1、Designation: C1307 15Standard Test Method forPlutonium Assay by Plutonium (III) Diode ArraySpectrophotometry1This standard is issued under the fixed designation C1307; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of las
2、t 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 describes the determination of totalplutonium as plutonium(III) in nitrate and chloride solutions.The te
3、chnique is applicable to solutions of plutonium dioxidepowders and pellets (Test Methods C697), nuclear grade mixedoxides (Test Methods C698), plutonium metal (Test MethodsC758), and plutonium nitrate solutions (Test Methods C759).Solid samples are dissolved using the appropriate dissolutiontechniqu
4、es described in Practice C1168. The use of thistechnique for other plutonium-bearing materials has beenreported (1-5), but final determination of applicability must bemade by the user. The applicable concentration range forplutonium sample solutions is 10200 g Pu/L.21.2 The values stated in SI units
5、 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 concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practi
6、ces and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3C697 Test Methods for Chemical, Mass Spectrometric, andSpectrochemical Analysis of Nuclear-Grade PlutoniumDioxide Powders and PelletsC698 Test Methods for Chemical, Mass Spectrometr
7、ic, andSpectrochemical Analysis of Nuclear-Grade Mixed Ox-ides (U, Pu)O2)C757 Specification for Nuclear-Grade Plutonium DioxidePowder, SinterableC758 Test Methods for Chemical, Mass Spectrometric,Spectrochemical, Nuclear, and RadiochemicalAnalysis ofNuclear-Grade Plutonium MetalC759 Test Methods for
8、 Chemical, Mass Spectrometric,Spectrochemical, Nuclear, and RadiochemicalAnalysis ofNuclear-Grade Plutonium Nitrate SolutionsC833 Specification for Sintered (Uranium-Plutonium) Diox-ide PelletsC859 Terminology Relating to Nuclear MaterialsC1168 Practice for Preparation and Dissolution of PlutoniumMa
9、terials for Analysis3. Terminology3.1 Definitions:3.1.1 For definitions of terms related to nuclear materials,refer to Terminology C859.4. Summary of Method4.1 In a diode array spectrophotometric measurement, as ina conventional spectrophotometric measurement, the substancebeing determined absorbs l
10、ight at frequencies characteristic ofthat substance. The amount of light absorbed at each wave-length is directly proportional to the concentration of thespecies of interest.The absorption is a function of the oxidationstate and the complexation obtained in the solution matrixselected for measuremen
11、t. Beers Law permits quantifying thespecies of interest relative to a traceable standard when bothsolutions are measured under the same conditions. The array ofphotosensitive diodes permits the (virtually) simultaneouscollection of spectral information over the entire range of theinstrument, for exa
12、mple, 190820 nm (or any selected portionof the range).An entire absorption spectrum can be obtained in0.1 s; however, optimum precision is obtained from multiplespectra collected over a 4-s period.4.2 Reduction to plutonium(III) is accomplished by theaddition of a measured quantity of reductant solu
13、tion to thesample aliquant.4.2.1 For nitrate solutions, ferrous sulfamate is the recom-mended reductant. Aliquants (1 mL or less) of the sample1This test method is under the jurisdiction ofASTM Committee C26 on NuclearFuel Cycle and is the direct responsibility of Subcommittee C26.05 on Methods ofTe
14、st.Current edition approved Jan. 1, 2015. Published January 2015. Originallyapproved in 1995. Last previous edition approved in 2014 as C1307 14. DOI:10.1520/C1307-15.2For solid samples, select the sample size and dissolved solution weight to yieldsample solutions in the 1030 g Pu/L range. With spec
15、ial preparation and spectralanalysis techniques, the method has been applied to nitrate solutions in the 0.110g Pu/L range.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, re
16、fer 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 States1solution are diluted with 10 mL of a ferrous reductant/matrixsolution to 1 g Pu/L, and measured.4.2.2 For chloride solutions
17、, ascorbic acid is the recom-mended reductant. Aliquants of the sample solution, eachcontaining 50100 mg of plutonium, are diluted with 2 mL ofzirconium solution to complex fluoride ions, 2 mL ascorbicacid reductant solution, and 1.0 M HCl to a total volume of 25mL, yielding 24 g Pu/L solutions for
18、measurement.4.3 Plutonium concentration is determined from light ab-sorption measurements taken on the sample solution in theblue-green region from 516 to 640 nm where a broad doubletband is observed. Spectral quantifying software capable offitting the sample spectrum with spectral information froms
19、tandard solutions is used to calculate the plutonium concen-tration. Both commercially available (6) and custom-designed(7-12) spectral fitting software have been developed whichmay be used for plutonium measurements. The users of thisprocedure are responsible for selecting or customizing, or both,t
20、he spectral fitting (and instrument control) software that bestmeets their individual measurement methodology and needs.Software selection will dictate many of the procedural specificsnot included in this procedure. This procedure is intended toaddress key measurement requirements and to allow users
21、discretion in establishing appropriate procedural details andtechnique variations. The software package selected shouldinclude a feature that indicates the quality of spectral fit,thereby providing information on the measurement reliabilityand the presence of interferences that absorb light or other
22、wisealter the plutonium(III) spectrum without requiring supplemen-tal measurements.5. Significance and Use5.1 This test method is designed to determine whether agiven material meets the purchasers specification for pluto-nium content.6. Interferences6.1 Materials meeting the applicable material spec
23、ificationsof theASTM standard for which this procedure was developed,when dissolved and diluted without introduction of interferingcontaminants as described in Practice C1168, will contain nointerfering elements or species.NOTE 1Fluoride, if present, would interfere if the zirconium, rou-tinely adde
24、d to the sample solution aliquant for the chloride matrix, wereomitted from the procedure. Zirconium may be added to the nitrate matrix.Ferrous-Reductant Solution to handle fluorides if present. Zirconium,when used, should be added to all samples, blanks, and standards to obtaina consistent matrix.
25、Refer to Specifications C833 and C757.6.2 Interferences are caused by: (1) materials that absorblight in the region of the plutonium absorption, (2) undissolvedsolids that cause light scattering, (3) strong oxidizing orcomplexing agents that prevent complete reduction of theplutonium to the plutoniu
26、m(III) oxidation state, and (4) anionsthat shift the spectrum.6.2.1 Absorption of light in the region of interest by anotherspecies is a potential interference. Identification of potentiallyinterfering species and inclusion of their spectra in the spectralcurve fitting process will significantly red
27、uce their effect. At aminimum, sample measurements should be flagged when thehigher than normal fitting error occurs, resulting from thepresence of unidentified absorbing species. Enhancement ofthe spectral curve fitting capabilities of the DAS can beachieved by taking double derivatives of the spec
28、trum col-lected. The spectral curve fitting software of the DAS is thenused to quantitate the mathematically manipulated spectrum.NOTE 2Care must be taken in the choice of the preprocessing methods(derivatives, mean centering, autoscaling, or channel selection, or combi-nations thereof) as these may
29、 affect the robustness of the final model,particularly with regard to unknown interferences. Use of residual analysiswill not always detect unknown interferences and results will varydepending on the preprocessing methods and models employed.6.2.2 This spectrophotometric assay method should not beus
30、ed on turbid (cloudy) solutions or solutions containingundissolved material. In addition to visual or turbidity metermeasurements, or both, the presence of undissolved solids maybe identified by the resulting shifts in the spectral baseline andby elevated spectral fitting errors.NOTE 3Plutonium oxid
31、es, mixed oxides, and plutonium metalsmeeting the material specifications for which this test method is intended,will dissolve when procedures in Practice C1168 are followed. Failure toachieve dissolution is an indication that the material does not meet thespecifications, and the application of this
32、 test method for plutonium assaymust be verified by the user. The user and customer are cautioned: whenundissolved solids that persist after exhaustive dissolution efforts are to beremoved by filtration through filter paper or other inert material ofappropriate porosity, the subsequent plutonium ass
33、ay measurementsrequire close scrutiny. While filtration of undissolved solids may permitthe reliable measurement of the concentration of plutonium in the filtrate,the resulting analysis may not be representative of their source material.Solids may indicate incomplete dissolution of the plutonium in
34、the samplematerial, not necessarily a plutonium-free refractory residue. When thistechnique is utilized in support of reprocessing operations, processsolutions containing solids may be an indication of incomplete dissolutionof the plutonium-bearing material being processed or of an error inprocess o
35、perations. In addition to process control considerations, theundissolved solids may represent accountability and criticality controlproblems.6.2.3 Strong oxidizing agents and complexing agents insufficient concentration to prevent complete reduction typicallyare not present in plutonium nitrate samp
36、les. Appreciableconcentrations of fluoride and sulfate anions have been foundto interfere. The concentration of hydrofluoric acid, added tocatalyze dissolution of oxides, may be removed by evaporationprior to measurement to ensure that the zirconium effectivelycomplexes the traces of fluoride ion. C
37、hanges in the plutoniumspectrum from incomplete reduction due to oxidizing agentsand shifts in the spectrum due to complexing agents are alsoindicated by increases in the spectral curve fitting error.6.2.4 Anion identity and concentration will shift the loca-tion and alter the shape of the absorptio
38、n curve. The systemcalibration must include the anion shift effect by encompassingthe expected range of anion identities and concentrations or byusing appropriate spectral fitting features that identify andcorrect for the effect.6.3 A study was conducted at the Los Alamos NationalLaboratory to deter
39、mine the immunity of the Pu(III) spectro-photometric assay method to a diverse species of potentialinterferences. The elements studied were element numbers 1,9, 1113, 17, 19, 2231, 35, 42, 4446, 48, 50, 53, 57, 58, 60,C1307 15262, 73, 74, 76, 77, 79, 83, 90, 92, 93, and 95. Potentialinterference fro
40、m nitrate, phosphate, sulfate, and oxalic acid isalso documented (13).7. Apparatus7.1 Diode Array Spectrophotometer (DAS)Wavelengthrange 190820 nm; wavelength accuracy6 2 nm; wavelengthreproducibility 60.05 nm; full dynamic range 0.0022 to 3.3;photometric accuracy at 1AU with a NBS 931 filter at 512
41、 nmis 60.005 AU; baseline flatness 0.0013 AU; noise at 500 nmis 0.0002AU RMS; stray light measured with a Hoya 056 filterat 220 nm 0.05 %;47.2 Analytical BalanceReadability of 0.1 mg; linearity 0.1mg over any 10 g range and 0.2 mg over 160 g full scale.7.3 Solution Density MeterReadability of 0.1 mg
42、/mL;precision of 0.3 mg/mL; linearity and accuracy 0.5 mg/mLover the range 0 to 2.0 g/mL.7.4 Adjustable, Fixed-Volume PipettersCalibrated to de-liver the desired range of volumes for sample and matrix-reductant solutions.8. Reagents and Materials8.1 Purity of ReagentsReagent grade chemicals shall be
43、used 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.5Other grades may be used,provided it is first ascertained that the reagent is o
44、f sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.8.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean distilled or deionizedwater.8.3 Ascorbic Acid-Reductant Solution (C6H8O6, amin-oguanidine bicarbonate (CH6N4H2C
45、O3), 0.4 M in eachreagent)Prepare fresh daily by dissolving7gofascorbicacid and 5.5 g aminoguanidine bicarbonate in 80 mL of 1 MHCl, then dilute to a final volume of 100-mL 1 M HCl.NOTE 4The ascorbic acid is stabilized by the addition of aminoguani-dine (Guanylhydrazine:HN:C(NH2)NHNH2). The stabiliz
46、ed reductantsolution has been found to be effective when ascorbic acid stabilityproblems are encountered.8.4 Ferrous-Reductant Solution (ferrous sulfamate, 0.05 M;sulfamic acid, 0.25 M; nitric acid, 1.0 M)Prepare freshweekly by adding 12 mL of freshly prepared ferrous sulfamate(2 M) to 90 mLof sulfa
47、mic acid (1.5 M). Stir, then add 175 mLof nitric acid (3.0 M) and dilute to 500 mL with water.8.5 Ferrous Sulfamate (Fe(NH2SO3)2, 2.0 M)Preparefresh for the preparation of the ferrous-reductant solution. Add220 g of solid sulfamic acid to 450 mL of water, stir, and heatat 7080C until dissolved. Cont
48、inue stirring and heating,while adding approximately 0.5-g portions of iron metalpowder (Fe0) until 56 g of iron have been dissolved in theheated sulfamic acid. Filter the solution while hot; allow tocool; then dilute to a final volume of 50 mL.NOTE 5The dissolution of the sulfamic acid need not be
49、quantitativebefore beginning the addition of the iron powder. Excessive heatingbeyond the time required to achieve the dissolution of the sulfamicacid/iron powder or at temperatures above 80C will cause excessivedecomposition of the sulfamic acid8.6 Hydrochloric Acid (HCl, 12 M)Concentrated, sp gr1.19.8.7 Hydrochloric Acid (HCl, 1.0 M)Add 84 mL of hydro-chloric acid (sp gr 1.19) to approximately 500 mL of water.Stir, then dilute to a final volume of 1 L.8.8 Nitric Acid (HNO3, 15.8 M)Concentrated, sp gr 1.42.8.9 Nitric Acid (1.0 M)Add 63 mL of nitri
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