1、Designation: C 1502 01Standard Test Method forDetermination of Total Chlorine and Fluorine in UraniumDioxide and Gadolinium Oxide1This standard is issued under the fixed designation C 1502; the number immediately following the designation indicates the year oforiginal adoption or, in the case of rev
2、ision, the year of last 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 This test method covers the determination of chlorineand fluorine in nuclear-grade uranium dioxide
3、 (UO2) powderand pellets, nuclear grade gadolinium oxide (Gd2O3) powderand gadolinium oxide-uranium oxide (Gd2O3-UO2) powderand pellets.1.2 With a 2 gram UO2sample size the detection limit of themethod is 4 g/g for chlorine and 2 g/g for fluorine. Themaximum concentration determined with a 2 gram sa
4、mple is500 g/g for both chlorine and fluorine. The sample size usedin this test method can vary from 1 to 10 grams resulting in acorresponding change in the detection limits and range.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is ther
5、esponsibility 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.2. Referenced Documents2.1 ASTM Standards:C 753 Specification for Nuclear-Grade, Sinterable UraniumDioxide Powder2C 776 Specificati
6、on for Sintered Uranium Dioxide Pellets2C 888 Specification for Nuclear-Grade Gadolinium Oxide(Gd2O3) PowderC 922 Specification for Sintered Gadolinium OxideUranium Dioxide PelletsD 1193 Specification for Reagent Water33. Summary of Test Method3.1 The halogens are separated from the test materials b
7、ypyrohydrolysis in a quartz tube with a stream of wet oxygen orair at a temperature of 900 to 1000C. (1-4) Chloride andfluoride are volatilized simultaneously as acids, absorbed in abuffer solution as chloride and fluoride and measured with ionselective electrodes (4-6).4. Significance and Use4.1 Th
8、e method is designed to show whether or not thetested materials meet the specifications as given in eitherSpecification C 753, C 776, C 888 or C 922.5. Interferences5.1 The buffer controls the pH of the measured solution toavoid hydroxide ion interference or the formation of hydrogencomplexes with f
9、luoride.5.2 Bromide, iodide, cyanide and sulfide, if present in thecondensate, interfere in the measurement of chloride withion-selective electrodes, but have very little effect upon themeasurement of fluoride with ion-selective electrodes.5.3 As the ionic activity of the chloride and fluoride ions
10、istemperature dependent, the standard solutions and samplesolutions should be measured at the same temperature.6. Apparatus6.1 Pyrohydrolysis Equipment, the assembly of suitableequipment is shown in Fig. 1.6.2 Gas Flow Regulator and Flowmeter.6.3 Hot Plate, used to warm the water saturating the spar
11、gegas to 5080C.6.4 Combustion Tube Furnace, having a bore of about 32mm with a length of about 300 mm and the capability ofmaintaining a temperature of 950 6 25C. Combustion tubefurnaces with different dimensions may be satisfactory. Tem-peratures between 900 and 1000C have been found to besatisfact
12、ory.6.5 Quartz Reaction Tube (Fig. 2)The exit end should notextend more than 50 mm beyond the furnace with a groundjoint connecting to the delivery tube. The delivery tube extendsinto a polyethylene or Pyrex absorption vessel with a tipcapable of giving a stream of very fine bubbles. A secondabsorpt
13、ion vessel connected in series, may be necessary toensure complete collection of the fluorine and chlorine fromthe sample.6.6 Combustion Boat, a ceramic, platinum or quartz boatwith a 10 mL capacity (approx. 90100 mm long, 13 mm wide,and 10 mm high). Boats with different dimensions may besatisfactor
14、y.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 June 10, 2001. Published September 2001.2Annual Book of ASTM Standards, Vol 12.01.3Annual Book of ASTM Standards
15、, Vol 11.01.1Copyright ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.6.7 Absorption Vessel, a 50-ml polyethylene graduate ortube is satisfactory.6.8 Ion-Selective Electrodes, fluoride-selective activity elec-trode4, chloride-selective activity electrode5. Combinationel
16、ectrodes may be suitable.6.9 Double-Junction Reference Electrode6, such as a silver-silver chloride with appropriate filling solutions.6.10 pH/mV MeterThe meter should have minimum reso-lution of 1 mV.6.11 Magnetic Stirrer.6.12 Beakers, 50 mL polyethylene.7. Reagents7.1 Purity of ReagentsReagent gra
17、de chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents conform to the specifications of the Committee onAnalytical Reagents of the American Chemical Society, wheresuch specifications are available.7Other grades may be used,provided it is first ascertained
18、 that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.7.2 AcceleratorTwo accelerators have been investigatedfor this system, halogen free U3O8and a flux of sodiumtungstate and tungsten trioxide. (1, 2) Halogen free U3O8requires no specia
19、l preparation before use but will require alonger pyrohydrolysis period. The flux of sodium tungstate(Na2WO4) with tungsten trioxide (WO3) may reduce thepyrohydrolysis period by half but it requires the followingspecial preparation. Dehydrate 165 g of Na2WO4in a largeplatinum dish. Transfer the drie
20、d material to a mortar, add 116gofWO3, and grind the mixture to ensure good mixing.4The Orion Model 9409 has been found satisfactory.5The Orion Model 9617 has been found satisfactory.6The Orion Model 9002 has been found satisfactory.7Reagent Chemicals, American Chemical Society Specifications, Ameri
21、canChemical Society, Washington, D.C. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Reagent Chemicals and Standards,byJoseph Rosin, D. Van Nostrand Company, Inc., New York, New York, and theUnited States Pharmacopeia.FIG. 1 Pyrohydrolysis EquipmentFIG. 2
22、Quartz Reaction TubeC 15022Transfer the mixture into a platinum dish and heat with aburner for 2 h. Cool the melt, transfer the flux to a mortar andgrind to a coarse powder. Store the flux in an airtight bottle.Mix about8goffluxwith each portion of sample to bepyrohydrolyzed.7.3 Buffer Solution (0.1
23、 M)Dissolve 10 g, potassiumacetate (KC2H3O2) in water, add 5 mL of acetic acid(CH3CO2H, sp gr 1.05), and dilute to 1 L. Other buffers may besatisfactory. It will be necessary to validate the buffers andoperating conditions with spike recovery determinations.7.4 Chloride, Standard Solution (100 g Cl/
24、mL)Dissolve0.165 g of dry sodium chloride (NaCl) in water and dilute to 1L. Commercially prepared standard solutions may be used.7.5 Fluoride, Standard Solution (50 g F/mL)Dissolve0.111 g of dried sodium fluoride (NaF) in water and dilute to 1L. Store the solution in a polyethylene bottle. Commercia
25、llyprepared standard solutions may be used.7.6 Compressed Oxygen or Air.7.7 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water conformingto Specification D 1193, Type I.8. Procedure8.1 Adjust the pyrohydrolysis system to operating conditionas foll
26、ows:8.1.1 Heat the furnace to 950 6 25C. (See 6.4).8.1.2 Fill the water reservoir and heat to 50 to 80C.8.1.3 Adjust the gas flow to 1 to 2 L/min.8.1.3.1 The furnace temperature, the gas flow and thedimensions of the delivery tube tip are critical variables thatwill affect the spike recovery of the
27、method.8.2 Flush the reaction tube and boat with moist oxygen.8.3 Run a pyrohydrolysis blank using a halogen-free ura-nium oxide or gadolinium oxide according to the procedure in8.5.8.3.1 Alternatively an empty combustion boat can be usedfor the pyrohydrolysis blank.8.3.2 A blank run should be made
28、each day and after anysample that contains abnormally high levels of chlorine orfluorine.8.4 Run samples, controls, duplicates and spikes in accor-dance with the users quality assurance control plan andrequirements.8.5 Sample Pyrohydrolysis:8.5.1 Pellets should be crushed prior to analysis.8.5.2 Wei
29、gh 1 to 10 g of sample and spread in the combus-tion boat. If an accelerator is desired, mix4gofU3O8accelerator or8gofthetungstate flux with the sample beforespreading in the boat. A flux to sample ratio of 1 has beenfound to work satisfactorily. Other ratios may be applicable asdetermined by the an
30、alyst.8.5.3 Place 15 mL of acetate buffer solution in the collectionflask and submerge the delivery tip in the solution.8.5.4 Remove the stopper from the entrance of the reactiontube and insert the boat into the hot area of the furnace.Quickly stopper the furnace tube.8.5.5 Check the gas flow and ad
31、just to 1 to 2 L/min.8.5.6 Continue the reaction for 1 hour. Thirty minutes maybe sufficient with the tungstate flux.NOTE 1The time required to complete the pyrohydrolysis will varywith differences in accelerator type, equipment and sample type. Toestablish the total time required for complete pyroh
32、ydrolysis, replace thebuffer solution at 15 to 30 minute intervals and continue the reaction untilcomplete.8.5.7 When the pyrohydrolysis is completed, transfer thebuffer solution to a 25-mL volumetric flask. Rinse the deliverytube (including inside) and collection tube with a minimum ofbuffer soluti
33、on. Make up to volume with buffer.8.6 Chloride and Fluoride Measurement:8.6.1 Assemble the mV meter and ion specific electrode andtake the meter readings in accordance with the manufacturersinstructions.8.6.2 Add 0, 0.1, 0.2, 0.4, 0.8, 1, 2, 4 and 10 mL of thechloride and the fluoride solutions prep
34、ared in 7.4 and 7.5 toseparate 25 mL flasks. Dilute each with buffer solution. Preparecalibration curves by plotting the millivolt readings of thestandards versus the concentration in micrograms per 25 mL onsemi-log paper. The concentration of chloride covers 10 g/25mL to 1000 g/25 mL and the fluori
35、de from 5 g/25 mL to 500g/25 mL.8.6.3 Use one half of the diluted sample from 8.5.7 for eachof the halide determinations. Read the concentrations from thecalibration curves. Alternatively the spike addition techniquemay be applicable as determined by the analyst.NOTE 2The chloride and fluoride measu
36、rements may be determinedusing ion chromatography. Appropriate buffer solutions that are compat-ible with ion chromatography, will be necessary. The solutions will requirespike recovery test work.9. Calculations9.1 ChlorineCalculate as follows:Cl, g/g 5C B!W(1)where:C = micrograms of total chlorine
37、in absorber solution,B = micrograms of total chlorine in the pyrohydrolysisblank, andW = sample weight in grams.9.2 If a second sample solution was generated in a second-ary impinger vessel as described in 6.5 calculate the result ofthe second impinger in the same manner as 9.1. The totalmicrograms
38、of chlorine in the sample is the sum of bothimpingers.9.3 FluorineCalculate as follows:F, g/g 5F B!W(2)where:F = micrograms of total fluorine in absorber solution,B = micrograms of total fluorine in the pyrohydrolysisblank, andW = sample weight in grams.9.4 If a second sample solution was generated
39、in a second-ary impinger vessel as described in 6.5 calculate the result ofthe second impinger in the same manner as 9.3. The totalmicrograms of fluorine in the sample is the sum of bothimpingers.C 1502310. Precision and Bias10.1 Uranium Dioxide:10.1.1 PrecisionThe standard deviation for the method
40、isgiven in Table 1. The data were obtained over several monthsby different analysts in laboratory A.10.1.2 BiasNo information can be presented on the biasof the procedure because no material having an acceptedreference value is available. The bias of the method is beingdetermined by spiking a sample
41、 of uranium oxide. The spikedata will be available on or before January 1, 2004.10.1.3 The supporting data for Table 1 are available fromASTM headquarters.10.2 Gadolinium Oxide:10.2.1 PrecisionThe standard deviation for the method isshown in Table 2. The data were obtained during a one monthperiod u
42、sing three different furnaces.10.2.2 BiasThere is no accepted reference material avail-able. The bias of the method was evaluated by spiking a sampleof Gd2O3-UO2pellets. The data in Table 2 were obtainedduring a one month period using three different furnaces atlaboratory B.10.2.3 The supporting dat
43、a for Table 2 are available fromASTM headquarters.11. Keywords11.1 chlorine; fluorine; gadolinium oxide; uranium dioxideREFERENCES(1) American Standards Association, Inc., “Referee Methods for theChemical Analysis of Nuclear Fuels,” ASA N5.7, 1965, p. 37.(2) Powell, R.H., and Menis, O., “Separation
44、of Fluoride from InorganicCompounds by Pyrolysis,” Analytical Chemistry, ANCHA, Vol 30,1958, p. 1546.(3) Warf, J.C., Cline, W.E., and Tevebaugh, R.D., “Pyrohydrolysis in theDetermination of Fluoride and Other Halides,” Analytical Chemistry,ANCHA, Vol 26, 1954, p. 342.(4) Plucinski, C.E., “Determinat
45、ion of Microgram Quantities of Fluoridein Metal Oxides,” USAEC Document BNWL-601, AEROB, 1968.(5) Frant, M.S., and Ross, J.W., Jr., “Electrode for Sensing Fluoride IonActivity in Solution,” Science, KAGTA, Vol 154, 1966, p. 1553.(6) Rechnitz, G.A., “Ion-Selective Electrodes,” Chemical and Engineerin
46、gNews, CENEA, Vol 25, 1967, p. 1946.The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connectionwith any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any suc
47、hpatent rights, and the risk of infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invite
48、d either for revision of this standard or for additional standardsand should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsibletechnical committee, which you may attend. If you feel that your comments have not received a fair hearing y
49、ou should make yourviews known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the above address or at610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website (www.astm.org).TABLE 1 Standard DeviationUranium DioxideSampleTypeElementConcentration(g/g)StandardDeviation
