1、Designation: C 1561 03Standard Guide forDetermination of Plutonium and Neptunium in UraniumHexafluoride by Alpha Spectrometry1This standard is issued under the fixed designation C 1561; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisio
2、n, 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 method covers the determination of plutonium andneptunium isotopes in uranium hexafluoride by alp
3、ha spectros-copy. The method could also be applicable to any matrix thatmay be 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 standard to establish appro-priate sa
4、fety and health practices and determine the applica-bility of regulatory requirements prior to use.2. Referenced Documents2.1 ASTM Standards:C 787 Specification for Uranium Hexafluoride for Enrich-ment2C 996 Specification for Uranium Hexafluoride Enriched toLess Than 5 % 235-U2C 1163 Test Method for
5、 Mounting Actinides for AlphaSpectrometry Using Neodymium Fluoride2C 1475 Guide for the Determination of Neptunium-237 inSoil2D 1193 Specification for Reagent Water3D 3084 Practice for Alpha-Particle Spectrometry of Water4D 3648 Practices for the Measurement of Radioactivity43. Terminology3.1 reagen
6、t 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 system.4. Sum
7、mary 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 solid phase
8、extractions. Theplutonium and neptunium are then co-precipitated with neody-mium as the fluorides and counted by alpha spectrometry.4.2 Tracer recoveries using this method are typically be-tween 75 and 90 %. The resolution of the tracer is typically lessthan 40 keV full-width at half-maximum.4.3 The
9、 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 compliance with the specifications set forth inSpecifications C 787 and C 996.6. Inter
10、ferences6.1 Incomplete removal of U-234 from the neptuniumfraction could result in a false positive for the Np-237 analysis.The method 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 consi
11、sting ofuranium at the same enrichment as the samples should beanalyzed to show adequate removal of the U-234.6.2 A Pu tracer is used to monitor the chemical recovery ofthe Np. Spiked analyses should be performed to confirm theappropriateness of this correction; fractionation of Np and Puduring the
12、separation could lead to incorrect test results.7. Instrumentation7.1 Alpha Spectrometry SystemSee Practices D 3084 andD 3648 for a description of the apparatus.8. Apparatus8.1 Ion Exchange Columns, able to hold a 10 mL resin bedand 15 mL solution washes.1This test method is under the jurisdiction o
13、f ASTM Committee C26 on NuclearFuel Cycle and is the direct responsibility of Subcommittee C26.05 on Methods ofTest.Current edition approved Feb 10, 2003. Published March 2003.2Annual Book of ASTM Standards, Vol 12.01.3Annual Book of ASTM Standards, Vol 11.01.4Annual Book of ASTM Standards, Vol 11.0
14、2.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.8.2 Filter Paper, 0.1 m pore size, 25-mm diameter, com-patible with HF.59. Reagents and Materials9.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherw
15、ise 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.69.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent
16、water as definedin Specification D 1193.9.3 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 while stirring until no more ascorbic acid willdissolve. Prepare fresh when n
17、eeded 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 final volume of 1 L.9.8 Hydrochloric Acid, 4MAdd 333 mL of concentratedHCl t
18、o 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 mL of water; dilute to a final volume of 1 L.9.11 Hydrofluoric Acid (HF), conc
19、entrated 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 until dissolved. Allow solution to cool and dilute to 100mL with water.9.14 N
20、eodymium Chloride (100 g Nd/mL)Dilute 1 mLof the 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 500 mL of water; dilute to a final volume of 1 L.9.17 Nitric Acid (2M)Add 125
21、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 goxalic acid dihydrate in 500 mL of 1M HCl; dilute to a finalvolume of 1 L with 1M HCl.9.19 Oxalic Acid in 2M HNO3(0.1M)Dissolve 12.6 goxalic acid dihydrate in 500 mL of 2
22、M 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.9.22 Extraction Chromatography Resin, containingoctylphenyl-N,N-di-isobutyl ca
23、rbamoylphosphine oxide(CMPO) dissolved in tri-n-butyl phosphate (TBP) as theimmobilized extractant.7,89.23 Extraction Chromatography Resin, containing diamylamylphosphonate (DAAP) as the immobilized extractant.9,1010. Calibration and Standardization10.1 The alpha spectrometry units should be calibra
24、ted 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 D 3084 and D 3648 for additional informa-tion.11. Procedure11.1 Uranium Removal:11.1.1 Pipett
25、e an aliquot of hydrolyzed UF6sample equiva-lent to 0.5 g uranium into a beaker. Add the Pu tracer to thesample and evaporate to dryness. Add 10 mL concentratednitric acid and evaporate to dryness. Option: Neptunium-239can be added as an independent tracer for the Np-237; seeGuide C 1475 for its use
26、.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 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
27、 the sample residue in the beaker above byadding 15 mL of the oxalic acid in 2M nitric acid solution. Heatgently to complete the dissolution. Add the sample to the firstof the extraction columns and collect the load solution in aclean beaker. Add an additional 15 mL of the oxalic acid in 2Mnitric ac
28、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
29、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
30、of 0.1M ammonium oxalate. Dispose of the eluant containing the uraniumaccording to site specific disposal procedures.5The Gelman Metricel filter has been found to be acceptable.6Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington DC.7Horwitz, E. P., Chia
31、rizia, R., Dietz, M. L., Diamond, H., and Nelson, D.,“Separation and Preconcentration of Actinides from Acidic Media by ExtractionChromatography,” Analytica Chemica Acta, 281, 1993, pp. 361-372.8TRU resin from EIChroM Industries, Darien IL, USA, has been found to beacceptable.9Horwitz, E. P., Dietz,
32、 M. L., Chiarizia, R., Diamond, H., Essling, A. M., andGraczyk, D., “Separation and Preconcentration of Uranium from Acidic Media byExtraction Chromatography,” Analytica Chemica Acta, 266, 1992, pp. 25-37.10U-TEVA resin from EIChroM Industries, Darien IL, USA, has been found tobe acceptable.C1561032
33、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 2.5 mL of the saturated ascorbic acid solution tothe sample.NOTE 3The ascorbic acid reduces the Fe from +3 to +2; the
34、Fethen serves to reduce the Pu from +4 to +3 and the Np from +5 to+4.11.2.2 Prepare one CMPO-TBP extraction column persample by loading 2 mL of resin per column.11Condition 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 th
35、e column and allow it to passthrough the column. 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 4The sodium nitrite oxidizes the Pu from +3 t
36、o +4.11.2.5 Rinse the column with 10 mL of 2M nitric 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 addin
37、g 15 mL of the oxalic acidin 1M HCl solution.11.3 Preparation for Counting:NOTE 5Refer to Test Method C 1163 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
38、 0.1 m, 25-mm diameter filter on a vacuumflask. Rinse 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
39、 to the next one. Remove the filter from the flaskand 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
40、-237 must be corrected for the U-234 in thesame region, or the sample should be re-extracted.12. Calculations12.1 Calculation of Tracer Yield:Y 5 Gt2 Bt! / E At! (1)where:Y = chemical yield,Gt= gross counts per second in the Pu tracer ROI,Bt= background counts per second in the Pu tracer ROI,E = det
41、ector counting efficiency (cps/dps), andAt= activity of the Pu tracer in Bq (dps).12.2 Calculation of Activity:The following equation is used to calculate the activity in thesample including any possible reagent blank:Ai5 Gi2 Bi! / Gt2 Bt!# At/ ABi W!# (2)where:Ai= activity of isotope of interest in
42、 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 reagent blank subtraction,can
43、be found in Practice D3084.12.3 Calculation of Minimum Detectable Activity:MDAi5 4.65 SB1 2.71! / E Y T ABi W! (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; neptunium; plutonium; uran
44、iumhexafluoride11The prepacked TRU column available from EIChroM Industries has beenfound to be acceptable.C1561033APPENDIX(Nonmandatory Information)X1.X1.1 This method does not have sufficient data to bequalified as a Standard Method for ASTM but is offered as aGuide for those wishing options for t
45、he 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.X1.2 Twenty samples of UF6
46、were 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 re
47、covery 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 with any item mentionedin this standard. Users of this standard are expressly advised that determination of
48、the validity of any such patent rights, and the riskof 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. Y
49、our comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West C
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