1、Designation:C143007(Reapproved 2011)1Standard Test Method forDetermination of Uranium,Oxygen to Uranium(O/U),andOxygen to Metal(O/M)in Sintered Uranium Dioxide andGadolinia-Uranium Dioxide Pellets by AtmosphericEquilibration1This standard is issued under the fixed designation C1430;the number immedi
2、ately 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.1NOTEA units statement w
3、as added editorially in June 2011.1.Scope1.1 This test method applies to the determination ofuranium,the oxygen to uranium(O/U)ratio in sintereduranium dioxide pellets,and the oxygen to metal(O/M)ratio insintered gadolinium oxide-uranium dioxide pellets with aGd2O3concentration of up to 12 weight%.T
4、he O/M calcula-tions assume that the gadolinium and uranium oxides arepresent in a metal dioxide solid solution.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 co
5、ncerns,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.For specific hazardsstatements,see Section 8.2.Referenced Documents2.1 ASTM Standar
6、ds:2C696 Test Methods for Chemical,Mass Spectrometric,andSpectrochemical Analysis of Nuclear-Grade Uranium Di-oxide Powders and PelletsC776 Specification for Sintered Uranium Dioxide PelletsC922 Specification for Sintered Gadolinium Oxide-UraniumDioxide PelletsC968 Test Methods for Analysis of Sinte
7、red GadoliniumOxide-Uranium Dioxide PelletsC1287 Test Method for Determination of Impurities inNuclear Grade Uranium Compounds by InductivelyCoupled Plasma Mass Spectrometry3.Summary of Test Method3.1 The uranium,and either O/U or O/M,are determined bymeasuring the weight change of a sintered pellet
8、 after it hasbeen exposed to an equilibrating atmosphere to bring it to thestoichiometric condition.Sintered pellets are weighed andloaded into a sample boat.The boat is placed in a tube furnacecapable of holding a temperature of 800 6 10C.The furnaceis purged with a moist gas flow of 4%hydrogen and
9、 96%argon or nitrogen to remove all air.The temperature of thefurnace is raised to 800C and held at this temperature withconstant gas flow for 4 h.The furnace then is turned off andallowed to cool,with gas purge on,to room temperature.Thesamples are removed from the furnace and reweighed.3.2 The wei
10、ght change,gadolinia content,and chemicalimpurity content are used to calculate%uranium and the O/Uor O/M.4.Significance and Use4.1 Uranium dioxide is used as a nuclear-reactor fuel.Thistest method is designed to determine whether the percenturanium and O/U or O/M content meet Specifications C776and
11、 C922.5.Interferences5.1 Parameters for temperature,gas composition,gas flow,and moist air purge must be monitored and maintained care-fully within the limits set in the procedure.5.2 This test method assumes that chemical impurities meetSpecifications C776 and C922 limits.Potential method inter-fer
12、ences from higher impurity concentrations will requireevaluation.5.3 Furnace tubes or boats made from metals that oxidizeunder the test conditions may prevent proper equilibration byconsuming available oxygen.1This test method is under the jurisdiction ofASTM Committee C26 on NuclearFuel Cycle and i
13、s the direct responsibility of Subcommittee C26.05 on Methods ofTest.Current edition approved June 1,2011.Published June 2011.Originallyapproved in 2000.Last previous edition approved in 2007 as C143007.DOI:10.1520/C1430-07R11E01.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orc
14、ontact 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 5.4 Precise weighing of sa
15、mples is critical to the accuracy ofthis test method.5.5 Loss of weight due to pellet chipping would invalidatethe analysis.Handle pellets with care.5.6 This test method assumes that pellets are sintered.Itdoes not correct for moisture or volatile additives.5.7 This test method assumes that UO2-Gd2O
16、3pellets haveformed a solid solution;however,the error from incompletedissolution of Gd2O3would be very small(see the calculationin 10.2).6.Apparatus6.1 Analytical Balance,capable of weighing to 6 0.0001 g.6.2 Tube Furnace,capable of controlling temperatures at800 6 10C,that has been fitted with a fused quartz furnacetube.6.3 Fused Quartz Sample Boats.6.4 Assorted Connectors,Tubing,Flasks,Stoppers,andDelivery TubesThe purge gas is passed through a humidifier,into the tube furnace.A bubbler flask
