ASTM_C_1561_-_10_2016.pdf

Designation:C156110(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 adoption 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 isotopes 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 standard 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%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.Terminology3.1 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 system.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 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 resolution 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 compliance 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 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 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 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 separation could lead to incorrect test results.7.Instrumentation7.1 Alpha Spectrometry SystemSee Practices D3084 andD3648 for a description 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 approved 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 ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 8.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 Purity 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 WaterUnless 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 to1 L.9.4 Ascorbic Acid Solution(Saturated)Add a