1、Designation: C1636 06aC1636 13Standard Guide for theDetermination of Uranium-232 in Uranium Hexafluoride1This standard is issued under the fixed designation C1636; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last re
2、vision. 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 232U in uranium hexafluoride by alpha spectrometry.1.2 The values stated in SI units
3、are to be regarded as standard. No other units of measurement are included in this standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health pract
4、ices and to determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C787 Specification for Uranium Hexafluoride for EnrichmentC996 Specification for Uranium Hexafluoride Enriched to Less Than 5 % 235UC1163 Practice for Mounting Actinides for Alpha
5、 Spectrometry Using Neodymium FluorideC1284 Practice for Electrodeposition of the Actinides for Alpha SpectrometryC1474 Test Method for Analysis of Isotopic Composition of Uranium in Nuclear-Grade Fuel Material by QuadrupoleInductively Coupled Plasma-Mass SpectrometryD1193 Specification for Reagent
6、WaterD3084 Practice for Alpha-Particle Spectrometry of WaterD3648 Practices for the Measurement of Radioactivity2.2 Other StandardsDIN 25711 Determination of the 232U isotopic content in uranium containing nuclear fuel solutions by spectrometry.3ISO 218473 Nuclear Fuel TechnologyAlpha SpectrometryPa
7、rt 3: Determination of uranium-232 in uranium and itscompounds.3. Terminology3.1 Definitions:3.1.1 region-of-interest (ROI)the channels, or region, in the alpha spectra in which the counts due to a specific radioisotopeappear on a functioning calibrated alpha spectrometry system.3.1.2 Reagent blankD
8、I water processed the same as the samples; used in the determination of the minimum detectable activity.4. Summary of Guide4.1 An aliquot of hydrolyzed uranium hexafluoride equivalent to 60 micrograms of uranium is converted to a nitric acid systemand the uranium is extracted onto a solid phase extr
9、action column. The daughters of uranium decay products are rinsed from thecolumn and the uranium is then selectively eluted. The uranium is reduced and then coprecipitated with neodymium fluoride. TestMethod C1163 provides further information on the use of neodymium fluoride to prepare actinide moun
10、ts for alpha spectrometry.The sample is then counted by alpha spectrometry, and the 232U is calculated based on the observed activities of the uraniumisotopes in the alpha spectra.1 This guide is under the jurisdiction of ASTM Committee C26 on Nuclear Fuel Cycle and is the direct responsibility of S
11、ubcommittee C26.05 on Methods of Test.Current edition approved July 1, 2006Jan. 1, 2013. Published July 2006January 2013. Originally approved in 2006. Last previous edition approved in 2006 asC1636 06.C1636 06a. DOI: 10.1520/C1636-06A.10.1520/C1636-13.2 For referencedASTM standards, visit theASTM we
12、bsite, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 Deutsches Institut fr Normung e.V., Berlin, Germany (www.din.de).This document is not an ASTM standard and
13、is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only th
14、e current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.2 While this guide does not present details on electrodeposition as an alternative to ne
15、odymium fluoride precipitation for thepreparation of a mount for alpha spectrometry Practice C1284 does present details on that option.4.3 Alternate separation chemistry approaches may be found in the literature. It is the responsibility of the user of suchalternative separation approaches to valida
16、te there effectiveness, especially the removal of potentially interfering thorium isotopes(section 6.1).5. Significance and Use5.1 The method is applicable to the analysis of materials to demonstrate compliance with the specifications set forth inSpecifications C787 and C996. Some other specificatio
17、ns may be expressed in terms of mass of 232U per mass of only 238U (seeISO 218473:2007).6. Interferences6.1 Incomplete removal of 228Th could possibly interfere with the 232U determination. Method DIN 25711 addresses thepotential capability for this method to eliminate this potential interference.6.
18、2 Since only the relative amount of 232U, relative to total uranium, is being determined in this method there is no impact tochemical loss in the separation or sample mounting chemistry. Therefore, unlike most alpha spectrometry methods, no yield traceris necessary or useful.6.3 The alpha emission e
19、nergies of 235U and 236U are relatively close. Thus there is the potential for overlap of counts fromone isotope into the ROI of the other. Where the alpha spectrometry system (section 7.1) provides spectral de-convolutionalgorithms may be used in the analysis of the spectra. Such de-convolution may
20、 allow for minimization of any possible bias inthe reported results. However, it should be noted that these two isotopes typically account for a relatively small amount of theoverall uranium mass. So any bias between the two should result in a relatively small overall bias in the reported 232U resul
21、t.7. Apparatus7.1 Alpha spectrometry system. See practices D3084 and D3648 for a description of the apparatus.7.1.1 A ROI for each uranium isotope (232U, 234U, 235U, 236U, and 238U) will need to be defined for the alpha spectrometrysystem being used. Based on these defined ROIs the fractional abunda
22、nce of alpha decays within the energy range of the ROI foreach isotope (ABi in section 12.1) must be determined.7.2 Ion Exchange Columns, able to hold a 10 mL resin bed and 15 mL solution washes.7.3 Filter Paper, 0.1 m pore size, 25-mm diameter, and compatible with HF.47.4 Vacuum FunnelPolysulfone t
23、wist-lock with stainless steel screen for filter mounting.8. Reagents and Materials8.1 Purity of ReagentsReagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that allreagents shall conform to the specifications of the Committee on Analytical Reagents of the
24、American Chemical Society, wheresuch specifications are available. Other grades of reagents may be used, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening the accuracy of the determination.58.2 Purity of WaterUnless otherwise indicate
25、d, references to water shall be understood to mean reagent water as defined inSpecification D1193.8.3 Ammonium oxalate (0.1M)Dissolve 14.2 g (NH4)2C2O4H2O in approximately 500 mL water and dilute to 1 litre.8.4 EthanolEthyl alcohol, absolute (200 proof), denatured.8.5 Hydrochloric acid (sp gr 1.19)C
26、oncentrated hydrochloric acid (HCl).8.6 Hydrochloric acid (9M)Add 750 mL concentrated HCl to 100 mL water and dilute to 1 litre.8.7 Hydrochloric acid (1.5M)Add 125 mL concentrated HCl to 500 mL water and dilute to 1 litre.8.8 Hydrochloric acid (1M)Add 83 mL concentrated HCl to 500 mL water and dilut
27、e to 1 litre.8.9 Hydrofluoric acid (minimum 48 % assay)Concentrated HF, reagent grade.WarningSevere burns can result from exposure of skin to concentrated hydrofluoric acid.4 Pall Life Sciences (formerly Gelman) Metricel filter has been found to be acceptable. If you are aware of alternative supplie
28、rs, please provide this information to ASTMInternational Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee,1 which you may attend.5 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC.
29、 For suggestions on the testing of reagents not listed bythe American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.C1636 1328.10 Neod
30、ymium chloride (10 mg Nd/mL)Heat 25 mL of concentrated hydrochloric acid and 1.17 g of neodymium oxide ona hotplate until the neodymium oxide is in solution. Cool the solution and dilute to 100 mL with water.8.11 Neodymium chloride (100 g Nd/mL)Dilute 1 mL of 10 mg Nd/mL solution to 100 mL with wate
31、r.8.12 Neodymium oxide (Nd2O3).8.13 Nitric acid (sp gr 1.42)Concentrated nitric acid (HNO3).8.14 Nitric acid (3M)Add 188 mL concentrated nitric acid to 500 mL water and dilute to 1 litre.8.15 Oxalic acid in 1M HCl (0.1M)Dissolve 12.6 g H2C2O4 H2O in 500 mL 1M HCl and dilute to 1 litre with 1M HCl.8.
32、16 20 % Titanium Trichloride (TiCl3) aqueous solutionavailable as a 20 % (w/v) solution of titanium trichloride fromcommercial suppliers.8.17 Extraction Chromatography Resin, containing octylphenyl-N,N-di-isobutyl carbamoylphosphine oxide (CMPO) dissolvedin tri-n-butyl phosphate (TBP) as the immobil
33、ized extractant.69. Hazards9.1 Adequate laboratory facilities, such as fume hoods and controlled ventilation, along with safe techniques must be used inthis procedure. Extreme care should be exercised in using hydrofluoric acid and other hot, concentrated acids. Use of rubber glovesis recommended.9.
34、2 HydrofluoricWarningHydrofluoric acid is a highly corrosive acid that can severely burn skin, eyes, and mucousmembranes. Hydrofluoric acid is similar to other acids in that the initial extent of a burn depends on the concentration, thetemperature, and the duration of contact with the acid. Hydroflu
35、oric acid differs from other acids because the fluoride ion readilypenetrates the skin, causing destruction of deep tissue layers. Unlike other acids that are rapidly neutralized, hydrofluoric acidreactions with tissue may continue for days if left unattended. Due to the serious consequences of hydr
36、ofluoric acid burns,prevention of exposure or injury of personnel is the primary goal. Utilization of appropriate laboratory controls (hoods) andwearing adequate personal protective equipment to protect from skin and eye contact is essential.Acute exposure to HF can causepainful and severe burns upo
37、n skin contact that require special medical attention. Chronic or prolonged exposure to low levels onthe skin may cause fluorosis. acid should be used with care by persons familiar with its hazards through review of the MaterialSafety Data Sheet (MSDS) and who are properly equipped to respond to cas
38、es of skin contact as suggested in the MSDS.10. Calibration and Standardization10.1 The alpha spectrometry units should be calibrated for energy, resolution and efficiency according to the manufacturers-manufacturers instructions. The background counting rate for the instrument should be measured at
39、 a frequency determined bythe user. See Practices D3084 and D3648 for additional information.11. Procedure11.1 Pipette an aliquot of hydrolyzed uranium hexafluoride equivalent to 60 g of uranium into a 150 mL beaker. Evaporate todryness. Dissolve the residue with 10 mL 3M HNO3 with gentle heating.11
40、.2 Condition a CMPO-TBP column by adding 5 mL 3M HNO3.711.3 Add the sample from Step 11.1 to the CMPO-TBP column and allow it to pass through the column.11.4 Rinse the CMPO-TBP column with 10 mL 3M HNO3.11.5 Rinse the CMPO-TBP column with 5 mL 9M HCl.11.6 Rinse the CMPO-TBP column with 30 mL 1.5M HC
41、l. This may be done with two 15-mL rinses.11.7 Rinse the CMPO-TBP column with 15 mL 0.1M H2C2O4 in 1M HCl.11.8 Elute the uranium from the column with 20 mL 0.1M (NH4)2C2O4H2O and collect in a PTFE beaker. If the alternativeof electrodeposition (see Practice C1284) is to be used the eluent may be col
42、lected in a glass beaker instead.6 TRU resin from Eichrom Technologies Inc., DarienLisle, IL, USA, has been found to be acceptable. If you are aware of alternative suppliers, please provide thisinformation to ASTM International Headquarters. Your comments will receive careful consideration at a meet
43、ing of the responsible technical committee,1 which you mayattend. Horwitz, E. P., Chiarizia, 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.The Eichrom Technol
44、ogies TRU resin is covered by a patent. Interested parties are invited to submit information regarding the identification of an alternative(s) to thispatented item to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee
45、, which you mayattend.7 The 2 mL prepacked TRU column from Eichrom Technologies Inc. has been found to be acceptable. If you are aware of alternative suppliers, please provide thisinformation to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of the res
46、ponsible technical committee,1 which you mayattend.C1636 13311.9 Add 3 drops 20 % TiCl3 aqueous solution, 0.75 mL of the 100 g Nd/mL solution, and 1 mL concentrated HF to theuranium fraction. Swirl to mix then allow the sample to sit for 30 minutes. Standard Method C1163 should be consulted foraddit
47、ional information on preparing the neodymium fluoride mount for alpha spectrometry.11.10 After placement of a 0.1 m, 25-mm diameter filter on the vacuum funnel rinse first with ethanol and then water.11.11 Add the uranium fraction to the filter and vacuum filter to dryness. Rinse the filter with wat
48、er and filter to dryness. Rinsethe filter with ethanol and filter to dryness. Dry the filter under a heat lamp.11.12 Count the sample for an appropriate counting time in a calibrated alpha spectrometer (see Section 10.1).12. Calculation of Results12.1 Calculation of uranium isotope sample activity:A
49、i 5 Gi 2Bi!T 3E 3ABi!(1)where:Ai = activity of uranium isotope of interest (Bq) (i=232, 234, 235, 236, or 238),Gi = gross counts in the analyte ROI accumulated in count duration T,Bi = background counts in the analyte ROI accumulated in count duration T,ABi = abundance of alpha decay of uranium isotope of interest in defined ROI (section 7.1.1), expressed as a fraction,E = detector alpha counting efficiency (cps/dps), andT = counting duration, s.Additional calculations, including reagent blank subtraction, can be found in Practice D3084.12
