ASTM_D_5411_-_10_2015.pdf

Designation:D541110(Reapproved 2015)Standard Practice forCalculation of Average Energy Per Disintegration(E)for aMixture of Radionuclides in Reactor Coolant1This standard is issued under the fixed designation D5411;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 practice applies to the calculation of the averageenergy per disintegration(E)for a mixture of radionuclides inreactor coolant water.1.2 The microcurie(Ci)is the standard unit of measure-ment for this standard.The values given in parentheses aremathematical conversions to SI units,which are provided forinformation only and are not considered standard.1.3 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.2.Referenced Documents2.1 ASTM Standards:2D1066 Practice for Sampling SteamD1129 Terminology Relating to WaterD3370 Practices for Sampling Water from Closed ConduitsD3648 Practices for the Measurement of RadioactivityD7282 Practice for Set-up,Calibration,and Quality Controlof Instruments Used for Radioactivity Measurements2.2 Code of Federal Regulations:10 CFR 100 Reactor Site Criteria33.Terminology3.1 DefinitionsFor definitions of terms used in thispractice,refer to Terminology D1129.4.Summary of Practice4.1 The average energy per disintegration,E(pronounced Ebar),for a mixture of radionuclides is calculated from theknown composition of the mixture.Eis computed by calcu-lating the total beta/gamma energy release rate,in MeV,anddividing it by the total disintegration rate.The resultant Ehasunits of MeV per disintegration.5.Significance and Use5.1 This practice is useful for the determination of theaverage energy per disintegration of the isotopic mixture foundin the reactor-coolant system of a nuclear reactor(1).4The Evalue is used to calculate a site-specific activity limit for thereactor coolant system,generally identified asAlimiting5 K/EwhereK=a power reactor site specific constant(usually in therange of 50 to 200).The activity of the reactor coolant system is routinelymeasured,then compared to the value ofAlimiting.If the reactorcoolant activity value is less thanAlimitingthen the 2-h radiationdose,measured at the plant boundary,will not exceed anappropriately small fraction of the Code of FederalRegulations,Title 10,part 100 dose guidelines.It is importantto note that the measurement of the reactor coolant systemradioactivity is determined at a set frequency by use of gammaspectrometry only.Thus the radionuclides that go into thecalculation of Eand subsequently Alimitingare only those thatare calculated using gamma spectrometry.5.2 In calculating E,the energy dissipated by beta particles(negatrons and positrons)and photons from nuclear decay ofbeta-gamma emitters.This accounting includes the energyreleased in the form of energy released from extra-nucleartransitions in the form of X-rays,Auger electrons,and conver-sion electrons.However,not all radionuclides present in asample are included in the calculation of E.1This practice is under the jurisdiction of ASTM Committee D19 on Water andis the direct responsibility of Subcommittee D19.04 on Methods of RadiochemicalAnalysis.Current edition approved Dec.15,2015.Published December 2015.Originallyapproved in 1993.Last previous edition approved in 2010 as D5411 10.DOI:10.1520/D5411-10R15.2For 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.3Available from Standardization Documents Order Desk,Bldg.4 Section D,700Robbins Ave.,Philadelphia,PA 19111-5094,Attn:NPODS.4The boldface numbers in parentheses refer to a list of references at the end ofthis practice.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 5.3 Individual,nuclear reactor,technical specifications varyand each nuclear operator must be aware of limitationsaffecting their plant operation.Typically,radioiodines,radio-nuclides with half lives of less than 10 min(except those inequilibrium with the parent),and those radionuclides,identi-fied using gamma spectrometry,with less than a 95%confi-dence level,are not typically included in the calculation.However,the technical requirements are that the reportedactivity must account for at least 95%of the activity afterexcluding radioiodines and short-lived radionuclides.There areindividual bases for each exclusion.5.3.1 Radioiodines are typically excluded from the calcula-tion of Ebeca