and Technology(NIST),100Bureau Dr.,Stop 1070,Gaithersburg,MD 20899-1070,http:/www.nist.gov.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 order to be suitable for this purpose,
15、these materials must meetcertain criteria for impurity content.This test method isdesigned to determine whether the carbon content meetsSpecifications C753,C776,C888,and C922.6.Interferences6.1 Contamination of carrier gas,crucibles,or samples withextraneous sources of carbon may cause a positive bi
16、as.Theblank correction will help to minimize the bias from carrier gasand crucibles.Interference from absorbed carbon on samplesmay be eliminated by keeping the sample in an inert atmo-sphere or vacuum.6.2 Powdered Gd2O3samples may adsorb CO/CO2from theatmosphere.Sample preheating to 120 for 2 h is recom-mended in this case.6.3 The purification system typically associated with therecommended combustion and detection equipment is de-signed to minimize other expected sources of interferences,such
