1、Designation: D 4922 09Standard Test Method forDetermination of Radioactive Iron in Water1This standard is issued under the fixed designation D 4922; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A numbe
2、r 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 covers the determination of55Fe in thepresence of59Fe by liquid scintillation counting. The a-prioriminimum detectable conc
3、entration for this test method is 7.4Bq/L.21.2 This test method was developed principally for thequantitative determination of55Fe. However, after proper cali-bration of the liquid scintillation counter with reference stan-dards of each nuclide,59Fe may also be quantified.1.3 This test method was us
4、ed successfully with Type IIIreagent water conforming to Specification D 1193.Itistheresponsibility of the user to ensure the validity of this testmethod for waters of untested matrices.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is th
5、eresponsibility 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. For a specifichazard statement, see Section 9.2. Referenced Documents2.1 ASTM Standards:3D 1068 Test Methods for Iron in WaterD
6、1129 Terminology Relating to WaterD 1193 Specification for Reagent WaterD 2777 Practice for Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterD 3370 Practices for Sampling Water from Closed ConduitsD 5847 Practice for Writing Quality Control Specificationsfor Sta
7、ndard Test Methods for Water AnalysisD 7282 Practice for Set-up, Calibration, and Quality Con-trol of Instruments Used for Radioactivity Measurements3. Terminology3.1 Definitions: For definitions of terms used in this testmethod, refer to Terminology D 1129. For terms not defined inthis test method
8、or in Terminology D 1129, refer to otherpublished glossaries.44. Summary of Test Method4.1 This test method describes the effective separation ofiron from the interfering cations of manganese, cobalt, zirco-nium, niobium, and cesium by anion exchange using acidwashes of various molarities. Subsequen
9、t elution of the iron isfollowed by phosphate precipitation to remove any residualzinc. The iron phosphate precipitate is dissolved in phosphoricacid and water and mixed with liquid scintillation cocktail. Thechemical yield is determined by the recovery of iron carrierusing atomic absorption spectro
10、photometry. Alternatively, anyprocedure described in Test Method D 1068 may be used, butthis will need to be validated by the user prior to reportingsample results.5. Significance and Use5.1 Radioactive iron is produced by neutron activation ofstable iron. Its concentration in reactor coolant is use
11、d tomonitor the corrosion of reactor parts such as reactor fuel-cladding material and reactor structural components.5.2 This technique effectively removes other activation andfission products such as isotopes of iodine, zinc, manganese,cobalt, and cesium by the addition of hold-back carriers and ana
12、nion exchange technique. The fission products (zirconium-95and niobium-95) are selectively eluted with hydrochloric-hydrofluoric acid washes. The iron is finally separated fromZn+2by precipitation of FePO4at a pH of 3.0.6. Interferences6.1 Samples of reactor origin will also contain59Fe afterother r
13、adioactive contaminants have been removed by anionexchange (see Fig. 1).59Fe is also an activation product whichdecays by b-g emission and will be a source of interference inthe quantitative determination of55Fe. The large difference in1This test method is under the jurisdiction of ASTM Committee D1
14、9 on Waterand is the direct responsibility of Subcommittee D19.04 on Methods of Radiochemi-cal Analysis.Current edition approved July 15, 2009. Published August 2009. Originallyapproved in 1989. Last previous edition approved in 2001 as D 4922 01.2Currie, L., “Limits for Qualitative Detection and Qu
15、antitative Determination,”Analytical Chemistry, Vol. 40, 1968, pp. 586593.3For 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
16、ASTM website.4“American National Standard Glossary of Terms,” Nuclear Science andTechnology (ANSI N1.1), American National Standards Institute, 1430 Broadway,New York, NY 10018.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.the ener
17、gies of their characteristic decay emissions makes itpossible to determine appropriate factors to correct for the59Fespectral cross-talk in the55Fe region.6.2 Quenching, which may be caused by a number offactors, results in a reduction in light output from the sample.The subsequent decrease in the s
18、pectral pulse height will causevariations in the counting efficiency with varying degrees ofquench. For this reason, it is necessary to monitor both thechanges in the55Fe efficiency and the59Fe cross-talk inthe55Fe region as a function of quench. This techniquerecommends the use of the automatic ext
19、ernal standard ratiosupplied by most liquid scintillation counters to monitor theamount of quench in a sample.6.3 The final heating of the sample solution will drive off allexcess hydrochloric acid, ammonia, and water. These sub-stances are, therefore, effectively removed as possible quench-ing agen
20、ts.6.4 Scintillation stock or sample solutions which have beenexposed to light must be dark adapted to avoid erratic resultsdue to light activation of the scintillator.NOTE 1It is the responsibility of the user to determine the requireddark adaptation period for the specific cocktail used.6.5 The st
21、able iron content in a sample will interfere in thedetermination of the chemical recovery. Since the amount ofstable iron in a sample will depend on its sources, a correctionfor the iron in the sample must be made.7. Apparatus7.1 Liquid Scintillation Counter, with an automatic externalstandard and m
22、ultiple energy region of interest (ROI) capabili-ties.7.2 Glass Scintillation Vials, 20-mLvials exhibiting suitableoptical reproducibility so as not to cause erratic results amongsamples.7.3 Atomic Absorption Spectrophotometer.7.4 Variable Speed Peristaltic Pump, with controller. Pumpspeed should be
23、 between 5 and 8 mL/min.7.5 Centrifuge, using 100 mL centrifuge tubes.7.6 Volumetric Flasks.7.7 Anion Exchange Columns:7.7.1 ColumnsCommercially available plastic dryingtubes and ends (40 mL volume, 1.5 cm diameter, 15 cm long).7.7.2 TubingPump inlet tubing, approximately 45.7 cm(18 in.) in length,
24、and pump outlet tubing, approximately 76.2cm (30 in.) in length.7.7.3 Polyethylene Porous Disc35-m pore size and 3.2mm thick.8. Reagents and Materials8.1 Purity of ReagentsReagent grade chemicals shall beused for all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to
25、 the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.5Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the deter
26、mination.8.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water conformingto Specification D 1193, Type III.8.3 ResinAGl-X8, AG1-X10, 200400 mesh; 25 mLpreviously equilibrated with 125 mLconcentrated hydrochloricacid.8.4 Scintillation CocktailComm
27、ercially prepared Insta-Gel scintillator or equivalent non-ionic detergent scintillator ofthe octyl-phenyl polyglycol ether type.6NOTE 2To obtain a clear aqueous final sample, the sample volumemust be kept below 1.8 mL with the addition of 15 mL Insta-Gel. It is theresponsibility of the user to dete
28、rmine the optimum sample volume tococktail volume to obtain a clear homogeneous solution for any otherliquid scintillation cocktail used.8.5 Ammonium Hydroxide (NH4OH)Concentrated (ap-proximately 15M) (sp gr 0.90).8.6 Ammonium Phosphate (0.5 M)Dissolve 66 g of am-monium monohydrogen phosphate (NH4)2
29、HPO4 in water anddilute to 1000 mL with water in a volumetric flask.8.7 Cesium Carrier Solution (1 mg/1 mL)Cesium ascesium chloride (CsCl) in dilute hydrochloric acid.78.8 Cobalt Carrier Solution (1 mg/1 mL)Cobalt as cobaltchloride (CoCl2) in dilute hydrochloric acid.75Reagent Chemicals, American Ch
30、emical Society Specifications, AmericanChemical Society, Washington, DC. For Suggestions on the testing of reagents notlisted by the American Chemical Society, see Annual Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S.
31、Pharmacopeial Convention, Inc. (USPC), Rockville,MD.6The sole source of supply of the apparatus known to the committee at this timeis Insta-Gel scintillator, available from PerkinElmer Life and Analytical Sciences,940 Winter Street, Waltham, MA 02451. If you are aware of alternative suppliers,please
32、 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.7Commercially available atomic absorption reference standards in 1 mg=1mLconcentrations may be used as carriers.FIG
33、. 1 Percent of Total Radionuclide Activity Removed Per AcidWashD49220928.9 Hydrochloric Acid (sp gr 1.187)Concentrated HCl.8.10 Hydrochloric Acid 10 MDilute 833 mL of concen-trated hydrochloric acid in 100 mL water and dilute to 1000mL with water in a volumetric flask.8.11 Hydrochloric Acid 6 MDilut
34、e 500 mL of concen-trated hydrochloric acid in 400 mL of water, dilute to 1000 mLwith water in a volumetric flask.8.12 Hydrochloric Acid 4 MDilute 333 mL of concen-trated hydrochloric acid in 600 mL of water, dilute to 1000 mLwith water in a volumetric flask.8.13 Hydrochloric Acid 0.5 MDilute 42 mL
35、of concen-trated hydrochloric acid in 900 mL of water, dilute to 1000 mLwith water in a volumetric flask.8.14 Hydrochloric Acid 0.01 MDilute 20 mL of 0.5 MHCl in 900 mL of water, dilute to 1000 mL with water in avolumetric flask.8.15 Hydrochloric(6 M)-Hydrofluoric Acid (0.5 M)Dilute 500 mL of concen
36、trated hydrochloric acid (HCl) (sp gr1.187) and 20 mL of 49 % concentrated hydrofluoric acid (HF)in 400 mL of water, dilute to 1000 mL with water in a plasticor TFE-fluorocarbon volumetric flask.8.16 Iron Carrier Solution (Fe+3as ferric chloride)7Dissolve 5.00 g of metallic iron in 300 mL of 6 M HCl
37、, filter,dilute to 1 L, and calibrate using an atomic absorptionspectrophotometer (Test Methods D 1068).8.17 Manganese Carrier Solution (1 mg/1 mL)Mn+2indilute nitric acid (HNO3).78.18 Niobium Carrier Solution (1 mg/1 mL)Nb+5in 5 %hydrofluoric acid (1 + 9 M).78.19 Nitric Acid (sp gr 1.42)Concentrate
38、d (HNO3).8.20 Phosphoric Acid (sp gr 1.834)Concentrated(H3PO4).8.21 Sodium Hydroxide (6 M)Dissolve 24 g sodium hy-droxide (NaOH) in 90 mL water, allow to cool, and dilute to100 mL with water and store in plastic bottles; a commerciallyprepared solution may also be used.8.22 Zinc Carrier Solution (1
39、mg/mL)Zn+2in dilutehydrochloric acid.78.23 Zirconium Carrier Solution (1 mg/mL)Zr+4in dilutehydrochloric acid.78.2455Fe Standard SolutionTraceable to a national stan-dards laboratory such as National Institute of Standards andTechnology (NIST) or UK National Physical Laboratory(NPL).8.2559Fe Standar
40、d SolutionTraceable to a national stan-dards laboratory such as NIST or NPL.9. Hazards9.1 HF is extremely hazardous and should be used in awell-ventilated hood. Wear rubber gloves, safety glasses orgoggles, and a laboratory coat.Avoid breathing any HF fumes.Clean all spills and wash thoroughly after
41、 using HF. Also, donot add HF to any glassware for it is a significant hazard andcan affect analytical accuracy.10. Sampling10.1 Collect samples in accordance with procedures pre-sented in Practices D 3370, as applicable.10.2 If the sample is not acidified at the time of collection,20 mLof concentra
42、ted HCl or HNO3should be added per 1000mL of sample. After acidification of the sample, the sampleshould be allowed to sit overnight prior to analysis.11. Calibration11.1 The reference standard for both iron isotopes willcontain 5 mg iron carrier. Add 6 drops of concentratedphosphoric acid to the ca
43、rrier solution and heat on a hot plateuntil it clears. This will drive off any excess hydrochloric acidand water (to less than 0.5 mL but do not allow to bake dry).Add 1 mL of water and swirl in the glass vial. This final carriersolution should be colorless. Cool the vial to room temperature.Spike w
44、ith the appropriate isotope and add 15 mL of scintil-lation cocktail. Cap and shake until the mixture is clear; thisstep ensures that the proper sample volume to scintillationcocktail volume ratio is obtained for a clear, homogeneoussolution. The volume of the reference standard should be suchthat i
45、ts addition to the sample does not cause additionalquench.11.2 Prepare a series of quenched55Fe standards and aseries of quenched59Fe standards using various weights of ironcarrier or concentration or volumes, or both, of acid. Use theleast quenched standards in each set to optimize the liquidscinti
46、llation counter (LSC) discriminator settings and amplifiergain. Ensure that the55Fe spectrum does not spill over intothe59Fe ROI. If your instrument does not allow for multiplenuclides to be optimized follow Practice D 7282 for instrumentoptimization.11.3 Count each set of standards with the LSC aut
47、omaticexternal standard ratio selected on to obtain approximately 1 %counting statistics (approximately 10 000 counts) in the ROI.11.4 Prepare a curve of the55Fe efficiency versus theexternal standard ratio.11.5 Prepare a crosstalk (XT) curve of the ratio of59Fecounts in the55Fe ROI to the59Fe count
48、s in the59Fe ROIversus the external standard ratio.11.6 Additional guidance on the set-up, calibration andcalibration verification of the instrument can be found inPractice D 7282.12. Procedure12.1 Measure an acidified and filtered aliquant of the sample(approximately 0.05 L) into a 100 mL centrifug
49、e tube.12.1.1 A background subtraction sample shall be processedin accordance with 12.2 through 12.16 with each set ofsamples.12.2 Add 5 mg iron carrier and mix well.12.3 Add NaOH (6 M), mix, and heat to precipitate ironhydroxide.12.4 Centrifuge and decant the supernatant solution towaste.12.5 Wash the precipitate with 50 mL of hot water, centri-fuge and decant the supernatant solution to waste.12.6 Dissolve the precipitate in 5 mL of 10 M HCl and add2 mL (2 mg) each of the appropriate hold-back carriers (Co+2,Zn+2,Zr+4,Nb+5,Mn+2, and Cs+1carriers)
