ASTM_D_4922_-_09.pdf

Designation:D492209Standard Test Method forDetermination of Radioactive Iron in Water1This standard is issued under the fixed designation D4922;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 test method covers the determination of55Fe in thepresence of59Fe by liquid scintillation counting.The a-prioriminimum detectable concentration 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 used successfully with Type IIIreagent water conforming to Specification D1193.It is theresponsibility 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 theresponsibility 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:3D1068 Test Methods for Iron in WaterD1129 Terminology Relating to WaterD1193 Specification for Reagent WaterD2777 Practice for Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterD3370 Practices for Sampling Water from Closed ConduitsD5847 Practice for Writing Quality Control Specificationsfor Standard Test Methods for Water AnalysisD7282 Practice for Set-up,Calibration,and Quality Controlof Instruments Used for Radioactivity Measurements3.Terminology3.1 DefinitionsFor definitions of terms used in this testmethod,refer to Terminology D1129.For terms not defined inthis test method or in Terminology D1129,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,zirconium,niobium,and cesium by anion exchange using acidwashes of various molarities.Subsequent 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 spectrophotometry.Alternatively,anyprocedure described in Test Method D1068 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 used 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 ananion 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 radioactive contaminants have been removed by anionexchange(see Fig.1).59Fe is also an activation product whichdecays by-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 D19 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 D4922 01.DOI:10.1520/D4922-09.2Currie,L.,“Limits for Qualitative Detection and Quantitative 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 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 the energies 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 subse