1、Designation: C 1539 08Standard Test Method forDetermination of Technetium-99 in Uranium Hexafluoride byLiquid Scintillation Counting1This standard is issued under the fixed designation C 1539; the number immediately following the designation indicates the year oforiginal adoption or, in the case of
2、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 test method is a quantitative method used todetermine technetium-99 (99Tc) in uranium hexaf
3、luoride (UF6)by liquid scintillation counting.1.2 The values stated in SI units 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
4、of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C 787 Specification for Uranium Hexafluoride for Enrich-mentC 996 Specification for Uranium Hexafluori
5、de Enriched toLess Than 5 %235UC 1215 Guide for Preparing and Interpreting Precision andBias Statements in Test Method Standards Used in theNuclear Industry2.2 Other Document:USEC-651 Uranium Hexafluoride: A Manual of Good Han-dling Practices33. Terminology3.1 Definition:3.1.1 quench standard curvea
6、 relationship betweensample quench and detection efficiency. A quench curve for anisotope in a given cocktail and vial combination is developedby counting a series of standards containing the same activityof that isotope, but each with different quench. Sample quenchis typically quantified by a vari
7、ety of parameters.4. Summary of Test Method4.1 Ameasured portion of hydrolyzed uranium hexafluoride(UF6) containing approximately 0.8 to 1.2 g of uranium or avolume of sample less than or equal to 30 mL is transferred toa centrifuge tube. The uranium is precipitated using ammo-nium hydroxide.After c
8、entrifuging, the decanted supernatant isacidified with sulfuric acid and extracted with tributyl phos-phate. An aliquot of the extract is transferred to a scintillationvial, where stannous chloride in hydrochloric acid and liquidscintillation cocktail are added. The99Tc beta activity is thendetermin
9、ed by liquid scintillation counting.5. Significance and Use5.1 Uranium hexafluoride is a basic material used to preparenuclear reactor fuel. To be suitable for this purpose, thematerial must meet the criteria for technetium composition.This test method is designed to determine whether the materialme
10、ets the requirements described in Specifications C 787 andC 996.5.2 Using the specified instrumentation and parameters, thismethod has a lower detection limit of 0.0004 gTc/gU.NOTE 1Different instrumentation or parameters may provide varyingdetection limits, as calculated in 11.4.6. Apparatus6.1 Liq
11、uid Scintillation Counter,4with alpha/beta discrimi-nation and enhanced low level discrimination over the entireenergy range of 0 to 2000 keV.6.2 Centrifuge.6.3 Analytical Balance, 1 mg sensitivity.6.4 Separatory Funnel, 125 mL volume.6.5 Liquid Scintillation Vials,20mL.6.6 Centrifuge Tubes with Cap
12、s,50mL.6.7 Laboratory Wipes, lint free disposable.1This test method is under the jurisdiction of ASTM Committee C26 on NuclearFuel Cycle and is the direct responsibility of Subcommittee C26.05 on Methods ofTest.Current edition approved July 1, 2008. Published July 2008. Originally approvedin 2002. L
13、ast previous edition approved in 2002 as C 1539 02 which waswithdrawn January 2008 and reinstated n July 2008.2For 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 st
14、andards Document Summary page onthe ASTM website.3Available from U.S. Enrichment Corporation, 6903 Rockledge Drive, Be-thesda, MD 20817.4The sole source of supply of the apparatus known to the committee at this timeis Packard Tri-Carb Model 1905 AB/LA. If you are aware of alternative suppliers,pleas
15、e provide this information to ASTM International Headquarters. Your com-ments will receive careful consideration at a meeting of the responsible technicalcommittee,1which you may attend.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States
16、.7. Reagents and Materials7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents conform to the specifications of the Committee ofAnalytical Reagents of the American Chemical Society wherespecifications are available.57.2
17、Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean laboratory accepteddeionized water.7.3 Ammonium Hydroxide (NH4OH), concentrated (14.5M).7.4 Hydrochloric Acid (HCl), concentrated (12M).7.5 Hydrochloric Acid (HCl), (1M). Add 82 mL of concen-trated (12M) HCl to
18、 900 mL of water, dilute to a final volumeof 1000 mL, and mix.7.6 Liquid Scintillation Cocktail.67.7 Potassium Permanganate (KMnO4), 1 % W/V in water.Dissolve1gofKMnO4in 100 mL of water, and mix.7.8 Stannous Chloride (SnCl2), 20 % (W/V) SnCl2in con-centrated hydrochloric acid. Dissolve 20 g of SnCl2
19、in 100 mLof concentrated hydrochloric acid, and mix.7.9 Sulfuric Acid (H2SO4), concentrated 18M.7.10 Sulfuric Acid (H2SO4), 9M. Add 500 mL concentratedH2SO4(18M) to 400 mL water, dilute to a final volume of 1000mL, and mix.7.11 Sulfuric Acid (H2SO4), 3M. Add 168 mL of concen-trated H2SO4(18M) to 800
20、 mL of water, dilute to a finalvolume of 1000 mL, and mix.7.12 Sulfuric Acid (H2SO4), 1M.Add 56 mLof concentratedH2SO4(18M) to 900 mL of water, dilute to a final volume of1000 mL, and mix.7.13 Technetium Standard(s) in a Basic Aqueous Solution.7.14 Tributyl Phosphate (TBP C12H27O4P), saturated solu-
21、tion. Equilibrate 500 mL TBP with 500 mL 3M H2SO4. Shakefor approximately 2 min. Allow to separate and discardaqueous layer.8. Hazards8.1 Since UF6is radioactive, toxic, and highly reactive,especially when reducing substances and moisture are present(see USEC-651), appropriate facilities and practic
22、es must beprovided.9. Procedure9.1 Transfer an aliquot up to 30 mL of one of the followingsolutions, as applicable, to a 50 mL centrifuge tube:9.1.1 Hydrolyzed UF6SampleUnknown UF6sample hy-drolyzed in water.9.1.2 StandardLaboratory control sample with aknown99Tc concentration.9.1.3 Spike SolutionUF
23、6sample spiked with a knownconcentration of99Tc (approximately ten times the sampleactivity).9.2 Add 2 drops of potassium permanganate solution (1 %W/V) and swirl to mix.9.3 Dilute with water to approximately 35 mL and swirl tomix.9.4 Add 5 mL concentrated ammonium hydroxide to pre-cipitate uranium.
24、9.5 Dilute with deionized water to 50 mL.9.6 Cap and shake vigorously to break up large particles ofammonium diuranate.9.7 Centrifuge for approximately 10 min at approximately1500 rpm.9.8 Add 25 mL 9M H2SO4to a clean 125-mL separatoryfunnel.9.9 Decant the supernatant containing the technetium intoth
25、e 125-mL separatory funnel.NOTE 2The precipitated uranium remains in the centrifuge tube.9.10 Add 5 mL of TBP solution to the separatory funnel.9.11 Stopper or cap the funnel and shake for approximately60 s.9.12 Allow phases to separate a minimum of 5 min.9.13 Drain off aqueous (lower) phase into a
26、waste beaker.9.14 Add 20 mL of 3M H2SO4.9.15 Stopper or cap the funnel and shake for approximately30 to 45 s.9.16 Allow phases to separate for a minimum of 5 min.9.17 Drain off aqueous (lower) phase into a waste beaker.9.18 Pipette up to 4 mL of the extract from the funnel intoa 20 mL scintillation
27、vial.9.19 Pipette 0.2 mL stannous chloride solution into the vial.9.20 Pipette 12 mL liquid scintillation cocktail into the vial.NOTE 3This test method has proven acceptable for 12 mL of liquidscintillation cocktail, but up to 16 mL can be added depending on theusers instrumentation.9.21 Cap the via
28、l and shake vigorously for approximately 5to 10 s.9.22 Wipe the outside of the vial with a damp laboratorywipe to remove static electricity, if necessary.9.23 Place the vial in the liquid scintillation counter.9.24 Allow vial to stand for approximately 15 min prior tocounting.10. Counting10.1 Progra
29、m the liquid scintillation counter according tothe manufacturers guidelines.710.2 Place reagent blank in position one and allow instru-ment to subtract background counts to obtain net counts perminute (cpm), as needed.10.3 Count vial for three consecutive 10 min counts, andaverage (avg).5Reagent Che
30、micals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, Merk Ltd., Poole, Dorset, U.K. and the United States Pharmacopeia andNation
31、al Formulary , U.S. Pharmacopoeil Convention, Inc. (USPC), Rockville,MD, or equivalent.6The sole source of supply of the apparatus known to the committee at this timeis Insta-Gel (trademarked). If you are aware of alternative suppliers, please providethis information to ASTM International Headquarte
32、rs. Your comments will receivecareful consideration at a meeting of the responsible technical committee,1whichyou may attend.7Packard Tri-Carb Model 1905 AB/LA uses a 0.8 to 293 keV counting window.C153908210.4 Calculate counting efficiency by spiking a knownamount of99Tc into vial containing 4 mL o
33、f TBP, 0.2 mL ofSnCl2, and 12 mL of liquid scintillation cocktail.Net cpmdpm of the known reference value5 Efficiency expressed as a decimal!(1)where:dpm = disintegrations per minute10.5 Convert cpm to dpm for the unspiked samples prior toperforming calculations.Avg dpm 5Avg cpmEfficiency expressed
34、as a decimal!(2)11. Calculations11.1 Calculate the99Tc concentration:g99TcgU5A 3 yB 3 Aliq! 3 C 3 37830(3)where:A = volume (mL) of TBP added to the separatoryfunnel in 9.10,B = uranium concentration in gU/mL of the hydro-lyzed UF6,C = aliquot (mL) of extract taken from the separatoryfunnel in 9.18,A
35、liq = sample (mL) from 9.1.1,37830 = specific activity of99Tc in dpm/g99Tc, andy= average dpm of sample as obtained in 10.4 and10.5.11.2 Manual Calculation of Spike Recovery8Spike Recovery %! 5Spiked Sampledpm!2Sampledpm!#Spike Concentrationdpm!3 100(4)11.3 Calculate the minimum detectable activity
36、(MDA)when the background and sample run times are equal.MDA 53 1 4.66 3 =gross counts# 3 AT 3 B 3 Aliq 3 C 3 37830 3 K5g99TcgU(5)where:4.66 = Curries Factor (a constant to achieve 2serror),T = time in min,gross counts = background cpm 3 T, andK = counting yield or counting efficiency ex-pressed as a
37、 decimal.NOTE 4Below is an example of some typical values. Please note thatsome values will vary depending on the instrumentation used, instrumentsetup, cocktail used, and lower detection limits.T = 30 min as designated in 10.3K = 0.93 to 0.95B = 0.8 to 1.2 g of uranium or a volume of sample # 30 mL
38、C =4mL11.4 Calculate the minimum detectable activity (MDA)when the background and sample run times are not equal.MDA 53 1 3.29 3 =Rbtg1 1 tg/tb!# 3 Atg3 B 3 Aliq 3 C 3 37830 K5g99TcgU(6)where:Rb= background, cpm,tg= gross counting time, min, andtb= background counting time, min.12. Precision and Bia
39、s12.1 Data9Data are presented for three99Tc controlshaving certified reference values traceable to recognized na-tional standards. The three standards were 229 6 3.05dpm99Tc, 1146 6 15.24 dpm99Tc, and 1923 6 21.92 dpm99Tc,where the 6 quantities are at the 2s error for the referencevalues. The standa
40、rd designations, function, reference valuesand uncertainties are listed in Table 1. The lowest (229 dpm)and highest (1923 dpm) controls were each prepared as alaboratory control sample (LCS) in deionized water to assessthe overall process for an inherent bias. In addition, the 1146dpm99Tc control wa
41、s prepared as a spike in UF6samples toindicate the appropriateness of the method by measuring99Tcrecovery in UF6. The UF6samples contained uranium concen-trations ranging from 0.0493 to 0.0675 gU/mL and99Tcconcentrations (prior to spiking) ranging from 0.0001 to 0.0301g99Tc/gU. Each of the three sta
42、ndards was analyzed over twomonths by different analysts in the same laboratory resulting ina total of at least 30 test results for each standard. Threedifferent analysts analyzed the 229 dpm99Tc and 1923 dpm99Tclaboratory control standards, with five different analysts ana-lyzing the 1146 dpm99Tc l
43、aboratory control sample. The datawere used to quantify precision and bias.12.2 Due to difficulties in movement and ownership ofnuclear materials, as referred to in section 1.4 of Guide C 1215,interlaboratory testing is not practical. The reproducibility wasobtained by treating the analysts as diffe
44、rent laboratories. Thisshould be taken into account when considering the reproduc-ibility results.12.3 PrecisionTable 2 summarizes the statistical resultsfor precision, giving both the repeatability and reproducibilityresults obtained using standard analysis of variance (ANOVA)techniques. The absolu
45、te standard deviation increaseswith99Tc concentration indicating the precision is a function ofthe test results (in this case, the relative standard deviation isthe more appropriate measure of precision). The relativerepeatability standard deviation (single analyst) has beendetermined to be 2.14 % (
46、averaged over the three standards)while the reproducibility standard deviation (between analysts)was determined to be 2.30 % in the same manner. The betweenanalysts variation was not statistically significant at the 99 %level.12.4 BiasTable 2 also summarizes the statistical resultsfor bias estimatio
47、n. The relative difference of the mean resulton each standard from its reference value, averaged over the8Spike Recovery is used for Laboratory QA/QC purposes to monitor the qualityof the analysis.9Supporting data, including raw data and statistical analysis, have been filed atASTM Headquarters and
48、may be obtained by requesting RR:C261011.C1539083three standards, is 2.94 %, indicating an average recovery of97.1 % on the standards. This difference is an indication ofbias.13. Keywords13.1 scintillation counter; technetium-99; uraniumhexafluorideASTM International takes no position respecting the
49、 validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of 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. Your comments are invited either for revision of this standard or for additional standards
