1、Designation: C1561 10 (Reapproved 2016)Standard Guide forDetermination of Plutonium and Neptunium in UraniumHexafluoride and U-Rich Matrix by Alpha Spectrometry1This standard is issued under the fixed designation C1561; the number immediately following the designation indicates the year oforiginal a
2、doption 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 method covers the determination of plutonium andneptunium isotop
3、es in uranium hexafluoride by alpha spectros-copy. The method can also be applicable to any matrix that maybe converted to a nitric acid system.1.2 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 standa
4、rd to establish appro-priate safety and health practices and determine the applica-bility of regulatory requirements prior to use.2. Referenced Documents2.1 ASTM Standards:2C787 Specification for Uranium Hexafluoride for Enrich-mentC996 Specification for Uranium Hexafluoride Enriched toLess Than 5 %
5、235UC1163 Practice for Mounting Actinides for Alpha Spectrom-etry Using Neodymium FluorideC1475 Guide for Determination of Neptunium-237 in SoilD1193 Specification for Reagent WaterD3084 Practice for Alpha-Particle Spectrometry of WaterD3648 Practices for the Measurement of Radioactivity3. Terminolo
6、gy3.1 reagent blankDI water processed the same as thesamples; used in the determination of the minimum detectableactivity.3.2 region-of-interest (ROI)the channels, or region, in thealpha spectra in which the counts due to a specific radioisotopeappear on a functioning calibrated alpha spectrometry s
7、ystem.4. Summary of Test Method4.1 An aliquot of hydrolyzed uranium hexafluoride equiva-lent to approximately 0.5 g of uranium is converted to an oxalicacid-nitric acid system and the uranium is selectively removedvia solid phase extraction. Plutonium and neptunium arefurther purified by additional
8、solid phase extractions. Theplutonium and neptunium are then co-precipitated with neo-dymium as the fluorides and counted by alpha spectrometry.4.2 Tracer recoveries using this method are typically be-tween 75 and 90 % for uranium hexafluoride, for differentmatrix (with impurities): 10 %. The resolu
9、tion of the tracer istypically less than 40 keV full-width at half-maximum.4.3 The minimum detectable activity will vary with tracerrecovery, sample size, instrument background, and countingefficiency.5. Significance and Use5.1 The method is applicable to the analysis of materials todemonstrate comp
10、liance with the specifications set forth inSpecifications C787 and C996.5.2 The method can be used to quantify Pu and Np in U-richmatrix before to recycle them.6. Interferences6.1 Incomplete removal of U-234 from the neptuniumfraction could result in a false positive for the Np-237 analysis.The meth
11、od has been shown to adequately remove uranium atenrichments up to 5 %. If the method is used for the analysis ofmaterials at greater than 5 % enrichment, a blank consisting ofuranium at the same enrichment as the samples should beanalyzed to show adequate removal of the U-234.6.2 A Pu tracer is use
12、d to monitor the chemical recovery ofthe Np. Spiked analyses should be performed to confirm theappropriateness of this correction; fractionation of Np and Puduring the separation could lead to incorrect test results.7. Instrumentation7.1 Alpha Spectrometry SystemSee Practices D3084 andD3648 for a de
13、scription of the apparatus.1This guide is under the jurisdiction of ASTM Committee C26 on Nuclear FuelCycle and is the direct responsibility of Subcommittee C26.05 on Methods of Test.Current edition approved June 1, 2016. Published July 2016. Originally approvedin 2003. Last previous edition approve
14、d in 2010 as C1561 10. DOI: 10.1520/C1561-10R16.2For 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.Copyright AST
15、M International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States18. Apparatus8.1 Ion Exchange Columns, able to hold a 10 mL resin bedand 15 mL solution washes.8.2 Filter Paper, 0.1 m pore size, 25-mm diameter, com-patible with HF.39. Reagents and Materials9.1 Puri
16、ty 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 Reagents of the American Chemical Society,where such specifications are available.49.2 Purity of WaterUnles
17、s otherwise indicated, referencesto water shall be understood to mean reagent water as definedin Specification D1193.9.3 Ammonium Oxalate (0.1M)Dissolve 12.4 g ammo-nium oxalate in approximately 500 mL of water and dilute to1L.9.4 Ascorbic Acid Solution (Saturated)Add ascorbic acidto 2M nitric acid
18、while stirring until no more ascorbic acid willdissolve. Prepare fresh when needed for use.9.5 Ethanol, ethyl alcohol, absolute (200 proof), denatured.9.6 Hydrochloric Acid (HCl), specific gravity 1.19, concen-trated.9.7 Hydrochloric Acid, 9MAdd 750 mL concentrated HClto 100 mL of water, dilute to a
19、 final volume of 1 L.9.8 Hydrochloric Acid, 4MAdd 333 mL of concentratedHCl to 500 mL of water; dilute to a final volume of 1 L.9.9 Hydrochloric Acid, 1.5MAdd 125 mL of concentratedHCl to 500 mL of water; dilute to a final volume of 1 L.9.10 Hydrochloric Acid, 1MAdd 83 mL of concentratedHCl to 500 m
20、L of water; dilute to a final volume of 1 L.9.11 Hydrofluoric Acid (HF), concentrated HF, minimumassay 48 %.9.12 Iron (III) Nitrate (10 mg Fe/mL)Dissolve 18.0 g ofFe(NO3)39H2O in 250 mL of water.9.13 Neodymium Chloride (10 mg Nd/mL)Add 25 mLconcentrated HCl to 1.17 g neodymium oxide and heat at100C
21、until dissolved. Allow solution to cool and dilute to 100mL with water.9.14 Neodymium Chloride (100 g Nd/mL)Dilute 1 mL ofthe 10 mg Nd/mL solution to 100 mL with water.9.15 Nitric Acid (HNO3), concentrated nitric acid, specificgravity 1.42.9.16 Nitric Acid (3M)Add 188 mL concentrated nitricacid to 5
22、00 mL of water; dilute to a final volume of 1 L.9.17 Nitric Acid (2M)Add 125 mL of concentrated nitricacid to 500 mL of water; dilute to a final volume of 1 L.9.18 Oxalic Acid in 1M HCl (0.1M)Dissolve 12.6 g oxalicacid dihydrate in 500 mL of 1M HCl; dilute to a final volumeof 1 L with 1M HCl.9.19 Ox
23、alic Acid in 2M HNO3(0.1M)Dissolve 12.6 goxalic acid dihydrate in 500 mL of 2M HNO3; dilute to a finalvolume of 1 L with 2M HNO3.9.20 Pu-236 or Pu-242 Tracer, traceable to a national orinternational standard.9.21 Sodium Nitrite (100 mg/mL)Dissolve 500 mgNaNO2in 5 mL water. Prepare fresh when using.9
24、.22 Extraction Chromatography Resin, containingoctylphenyl-N,N-di-isobutyl carbamoylphosphine oxide(CMPO) dissolved in tri-n-butyl phosphate (TBP) as theimmobilized extractant.5,69.23 Extraction Chromatography Resin, containing diamylamylphosphonate (DAAP) as the immobilized extractant.7,810. Calibr
25、ation and Standardization10.1 The alpha spectrometry units should be calibrated forenergy, resolution and efficiency according to the manufactur-ers instructions. The background counting rate for the instru-ment should be measured at a frequency determined by theuser. See Practices D3084 and D3648 f
26、or additional informa-tion.11. Procedure11.1 Uranium Removal:11.1.1 Pipette an aliquot of hydrolyzed UF6sample equiva-lent to 0.05 to 0.5 g uranium into a beaker. Add the Pu tracerto the sample and evaporate to dryness. Add 10 mL concen-trated nitric acid and evaporate to dryness. This operation may
27、be repeated to remove fluoride. Option: Neptunium-239 can beadded as an independent tracer for the Np-237; see GuideC1475 for its use.11.1.2 Prepare 2 DAAP extraction columns per sample byadding resin slurried in water to the column.Allow the water todrain to obtain a 10 mL bed volume. Condition the
28、 columns byadding 15 mL of the oxalic acid in 2M nitric acid solution.Allow the solution to pass through the columns.11.1.3 Dissolve the sample residue in the beaker above byadding 15 mLof the oxalic acid in 2M nitric acid solution. Heatgently to complete the dissolution. Add the sample to the first
29、of the extraction columns and collect the load solution in a3The Gelman Metricel filter has been found to be acceptable.4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemica
30、l Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.5Horwitz, E. P., Chiarizia, R., Dietz, M. L., Diamond, H., and Nelson, D.,“Separation and Preconc
31、entration of Actinides from Acidic Media by ExtractionChromatography,” Analytica Chemica Acta, 281, 1993, pp. 361-372.6TRU resin from EIChroM Industries, Darien IL, USA, has been found to beacceptable.7Horwitz, E. P., Dietz, M. L., Chiarizia, R., Diamond, H., Essling, A. M., andGraczyk, D., “Separat
32、ion and Preconcentration of Uranium from Acidic Media byExtraction Chromatography,” Analytica Chemica Acta, 266, 1992, pp. 25-37.8U-TEVAresin from EIChroM Industries, Darien IL, USA, has been found to beacceptable.C1561 10 (2016)2clean beaker.Add an additional 15 mL of the oxalic acid in 2Mnitric ac
33、id solution to the column and collect the rinsate in thesame beaker.NOTE 1The column retains the U; Pu and Np will pass through in theload and rinse solutions.11.1.4 Add the combined solutions from the two stepsabove to the second DAAP extraction column. Collect the loadsolution in a clean beaker. R
34、inse the column with 15 mL of theoxalic acid in 2M nitric acid solution and collect in the samebeaker.11.1.5 Evaporate the combined solution from above todryness. Add 10 mL of concentrated nitric acid to the beakerand evaporate to dryness.NOTE 2Elute the uranium from the DAAP columns by adding 40 mL
35、of 0.1M ammonium oxalate. Dispose of the eluant containing the uraniumaccording to site specific disposal procedures.11.2 Preparation of Plutonium and Neptunium for Count-ing:11.2.1 Dissolve the residue from above in 10 mL of 3Mnitric acid by gently heating. Add 1 mL of the 10 mg Fe/mLsolution and 2
36、.5 mL of the saturated ascorbic acid solution tothe sample.NOTE 3The ascorbic acid reduces the Fe from +3 to +2; the Fethen serves to reduce the Pu from +4 to +3 and the Np from +5 to+4.NOTE 4Hydroxylamine chlorhydrate can be used instead of ascorbicacid.NOTE 5It is possible to work without Fe when
37、only Pu is necessary.11.2.2 Prepare one CMPO-TBP extraction column persample by loading 2 mL of resin per column.9Condition thecolumn by adding 5 mL of 3M nitric acid to the column andallowing it to drain completely through.11.2.3 Add the sample to the column and allow it to passthrough the column.
38、Rinse the column with 5 mL of 3M nitricacid. Discard all the rinses.11.2.4 Add 0.1 mL of the 100 mg/mL sodium nitritesolution to 5 mL of 2M nitric acid and swirl to mix. Add thissolution to the column.NOTE 6The sodium nitrite oxidizes the Pu from +3 to +4.11.2.5 Rinse the column with 10 mL of 2M nit
39、ric acid.11.2.6 Rinse the column, in succession, with 5 mL 9M HCl(crossover solvent), 10 mL 4M HCl (elutes Am) and 35 mL1.5M HCl (elutes Th). Discard all the rinses.11.2.7 Place a PTFE beaker under the column. Elute theplutonium and neptunium by adding 15 mL of the oxalic acidin 1M HCl solution.11.3
40、 Preparation for Counting:NOTE 7Refer to Test Method C1163 for additional guidance.11.3.1 Add 0.5 mL of the 100 g Nd/mL solution and 1 mLof concentrated HF to the Np and Pu fraction from above andmix. Allow the sample to sit for 30 min.11.3.2 Place a 0.1 m, 25-mm diameter filter on a vacuumflask. Ri
41、nse the filter first with ethanol and then with water.11.3.3 Pour the sample through the filter. After the samplesolution has passed through the filter rinse the filter with waterand then with ethanol, allowing each solution to pass com-pletely prior to the next one. Remove the filter from the flask
42、and dry under a heat lamp.11.3.4 Count the sample in a calibrated alpha spectrometrysystem for an appropriate amount of time.11.3.5 Confirm the removal of uranium by examining theU-238 region of the alpha spectrum. If detectable uraniumremains the Np-237 must be corrected for the U-234 in thesame re
43、gion, or the sample should be re-extracted.NOTE 8Alternatively, electrodeposition can be used (refer to elec-trodeposition guide).12. Calculations12.1 Calculation of Tracer Yield:Y 5 Gt2 Bt!/EAt! (1)where:Y = chemical yield,Gt= gross counts per second in the Pu tracer ROI,Bt= background counts per s
44、econd in the Pu tracer ROI,E = detector counting efficiency (cps/dps), andAt= activity of the Pu tracer in Bq (dps).12.2 Calculation of Activity: The following equation is usedto calculate the activity in the sample including any possiblereagent blank:Ai5 Gi2 Bi!/Gt2 Bt!#At/ABiW!# (2)where:Ai= activ
45、ity of isotope of interest in Bq per gram U(Pu-238, Pu-239+240, Np-237),Gi= gross counts per second in the analyte ROI,Bi= background counts per second in the analyte ROI,ABi= abundance of alpha decay in ROI, expressed as afraction, andW = weight of U analyzed, g.Additional calculations, including r
46、eagent blank subtraction,can be found in Practice D3084.12.3 Calculation of Minimum Detectable Activity:MDAi5 4.65SB12.71!/EYTABiW! (3)where:MDA = minimum detectable activity (Bq/g),SB= standard deviation of the reagent blank counts, andT = counting time, s.13. Keywords13.1 alpha spectrometry; neptu
47、nium; plutonium; uraniumhexafluoride9The prepacked TRU column available from EIChroM Industries has been foundto be acceptable.C1561 10 (2016)3APPENDIX(Nonmandatory Information)X1.1 This method does not have sufficient data to bequalified as a Standard Method for ASTM but is offered as aGuide for th
48、ose wishing options for the analysis of Pu and Npin UF6. At present there are no Certified Reference Materialsavailable from the national standards bodies to provide acomplete Precision and Bias statement, however the informa-tion below is offered as an example of data produced followingthis Guide.X
49、1.2 Twenty samples of UF6were spiked at the 0.01 Bq/g(0.27 pCi/g) level with Np-237 and with Pu-239 and analyzedto give an indication of the precision and bias. The relativestandard deviation of the 20 results was determined to be 15 %and 14 % for Np-237 and Pu-239, respectively, as an indicationof precision. The percent recovery was 103 % and 98 % forNp-237 and Pu-239, respectively, as an indication of bias.ASTM International takes no position respecting the validity of any patent rights asserted in connection wi
