ML003714744

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Draft Regulatory Guide DG-8026 (Proposed Revision 1 to Regulatory Guide 8.30), Health Physics Surveys in Uranium Recovery Facilities
ML003714744
Person / Time
Issue date: 09/30/2000
From:
Office of Nuclear Regulatory Research
To:
Lusher J H
References
DG-8026 RG-8.030, Rev 1
Download: ML003714744 (35)
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Thisregulatoryguideisbeingissuedindraftformtoinvolvethepublicintheearlystagesofthedevelopmentofaregulatorypositioninthisarea.It hasnotreceivedcompletestaffreviewanddoesnotrepresentanofficialNRCstaffposition.Publiccommentsarebeingsolicitedonthedraftguide(includinganyimplementationschedule)anditsassociatedregulatoryanalysisorvalue/impactstatement.Commentsshouldbeaccompaniedbyappropriatesupportingdata.WrittencommentsmaybesubmittedtotheRulesandDirectives Branch,OfficeofAdministration,U.S.NuclearRegulatoryCommission,Washington,DC20555-0001.Commentsmaybesubmittedelectronicallyor downloadedthroughtheNRC'sinteractivewebsite,<WWW.NRC.GOV>throughRulemaking.CopiesofcommentsreceivedmaybeexaminedattheNRCPublicDocumentRoom,2120LStreetNW.,Washington,DC.CommentswillbemosthelpfulifreceivedbyDecember15,2000.Requestsforsinglecopiesofdraftoractiveregulatoryguides(whichmaybereproduced)orforplacementonanautomaticdistributionlistforsingl ecopiesoffuturedraftguidesinspecificdivisionsshouldbemadeinwritingtotheU.S.NuclearRegulatoryCommission,Washington,DC20555, Attention:ReproductionandDistributionServicesSection,orbyfaxto(301)415-2289;orbyemailto<DISTRIBUTION@NRC.GOV>.Electroniccopiesofthisdraftguide,AccessionNumberML003714744,areavailableinNRC'sPublicElectronicReadingRoom,whichmaybeaccessedthroughthe NRC'swebsite,<

WWW.NRC.GOV>.U.S.NUCLEARREGULATORYCOMMISSIONSeptember2000OFFICEOFNUCLEARREGULATORYRESEARCHDivision8DraftDG-8026DRAFTREGULATORYGUIDEContact:J.H.Lusher(301)415-7694DRAFTREGULATORYGUIDEDG-8026(ProposedRevision1ofRegulatoryGuide8.30)HEALTHPHYSICSSURVEYSINURANIUMRECOVERYFACILITIESA.INTRODUCTIONThisguideisbeingrevisedtodescribehealthphysicssurveysthatareacceptabletotheNRCstaffforprotectingworkersaturaniumrecovery(UR)facilities(e.g.,uraniummills,in-situ leach(ISL)facilities,ionexchangerecoveryfacilities)fromradiationandthechemicaltoxicityof uraniumwhileonthejob.Theguidancecanalsobeapplied,inpart,toothertypesofURfacilities andportionsofconversionfacilitiessincesomeoftheprocessesusedinthesefacilitiesaresimilar tothoseinURfacilities.Section40.32,"GeneralRequirementsforIssuanceofSpecificLicenses,"of10CFRPart40,"DomesticLicensingofSourceMaterial,"indicatesthattheNRCwillapproveanapplicationto operateaURfacility(e.g.,uraniummilling,uraniumhexafluoridefacility)iftheapplicantisqualified byreasonoftrainingandexperiencetobeabletoprotecthealthandminimizedangertolifeand propertyandiftheapplicant'sproposedequipment,facilities,andproceduresarealsoadequate.ThefollowingsectionsoftheNRC'sregulationsin10CFRPart20,"StandardsforProtectionAgainstRadiation,"dealwiththeprotectionofworkers:§20.1501requiresadequate surveys,§20.1201providesoccupationaldoselimitsforadults,§20.1208providesdoselimitsfor declaredpregnantwomen,§20.1502requirespersonnelradiationdosimetersincertaininstances,

§20.1902requirespostingofwarningsigns,§20.1602requirescontrollingaccesstoareaswith highradiationlevels,§20.2106requiresrecordsofradiationsurveysandpersonnelmonitoring reports,and§20.2203requiresreportsofoverexposures.Thisguidedoesnotcoversurveystopreventthereleaseofradioactivematerialtounrestrictedareasorsurveystomeasuretheexposureofthepublictoradioactivematerialsin effluents,exceptforsurveysoftheskinandclothingofworkersleavingtheURfacilityandsurveys ofequipmentandpackagesleavingtheURfacility.

2RegulatoryguidesareissuedtodescribetothepublicmethodsacceptabletotheNRCstaffforimplementingspecificpartsoftheNRC'sregulations,toexplaintechniques usedbythestaffinevaluatingspecificproblemsorpostulatedaccidents,andtoprovide guidancetoapplicants.Regulatoryguidesarenotsubstitutesforregulations,and compliancewithregulatoryguidesisnotrequired.Regulatoryguidesareissuedindraft formforpubliccommenttoinvolvethepublicindevelopingtheregulatorypositions.Draft regulatoryguideshavenotreceivedcompletestaffreview;theythereforedonotrepresent officialNRCstaffpositions.Theinformationcollectionscontainedinthisdraftregulatoryguidearecoveredbytherequirementsof10CFRParts20,whichwereapprovedbytheOfficeofManagementand Budget,approvalnumber3150-0014.Ifameansusedtoimposeaninformationcollectiondoes notdisplayacurrentlyvalidOMBcontrolnumber,theNRCmaynotconductorsponsor,anda personisnotrequiredtorespondto,theinformationcollection.B.DISCUSSIONRegulatoryGuide3.5,"StandardFormatandContentofLicenseApplicationsforUraniumMills"(Ref.1),outlinesthetypeofinformationthatapplicantsforaURfacility licenseshouldincludeintheirapplicationsandsuggestsauniformformatforpresenting thatinformation.Thisregulatoryguidedescribesoccupationalhealthphysics(radiation protection)surveysacceptabletotheNRClicensingstaffthatanapplicantmayusefor describingsurveysinSection5.5,"RadiationSafety,"inRegulatoryGuide3.5.ThecontentsofthisguideconformwithNRC'scurrentlicensingpractice.ThecontentsofthisguidearealsobasedtoalargeextentontheInternationalAtomicEnergy Agency(IAEA)"ManualofRadiologicalSafetyinUraniumandThoriumMinesandMills" (Ref.2).Respiratoryprotection,uraniumbioassay,andprogramsformaintainingoccupationalexposurestoradiationaslowasreasonablyachievablearenotincludedin thisguide.ThosesubjectsarecoveredinRegulatoryGuide8.15,"AcceptablePrograms forRespiratoryProtection"(Ref.3);RegulatoryGuide8.22,"BioassayatUraniumMills" (Ref.4);AmericanNationalStandardHPSN13.22-1995,"BioassayProgramsfor Uranium"(Ref.5);AmericanNationalStandardHPSN13.30-1996,"PerformanceCriteria forRadiobioassay"(Ref.6);andRegulatoryGuide8.31,"InformationRelevantto EnsuringthatOccupationalRadiationExposuresatUraniumMillsWillBeAsLowAsIs ReasonablyAchievable"(Ref.7).C.REGULATORYPOSITION1.OCCUPATIONALDOSELIMITSIn10CFRPart20,"StandardsforProtectionAgainstRadiation,"10CFR20.1201establishesradiationdoselimitsforoccupationallyexposedadults.Thesedoselimits applytothesumofthedosereceivedfromexternalexposureandthedosefrominternally depositedradioactivematerial.ThesedoselimitsaresummarizedinTable1.The occupationaldoselimitsforminorsaccordingto10CFR20.1207are10%ofthedose limitforadults,and10CFR20.1208establishesadoselimitfortheembryo/fetusof0.5 rem(0.005Sv)duringtheentiredeclaredpregnancy.

3The"totaleffectivedoseequivalent"isdefinedasthesumofthe"deep-doseequivalent"(forexternalexposures)andthe"committedeffectivedoseequivalent"(for internalexposures).Thelimitof50rems(0.5Sv)specifiedin10CFR20.1201(a)(1)(ii) appliestothesumofthe"deep-doseequivalent"andthe"committeddoseequivalent"to anyindividualorganortissueotherthanthelensoftheeyes.Therequirementsin10 CFR20.1202areforsummingexternalandinternaldosesifthelicenseeisrequiredto monitorunderboth10CFR20.1502(a)and(b)todemonstratecompliancewiththedose limitsof10CFR20.1201.Inadditiontotheselimits,10CFR20.1201(e)establishesalimitfortheintakeofsolubleuraniumof10milligramsperweek,basedonchemicaltoxicitytothekidney.ThePart20requirementsforrecordingindividualmonitoringresultsarein10CFR20.2106.Whenmonitoringisrequiredunder10CFR20.1502,themonitoringresults mustberecordedonNRCForm5oritsequivalentaccordingto10CFR20.2106(c).TABLE1DoseLimitsandAssociatedTerminologyTypeofExposure10CFRPart20DesignationDoseLimitTotalWholeBodyDose(SumofExternalandInternal)TotalEffectiveDoseEquivalent(TEDE)TEDE=DDE+CEDE5rem/yearExternalDoseDeepDoseEquivalent(DDE)(a)InternalWholeBodyDoseCommittedEffectiveDoseEquivalent(CEDE)(a)

TotalOrganDose(SumofExternalandInternal)TotalOrganDoseEquivalent(TODE)TODE=DDE+CDE50rem/yearInternalOrganDoseCommittedDoseEquivalent(CDE)(a)SkinDoseShallowDoseEquivalent(SDE),SkinofWholeBody50rem/yearExtremityDoseShallowDoseEquivalent(SDE),MaximumExtremity50rem/yearEyeDoseEyeDoseEquivalenttoLensoftheEye(LDE)15rem/year(a)Includedinlimitsforwholebodyandindividualorgans.Intheabsenceofanyinternalexposure,externaldoseislimitedto5remperyear.Intheabsenceofanyexternalexposure,internalexposureislimitedto 2000DAC-hoursperyearor1annuallimitonintake(ALI)(50rem/yrnon-stochastic,5rem/yrstochastic).2.SURVEYS2.1SurveysforAirborneUraniumOreDustSurveysforairborneuraniumoredustarenecessaryto(1)demonstratecompliancewiththeoccupationaldoselimitsforworkersspecifiedin10CFR20.1201,(2) meetthepostingrequirementsforairborneradioactivityareasin10CFR20.1902(d),(3) determinewhetherprecautionaryproceduressuchasprocessorotherengineering controls,increasedsurveillance,limitationonexposuretimes,useofrespiratoryprotection equipment,orotherprecautionsshouldbeconsideredtomeet10CFR20.1701and 1Microgramsofuraniumcanbeconvertedtomicrocuriesbyusingthespecificactivityofnaturaluranium:6.77x10-7mCi/mg.4DAC m=f nuDAC nu f odDAC od 1+-éûúúúú20.1702,and(4)determinewhetherexposurestoradioactivematerialsarebeingmaintainedaslowas isreasonablyachievableasstatedin10CFR20.1101 and20.1702.TheDerivedAirConcentration(DAC)applicabletolimitingexposuretoairborneuraniumoredustinrestrictedareasisgiveninparagraph3oftheNotetoAppendixB, "AnnualLimitsonIntake(ALIs)andDerivedAirConcentrations(DACs)ofRadionuclides forOccupationalExposure;EffluentConcentrations;ConcentrationsforReleaseto Sewerage,"of10CFRPart20.Ifgrossalphacountingoftheairsampleisperformed,theDACvalueis6x10

-11microcuries(mCi)ofalphaactivitypermilliliter(ml)ofair.Thisconcentrationappliestothealphaemissionsofuranium-238,uranium-234,thorium-230,andradium-226.Ifchemicalseparationofuraniumfollowedbyalphacounting,alpha spectrometry,orfluorometricproceduresareusedtodeterminetheuraniumconcentrationalone,theDACvalueis3x10

-11 mCiofnaturaluraniumpermlofair.Inmassunits,theconcentrationis45micrograms(mg)ofnaturaluraniumpercubicmeterofair.

1Theuraniumoredustconcentrationisapplicabletoareaswhereoreishandledpriortochemicalseparationoftheuraniumfromtheore.Wheretheorecrushingandgrinding circuits,chemicalleachingareas,andyellowcakeareasarephysicallyisolatedfromeach other,theoredustconcentrationobviouslyappliestotheorehandlingareas.Whereorehandlingandyellowcakeprocessingarenotphysicallyisolatedfromeachother,theconcentrationvalueof6x10

-11 mCi/mlmaybeusedprovidedthatgrossalphacountingisperformed.Forothermethodsofanalysisthatincludeonlymeasurementsofuranium,itisnecessarytodeterminethefractionofthealphaactivity thatisduetooredust.Forexample,inaURfacilitythatproduceslittleoredustbecause ithasawetoregrindingprocessbuthassignificantemissionsfromyellowcakeprocessingequipment,thenaturaluraniumconcentrationof3x10

-11 mCiofnaturaluraniumpermlofairmaybeapplicablethroughouttheplant.Ifuraniumoredustconcentrationsarebelow10%oftheapplicableconcentrationvalueinAppendixBtoPart20(i.e.,below3x10

-12 mCi/ml),uraniumoredustmaybeconsideredtobenotpresent,andtheappropriatevaluefornaturaluranium(3x10

-11 mCi/ml)maybeusedinstead.Iforedustconcentrationsexceed10%oftheAppendixBvalue,theairbornemixturemayeitherbeconsidered entirelyoredust(forwhichtheconcentrationvalueof6x10

-11 mCi/mlapplies)oranewconcentrationvalueforthemixture,DAC m,maybecalculatedusingEquation1.Equation1where 2Thetitle"RadiationSafetyOfficer"isusedbymanylicenseesand,inthisguide,meansthepersonresponsibleforconductinghealthphysicssurveyprograms;othertitlesareequallyacceptable.

5 DAC m=regulatoryconcentrationvaluefornaturaluranium DAC od=regulatoryconcentrationvalue(inradio-metricunits)fornaturaluraniuminoredust f nu=fractionofalphaactivityfromnaturaluraniumasyellowcake,i.e., C nu/(C nu+C od).C nu:alphaconcentrationfromnaturaluranium;C od:alphaconcentrationfromoredust.

f od=fractionofalphaactivityfromnaturaluraniuminoredust,i.e., C od/(C nu+Co od)Sincethisequationwouldonlybeusedwiththe6x10

-11 mCi/mlvalueofC od ,f od iscalculatedasthefractionoftheuraniumalphaactivityonly.Thisequationwasderivedfrom,andisthusequivalentto,theinequalityshowninparagraph1oftheNoteto AppendixBto10CFRPart20(seeAppendixAofthisguide).Inareasthatarenot"airborneradioactivityareas,"anacceptablesamplingprogramforairborneuraniumoredustincludesmonthlygrabsamplesof30minutes durationinworker-occupiedareaswhileoreisbeingactivelyhandled.Asanalternative, weeklygrabsamplesof5minutesduration,eachusingahigh-volumesampler(roughly 30cfm),areacceptableaslongasthelicenseecandemonstratethatthevolumesampled isaccuratelyknown.Thequantityofairsampledandthemethodofanalysisshouldallowalowerlimitofdetection(LLD)of3x10

-12 mCiofnaturaluraniumpermlofair(or4.5 mgofuraniumperm 3ofair).AppendixBtothisguideshowshowtocalculatetheLLDwhenafluorometricanalysisforuraniumisused.Ifanyareaisan"airborneradioactivityarea,"as definedin10CFR20.1003,30-minutesamplesshouldbetakenweeklyifworkersoccupy thearea.Airsamplesfromoutdoorareassuchastheorepadshouldbecollected quarterly.Onlyoredustsamplesrepresentativeoftheairinhaledbytheworkerspresentareacceptable.Samplestakenataheightofabout3to6feetandpositionedbetweenthe sourceandtheworkerarenormallyconsideredrepresentative.Samplesshouldbetaken whilenormalorehandlingistakingplace.Thestateofoperationofmajorequipment duringsamplingshouldberecorded.Inlargerooms,severallocationsshouldbe sampled.Specialbreathingzonesampling(lapelsamplingorothersamplingofthe immediatebreathingzoneofaparticularworker)isnotnecessaryfororedust;however,it maybewarrantedinspecialsituations.Duringthefirstyearofoperation,newURfacilitieswillneedamoreextensiveairsamplingprogramtodeterminethelocationsthatprovidemeasurementsofthe concentrationrepresentativeoftheconcentrationtowhichworkersareexposed.Sampleanalysisshouldusuallybecompletedwithintwoworkingdaysaftersamplecollection.UnusualresultsshouldbereportedpromptlytotheRadiationSafetyOfficer (RSO).2 6IntakeandexposurecalculationsfororedustarediscussedinRegulatoryPosition3ofthisguide.2.2SurveysforAirborneYellowcakeItisgenerallyacceptedthaturaniumdissolvedinthelungorabsorbedbythegastrointestinaltractentersthebloodstreamandisdistributedtovariousbodyorgans.

Therateofdissolutionforyellowcakeappearstodependonitstemperaturehistoryduring processing.Yellowcakedriedatlowtemperature,whichispredominantlycomposedof ammoniumdiuranate,ismoresolubleinbodyfluidsthanyellowcakedriedathigher temperature;andarelativelylargefractionisrapidlytransferredtokidneytissues(Refs.8 to10).Iftheintakeofsuchyellowcakeiscontrolledtoprotectthekidneyfromthe chemicaltoxicityofuranium,radiologicalprotectioncriteriafornaturaluraniumwillalsobe satisfied.Forpurposesofcompliancewith10CFRPart20,yellowcakeundriedordriedat lowtemperatureshouldbeclassifiedassoluble.Yellowcakedriedathightemperatureisamixtureofcompoundsthatcontainsamajorportionofmoreinsolubleuraniumoxides.Radiationdosetothelungandother organsisthelimitingconsiderationratherthanchemicaltoxicity;thisisprimarilyduetothe largeinsolublecomponent.Forcompliancepurposes,yellowcakedriedat400 oC(752F)andaboveshouldbeclassifiedasinsoluble(Refs.11and12).Thus,surveysforairborneyellowcakearenecessarytodemonstratecompliancewiththeoccupationaldoselimitsin10CFR20.1201.Surveysarealsonecessaryto establishtheboundariesofairborneradioactivityareasandtodeterminewhether surveillance,limitationonworkingtimes,provisionsofrespiratoryequipment,orother precautionsshouldbeconsideredincompliancewith10CFR20.1701and20.1702.Therecommendedsurveyprogramforyellowcakeusesacombinationofgeneralairsamplingandbreathingzonesamplingduringoperationsthatmayinvolveconsiderable intake,suchasthosethatrequireaRWP.Grabsamplesforyellowcakewithadurationof30minutesshouldbeperformedweeklyinairborneradioactivityareasandmonthlyinareasnotdesignatedasairborne radioactivityareas.Asanalternative,weeklygrabsamplesof5minutesdurationusinga high-volumesampler(roughly30cfm)areacceptableinareasthatarenotairborne radioactivityareasinsteadofmonthly30-minutesamplesaslongasthelicenseecan demonstratethatthevolumeofairsampledisaccuratelyknown.Breathingzonesamplingforspecificjobsshouldbeusedtomonitorintakesofindividualworkersdoingspecialhigh-exposurejobsifthespecialjobsarelikelytoinvolve morethan12DAC-hoursinanyoneweek.Anexampleofajobduringwhichsuch breathingzonesamplingmaybeusedismaintenanceofyellowcakedryingandpackaging equipment.Samplesshouldberepresentativeoftheairinhaledbytheworkers.Thestateofoperationofmajorequipmentduringsamplingshouldberecorded.Thequantityofairsampledandthemethodofanalysisshouldallowalowerlimitofdetectionofatleast3x10-12 mCi/ml(10%oftheAppendixBto10CFRPart20 3Theterm"radon"usedinthisguidemeans"radon-222."

7concentrationfornaturaluranium).AppendixBtothisguideshowsacalculationofthe LLD.Sampleanalysisshouldusuallybecompletedwithin2workingdaysaftersamplecollectiontopermitpromptcorrectiveactionifneeded.Unusualresultsshouldbe reportedpromptlytotheRSO.2.3SurveysforRadon-222andItsDaughtersInURfacilities,significantairconcentrationsofradon-222anditsdaughtersmayoccurnearorestoragebinsandcrushingandgrindingcircuitsoranywherelarge quantitiesoforearefound,particularlydryore.Inaddition,anypoorlyventilatedroom canhavehighradon 3daughterconcentrationseveniflargequantitiesoforearenotpresent.NRCregulationspermitmeasurementsofconcentrationsofeitherradonitselfortheradondaughters.Thuseithertypeofmeasurementisacceptable.However,atUR facilities,measurementsofdaughtersareconsideredbythestafftobemoreappropriate.

Measurementsofradondaughterconcentrationsaremoreappropriatebecauseradon daughterconcentrationsareeasytomeasureandbecauseradondaughterconcentrations arethebestindicatorofworkerdose.Thedosefromradonwillbenegligiblein comparisonwiththedosefromradondaughters(Ref.13,p.78,andRef.14).Monthlymeasurementsofradondaughterconcentrationsshouldbemadewhereradondaughtersroutinelyexceed10%ofthelimitor0.03workinglevelabove background.Ifradondaughterconcentrationsarenormallygreaterthan0.08workinglevel(25%oflimit)orradonconcentrationsareabove3x10

-8 mCi/ml,thesamplingfrequencyshouldbeincreasedtoweekly.Samplingshouldcontinuetobeperformedweeklyuntilfourconsecutiveweeklysamplesindicateconcentrationsofradondaughtersbelow0.08workinglevelorradonbelow3x10

-8 mCi/ml.Afterthat,radondaughtersurveysmayberesumedonamonthlybasis.Quarterlysamplingforradondaughtersshouldbemadewherepreviousmeasurementshaveshownthedaughtersarenotgenerallypresentinconcentrations exceeding0.03workinglevel(10%ofthelimit)butwhereproximitytosourcesofradon daughtersmightallowthemtobepresent.Forexample,quarterlymeasurementsmight beappropriateforashopareaattachedtothecrushingandgrindingcircuitbuilding.Radondaughtersamplesshouldberepresentativeofworkerexposures.Samplesshouldbetakenfromlocationswhereworkersaremostoftenpresent.Thestateof operationofmajorequipmentduringsamplingandthetimeofdaythesamplewastaken shouldberecorded.TheLLDforradondaughtermeasurementsshouldbe0.03workinglevel.AppendixBtothisguideshowshowtocalculatetheLLDforaradondaughter measurement.MeasuredvalueslessthantheLLD,includingnegativevalues,shouldstill berecordedondatasheets.TheLLDissethighenoughtoprovideahighdegreeof confidencethat95%ofthemeasuredvaluesabovetheLLDtrulyrepresentradon daughtersandarenot"falsepositive"values.However,themostaccurateaveragefora 8samplinglocationisobtainedbyaveragingallrepresentativevalues,includingvaluesobtainedthatarebelowtheLLD.ThemodifiedKusnetzmethodformeasuringradondaughterworkinglevelsisasuitablemethodforURfacilities.Theprocedureconsistsofsamplingradondaughterson ahigh-efficiencyfilterpaperfor5minutesand,afteradelayof40to90minutes, measuringthealphacountsonthefilterduringa1-minuteinterval.TheoriginalKusnetz methodmeasuredthealphacountrate.InthemodifiedKusnetzmethod,theratemeteris replacedbyascaler.Thisimprovesthesensitivitytoapracticallowerlimitof0.03 workinglevelfora1-minutecountona10-liter(0.01cubicmeter)sample.Thisisabouta factorof10lowerthanthatoriginallyobtainedusingtheoriginalKusnetzmethod.A4-minutecountgivesalowerlimitofabout0.003workinglevel(Ref.2).High-efficiency membraneorglassfiberfiltersshouldbeusedtominimizelossofalphacountsby absorptioninthefilter.However,acorrectionfactortoaccountforalphaabsorptioninthe filterpapershouldstillbeused.Careshouldbetakentoavoidcontaminationofthealpha counter.ThemodifiedKusnetzmethodisdiscussedinmoredetailinReferences2and15.OtheracceptablemethodsdiscussedinReference2aretheoriginalKusnetzmethodwith greaterthan10litersofairsampled,themodifiedTsivogloumethod,andtheRolle method.ThemodifiedTsivogloumethodisslightlymoreaccuratebutisalsomore complicatedthanthemodifiedKusnetzmethod.TheRollemethodisquickerthanthe Kusnetzmethod,butislesssensitive.Alphaspectroscopyyieldsacceptableresults,but theinstrumentsareexpensiveandfragileandlackportability.The"instantworkinglevel" metersarealsoacceptableifanLLDof0.03workinglevelcanbeachieved.2.4SurveysforExternalRadiationMost,butnotall,URfacilityworkersreceiveexternalgammaradiationdosesoflessthan1remperyear(Ref.2).Gammaradiationexposureratesaregenerallybelow1 milliroentgenperhour(mR/hr)incontactwithincomingoreandareabout1.2mR/hrin contactwithfreshyellowcake(Ref.2).Duringthebuildupoftheuraniumdaughters thorium-234andprotactinium-234infreshyellowcake,theradiationlevelsincrease somewhatforseveralmonthsfollowingyellowcakeproduction.Gammaradiationsurveysshouldbeperformedsemi-annuallythroughouttheURfacilityatlocationsrepresentativeofworkers'exposuretodeterminewheretopost "radiationarea"boundariesinaccordancewith10CFR20.1902(a)andtodetermine externalradiationdosimetryrequirements,inaccordancewith10CFR20.1502.Atnew URfacilities,agammaradiationsurveyshouldbeperformedshortlyafterplantoperation

starts.Ifthesemiannualsurveyrevealsanyareasaccessibletopersonnelwherethegammaexposureratesarehighenoughthatamajorportionofthebodyofanindividual couldreceiveadoseinexcessof0.005reminanhour(0.05mSv)at30centimetersfrom theradiationsourceorfromanysurfacethattheradiationpenetrates,theareamustbe designateda"radiationarea,"asdefinedin10CFR20.1003.FewURfacilitieswillhave radiationdoseratesthishigh,butsuchdoserateshavebeenfoundwhereradium-226 buildsupinpartofthecircuit.

4See10CFR20.1903anditem6(a)ofRegulatoryGuide10.6,"GuideforthePreparationofApplicationsforuseofSealedSourcesandDevicesforPerformingIndustrialRadiography"(Ref.16).

9Thesurveyfrequencyinradiationareasshouldbequarterly.Surveymeasurementsshouldberepresentativeofwhereworkersmightstandsothattheirwhole-bodyradiationexposurescanbeestimated.Thus,measurementsshouldgenerallybe madeatabout30centimeters(12inches)fromthesurfaces.

4Surface"contact"exposureratemeasurementsarenotrequiredforestablishingradiationareaboundariesor estimatingpersonnelwhole-bodyexposuresbecausetheseexposureswouldnotbe representativeoftheexposuresworkerswouldreceive.Alistoftheradiationlevelsineachareaoftheplantshouldbepreparedaftereachsurvey.Thenumberofareasonthelistshouldbeheldtoamanageablenumber.In general,aminimumof20surveylocationsisnecessarytocharacterizetheradiation levelsintheURfacility.Personnelmonitoringandrecordingofmonitoringresultsaregenerallyrequiredforanyindividuallikelytoexceed10percentofthelimitsstatedinRegulatoryPosition1of thisguide.Forallworkerswhoarerequiredtobemonitored,thelicenseeisrequiredto adviseeachworkerannuallyoftheworker'sdoseasshowninrecordsmaintainedbythe licenseepursuanttotheprovisionsof10CFR20.2106(requiredby10CFR19.13).Inadditiontogammasurveys,betasurveysofspecificoperationsthatinvolvedirecthandlingoflargequantitiesofagedyellowcakeareadvisedtoensurethatextremity andskinexposuresforworkerswhowillperformthoseoperationsarenotundulyhigh.

Betasurveysshouldbeusedtodeterminetheneedforprotectiveclothingforthese operations(e.g.,thickrubbergloves).Betasurveysshouldalsobeusedtodetermine whetherprocedurescouldbechangedtoreducebetadosewhilestillallowingtheworker todotheoperationefficiently.Becauseoftheseneeds,betadoserates,unlikegamma doserates,areusuallymeasuredonthesurfaceandatshortdistancesratherthanat30 cm(12in).inches).Betasurveysneedbedoneonlyonceforanoperationbutshouldberepeatedforanoperationanytimetheequipmentoroperatingprocedureismodifiedinawaythat mayhavechangedthebetadosethatwouldbereceivedbytheworker.Thebetadoserateonthesurfaceofyellowcakejustafterseparationfromoreisnegligible,asshowninFigure1;butthisdoseraterisessteadilythereafter.Thebeta doseratefromyellowcakeagedforafewmonthsafterchemicalseparationfromtheore sothatequilibriumwithprotactinium-234andthorium-234hasbeenreachedisabout150 mrem/hr(Ref.10).Figure2showsthebetadoseratefromagedyellowcakeasafunction ofdistancefromthesurface(Ref.17).Thediameteroftheyellowcakesourceusedto measure 10 Thiscurvewas preparedbyS.McGuire, NRCstaff,bycalculatingthebuildupofthorium-234andprotactinium-234fromthe parenturanium-238,andthebuildupofthorium-231fromthe parenturanium-235.Thesurfacebetadoseratewasnormalizedto150mrem/hr(Figure2showsthemeasuredvalueonthesurface).Sincemeasurementsshowthatlessthan1%ofthethorium,radium,andleadinitiallypresentintheoreremainsafterthechemicalseparationprocess,betasfromthorium-234,lead-210,and lead-214intheorebeforeseparationarenegligibleintheyellowcakeafterseparation(Ref18).thedoseratesshowninFigure2was9.5cm.Rubberworkgloves(thickness:0.04cmor50mg/cm 2)willreducethebetadosetothehandsfromagedyellowcakebyabout15%.Conditionsrequiringindividualmonitoringofexternalandinternaloccupationaldosearespecifiedin10CFR20.1502.ItisusuallyacceptabletosubstituteevaluationsofbetadosesbasedonFigures1and2inplaceofbetasurveysusingradiationsurveyinstruments.ItshouldbenotedthatcommerciallyavailablefilmbadgeandTLDservicesoftenhavenotbeenabletomeasurebetaradiationinthemixedbeta-gammafieldofaUR facility(see,forexample,TablesA-11andA-12ofReference19andTables6and9of 11Reference20).Workers'betadosesshouldbeestimatedfromthebetasurveysdescribedaboveratherthanfrompersonnelmonitoringreports.2.5SurveysforSurfaceContaminationinRestrictedAreaNRCregulationsprovidenospecificlimitonsurfacecontaminationlevelsinrestrictedareas.However,yellowcakeororedustlyingonsurfacescanbecome resuspendedandcontributetotheintakeofradionuclides,whichislimitedby10CFR 20.1204.Inorehandlingareas,surfacecontaminationisnotaproblembecauseoftheverylow specificactivityoftheore.Infact,cleanupattemptsbymethodssuchassweepingare likelytoproduceamoreserioushazardthroughresuspensionintheairthaniftheore

dust 12wereallowedtoremainwhereitlies.Whennecessary,cleanupmaybeperformedbyhosingdowntheoredustintofloorsumpsorbyusingvacuumsuctionsystemswith filteredexhausts.Inleachingandchemicalseparationareasthereisusuallylittledustandlittledifficultywithsurfacecontamination.Intheprecipitationcircuitandtheyellowcakedryingandbarrelingareas,surfacecontaminationcanbeaproblembecauseoftheconcentratednatureoftheyellowcake.

TheInternationalAtomicEnergyAgency(IAEA)recommends(Ref.2)alimitforalphacontaminationonsuchareasaswalls,floors,benches,andclothingof10

-3 mCi/cm 2(220,000dpm/100cm 2),whichisequivalenttoabout2mg/cm 2ofnaturaluranium.Basedonexperience,theIAEAconcludedthatifsurfacecontaminationlevelsarekeptbelowthis value,thecontributiontoairborneradioactivityfromsurfacecontaminationwillbewell belowapplicablelimits.TheBritishNationalRadiologicalProtectionBoardalsorecommendsalimitof10

-3 mCi/cm 2foruraniumalphacontaminationinactiveareasofplants(Ref.21),basedoncalculationsusingresuspensionfactorsratherthanexperience.TheNRCstaffconsiderssurfacecontaminationlevelsof10

-3 mCi/cm 2acceptabletomeettheALARAconceptinURfacilities.Thelevelsarelowenoughtoensurelittlecontributiontoairborneradioactivity,yetarepracticaltomeet.Suchanamountof yellowcakesurfacecontaminationisreadilyvisiblebecauseofthelowspecificactivityof uraniumanddoesnotrequireasurveyinstrumentfordetection.Itisrecommendedthat surfaceswhereyellowcakemayaccumulatebepaintedincontrastingcolorsbecause surveysforsurfacecontaminationinworkareasarevisualratherthanbyinstrument.Inyellowcakeareas,dailyvisualinspectionsshouldbemadeforlocatingyellowcakecontaminationonsurfaces.Visibleyellowcakeshouldbecleaneduppromptly, especiallywherecontaminationwillbedisturbedandresuspendedonwalkways,railings, tools,vibratingmachinery,andsimilarsurfaces.Spillsshouldbecleanedupbeforethe yellowcakedriessothatresuspensionduringcleanupwillbelessened.Inroomswhereworkwithuraniumisnotperformed,suchaseatingrooms,changerooms,controlrooms,andoffices,alowerlevelofsurfacecontaminationshouldbe maintained.Theseareasshouldbespot-checkedweeklyforremovablesurface contaminationusingsmeartests.Theareasshouldbepromptlycleanedifsurface contaminationlevelsexceedthevaluesshowninTable2.

13TABLE2SurfaceContaminationLevelsforUraniumandDaughtersonEquipmentToBeReleasedforUnrestrictedUse,onClothing,andonNonoperatingAreasofURFacilities*Average**5,000dpmalphaper100 cm 2Averageovernomorethan1m 2Maximum**15,000dpmalphaper100cm 2Appliestoanareaofnotmorethan100cm 2Removable1,000dpmalphaper100cm 2Determinedbysmearingwithdryfilteror softabsorbentpaper,applyingmoderate pressure,andassessingtheamountof radioactivematerialonthesmear*ThesevaluesaretakenfromRegulatoryGuide1.86,"TerminationofOperatingLicensesforNuclearReactors"(Ref.22),andfrom"GuidelinesforDecontaminationofFacilitiesandEquipmentPriortoReleasefor UnrestrictedUseorTerminationofLicensesforByproductSource.orSpecialNuclearMaterial,"Divisionof FuelCycleandMaterialSafety,USNRC,Washington,DC20555,August1987(Ref.23).AvailableinNRC PublicDocumentRoomforinspectionandcopyingforafee.**Thevalueincludesbothfixedandremovablecontamination

.(ThecontaminationlevelsinTable2aregiveninunitsofdpm/100cm 2becausethisistheminimumareatypicallysurveyed.Whenperformingasmearorwipetest,theareashouldveryroughlyapproximate100cm 2.However,thereisnoneedtobeverypreciseabouttheareatobesmeared.)2.6SurveysforContaminationofSkinandPersonalClothingContaminationofskinandpersonalclothingshouldbecontrolledtopreventthespreadofcontaminationtounrestrictedareas(e.g.,theworkers'carsandhomes).Alpha radiationfromuraniumontheskinorclothingisnotadirectradiationhazardbecausethe alphaparticlesdonotpenetratethedeadlayeroftheskin.Rather,uraniumisprimarilya hazardifitisinhaledorswallowed.Visualexaminationforyellowcakeisnotsufficientevidencethattheworker'sskinorclothingissufficientlyfreeofcontaminationtopermittheworkerstoleavethework environment.Normallysuchcontaminationcanbeadequatelycontrolledifyellowcake workerswashtheirhandsbeforeeating,showerbeforegoinghome,anddonotwear streetclotheswhileworkingwithyellowcakeintheURfacility.Beforeleavingthe restrictedarea,everyonewhohasworkedwithyellowcakeduringthedayshouldeither showerormonitortheirskinafterchangingclothes.Iftheworkerdoesnotchange clothes,theclothesshouldalsobemonitored.Thesolesoftheshoesofanyoneentering theyellowcakeareaoftheURfacilityshouldeitherbebrushedormonitoredbefore leavingtheURfacility.Analphasurveyinstrumentshouldbeavailableattheexitofthe employeechangeroom.Inaddition,thelicenseeshouldatleastquarterlyusea calibratedalphasurveyinstrumenttoperformanunannouncedspotsurveyforalpha contaminationonselectedyellowcakeworkersleavingtheURfacility.LimitsonacceptablelevelsofalphacontaminationofskinandclothingarethoseinTable2,butaretobeusedinthefollowingmanner.Allalphacontaminationonskinand clothingshouldbeconsideredtoberemovablesothatthelimitof1,000dpmalphaper 5Thisvalueiscomparabletothelimitof10

-5Ci/cm 2or2.200dpmper100cm 2,whichisrecommendedbytheInternationalAtomicEnergyAgencyonpage15ofReference2andtheUnitedKingdomAtomicEnergy AuthorityinReference24.

6SeeRegulatoryGuide1.86,"TerminationofOperatingLicensesforNuclearReactors"(Ref.22),and"GuidelinesforDecontaminationofFacilitiesandEquipmentPriortoReleaseforUnrestrictedUseor TerminationofLicensesforByproduct,Source,orSpecialNuclearMaterial"(Ref.23).

14100cm 2 applies.5Theworkermustshowerorwashifthelimitisexceeded.Thevalueof5,000dpmalphacontaminationper100cm 2shouldbeusedforthesolesofshoesusingaportablealphasurveyinstrumenttomeasuretotalalphaactivity.Ifalphalevelsexceed thevalueinTable2,theclothingshouldbelaunderedbeforeleavingthesite.Ifthesoles ofshoesexceedthevalueinTable2,theshoesshouldbebrushedorscrubbeduntilthey arebelowthelimit.2.7SurveysofEquipmentPriortoReleasetoUnrestrictedAreasSurfacecontaminationsurveysshouldbeconductedbeforepotentiallycontaminatedequipmentisreleasedtounrestrictedareas.Thesurfacecontamination limitslistedinTable2arerecommended.

6Ifcontaminationabovetheselimitsisdetected,theequipmentshouldbedecontaminateduntiladditionaleffortsdonotsignificantlyreduce contaminationlevels.Thelicenseeshoulddevelopmethodstopreventpotentiallycontaminatedequipmentfromleavingtherestrictedareawithoutbeingmonitored.Insomecasesthisis facilitatedifparkingareasforworkersandvisitorsarelocatedoutsidetherestrictedarea.2.8SurveysofPackagesPreparedforShipmentAfterbeingfilled,yellowcakepackagesshouldbewasheddowntoremovesurfacecontamination.Surveysofexternalsurfacesofyellowcakepackagespreparedfor shipmentshouldbecarriedoutbeforeshipment.Thesurveysconductedshouldbe adequatetoensurethatthewash-downsarereducingsurfacecontaminationlevelstoless thanDepartmentofTransportation(DOT)limits,butdonotnecessarilyincludeasurveyof eachpackage.Thebottomsofallbarrelsshouldbesurveyedtodeterminethe effectivenessofthewash-downs.ContaminationonpackagesshouldnotexceedDOTlimitsin49CFR173.443.Theaveragemeasuredremovablealphacontaminationdeterminedbywipingtheexternal surfaceofthepackagewithanabsorbentmaterialshouldbebelow2200dpm/100cm 2ifanon-exclusive-usevehicleistobeused(49CFR173.443(a)and(a)(1))or22,000 dpm/100cm 2ifanexclusive-usevehicleistobeused(49CFR173.443(b)and(a)(1)).Packageshavinghighercontaminationlevelsshouldbecleanedandresurveyedpriorto shipment.Visibleyellowcakeshouldbecleanedoff.2.9VentilationSurveysAproperlyoperatingventilationsystemisthemosteffectivemeansofworkerprotectionfrominhalationhazardsataURfacility.Theoperationoftheventilationsystem shouldbecheckedeachdaybytheradiationsafetystaffduringthedailywalk-throughof theURfacility.

15WheneverequipmentorproceduresintheURfacilityarechangedinamannerthataffectsventilation,asurveyshouldbemadeoftheventilationratesintheareatoensure thattheventilationsystemisoperatingeffectively.2.10SurveysforContaminationonRespiratorsBeforebeingreused,respiratorfacepiecesandhoodsshouldbesurveyedforalphacontaminationbyastandardwipeorsmeartechnique.Removablealpha contaminationlevelsshouldbelessthan100dpm/100cm 2(Ref.16,Section9.6).2.11SummaryofSurveyFrequenciesTable3summarizesthesurveyfrequenciesgiveninthisguide.3.INTAKEANDEXPOSURECALCULATIONSTheinternaldosecomponentneededforevaluatingthetotaleffectivedoseequivalentisthecommittedeffectivedoseequivalent.Thecommittedeffectivedose equivalentisthe50-yeareffectivedoseequivalentthatresultswhenradioactivematerialis takenintothebody,whetherthroughinhalation,ingestion,absorptionthroughtheskin, accidentalinjection,orintroductionthroughawound.Thecontributionsfromall occupationalintakesforthesemodesofintakeareaddedovertheyearlytimeperiodfor whichthetotalcommittedeffectivedoseequivalentisbeingevaluated.Theregulatory requirementsfordeterminingtheinternaldosearecontainedin10CFR20.1204.Thisguidepresentstwoalternativemethodsforcalculatingcommittedeffectivedoseequivalentfrominhalation.ThefirstmethodusesstochasticinhalationALIsfrom10 CFRPart20.ThesecondmethodusesDACsfrom10CFRPart20.Themethodsare equivalentandeithermaybeused.Method1:UseofStochasticInhalationALIsfrom10CFRPart20ALIvalueshavebeenestablishedforindividualradionuclidesandarepresentedinTable1inAppendixBto10CFRPart20.TheALIvaluesforinhalation,presentedin Column2inTable1,correspondtoacommittedeffectivedoseequivalentof5rems(0.05 Sv)oracommitteddoseequivalentof50rems(0.5Sv)toanyindividualorganortissue, whicheverismorelimiting.IftheALIvaluepresentedinTable1islimitedbythe50-rem committeddoseequivalent,thecontrollingorganislisteddirectlybelowtheALIvalue,and thestochasticALIvaluebasedonthe5-remcommittedeffectivedoseequivalentislisted inparenthesesdirectlybelowtheorganname.IfastochasticALIislistedinparentheses, that 16TABLE3

SUMMARY

OFSURVEYFREQUENCIESTypeofSurveyTypeofAreaSurvey FrequencyLowerLimitofDetection1.UraniumoredustAirborneradioactivityareasOtherindoorprocessareas OutdoorareasWeeklygrab samples Monthlygrab

samples Quarterlygrab

samples5x10-12Ci/ml (uranium)2.YellowcakeAirborneradioactivityareasOtherindoorprocessareas Specialmaintenanceinvolvinghigh airborneconcentrationsofyellowcakeWeeklygrab samples Monthlygrab

samples Extrabreathing zonegrab samples1x10-11Ci/ml3.RadondaughtersAreasthatexceed0.08workinglevelAreasthatexceed0.03workinglevel Areasbelow0.03workinglevelWeeklyradondaughtergrab

samples Monthlyradon daughtergrab

samples Quarterlyradon daughtergrab

samples0.03WL4.Externalradiation:Gamma BetaThroughoutURfacilityRadiationareasWhereworkersareinclosecontactwithyellowcake SemiannuallyQuarterlySurveybyoperationdone onceplus whenever procedures

change0.1mrad/hr1mrem/hr5.SurfacecontaminationYellowcakeareasEatingrooms,changerooms,control rooms,officesDailyWeekly Visual500dpmalphaper 100cm 26.Skinandpersonal

clothingYellowcakeworkerswhoshowerYellowcakeworkerswhodonotshowerQuarterlyEachdaybeforeleaving500dpmalphaper100cm 27.Equipmenttobe

releasedEquipmenttobereleasedthatmaybe contaminatedOncebefore release500dpmalphaper100cm 28.Packagecontaining yellowcakePackagesSpotcheckbeforerelease500dpmalphaper100cm 29.VentilationAllareaswithairborneradioactivityDailyNotapplicable10.RespiratorsRespiratorfacepiecesandhoodsBeforereuse100dpmalphaper100cm 2 17valueshouldbeusedtocalculatethecommittedeffectivedoseequivalent.Thecommittedeffectivedoseequivalentforeachradionuclidemaybecalculated,usingtheestimated radionuclideintake,byEquation2.Equation2i,Ei,E H 5 i I ALI=where Hi,E=Committedeffectivedoseequivalentfromradionuclidei(rems)

I i=Intakeofradionuclideibyinhalationduringthecalendaryear(µCi)(Ifmultipleintakesoccurredduringtheyear,isthesumofall intakes.)ALIi,E=ValueofthestochasticinhalationALI(basedonthecommittedeffectivedoseequivalent)fromColumn2ofTable1inAppendixB toPart20(µCi)5=Committedeffectivedoseequivalentfromintakeof1ALI(rems)Ifintakesofmorethanoneradionuclideoccurred,thetotalcommittedeffectivedoseequivalentwillbethesumofthecommittedeffectivedoseequivalentsforallradionuclides.TheALIsinPart20arebasedonaparticledistributionwitha1-micro-meteractivitymedianaerodynamicdiameter.ThoseALIsmaybeusedregardlessoftheactualmedian diameter.However,theNRCallowsadjustmentofALIstoaccountforparticlesize,but onlywithpriorapproval(10CFR20.1204(c)).SomenoblegasesinAppendixBto10CFRPart20donothaveinhalationALIvalueslistedandarelistedas"submersion"class.Fortheseradionuclides,theinternal doseisnegligiblecomparedtotheexternaldose.Theseradionuclidesmaybeexcluded fromthedeterminationoftheinternaldose.Method2:UseofDACsfrom10CFRPart20CommittedeffectivedoseequivalentmayalsobecalculatedfromexposuresexpressedintermsofDAC-hours.IftheDACinAppendixBto10CFRPart20fora radionucliderepresentsastochasticvalue(i.e.,thecorrespondingALIdoesnothavethe nameofanorganbelowit),theDACmaybeuseddirectly.IfAppendixBto10CFRPart 20doesnotlistastochasticDAC(whichwillbethecaseanytimethereisastochasticALI valueinparentheses),itispreferred(butnotrequired)thatthelicenseecalculateandusea stochasticDAC.ThestochasticDACcanbecalculatedfromthestochasticALI(theALIin parentheses)byusingEquations3and4.Equation3stoc,iDACstoc,i ALI2.4x10 9=

18where DACstoc,i=ThestochasticDACforradionuclidei(microcuries/ml)

ALIstoc,i=ThestochasticALIforradionuclidei(microcuries)2.4x10 9=Thevolumeofairinhaledbyaworkerinaworkyear(ml)Equation4i,E H 5 i C t 2000DACstoc,i=where Hi,E=Committedeffectivedoseequivalentfromradionuclidei(rems)

C i=Theairborneconcentrationofradionuclideitowhichtheworkerisexposed(microcuries/ml)t=Thedurationoftheexposure(hours)2000=Thenumberofhoursinaworkyear5=Committedeffectivedoseequivalentfromannualintakeof1ALIor2000DAC-hours(rems)Ifthereisamixtureofseveralradionuclides,itispermissibletodisregardcertainradionuclidesinthemixturethatarepresentinrelativelysmallquantities(10CFR 20.1204(g)).Theseradionuclidesmaybedisregardedifthefollowingconditionsaremet:

(1)theconcentrationofanyradionuclidedisregardedislessthan10%ofitsDAC;(2)the sumofthesepercentagesforalltheradionuclidesdisregardedinthemixturedoesnot exceed30%;and(3)thelicenseeusesthetotalactivityofthemixtureindemonstrating compliancewiththedoselimitsandmonitoringrequirements.4.ADMINISTRATIVEACTIONLEVELSThelicenseeshouldestablishadministrativeactionlevelstoprotectworkers.Actionlevelsshouldbeestablishedasshownbelow.Arecordofeachinvestigationmadeandthe actionstaken,ifany,shouldbekept.4.1UraniumOreDustTheRSOshouldestablishanactionlevelforeachoredustsamplinglocation.Theactionlevelforthelocationshouldbesetsomewhatabovethenormalfluctuationsthat occurwhentheURfacilityisoperatingproperly.Ifanysampleisabovetheactionlevelfor thatlocation,theRSOshouldfindoutwhyandshouldtakecorrectiveactionifappropriate.4.2Yellowcake 19Similarly,foryellowcaketheRSOshouldestablishanactionlevelforeachsamplinglocation.Inaddition,actionlevelsshouldbeestablishedformaintenanceactivitieswhere breathingzonesamplingisused.Theactionlevelformaintenanceactivitiescanbe expressedeitherinairborneconcentrationorinDAC-hours.Ifanyactionlevelis exceeded,theRSOshouldfindoutwhyandshouldtakecorrectiveaction,ifappropriate.4.3RadonDaughtersTheRSOshouldestablishanactionlevelforradondaughtersforeachsamplinglocation.Iftheactionlevelforanylocationisexceeded,theRSOshouldfindoutwhyand shouldtakecorrectiveaction,ifappropriate.4.4Time-WeightedExposuretoAirborneRadioactivityIfanyworker'stime-weightedexposure,calculatedbyeitherofthetwomethodsinMethod2ofRegulatoryPosition3ofthisguide,exceeds25%oftheexposurelimits,as listedinTable1ofthisguide,theRSOshoulddeterminethecausesoftheexposure, shouldinvestigatewhytheexposurewashigherthanpreviousexposuresinperformingthe work,andshouldtakecorrectiveactionifappropriate.Thisactionlevelwillbeonaweekly basisforsolubleuranium(yellowcakedriedatlessthan400ºC),aquarterlybasisfor uraniumoredustandyellowcakecombined,andanannualbasisforradondaughtersof4 WorkingLevelMonthsor2000DAC-hours.4.5GammaDoseRatesTheRSOshouldestablishanactionlevelforeachlocationwherethegammadoserateisperiodicallymeasured.Iftheactionlevelforanylocationisexceeded,theRSO shoulddeterminethecauseoftheelevationandshouldtakecorrectiveaction,if appropriate.4.6DosimeterResultsTheRSOshouldestablishactionlevelsforthemonthlydosimeterresults.Iftheactionlevelforanypersonisexceeded,theRSOshoulddeterminethecauseandtake correctiveaction,ifappropriate.4.7ContaminationonSkinandClothingIfalphacontaminationoftheskinorclothingofworkersleavingtheURfacilityisfoundtoexceed1000dpm/100cm 2,aninvestigationofthecauseofthecontaminationshouldbemadeandcorrectiveactiontaken,ifappropriate.4.8LowAirborneRadioactivityConcentrationsAbnormallylowconcentrationsofairborneradioactivity(uraniumoredust,yellowcake,andradondaughters)shouldalsobeinvestigatedsinceverylow concentrationsmayindicateanequipmentmalfunctionorproceduralerror.TheRSO shouldestablishactionlevelsforlowreadingsofairborneradioactivity.Ifconcentrations arebelowtheseactionlevels,theRSOshoulddeterminethereasonandshouldtake correctiveaction,ifappropriate.

205.REPORTINGREQUIREMENTSEachlicenseeisrequiredtonotifytheNRCassoonaspossibleofexposures,radiationlevels,andconcentrationsofradioactivematerialsexceedingtheconstraintsor limitsasrequiredinSubpartMof10CFRPart20andin10CFR40.60.6.ESTABLISHING"AIRBORNERADIOACTIVITYAREAS"Ingeneral,yellowcakedryingandpackagingroomsandenclosuresshouldalwaysbeconsideredtobeairborneradioactivityareasbecauseofthehighconcentrationsthat canresultifanyequipmentmalfunctions.Ontheotherhand,orecrushingandgrinding areasandareasoutsideyellowcakedryingandpackagingareaswillnotnormallyneedto beclassifiedasairborneradioactivityareaswhennormalengineeringcontrolsareused.Anyarea,room,orenclosureisan"airborneradioactivityarea"asdefinedin10CFR20.1003if(1)atanytimetheairborneuraniumconcentrationexceeds5x10-11 mCi/mlinthecaseoforedustor1x10-10 mCi/mlinthecaseofyellowcake(i.e.,thevaluesinAppendixBto10CFRPart20)or(2)theconcentrationexceeds25%ofthevaluesinAppendixBto10CFRPart20averagedoverthenumberofhoursinanyoneweekin whichindividualsarepresentinsucharea,room,orenclosure.Forexample,anareathat isoccupied20hoursperweek(outofthe40hoursusedasabasisforthelimits)isan airborneradioactivityareaiftheconcentrationofuraniuminyellowcakeexceeds0.5x10-10 mCi/mlofair.Thelicenseeshouldmaintainrecordstoshowthatoccupancyisinfactthuslimited.Ifcombinationsofradondaughters,oredust,andyellowcakearepresent(seeRegulatoryPosition2.3ofthisguide),theirconcentrationsdividedbytheappropriateTable 1ofAppendixBvalueshouldbeadded.Ifthesumofthesefractionsexceedsunityorif thesumexceeds0.25afteradjustmentfortheoccupancyfactor,theareaisanairborne radioactivityarea.7.POSTINGOFCAUTIONSIGNS,LABELS,ANDNOTICESTOEMPLOYEESTheradiationprotectionstaffshouldperiodicallysurveytoensurethatsigns,labels,requirednoticestoemployees,copiesoflicenses,andotheritemsareproperlypostedas requiredby10CFR19.11and10CFRPart20.TheURfacilityandtailingsareashouldbefencedtorestrictaccess,andthefenceshouldbepostedwith"Caution,RadioactiveMaterialArea"signsasrequiredin10CFR 20.1902.Ifthefenceandallentrancesarepostedandalsostatethewords"Anyarea withinthisURfacilitymaycontainradioactivematerial,"theentireareaisposted adequatelytomeettherequirementin10CFR20.1902.Additionalpostingofeachroom with"RadioactiveMaterial"signsisnotnecessary."RadiationAreas"and"AirborneRadioactivityAreas"mustbepostedinaccordancewith10CFR20.1902.Thelicenseeshouldavoidpostingradiationareasignsandairborne radioactivityareasignsinareasthatdonotrequirethem.Thepurposeofthesignsisto 21warnworkerswhereadditionalprecautionstoavoidradiationexposureareappropriate.PostingallareasintheURfacilitywithsuchsignsdefeatsthispurpose.8.CALIBRATIONOFSURVEYINSTRUMENTSPortablesurveyinstrumentsshouldbeplacedonaroutinemaintenanceandcalibrationprogramtoensurethatproperlycalibratedandoperablesurveyinstrumentsare availableatalltimesforusebythehealthphysicsstaff.Surveyinstrumentsshouldbecheckedforconstancyofoperationwitharadiationchecksourcepriortoeachusage.Iftheinstrumentresponsetotheradiationchecksource differsfromthereferencereadingbymorethan20%,theinstrumentshouldberepairedif necessaryandrecalibrated(Ref.26,paragraph4.6).Thisconstancycheckshouldbesupplementedbycalibrationsat12-monthintervalsoratthemanufacturer'ssuggestedinterval,whicheverisshorter(Ref.26,paragraph 4.7.1).Anadequatecalibrationofsurveyinstrumentscannotbeperformedsolelywith built-inchecksources.Electroniccalibrationsthatdonotinvolveasourceofradiationwill notdeterminetheproperfunctioningandresponseofallcomponentsofaninstrument.

However,aninitialcalibrationwithagammasourceandperiodictestsusingelectronic inputsignalsmaybeconsideredadequateforthehighdoserangesonsurveyinstruments ifthoserangesarenotusedroutinely.Eachinstrumentshouldbecalibratedattwopoints ataboutone-thirdandtwo-thirdsofeachlinearscaleroutinelyusedorwithacalibrationat onepointnearthemidpointofeachdecadeonlogarithmicscalesthatareroutinelyused.

Digitalreadoutinstrumentswitheithermanualorautomaticscaleswitchingshouldbe calibratedinthesamemannerasaremeter-dialinstruments.Digitalreadoutinstruments withoutscaleswitchingshouldbecalibratedinthesamemannerasarelogarithmicreadout instruments.Surveyinstrumentsshouldbecalibratedfollowingrepair.Asurvey instrumentmaybeconsideredproperlycalibratedwhentheinstrumentreadingsarewithin

+/-20%ofthecalculatedorknownvaluesforeachpointchecked(seeAppendixAto RegulatoryGuide10.6,"GuideforthePreparationofApplicationsforUseofSealed SourcesandDevicesforPerformingIndustrialRadiography"(Ref.16)).Calibrationforbetadoseratemeasurementsmaybeperformedinthefollowingmanner.Ausualtechniqueformakingabetasurveyistonotethedifferencebetweenthe open-windowandclosed-windowreadingonaGMorionizationchambersurveymeter.

Thedifferenceisconsideredtobeanindicationofthebetadoserate.Thisapproachis incorrectifthesurveymeterhasbeencalibratedwithagammasourcealone.Acorrection factormustbeappliedtodeterminethebetadoserate.Todeterminethebetacorrectionfactor,useFigure2inthisguide.Placethedetectorofthesurveymeteratthesurfaceofanextendedyellowcakesourcethathas beenseparatedfromoreforatleast100days.Useapieceofpaperorthinplastic betweenthedetectorandyellowcaketoavoidcontaminatingthedetector.Notethe differencebetweentheopen-windowandclosed-windowreadings.Computeacorrection factorthatappliestothesurfacedoseratethatwillmakethedifferencebetweentheopen-windowandclosed-windowreadingsequaltothesurfacebetadoserateof150mrad/hr,as showninFigure2.Todeterminethecorrectionfactorthatappliesatadistancefromthe surface,placetheaxisofthedetectorat2cmfromthesurface.Notethedifference betweentheopen-windowandclosed-windowreadings.Computeacorrectionfactorthat 22willmakethedifferencebetweentheopen-windowandclosed-window,readingsequalto75mrad/hr,asshowninFigure2.AsamplecalculationisshowninAppendixCtothis guide.Errorsinestimatesofthevolumeofairthathaspassedthroughfiltersshouldbeavoidedbyaccuratecalibrationoftheflowrateandbypreventingorcorrectingfortheloss offlowcausedbyaccumulationofmaterialonthefilter.Asmaterialaccumulatesonfilter papertheairflowratewilldrop.Thuslessairvolumewillbesampled.Airflowrates throughfiltersshouldbedeterminedbycalibratingpumpswiththefilterpaperinplaceonce every6monthsto+/-20%accuracy.Thesecalibrationsshouldbedoneinaccordancewith themanufacturer'srecommendations.Furtherinformationonthesecalibrationsis containedinRegulatoryGuide8.25,"CalibrationandErrorLimitsofAirSampling InstrumentsforTotalVolumeofAirSampled"(Ref.27).Thefluorometricanalysisshouldbecalibratedbyprocessingaknownstandarduraniumsolutionandablanksamplewitheachbatch.Everyquarter,thefluorometer responseshouldbecheckedbyacompleteserialdilution.Alphacountingsystemsusedforradondaughtermeasurementsshouldbecalibratedatleastmonthlybyusingaknownstandardalphasource.Alphasurveymetersusedtodetectcontaminationonskinandequipmentshouldreceivearesponsecheckbeforeeachuse,constancycheckeachweek,andacalibration inaccordancewiththemanufacturer'srecommendationsorannually,whicheverisshorter (Ref.26,paragraph4.7.1).9.PROTECTIVECLOTHINGWorkersworkingwithyellowcakeshouldbeprovidedwithprotectiveclothingsuchascoverallsandshoesorshoecovers.Rubberworkglovesshouldbeusedwhenaged yellowcakewillbehandledinordertoreducethebetadoseandtoavoidcontaminationof theskinwithuranium.Protectiveclothingshouldbechangedanddiscardedorlaunderedweeklyorwheneveryellowcakeisvisibleontheclothing.Potentiallycontaminatedclothingshould notbesenttoalaundrythatisnotspecificallyauthorizedbytheNRCoranAgreement Statetoprocessclothingcontaminatedwithuraniumunlesstheclothinghasbeen surveyedandfoundtohavelessuraniumcontaminationthanthevaluesinTable2ofthis guide.10.QUALITYASSURANCEPROGRAMThelicenseeshouldensuretheaccuracyofsurveymeasurementsbyhavingaqualityassuranceprogram.RegulatoryGuide4.15,"QualityAssuranceforRadiological MonitoringPrograms(NormalOperations)--EffluentStreamsandtheEnvironment"(Ref.

28),shouldbeconsultedforguidanceonqualityassurance.D.IMPLEMENTATION 23ThepurposeofthissectionistoprovideinformationtoapplicantsandlicenseesregardingtheNRCstaff'splansforusingthisregulatoryguide.Thisproposedrevisionhasbeenreleasedtoencouragepublicparticipationinitsdevelopment.Exceptinthosecasesinwhichanapplicantproposesanacceptable alternativemethodforcomplyingwithspecifiedportionsoftheNRC'sregulations,the methodtobedescribedintheactiveguidereflectingpubliccommentswillbeusedinthe evaluationofapplicationsfornewURfacilitiesandrenewalapplications.

1Singlecopiesofregulatoryguides,bothactiveanddraft,anddraftNUREGdocumentsmaybeobtainedfreeofchargebywritingtheReproductionandDistributionServicesSection,OCIO,USNRC,Washington,DC20555-0001, orbyfaxto(301)415-2289,orbyemailto<DISTRIBUTION@NRC.GOV>.Activeguidesmayalsobepurchased fromtheNationalTechnicalInformationServiceonastandingorderbasis.Detailsonthisservicemaybeobtained bywritingNTIS,5285PortRoyalRoad,Springfield,VA22161;telephone(703)487-4650;online

<http://www.ntis.gov/ordernow>.CopiesofactiveanddraftguidesareavailableforinspectionorcopyingforafeefromtheNRCPublicDocumentRoomat2120LStreetNW.,Washington,DC;thePDR'smailingaddressisMail StopLL-6,Washington,DC20555;telephone(202)634-3273or(800)397-4209;fax(202)634-3343;email

<PDR@NRC.GOV>.

2AvailablefromUNIPUB,P.O.Box433,MurrayHillStation,NewYork,NY10016.

3CopiesareavailableatcurrentratesfromtheU.S.GovernmentPrintingOffice,orfromtheNationalTechnicalInformationService,ortheNRCPublicDocumentRoom.SeetheinformationinFootnote1above.

24 REFERENCES1.USNRC,"StandardFormatandContentofLicenseApplicationsforUraniumMills,"RegulatoryGuide3.5,Revision1,November1977.

12.InternationalAtomicEnergyAgency,ManualonRadiologicalSafetyinUraniumandThoriumMinesandMills,IAEASafetySeriesNo.43,Vienna,1976.

23.USNRC,"AcceptableProgramsforRespiratoryProtection,"RegulatoryGuide8.15,Revision1,October1999.

14.USNRC,"BioassayatUraniumMills,"RegulatoryGuide8.22,Revision1,August 1988.15.HealthPhysicsSociety,"BioassayProgramsforUranium,"AmericanNationalStandardHPSN13.22-1995.6.HealthPhysicsSociety,"PerformanceCriteriaforRadiobioassay,"AmericanNationalStandardHPSN13.30-1996.7.USNRC,"InformationRelevanttoEnsuringthatOccipationalRadiationExposuresatUraniumMillsWillBeAsLowAsIsReasonablyAchievable,"RegulatoryGuide 8.31,May1983.

18.D.R.Kalkwarf,"SolubilityClassificationofAirborneProductsfromUraniumOresandTailingsPiles,"NUREG/CR-0530,USNRC,January1979.

39.F.EidsonandJ.A.Mewhinney,"InVitroDissolutionofUraniumProductSamplesfromFourUraniumMills,"NUREG/CR-0414,USNRC,October1978.

310.N.A.Dennis,H.M.Blauer,andJ.E.Kent,"DissolutionFractionsandHalf-timesofSingleSourceYellow-CakeinSimulatedLungFluids,"HealthPhysics,vol.42,p.469,April1982.11.R.C.Merritt,TheExtractiveMetallurgyofUranium,ColoradoSchoolofMinesResearchInstitute,pp.252-254,1971.

2512.L.M.SteckelandC.M.West,"CharacterizationofY-12UraniumProcessMaterialsCorrelatedwithInVitroExperience,"ReportY-1544-A,U.S.AtomicEnergy Commission,1966.

413.NationalCouncilonRadiationProtectionandMeasurements,"NaturalBackgroundRadiationintheUnitedStates,"NCRPReportNo.45,Washington,DC,1975.14.InternationalCommissiononRadiologicalProtection,"OccupationalLimitsforInhalationofRadon-222,Radon-220andtheirShort-LivedDaughters,"ICRP Publication32,PergamonPress,Oxford,England,1981.15.AmericanNationalStandardsInstitute,"RadiationProtectioninUraniumMines,"ANSIN13.8-1973(Reaffirmedin1989).16.USNRC,"GuideforthePreparationofApplicationsforUseofSealedSourcesandDevicesforPerformingIndustrialRadiography,"RegulatoryGuide10.6,Revision1, December1981.

117.D.Haggard,Battelle-PacificNorthwestLaboratory,lettertoDr.StephenA.McGuire,USNRC,June29,1982.

418.M.H.Momenietal.,"RadioisotopicCompositionofYellowcake,"NRCReportNUREG/CR-1216,1979.

319.L.L.Nichols,"ATestofthePerformanceofPersonnelDosimeters,"Battelle-PacificNorthwestLaboratoriesReportBNWL-2159,April1977.20.P.PlatoandG.Hudson,"PerformanceTestingofPersonnelDosimetryServices,"NUREG/CR-1064,USNRC,1980.

321.A.D.Wrixon,G.S.Linsley,K.C.Binns,andD.F.White,"DerivedLimitsforSurfaceContamination,"BritishNationalRadiologicalProtectionBoardReportNRPB-DL2, November1979.22.USNRC,"TerminationofOperatingLicensesforNuclearReactors,"RegulatoryGuide1.86,June1974.

123.USNRC,"GuidelinesforDecontaminationofFacilitiesandEquipmentPriortoReleaseforUnrestrictedUseorTerminationofLicensesforByproduct,Source,or SpecialNuclearMaterial,"DivisionofFuelCycleandMaterialSafety,August1987.

424.UnitedKingdomAtomicEnergyAuthority,HealthandSafetyCode,"MaximumPermissibleDosesfromInhaledandIngestedRadioactiveMaterials,"AuthorityCode No.E.1.2,IssueNo.1,London,June1961.25.J.L.Caplinetal.,"ManualofRespiratoryProtectionAgainstAirborneRadioactiveMaterial,"NRCReportNUREG-0041,October1976.

326.AmericanNationalStandardsInstitute,"RadiationProtectionInstrumentationTestandCalibration,"ANSIN323-1978.

2627.USNRC,"AirsamplingintheWorkplace,"RegulatoryGuide8.25,Revision2,June 1992.128.USNRC,"QualityAssuranceforRadiologicalMonitoringPrograms(NormalOperations)-EffluentStreamsandtheEnvironment,"RegulatoryGuide4.15, Revision1,February1979.

1 27APPENDIXADERIVATIONOFEQUATIONFORDAC mTheequationforDAC misderivedhere.Theequationformixturesinparagraph1oftheNotetoAppendixBofPart20is:EquationA-1 C aDAC a C bDAC b C cDAC c 1++£ConsideramixtureofnaturaluraniumasyellowcakewithaconcentrationofC nuandoredustwithaconcentrationC od.IfthesumoftheconcentrationsequalstheDACforthemixtureEquationA-2 C nu C odDAC m 1+=theequalityinthefirstequationwillapply.Therefore:EquationA-3 C nuDAC nu C od DAC od C nu C odDAC m+=+SolveforDAC mEquationA-4DAC m C nu C od C nuDAC nu C odDAC od=++Dividethenumeratoranddenominatoroftheright-handsidebyC nu+C odEquationA-5DAC m 1 C nu (C nu C od)(DAC nu)C od (C nu C od)(DAC od)=+++Theterm C nu C nu C od+

28canberecognizedasf nu,thefractionofactivityfromnaturaluraniumasyellowcake.Therefore:EquationA-6DAC m f nuDAC nu f od DAC od 1=+-éûú 1ThedefinitionofLLDwaschosentobeconsistentwiththeNRCpositionstatedinTables1and3ofRegulatoryGuide4.8,"EnvironmentalTechnicalSpecificationsforNuclearPowerPlants"(Ref.B-1).The basisforthedefinitionisgiveninReferencesB-2andB-3ofthisguide.Thedefinitionisalsousedinother regulatoryguides,amongthemRegulatoryGuides4.14,"RadiologicalEffluentandEnvironmental MonitoringatUraniumMills"(Ref.B-4),and8.14,"PersonnelNeutronDosimeters"(Ref.B-5),aswellasin NUREG-1575,"Multi-AgencyRadiationSurveyandSiteInvestigationManual(MARSSIM)"(pages6-32 through6-37)(Ref.B-6),andAppendixAtoANSIN13.30(1996a)(Ref.B-7).

29APPENDIXBLOWERLIMITOFDETECTIONForthepurposeofthisguide,thelowerlimitofdetection(LLD)isdefinedasthesmallestconcentrationofradioactivematerialthathasa95%probabilityofbeingdetected.

1Radioactivematerialis"detected"ifthevaluemeasuredonaninstrumentishighenoughto concludethatactivityabovethesystembackgroundisprobablypresent.Foraparticularmeasurementwhereradioactivedisintegrationsaredetected(whichmayincludearadiochemicalseparation):EquationB-1LLD3+4.65S b3.7x10 4EVYe t=-lwhere:LLD=thelowerlimitofdetection(mCi/ml)S b=thestandarddeviationofbackgroundcountrate(countsper second)3.7x10 4=thenumberofdisintegrations/sec/

mCi(thistermisomittedifSbisgivenintermsofmicrocuries)E=thecountingefficiency(countsperdisintegration)

V=thesamplevolume(ml)

Y=thefractionalradiochemicalyield(ifapplicable) l=thedecayconstantfortheparticularradionuclidet=theelapsedtimebetweensamplecollectionandcountingExample:LLDforUraniumwhenFluorometricAnalysisIsUsedWorkthisexampleintermsofmicrocuriesofnaturaluranium.TheLLDcouldjustaswellbecalculatedintermsofmicrogramsofuranium.Aconversionfactorof6.77x10

-7mCi/mgfornaturaluraniumcanbeusediftheuraniumquantityisknowninmicrograms.First,determinethestandarddeviationofthebackgroundcountrateS b.Todothis,performafluorometricanalysisforseveralcleanfilterpapersthathavenotbeenusedto collectairsamples.Atleast5filterpaperswouldhavetobeanalyzedovermanymonths.

ThevalueofS bwillbeintermsofmicroamperesbecausefluorometersusuallygivereadingsinmicroamperes.

30ThevalueofS bcanthenbeconvertedeithertomicrocuriesortocountspersecondbyusingacalibrationfactor.Asamplecalculationisshownhere.Thefluorometricreadingfor10cleanfilterpapersareasfollows:FLUOROMETRICREADING(X i)SAMPLENUMBER(microamperes)10.08220.072 30.05 40.05 50.0560.0470.086 80.088 90.08100.018CalculatethestandarddeviationS bbyEquationB-2(orbypocketcalculator):EquationB-2 S b 2 1 n1 (X i i1 n)2=-=-Cwhere:n=thenumberofsamples X i=thereadingforsamplei C=theaverageofthereadingsForthedataabove,thestandarddeviationis:

S b=0.023 mAConvertS btomicrogramsofuranium.Onthisfluorometer0.1mgofU 3 O 8givesareadingof0.67mA.Thefluorometerwillread6.7mA/mgofU 3 O 8.Thiscompoundis85%uraniumbyweight(238x3=214,16x8=128,714/842=0.85).Therefore,thefluorometerwill read7.9mA/mgofuranium(6.7/0.85=7.9).Nowcalculatethestandarddeviationinmicrogramsofuranium:

S b0.023mA7.9Ag=mm/=0.0029mgofuranium 31Toconverttomicrocuries,useaconversionfactorof6.77x10

-7Ci/mgofuranium.Therefore:

S b=0.0029mgx6.77x10

-7Ci/mg=1.97x10-9CiIntheequationforLLD,thecountingefficiencyEwillbe1.(ThetermEisnotapplicabletoafluorometricanalysis.)ThesamplevolumeVwillbeequaltothecollectionrateoftheairsamplertimesthesamplecollectiontime.Assumealow-volumeairsamplerwithanairflowrateof10liters perminuteanda30-minutesamplecollectiontime.V=10liters/minx30minutes=300liters

=300,000mlForafluorometricanalysis,theradiochemicalyieldisnotapplicable,andYmaybesetequalto1.Theexponentialtermforradioactivedecaye

-ÿtwillalsobeequalto1becausethehalf-lifeofuraniumissolongthattheamountofdecaybetweencollectionandanalysiswillbe negligible.Therefore LLD3+4.65x1.97x10Ci300,000ml 9=-m=5x10-12Ciofuranium/mlofairThisLLDisabout100timesmoresensitivethanrecommendedintheguideasanacceptablelowerlimitofdetection.Example:LLDforradondaughterwhenthemodifiedKusnetzmethodisused.Thebackgroundstandarddeviationisestablishedbyusingblankfilters.Assumethealphacountson10blankfilterscountedfor1minuteeachareasshownbelow:

32SampleNumberAlphaCounts 12 23 31 43 52 62 72 83 92104ForthesefiltersSbcanbecalculatedtobe0.84countsfora1-minutecount.AssumethecountingefficiencyEis0.27.Consideralow-volumesamplerwithaflowrateof5litersperminuteanda5-minutecollectiontime.Therefore,thesamplevolumewillbe 25,000ml.TheradiochemicalyieldYisnotapplicable,andissetequalto1.Tocalculateradioactivedecaythevalueof

ÿcanbetakentoberoughly0.026perminute(forlead-214,theradondaughterwiththelongesthalf-life).Thevalueoftistakentobe 60minutes.Itwillbeaccurateenoughtouse60minutesforthisvalueeventhoughit couldbeasshortas40minutesoraslongas90minutes.Thereforee

-ÿtequals0.21.Thelowerlimitofdetectioncannowbecalculated:

LLD3+4.65x0.84counts/min0.27counts/disx25lietersx1x0.21

==4.5dpm/literToconvertthisLLDtoworkinglevels(WL),dividebythefactorfromFigure1inANSIN13.8-1989(Ref.9.)Thefactoris110dpm/liter/WLforasamplecounted60minutesafter collection.Therefore:LLD=0.025WL ThisisbelowtheLLDforradondaughtersrecommendedinthieguide.

33APPENDIXBREFERENCESB-1.USNRC,"EnvironmentalTechnicalSpecificationsforNuclearPowerPlants,"RegulatoryGuide4.8,December1975.B-2.J.H.Harley,Editor,"EMLProceduresManual,"DOEReportHASL-300,p.D-08-01,revisedannually.B-3.L.A.Currie,"LimitsforQualitativeDetectionandQuantitativeDetermination--ApplicationtoRadioactivity,"AnalyticalChemistry,Vol.40,pp.586-593,1968.B-4.USNRC,"RadiologicalEffluentandEnvironmentalMonitoringatUraniumMills,"RegulatoryGuide4.14,Revision1,April1980.B-5USNRC,"PersonnelNeutronDosimiters,"RegulatoryGuide8.14,Revision1,August1977.B-6USNRC,"Multi-AgencyRadiationSurveyandSiteInvestigationManual(MARSSIM),"NUREG-1575,December1997.B-7.ANSI,AppendixA,"PerformanceCriteriaforRadiobioassay,"ANSIN13.30,1996a.

34APPENDIXCBETACORRECTIONFACTORFORSURVEYINSTRUMENTHereisanexampleforcalculatingthebetacorrectionfactorforthesurveyinstrument.Atthesurface,theclosed-windowreadingis3mR/hr.Theopen-windowreadingis28mR/hr.Thedifferenceis25mR/hr.Sincethebetadoserateatthesurfaceis150 mrem/hr,thecorrectionfactorCf surcanbecalculatedfromtheequationbelow:ObserveddoseratexCF=actualdoserate 25mR/hrxCf sur=150mrem/hrCfsur=(150mrem/hr)/25mR/hr Cfsur=6mrem/mR(atthesurface)

At2cm:Placetheaxisofthedetectorat2cmfromthesurfaceoftheyellowcake.Theclosed-windowreadingis3mR/hr.Theopen-windowreadingis23mR/hr.Thedifference is20mR/hr.Sincethebetadoserateat2cmis75mrem/hr,thecorrectionfactorCF 2cmcanbecalculated:

CF 2cm=(75mrem/hr)/(20mR/hr)

CF 2cm=3.75mrem/mR(at2cm)Thevalueobtainedat2cmwillgenerallybeaccurateenoughtouseatalldistancesgreaterthan2cm.DetectorAxisYellowcake

ÿ 35REGULATORYANALYSISAseparateregulatoryanalysiswasnotpreparedforthisRevision1toRegulatoryGuide8.30.Avalue/impactstatementaccompaniedRegulatoryGuide8.30whenitwas issuedinJune1983.TheRevision1toRegulatoryGuide8.30isneededtoconformwiththerevised10CFRPart20,"StandardsforProtectionAgainstRadiation."Theregulatoryanalysis preparedfor10CFRPart20providestheregulatorybasisforthisRevision1ofRegulatory Guide8.30,anditexaminesthecostandbenefitsoftheruleasimplementedbytheguide.

Acopyofthe"RegulatoryAnalysisfortheRevisionof10CFRPart20"(PNL-6712, November1988),isavailableforinspectionandcopyingforafeeintheNRC'sPublic DocumentRoomat2120LStreetNW.,Washington,DC20555-0001.ADAMSAccessionNumberML003714744

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