Automatic

    FUNDAMENTALANDAPPLIEDFUNDMENTALRESEARCH?Radiochemistryand

    NuclearChemistry

    coating,wereconstructedthepulsepower.Throughthereconstruction,therangeofvoltageandcurrent

    waswidenedandtheopentimeandshuttimeCanbeadjustedindependently.TheTable1liststhe

    parametersofthenewandtheformerpulsepower.

    Table1Parametersofnewandformerpulsepower

    OnthebasicoftheformerresearchaboutdirectcurrentplatingmadebyYanShuhengetal,a constantdirect—

    currentplatingwascarriedoutinisopropanolandDMFcont~ningasmallamountof nitricacidrespectively.TheadherentandhomogeneoustargetofuraniumCanbepreparedbythismethod.

    Thesurfacedensitychangesbetween1.2—

    2.3mg/cme.Throughchangingthecurrent,theinfluenceofthe

    currentdensityontheyieldsandthesurfacedensityinthesetwodifferentsolventswasinvestigated.The

    resultsareshownintheFig.1andFig.2.

    Theresultsshowthatinbothsolvents,theyieldsincreasewiththecurrentdensityandarriveatthe

    topatthe8—

    10mA]cm,respectively96.11%(isopropano1)and88.45%(DMF).Afterthat,whenthe currentdensitycontinuestobeimproved,theyieldsdonotincreasebecauseofthereleasehydrogenand

    thequalityofcoatingbecomeworse.Theresultsshowthatwithconstantdirect—

    currentplatingmethod,

    theyieldandsurfacedensitywereallhigherintheisopropanolthanintheDMF. AutomaticDeterminationofAbout100

    DevelopedPotentiometricTitrationBasedon

    mgUranium

    ConventionalMethod

    LIUQuan—wei,ZHUHal—qiao,LUOZhong—yan,LIANGLiang,

    HAOXiao-juanWUJi—zong

    Accuratedeterminationofuraniumissignificantinthenuclearfuelproduction,accountancy,nuclear

    safeguardsandotherproceduresofnuclearfuelcycle.Electrochemicalmethodbasedontheredox

    titrationisconventionallyusedforthedeterminationofaboutagramamountofuraniumindifferent

    nuclearfuelmaterials.

    Intheconventionalmethod,rnleU(?)isreducedtoU(?)withFe(II)sulfatesolutionin

    concentratedphosphateacid.ThentheexcessofFe(II)isoxidizedwithnitricacidintheexistenceofMo.

    AtlastUfIV)istitratedwithpotassiumdichromate.

    Inthisworkautomaticdeterminationofaboutahundredmilligramamountofuraniumwas developedbasedontheconventionalmethodofpotentiometrictitrationofaboutagramamountof

    uranium.

    Inthismethodofpotentiometrictitration,thesuitableconcentrationofpotassiumdichromate

....:,......:..

    .::,....——,—一.——

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    ::i.

solutionoptimizestheprecisionofanalyticalresult.ThereasonisthatifthemorecOncen?

    atedpOtassium

    dichromatesolutionisadopted,theratiooftheendpointexcursiontothetitrationvolumeisbiggerwt1ich

    makestheprecisionworse,ifmoredilutedpotassiumdichromatesolutionisadopted .kurtosisOf

    potentiometriccurve1slesswhichalsomakestheprecisionworse.InthisworkconcentratiOnOf

    potassiumdichromatesolutionwasoptimizedwithselectionofdifferentconcentrationofthesolution.At

    last2.06228g/LofpotassiumdichromatesolutionisadoptedasthetitrationsolutiOn. Thetitrationvolumeofpotassiumdichromatesolutionissmallbecausetheti仃

    ateduraniumison1v

    about100mg,SOtheaccuracyoftheburettescaleissignificantfortheaccuracyoftheanalyticalresult

    .

    In

    thisworktheburettewasscaledformoreaccuratedeterminationbyweighingofpurifiedwateraccordin

    g

    tothedensityofthewaterintheverifiedtemperature.

    TheamountofreagentsusedinthistitrationrequiresascertainmentaccordingtotheamOuntOf

    uranium?Inthisworktheexperimentsforthesuitableamountofreagentswasconducted .Theoptimized

    amountofreagentsisverifiedthroughcomparingtheresultsoftitration. Thistitrationprocedureneedbecompletedwithin7mintoavoidtheu(IV)oxidizedbyoxygenin

    theairandmaketheresultonthelowside.Inthiswork,thecomputercontrolprogramwasoptjzed

    throughdividingthetitrationprocedureintofleettitrationofpreparationandtitrationofendpointwiml0

    pLeverystep-Theabovemeasurenotonlymakestheprocedurebecompletedwithin7rnin .

    butalso

    ensurestheaccuracyoftheendpoint.

    TheChinanationalreferencematerialofU8O3wasdeterminedaccordingtotheaboveoptimized

    experimentalconditions(Table1).TheresultshowsthattheprecisionvaluebetterthaI10.01%and

    accuracyofthemethodwasverifiedbythevalueofChinanationalreferencematerialofUsO. DevelopmentofSeriesofUraniumIsotopicReferenceMaterials

    ZHUHai.qiao,LUOZhong.yan,HAOXiao-juan,LIANGLiang,LIUJun.1ing,LIUQual1一wei

    AseriesofstandarduraniumisotopereferencesolutionwerepreparedwithhighpurityUaI1d238U

    BasicprocedureshowsinFig.1.