1、Designation: C1453 00 (Reapproved 2011)Standard Test Method forthe Determination of Uranium by Ignition and the Oxygen toUranium (O/U) Atomic Ratio of Nuclear Grade UraniumDioxide Powders and Pellets1This standard is issued under the fixed designation C1453; the number immediately following the desi
2、gnation 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 This test method covers the de
3、termination of uraniumand the oxygen to uranium atomic ratio in nuclear gradeuranium dioxide powder and pellets.1.2 This test method does not include provisions for pre-venting criticality accidents or requirements for health andsafety. Observance of this test method does not relieve the userof the
4、obligation to be aware of and conform to all interna-tional, national, or federal, state and local regulations pertain-ing to possessing, shipping, processing, or using source orspecial nuclear material.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with
5、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.1.4 This test method also is applicable to UO3and U3O8powder.2. Referenced Documents2.1 ASTM Standards:2C696 Tes
6、t Methods for Chemical, Mass Spectrometric, andSpectrochemical Analysis of Nuclear-Grade Uranium Di-oxide Powders and PelletsC753 Specification for Nuclear-Grade, Sinterable UraniumDioxide PowderC776 Specification for Sintered Uranium Dioxide PelletsC1267 Test Method for Uranium by Iron (II) Reducti
7、on inPhosphoric Acid Followed by Chromium (VI) Titration inthe Presence of VanadiumC1287 Test Method for Determination of Impurities inNuclear Grade Uranium Compounds by InductivelyCoupled Plasma Mass Spectrometry3. Summary of Test Method3.1 A weighed portion of UO2is converted to U3O8byrepeated ign
8、ition at 900C in air, to a constant weight.Corrections are made for nonvolatile and volatile impuritiesincluding moisture, based on independent determinations de-scribed in Test Methods C696 and C1287.3,44. Significance and Use4.1 The test method is designed to show whether or not amaterial meets th
9、e specifications as given in SpecificationsC753 or C776.4.2 The powders stoichiometry is useful for predicting theoxides sintering behavior in the pellet production process.5. Interferences5.1 The moisture content must be determined and a correc-tion must be made for the moisture content otherwise a
10、 highbias will occur for the O/U ratio.5.2 A nonvolatile impurity correction must be made other-wise a high bias will occur for the uranium value.An extendedignition time may be required if significant amounts of anionsthat are difficult to decompose are present.5.3 The U3O8to uranium conversion fac
11、tor and the uraniumatomic weight will require adjustment for nonnatural isotopicconcentrations otherwise a bias will be present.6. Apparatus6.1 Desiccator, containing a moisture absorbent.6.2 Muffle Furnace, capable of maintaining and controllingtemperatures to 900 6 25C.6.3 Analytical Balance, capa
12、ble of weighing to 6 0.1 mg.1This test method is under the jurisdiction of ASTM committee C26 on NuclearFuel Cycle and is the direct responsibility of Subcommittee C26.05 on Methods ofTest.Current edition approved July 1, 2011. Published July 2011. Originally approvedin 2000. Last previous edition a
13、pproved in 2006 as C1453 00R06. DOI: 10.1520/C1453-00R11.2For 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.3Jon
14、es, R.J., Ed., “Selected Measurement Methods for Plutonium and Uraniumin the Nuclear Fuel Cycle,” USAEC Document TID-7029, 1963, AERDB, pp.9193.4Petit, G.D. and Keinberger, C.A., “Preparation of Stoichiometric U3O8,”Analytical Chemistry, ANCHA, Vol 25, 1961, p. 579.1Copyright ASTM International, 100
15、 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6.4 Platinumware.7. Reagents and Materials7.1 Anhydrous magnesium perchlorate Mg (ClO4)2, mois-ture absorbent, or equivalent.8. Procedure8.1 Transfer 2 to 12 g of UO2powder or pellets to a taredplatinum crucible and wei
16、gh to within 0.1 mg.8.1.1 UO2PowderPlace the platinum crucible containingthe UO2powder sample in a muffle furnace and ignite for 3 hat 900 6 25C.8.1.2 UO2PelletsPreheat the pellets at 500C for 3 h, inthe muffle furnace, then ignite for3hat9006 25C.8.2 Remove the crucible from the furnace, allow to c
17、ool inthe air 2 to 3 minutes, then place the crucible in a desiccatorand cool to room temperature. Weigh the crucible.8.3 Repeat the ignition for 3 h at 900C and repeat step 8.2until a constant weight of 60.3 mg is obtained.8.4 Other ignition and cooling schemes may be used as longas the analyst ver
18、ifies the precision and the bias of themeasurement.9. Calculation9.1 Uranium ContentCalculate as follows:U, wt% 5 0.8480 W 2 WI!/S! X 100 2 C (1)where:0.8480 = U3O8to uranium conversion factor for naturaluranium.This factor will require adjustment whenthe uranium isotopic abundance deviates fromnatu
19、ral uranium. See Appendix X1.2.W = Grams of U3O8after ignition.I = Total of all detected nonvolatile impurities ex-pressed as grams of oxide per gram of ignitedU3O8. See Table 1 to obtain oxide conversionfactors for many common impurity elements en-countered. The impurities are determined as de-scri
20、bed in either Test Method C696 or C1287.S = Initial sample weight, in g.C = Total of all nonvolatile impurities analyzed as lessthan the lower detection limit of the analyticalmethod. The detection limit values shall be takenas the concentration of that element. The total isexpressed as percent. The
21、se impurities are deter-mined as described in Test Method C696 orC1287. Alternatively, the these impurities can beconsidered to contribute a total correction of0.01 % to the uranium percent.9.2 Oxygen-to-Uranium RatioCalculate as follows fromthe original sample U, wt%:O/U 5 100 2 Uwt% 2 Z 2 m!A!# /1
22、5.999!Uwt%!# (2)where:O = atom % of oxygenU = atom % of uraniumU wt% = U, weight %, as calculated in 9.1Z = total non-volatile impurities correction, %, asdetermined in Test Method C696 or C1287.m = moisture and volatile impurity content, %, deter-mined in Test Method C696 or C1287.A = atomic weight
23、 of uranium based on isotopicabundance. See X1.1.15.999 = atomic weight of oxygen10. Precision and Bias10.1 UO2PowderThe precision for the O/U ratio for UO2powder is shown in Table 2. The bias was not determined asthere are no standards due to the relative reactivity of thepowder. The data in Table
24、2 were determined by one analystover a three-day period.10.2 UO2Pellets:TABLE 1 Oxide Conversion Factors for Impurity CorrectionImpurity Assumed Oxide Form Oxide Conversion FactorAAl Al2O31.89BB2O33.23Ba BaO 1.12Be BeO 2.78Bi Bi2O31.11Ca CaO 1.40Cd CdO 1.14Co Co2O31.41Cr Cr2O31.46Cu CuO 1.25Fe Fe2O3
25、1.43InBIn2O31.21Li Li2O 2.15Mg MgO 1.66Mn MnO21.58Mo MoO31.50Na Na2O 1.35Ni NiO 1.27PP2O52.29Pb PbO21.15Sb Sb2O41.26Si SiO22.14Sn SnO21.27Ti TiO21.67VV2O51.79Zn ZnO 1.24Zr ZrO21.35Ta Ta2O51.22WW31.26AOxide conversion factor is defined as grams oxide per gram of element.BThis element is not required
26、by the UO2Specifications C753 and C776 but isincluded for information only.TABLE 2 UO2Powder ResultsSample TypeUranium wt% AbsoluteStandardDeviationO/U RatioStandardDeviationNo. ofDeterminationsSample A 87.796 0.005 2.065 0.001 12Sample B 86.996 0.004 2.225 0.001 12C1453 00 (2011)210.2.1 The precisi
27、on for the O/U ratio for UO2pellets isshown in Table 3.5The data were determined by two differentlaboratories. The data for Laboratory A were determined overseveral days by one analyst. The data for laboratory B weredetermined over seven days by four analysts using threefurnaces.10.2.2 The precision
28、 for the uranium content for UO2pelletsis shown in Table 4.5The data were determined as describedfor Table 3.10.2.3 The reference value for G-2 working pellet standardwas obtained from the weighted average of eight ferroussulphate type titration measurements and nine ignition typemeasurements. The m
29、easurements were standardized againstNBL 125 standard. One analyst performed the measurementsover two weeks. The determined uranium value was 88.103 %with a standard deviation of 0.053 %. The value is notstatistically different from the values determined by this testmethod. The data does not indicat
30、e any statistically significantbias at the 88.103 % level.11. Keywords11.1 gravimetric; ignition; O/U ratio; oxygen; oxygen touranium ratio; uraniumAPPENDIX(Nonmandatory Information)X1. ADDITIONAL CALCULATIONS AND INFORMATIONX1.1The atomic weight of uranium based on the mass fraction ofthe individua
31、l isotopes is calculated as follows:A 5 ( Fi Ai (X1.1)where:A = Atomic weight of uranium;Fi = Mass fraction of uranium isotope i; andAi = Atomic weight of uranium isotope i.X1.2 The conversion factor for U3O8to uranium is calcu-lated as follows:Conversion Factor 53A3A 1 8O(X1.2)where:A = Atomic weig
32、ht of uranium;O = Atomic weight of oxygen (15.9994).For natural isotopic abundance uranium the conversionfactor is 0.8480.X1.3 Uranium TrioxideThe uranium content of UO3canbe determined using this test method.3(See Note X1.1). Theresults for the UO3were determined by a single set ofcomparative data.
33、 (See Table X1.1.)NOTE X1.1Sulphur, which is commonly present in UO3as UO2SO4is not completely volatilized in the conversion to U3O8if the ignition timeis less than 3 h.35Supporting data for Tables 2-X1.1 are available from ASTM Headquarters.TABLE 3 Comparison of Interlab O/U ResultsLaboratory Sampl
34、e Type O/U RatioStandardDeviationNo. ofDeterminationsA Sintered depleted UO2pellet G-22.001 0.001 4B Sintered depleted UO2pellet G-22.000 0.002 18TABLE 4 Comparison of Interlab Uranium ResultsMethod Laboratory Sample TypeUraniumwt%AbsoluteStandardDeviationNo. ofDeterminationsGravimetric A Sintered d
35、epletedUO2pellet G-288.106 0.003 4Gravimetric B Sintered depletedUO2pellet G-288.114 0.010 18Referencevalue, see10.2.3B Sintered depletedUO2pellet G-288.103 0.053 See 10.2.3TABLE X1.1 Uranium Content of UO3SampleGravimetricUranium %TitrimetricAUranium %UO382.78 Technician A Technician B82.74 82.81AT
36、he titrimetric method refers to the Davies-Gray method in C1267.C1453 00 (2011)3ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the val
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