1、Designation:C96806 Designation: C968 12Standard Test Methods forAnalysis of Sintered Gadolinium Oxide-Uranium DioxidePellets1This standard is issued under the fixed designation C968; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision,
2、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 These test methods cover procedures for the analysis of sintered gadolinium oxide-uranium dioxide pellets
3、to determinecompliance with specifications.1.2 The analytical procedures appear in the following order:SectionCarbon (Total) by Direct CombustionThermal Conductivity Method2C1408 Test Method for Carbon (Total) in Uranium Oxide Powdersand Pellets By Direct Combustion-Infrared Detection Method3Chlorin
4、e and Fluorine by Pyrohydrolysis Ion-Selective ElectrodeMethod4C1502 Test Method for Determination of Total Chlorine and Fluorinein Uranium Dioxide and Gadolinium Oxide3Gadolinia Content by Energy-Dispersive X-Ray Spectrometry4C1456 Test Method for Determination of Uranium or Gadolinium, orBoth, in
5、Gadolinium Oxide-Uranium Oxide Pellets or by X-RayFluorescence (XRF)3Hydrogen by Inert Gas Fusion4C1457 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 Spec
6、trometric Method2C1413 Test Method for Isotopic Analysis of Hydrolysed UraniumHexafluoride And Uranyl Nitrate Solutions By Thermal IonizationMass Spectrometry3C1347 Practice for Preparation and Dissolution of Uranium Materialsfor Analysis3Nitrogen by DistillationNessler Reagent (Photometric) Method
7、6 to 16Oxygen-to-Metal Ratio of Sintered Gadolinium Oxide-Uranium Diox-ide Pellets4C1430 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 Determinatio
8、n of Trace Impurity Elements4C1517 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 24Ceramo
9、graphic Determination of Average Grain Size by Linear Inter-cept after Chemical Etching25 to 321.3 The values stated in SI units are to be regarded as the standard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof th
10、e user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.1These test methods are under the jurisdiction of ASTM C26 on Nuclear Fuel Cycle and are the direct responsibility of C26.05 on Methods of Test.Current e
11、dition approved JulyJan. 1, 2006.2012. Published August 2006.February 2012. Originally approved in 1981. Last previous edition approved in 19992006 asC96899.C968 06. DOI: 10.1520/C0968-06.10.1520/C0968-12.2Discontinued 1999. See C968 94.3For referenced ASTM standards, visit the ASTM website, www.ast
12、m.org, or contact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.4Discontinued 2005. See C968 99.1This document is not an ASTM standard and is intended only to provide the user of an ASTM
13、 standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published b
14、y ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.2. Referenced Documents2.1 ASTM Standards:3C922 Specification for Sintered Gadolinium Oxide-Uranium Dioxide PelletsC1347 Practice for Pre
15、paration and Dissolution of Uranium Materials for AnalysisC1408 Test Method for Carbon (Total) in Uranium Oxide Powders and Pellets By Direct Combustion-Infrared DetectionMethodC1413 Test Method for Isotopic Analysis of Hydrolyzed Uranium Hexafluoride and Uranyl Nitrate Solutions by ThermalIonizatio
16、n Mass SpectrometryC1430 Test Method for Determination of Uranium, Oxygen to Uranium (O/U), and Oxygen to Metal (O/M) in SinteredUranium Dioxide and Gadolinia-Uranium Dioxide Pellets by Atmospheric EquilibrationC1456 Test Method for Determination of Uranium or Gadolinium (or both) in Gadolinium Oxid
17、e-Uranium Oxide Pellets or byX-Ray Fluorescence (XRF)C1457 Test Method for Determination of Total Hydrogen Content of Uranium Oxide Powders and Pellets by Carrier GasExtractionC1502 Test Method for Determination of Total Chlorine and Fluorine in Uranium Dioxide and Gadolinium OxideC1517 Test Method
18、for Determination of Metallic Impurities in Uranium Metal or Compounds by DC-Arc EmissionSpectroscopyD1193 Specification for Reagent WaterE112 Test Methods for Determining Average Grain SizeE146 Methods of Chemical Analysis of Zirconium and Zirconium Alloys (Silicon, Hydrogen, and Copper)53. Signifi
19、cance and Use3.1 The test methods in this method are designed to show whether a given material is in accordance with Specification C922.4. Reagents4.1 Purity of ReagentsReagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that allreagents shall conform to th
20、e specifications of the committee onAnalytical Reagent of theAmerican Chemical Society, where suchspecifications are available.6Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purityto permit its use without lessening the accuracy of the determinat
21、ion.4.2 Purity of WaterUnless otherwise indicated, references to water shall be understood to mean reagent water conforming toType IV of Specification D1193.5. Safety Precautions5.1 Proper precautions should be taken to prevent inhalation or ingestion of gadolinium oxide or uranium dioxide dust duri
22、nggrinding or handling operations.CARBON (TOTAL) BY DIRECT COMBUSTIONTHERMAL CONDUCTIVITY METHODThis Test Method was discontinued in January 1999 and replaced by Test Method C1408CHLORINE AND FLUORINE BY PYROHYDROLYSIS ION-SELECTIVE ELECTRODE METHODThis Test Method was discontinued in March 2005 and
23、 replaced by Test Method C1502GADOLINIA CONTENT BY ENERGY-DISPERSIVE X-RAY SPECTROMETRYThis Test Method was discontinued in March 2005 and replaced by Test Method C1456HYDROGEN BY INERT GAS FUSIONThis Test Method was discontinued in March 2005 and replaced by Test Method C1457ISOTOPIC URANIUM COMPOS
24、ITION BY MULTIPLE-FILAMENT SURFACE-IONIZATION MASSSPECTROMETRIC METHODThis Test Method was discontinued in January 1999 and replaced with C1413Samples can be dissolved using the appropriate dissolution techniques described in Practice C1347NITROGEN BY DISTILLATIONNESSLER REAGENT (PHOTOMETRIC) METHOD
25、6. Scope6.1 This test method describes the determination of nitrogen in gadolinium oxide-uranium dioxide pellets (Gd2O3/UO2). With5Withdrawn. The last approved version of this historical standard is referenced on www.astm.org.6Reagent Chemicals, American Chemical Society Specifications, American Che
26、mical Society, Washington, DC. For suggestions on the testing of reagents not listed bythe American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Pharmacopeial Convention, Inc. (USPC), Ro
27、ckville, MD.C968 122a 2 to 5-g sample, concentrations from 5 to 100 g of nitrogen are determined without interference.7. Summary of Test Method7.1 Pellet samples of gadolinium oxide-uranium dioxide are crushed, then dissolved in phosphoric acid. Hydrochloric acid withhydrogen peroxide can also be us
28、ed. The resulting solution is made alkaline with sodium hydroxide, and the nitrogen is separatedas ammonia by steam distillation (see Method E146). Nessler reagent is added to the distillate to form the yellow ammoniumcomplex, and the absorbance of the solution is measured at approximately 430 nm, u
29、sing a cell depth of 2 cm (1, 2).77The boldface numbers in parentheses refer to the list of references at the end of this standard.C968 123NOTE 1This procedure has been written for a cell having a 2-cm light path. The range of the method can be extended by suitably varying samplemass, aliquot size,
30、amounts of reagents, and cell depth.8. Interferences8.1 There are no known interfering elements.9. Apparatus9.1 Nitrogen Distillation Apparatus, with 100-mL flask, Fig. 1; micro-Kjeldahl apparatus.9.2 PhotometerA filter photometer with a narrow-band filter; or a spectrophotometer equipped with 2-cm
31、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). Add asaturated solution of mercuric chloride (HgCl2) slowly until the first slight precipitate of red mercuric iodide
32、 persists. Add 400 mLof potassium or sodium hydroxide solution (505 g of KOH or 360 g of NaOH/L). Dilute the solution to 1 L with ammonia-freewater, mix, and allow the solution to stand overnight. Decant the supernatant liquid and store it in a brown bottle. This reagentis stable indefinitely.10.2 A
33、mmonium Chloride (NH4Cl)Dry the ammonium chloride 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 the solution to 1 L.Transfer 10 mL of this solution to a 1-L volumetric flask and dilute it to volume with water.10.4 Hydrochlo
34、ric Acid (6 N)Dilute 6 volumes of concentrated hydrochloric acid (HCl) to 12 volumes.10.5 Hydrogen Peroxide (30 %).11. Precautions11.1 The use of ammonia or other volatile nitrogenous compounds in the vicinity of the experiment can lead to serious errors.To ensure freedom from contamination, take th
35、e following precautionary measures:11.1.1 Steam clean all glassware immediately prior to use.FIG. 1 Micro-Kjeldahl ApparatusC968 12411.1.2 Use ammonia-free water in all cases.12. Purity of Water12.1 Unless otherwise indicated, all references to water in this method shall be understood to mean ammoni
36、a-free water,prepared as follows: Pass distilled water or other water of equivalent purity through a mixed-bed resin demineralizer. Prepare allsolutions in an ammonia-free atmosphere and store them in tightly stoppered chemical-resistant glass bottles. Boil all rubberstoppers used for 30 min in sodi
37、um hydroxide solution (100 g NaOH/L) and rinse them with ammonia-free water.13. Preparation of Calibration Curve13.1 Calibration SolutionsPipet 5, 10, 25, 50, 100, and 150 g of the reference nitrogen solution (1 mL= 10 g N) into 50-mLvolumetric flasks containing 25 mL of water. Pipet 1.0 mL of Nessl
38、er reagent into each flask and dilute to the mark with water.Stopper the flask and mix well.13.2 Reference SolutionPipet 1.0 mL of Nessler reagent into a small volume of water in a 50-mL volumetric flask. Dilute tovolume with water. Stopper and mix well.13.3 PhotometryTransfer a suitable portion of
39、water to a 2-cm absorption cell and adjust the photometer to the initial setting,using a light band centered at approximately 430 nm. While maintaining this photometer adjustment, take the photometric readingsof the reference solution and the calibration solutions.13.4 Calibration CurveCorrect for t
40、he blank (reference solution) reading and plot the photometric readings of the calibrationsolutions against micrograms of nitrogen per 50 mL of solution.14. Procedure14.1 Test Solution:14.1.1 Weigh and transfer to a 500-mL Erlenmeyer flask 2 to3gofthecrushed gadolinium oxide-uranium dioxide pelletsa
41、mple. (The pellets should be crushed to a fine powder with a stainless steel mortar and pestle.)14.1.2 Add to the distillation flask 60 mL of 6 N hydrochloric acid and 20 mL of 30 % hydrogen peroxide.14.1.3 Boil for 10 min. While the solution is boiling, carefully add additional 30 % hydrogen peroxi
42、de dropwise until the solidsare dissolved and a clear yellow solution is obtained; cool the solution.14.1.4 While the samples are dissolving, fill the steam-generating flask of the distillation unit with water. Apply heat and passsteam through the distillation flask and into the condenser. Collect 5
43、0-mL portions of the distillate and add 1.0 mL of Nesslerreagent to each. When the absorbance of these solutions shows the apparatus to be free of ammonia, the distillation unit is readyfor use with the samples.14.1.5 Transfer quantitatively the dissolved gadolinia-urania solution into the 100-mL di
44、stillation flask.14.1.6 Connect the distillation flask containing the sample solution to the distillation unit. Add 25 mL of NaOH solution(37.5 %) to the sample solution through the thistle tube so as to form two layers in the flask. Close the thistle tube stopcock anddistill until 40 mL of distilla
45、te is collected. (The NaOH solution must be added slowly to avoid a violent reaction which may leadto a loss of sample.)14.1.7 Pipet 1.0 mL of Nessler reagent to the distillate, dilute to the mark with water, stopper, and mix well.14.2 Reference SolutionCarry a reagent blank through the entire proce
46、dure, using the same amount of all reagents.14.3 PhotometryTake the photometric reading of the samples as described in 13.3.15. Calculation15.1 Correct for the blank and convert the photometric reading of the sample to micrograms of nitrogen by means of thecalibration curve.15.2 Calculate the nitrog
47、en content, N, in micrograms per gram 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 standard deviation for the measurement of nitrogen at the 100 g/g level is 3 %.C968 125OXYGEN-TO-METAL RATIO OF
48、 SINTERED GADOLINIUM OXIDE-URANIUM DIOXIDE PELLETSThis Test Method was discontinued in March 2005 and replaced by Test Method C1430SPECTROCHEMICAL DETERMINATION OF TRACE, IMPURITY ELEMENTSThis Test Method was discontinued in March 2005 and replaced by Test Method C1517TOTAL GAS BY HOT VACUUM EXTRACT
49、IONThis procedure was discontinued in January 1999CERAMOGRAPHIC DETERMINATION OF FREE Gd2O3AND FREE UO2TO ESTIMATE THE HOMOGENEITYOF (U,Gd)O2PELLETS17. Scope17.1 The homogeneity of Gd2O3in UO2has been cited in Specification C922 as an important requirement for this fuel form.The uniform distribution of gadolinia in urania will result in up to three components in the pellet: free Gd2O3, free UO2, and aGd2O3-UO2solid solution. There are a number of ways for assessing uniformity of which the ceramographic method describedhere may not be the most defi
