1、Designation: C 968 06Standard Test Methods forAnalysis of Sintered Gadolinium Oxide-Uranium DioxidePellets1This standard is issued under the fixed designation C 968; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last
2、revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 These test methods cover procedures for the analysis ofsintered gadolinium oxide-uranium dioxide pellets to deter-mine com
3、pliance with specifications.1.2 The analytical procedures appear in the following order:SectionCarbon (Total) by Direct CombustionThermal Conductivity Method2C 1408 Test Method for Carbon (Total) in Uranium Oxide Powdersand Pellets By Direct Combustion-Infrared Detection Method3Chlorine and Fluorine
4、 by Pyrohydrolysis Ion-Selective ElectrodeMethod4C 1502 Test Method for Determination of Total Chlorine and Fluorinein Uranium Dioxide and Gadolinium Oxide3Gadolinia Content by Energy-Dispersive X-Ray Spectrometry4C 1456 Test Method for Determination of Uranium or Gadolinium, orBoth, in Gadolinium O
5、xide-Uranium Oxide Pellets or by X-RayFluorescence (XRF)3Hydrogen by Inert Gas Fusion4C 1457 Test Method for Determination of Total Hydrogen Content ofUranium Oxide Powders and Pellets by Carrier Gas Extraction3Isotopic Uranium Composition by Multiple-Filament Surface-Ionization Mass Spectrometric M
6、ethod2C 1413 Test Method for Isotopic Analysis of Hydrolysed UraniumHexafluoride And Uranyl Nitrate Solutions By Thermal IonizationMass Spectrometry3C 1347 Practice for Preparation and Dissolution of Uranium Materi-als for Analysis3Nitrogen by DistillationNessler Reagent (Photometric) Method 6 to 16
7、Oxygen-to-Metal Ratio of Sintered Gadolinium Oxide-Uranium Diox-ide Pellets4C 1430 Test Method for Determination of Uranium, Oxygen to Ura-nium, and Oxygen to Metal (O/M) in Sintered Uranium Dioxideand Gadolinia-Uranium Dioxide Pellets by Atmospheric Equilibra-tion3Spectrochemical Determination of T
8、race Impurity Elements4C 1517 Test Method for Determination of Metallic Impurities in Ura-nium Metal or Compounds by DC-Arc Emission Spectroscopy3Total Gas by Hot Vacuum Extraction2Ceramographic Determination of Free Gd2O3and Free UO2to Esti-mate the Homogeneity of (U,Gd)O2Pellets17 to 241.3 The val
9、ues stated in SI units are to be regarded as thestandard.1.4 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 and health practices and determine the applica-bili
10、ty of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3C 922 Specification for Sintered Gadolinium Oxide-Uranium Dioxide PelletsC 1347 Practice for Preparation and Dissolution of UraniumMaterials for AnalysisC 1408 Test Method for Carbon (Total) in Uranium OxidePowders
11、and Pellets By Direct Combustion-Infrared De-tection MethodC 1413 Test Method for Isotopic Analysis of HydrolyzedUranium Hexafluoride and Uranyl Nitrate Solutions byThermal Ionization Mass SpectrometryC 1430 Test Method for Determination of Uranium, Oxy-gen to Uranium (O/U), and Oxygen to Metal (O/M
12、) inSintered Uranium Dioxide and Gadolinia-Uranium Diox-ide Pellets by Atmospheric EquilibrationC 1456 Test Method for the Determination of Uranium orGadolinium, or Both, in Gadolinium Oxide-Uranium Ox-ide Pellets or by X-Ray Fluorescence (XRF)C 1457 Test Method for Determination of Total HydrogenCo
13、ntent of Uranium Oxide Powders and Pellets by CarrierGas ExtractionC 1502 Test Method for Determination of Total Chlorineand Fluorine in Uranium Dioxide and Gadolinium Oxide1These test methods are under the jurisdiction of ASTM Committee C26 onNuclear Fuel Cycle and are the complete responsibility o
14、f Subcommittee C26.05 onTest Methods.Current edition approved July 1, 2006. Published August 2006. Originallyapproved in 1981. Last previous edition approved in 1999 as C 968 99.2Discontinued 1999. See C 968 94.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Cust
15、omer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.4Discontinued 2005. See C 968 99.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.C
16、1517 Test Method for Determination of Metallic Impuri-ties in Uranium Metal or Compounds by DC-Arc EmissionSpectroscopyD 1193 Specification for Reagent WaterE 146 Methods of Chemical Analysis of Zirconium Alloys-(Silicon, Hydrogen, and Copper53. Significance and Use3.1 The test methods in this metho
17、d are designed to showwhether a given material is in accordance with SpecificationC 922.4. Reagents4.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the commit-tee on Analytical
18、Reagent of the American Chemical Society,where such specifications are available.6Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.4.2 Purity of WaterUnless otherwise indicate
19、d, referencesto water shall be understood to mean reagent water conformingto Type IV of Specification D 1193.5. Safety Precautions5.1 Proper precautions should be taken to prevent inhalationor ingestion of gadolinium oxide or uranium dioxide dustduring grinding or handling operations.CARBON (TOTAL)
20、BY DIRECT COMBUSTIONTHERMAL CONDUCTIVITY METHODThis Test Method was discontinued in January 1999 andreplaced by Test Method C 1408CHLORINE AND FLUORINE BY PYROHYDROLYSISION-SELECTIVE ELECTRODE METHODThis Test Method was discontinued in March 2005 andreplaced by Test Method C 1502GADOLINIA CONTENT BY
21、 ENERGY-DISPERSIVEX-RAY SPECTROMETRYThis Test Method was discontinued in March 2005 andreplaced by Test Method C 1456HYDROGEN BY INERT GAS FUSIONThis Test Method was discontinued in March 2005 andreplaced by Test Method C 1457ISOTOPIC URANIUM COMPOSITION BYMULTIPLE-FILAMENT SURFACE-IONIZATIONMASS SP
22、ECTROMETRIC METHODThis Test Method was discontinued in January 1999 andreplaced with C 1413Samples can be dissolved using the appropriatedissolution techniques described in Practice C 1347NITROGEN BY DISTILLATIONNESSLERREAGENT (PHOTOMETRIC) METHOD6. Scope6.1 This test method describes the determinat
23、ion of nitrogenin gadolinium oxide-uranium dioxide pellets (Gd2O3/UO2).Witha2to5-gsample, concentrations from 5 to 100 g ofnitrogen are determined without interference.7. Summary of Test Method7.1 Pellet samples of gadolinium oxide-uranium dioxide arecrushed, then dissolved in phosphoric acid. Hydro
24、chloric acidwith hydrogen peroxide can also be used. The resultingsolution is made alkaline with sodium hydroxide, and thenitrogen is separated as ammonia by steam distillation (see5Withdrawn.6Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For
25、suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,MD.C968062Method E 146). Ne
26、ssler reagent is added to the distillate toform the yellow ammonium complex, and the absorbance ofthe solution is measured at approximately 430 nm, using a celldepth of 2 cm (1, 2).7NOTE 1This procedure has been written for a cell having a 2-cm lightpath. The range of the method can be extended by s
27、uitably varying samplemass, aliquot size, amounts of reagents, and cell depth.8. Interferences8.1 There are no known interfering elements.9. Apparatus9.1 Nitrogen Distillation Apparatus, with 100-mLflask, Fig.1; micro-Kjeldahl apparatus.9.2 PhotometerA filter photometer with a narrow-bandfilter; or
28、a spectrophotometer equipped with 2-cm cells.9.3 Heater, 750-W, electric, full-control.10. Reagents and Materials10.1 Nessler ReagentDissolve 50 g of potassium iodide(KI) in a minimum of cold water (approximately 35 mL). Adda saturated solution of mercuric chloride (HgCl2) slowly untilthe first slig
29、ht precipitate of red mercuric iodide persists. Add400 mL of potassium or sodium hydroxide solution (505 g ofKOH or 360 g of NaOH/L). Dilute the solution to 1 L withammonia-free water, mix, and allow the solution to standovernight. Decant the supernatant liquid and store it in a brownbottle. This re
30、agent is stable indefinitely.10.2 Ammonium Chloride (NH4Cl)Dry the ammoniumchloride at 110 to 120C for 2 h.10.3 Nitrogen Reference Solution (1 mL = 10 g N)Dissolve 3.819 g of dried NH4Cl in water and dilute thesolution to 1 L. Transfer 10 mL of this solution to a 1-Lvolumetric flask and dilute it to
31、 volume with water.10.4 Hydrochloric Acid (6 N)Dilute 6 volumes of con-centrated hydrochloric acid (HCl) to 12 volumes.10.5 Hydrogen Peroxide (30 %).11. Precautions11.1 The use of ammonia or other volatile nitrogenouscompounds in the vicinity of the experiment can lead to seriouserrors. To ensure fr
32、eedom from contamination, take the fol-lowing precautionary measures:11.1.1 Steam clean all glassware immediately prior to use.11.1.2 Use ammonia-free water in all cases.12. Purity of Water12.1 Unless otherwise indicated, all references to water inthis method shall be understood to mean ammonia-free
33、 water,prepared as follows: Pass distilled water or other water of7The boldface numbers in parentheses refer to the list of references at the end ofthis standard.FIG. 1 Micro-Kjeldahl ApparatusC968063equivalent purity through a mixed-bed resin demineralizer.Prepare all solutions in an ammonia-free a
34、tmosphere and storethem in tightly stoppered chemical-resistant glass bottles. Boilall rubber stoppers used for 30 min in sodium hydroxidesolution (100 g NaOH/L) and rinse them with ammonia-freewater.13. Preparation of Calibration Curve13.1 Calibration SolutionsPipet 5, 10, 25, 50, 100, and150 g of
35、the reference nitrogen solution (1 mL = 10 g N) into50-mL volumetric flasks containing 25 mL of water. Pipet 1.0mL of Nessler reagent into each flask and dilute to the markwith water. Stopper the flask and mix well.13.2 Reference SolutionPipet 1.0 mL of Nessler reagentinto a small volume of water in
36、 a 50-mL volumetric flask.Dilute to volume with water. Stopper and mix well.13.3 PhotometryTransfer a suitable portion of water to a2-cm absorption cell and adjust the photometer to the initialsetting, using a light band centered at approximately 430 nm.While maintaining this photometer adjustment,
37、take the pho-tometric readings of the reference solution and the calibrationsolutions.13.4 Calibration CurveCorrect for the blank (referencesolution) reading and plot the photometric readings of thecalibration solutions against micrograms of nitrogen per 50 mLof solution.14. Procedure14.1 Test Solut
38、ion:14.1.1 Weigh and transfer to a 500-mL Erlenmeyer flask 2to3gofthecrushed gadolinium oxide-uranium dioxide pelletsample. (The pellets should be crushed to a fine powder with astainless steel mortar and pestle.)14.1.2 Add to the distillation flask 60 mL of 6 N hydrochlo-ric acid and 20 mL of 30 %
39、hydrogen peroxide.14.1.3 Boil for 10 min. While the solution is boiling,carefully add additional 30 % hydrogen peroxide dropwiseuntil the solids are dissolved and a clear yellow solution isobtained; cool the solution.14.1.4 While the samples are dissolving, fill the steam-generating flask of the dis
40、tillation unit with water. Apply heatand pass steam through the distillation flask and into thecondenser. Collect 50-mL portions of the distillate and add 1.0mL of Nessler reagent to each. When the absorbance of thesesolutions shows the apparatus to be free of ammonia, thedistillation unit is ready
41、for use with the samples.14.1.5 Transfer quantitatively the dissolved gadolinia-urania solution into the 100-mL distillation flask.14.1.6 Connect the distillation flask containing the samplesolution to the distillation unit. Add 25 mL of NaOH solution(37.5 %) to the sample solution through the thist
42、le tube so as toform two layers in the flask. Close the thistle tube stopcock anddistill until 40 mLof distillate is collected. (The NaOH solutionmust be added slowly to avoid a violent reaction which maylead to a loss of sample.)14.1.7 Pipet 1.0 mL of Nessler reagent to the distillate,dilute to the
43、 mark with water, stopper, and mix well.14.2 Reference SolutionCarry a reagent blank through theentire procedure, using the same amount of all reagents.14.3 PhotometryTake the photometric reading of thesamples as described in 13.3.15. Calculation15.1 Correct for the blank and convert the photometric
44、reading of the sample to micrograms of nitrogen by means ofthe calibration curve.15.2 Calculate the nitrogen content, N, in micrograms pergram of sample as follows:N 5 A/W (1)where:A = micrograms of nitrogen found, andW = sample mass, grams of Gd2O3/UO2.16. Precision and Bias16.1 The relative standa
45、rd deviation for the measurement ofnitrogen at the 100 g/g level is 3 %.OXYGEN-TO-METAL RATIO OF SINTEREDGADOLINIUM OXIDE-URANIUM DIOXIDEPELLETSThis Test Method was discontinued in March 2005 andreplaced by Test Method C 1430SPECTROCHEMICAL DETERMINATION OF TRACE,IMPURITY ELEMENTSThis Test Method wa
46、s discontinued in March 2005 andreplaced by Test Method C 1517TOTAL GAS BY HOT VACUUM EXTRACTIONThis procedure was discontinued in January 1999CERAMOGRAPHIC DETERMINATION OF FREEGd2O3AND FREE UO2TO ESTIMATE THEHOMOGENEITY OF (U,Gd)O2PELLETS17. Scope17.1 The homogeneity of Gd2O3in UO2has been cited i
47、nSpecification C 922 as an important requirement for this fuelform. The uniform distribution of gadolinia in urania will resultin up to three components in the pellet: free Gd2O3, free UO2,andaGd2O3-UO2solid solution. There are a number of waysfor assessing uniformity of which the ceramographic meth
48、oddescribed here may not be the most definitive. This techniquehas been used over the gadolinia concentration range from 1 to10 weight %.18. Summary of Test Method18.1 This ceramographic test, similar to those reported byRooney (3) and by Hammerschmidt and Saiger (4), consists ofmaking micrographs o
49、f polished pellet surfaces that have beenchemically etched with a hydrogen peroxide-sulfuric acidsolution. Oxidation makes it possible to differentiate betweencomponents.19. Apparatus19.1 Diamond Saw, low-speed.19.2 Ultrasonic Cleaner.19.3 Polisher/Grinder Table.C96806419.4 Metallurgical Microscope, with camera attachment.20. Reagents and Materials20.1 Hydrogen Peroxide (30 %).20.2 Hydrogen PeroxideSulfuric Acid Etch Solution10parts 30 % hydrogen peroxide mixed with 1 part concentratedsulfuric acid.20.3 Silicon Carbide Grinding Disks, 240, 320, 400, and
