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Session I.4.9dSession I.4.9d

Part I Review of Fundamentals

Module 4 Sources of Radiation

Session 9d Fuel Cycle - Conversion

IAEA Post Graduate Educational CourseIAEA Post Graduate Educational CourseRadiation Protection and Safe Use of Radiation SourcesRadiation Protection and Safe Use of Radiation Sources

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ConversionConversion

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MillsMills Concentrate ores from ~1% to ~60%Concentrate ores from ~1% to ~60% Yellowcake (UYellowcake (U33OO8 8 - really a mix of UO- really a mix of UO22 and UO and UO33)) Ammonium Diuranate (ADU – (NHAmmonium Diuranate (ADU – (NH44))22UU22OO77))

Conversion Output is UFConversion Output is UF66

Fluorine is used for two reasons:Fluorine is used for two reasons: Only one isotopeOnly one isotope Physical properties are commercially viablePhysical properties are commercially viable

ConversionConversion

4/2003 Rev 24/2003 Rev 2 I.4.9d – slide I.4.9d – slide 44 of 23 of 23

Uranium HexafluorideUranium Hexafluoride

Key compound in Nuclear Fuel CycleKey compound in Nuclear Fuel Cycle Solid for storageSolid for storage Liquid for feeding/withdrawingLiquid for feeding/withdrawing Gas for processingGas for processing

Solid is white, dense, crystallineSolid is white, dense, crystalline Reacts with water vapor to produce toxic Reacts with water vapor to produce toxic

and corrosive hydrofluoric acidand corrosive hydrofluoric acid

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UFUF66 + 2H + 2H22O O UO UO22FF22 + 4HF + 4HF

When UFWhen UF66 reacts with moisture in air, it creates reacts with moisture in air, it creates

deadly hydrogen fluoride (HF)deadly hydrogen fluoride (HF)

ConversionConversion

Uranyl FluorideUranyl Fluoride Hydrofluoric AcidHydrofluoric AcidChemical HazardChemical Hazard

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Uranium CompoundsUranium Compounds

UU33OO88 UO UO22 UF UF44 UF UF6 6

Ore – conversion - enrichmentOre – conversion - enrichment

UFUF66 UO UO22FF22 UO UO33 U U33OO88 UO UO22

Fuel fabrication “dry” process”Fuel fabrication “dry” process”

(NH(NH44))22UU22OO77 2NH 2NH33 + 2UO + 2UO33

Aammonium diuranate (ADU) crystalsAammonium diuranate (ADU) crystals

2UO2UO44 2UO 2UO33 + O + O22

Precipitation of uranyl nitrate and hydrogen Precipitation of uranyl nitrate and hydrogen peroxide.peroxide.

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Comparison of DryComparison of Dryand Wet Conversionand Wet Conversion

DRY ProcessDRY Process

PretreatmentPretreatment Prepared Feed and Prepared Feed and

CalcinationCalcination Reduction (NHReduction (NH33)) HydrofluorinationHydrofluorination FluorinationFluorination DistillationDistillation Product Loading and Product Loading and

ShippingShipping

WET ProcessWET Process

DigestionDigestion Solvent ExtractionSolvent Extraction Evaporation/ConcentrateEvaporation/Concentrate Denitration/CalcinationDenitration/Calcination

Reduction (HReduction (H22 in steam) in steam) HydrofluorinationHydrofluorination FluorinationFluorination

Product Loading and Product Loading and ShippingShipping

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Dry Fluoride VolatilityDry Fluoride VolatilityConversion ProcessConversion Process

PretreatmentPretreatment Prepared Feed and CalcinationPrepared Feed and Calcination ReductionReduction HydrofluorinationHydrofluorination FluorinationFluorination DistillationDistillation Product Loading and ShippingProduct Loading and Shipping

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ConversionConversion

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ConversionConversion

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ConversionConversion

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ReductionReduction

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HydrofluorinationHydrofluorination

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FluorinationFluorination

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DistillationDistillation

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Product Loading and ShippingProduct Loading and Shipping

UFUF66 product is 99.99% pure product is 99.99% pure

Packaged in 10 and 14 ton cylindersPackaged in 10 and 14 ton cylinders Allowed to cool for 5 days to solidifyAllowed to cool for 5 days to solidify Overfill is the highest safety concernOverfill is the highest safety concern

Product (source material) is shipped to Product (source material) is shipped to the Gaseous Diffusion Plants for the Gaseous Diffusion Plants for enrichment (special nuclear material)enrichment (special nuclear material)

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ConversionConversion

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Wet Acid Digestion Conversion Wet Acid Digestion Conversion Process (SFC)Process (SFC)

Nitric acid digestion of yellowcakeNitric acid digestion of yellowcake Dilute uranyl nitrate (UODilute uranyl nitrate (UO22(NO(NO33))22))

Selective solvent extractionSelective solvent extraction Purified UOPurified UO22(NO(NO33))22 solution solution

Evaporation/concentrationEvaporation/concentration Denitration/calcination Denitration/calcination UO UO33 (Orange oxide) (Orange oxide)

Reduction with HReduction with H2 2 UO UO22 (Brown oxide) (Brown oxide)

Hydrofluorination Hydrofluorination UF UF44 (Green Salt) (Green Salt)

Fluorination Fluorination UF UF66

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Other Conversion ProcessesOther Conversion Processes

British ProcessBritish Process Calcination of ammonium diuranate Calcination of ammonium diuranate

crystals by batch crystals by batch (NH(NH44))22UU22OO77 2NH 2NH33 + H + H22O + 2UOO + 2UO33

In the same furnace, the UOIn the same furnace, the UO33 is is

further reduced to UOfurther reduced to UO22 in the in the

presence of hydrogen in a batchwise presence of hydrogen in a batchwise manner.manner.

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Other Conversion Processes Other Conversion Processes (cont)(cont)

French ProcessFrench Process Uranium peroxide is precipitated Uranium peroxide is precipitated

through the addition of hydrogen through the addition of hydrogen peroxide to an aqueous solution of peroxide to an aqueous solution of uranyl nitrate in a batch processuranyl nitrate in a batch process

UOUO22(NO(NO33))22 6H 6H22O +HO +H22OO22 UO UO44 2H 2H22OO UOUO44 2UO 2UO33 + O + O22 (Calcined) (Calcined) UOUO33 + NH + NH33 UO UO22 (Reduction – (Reduction –

ammonia “cracks” @ 750 ammonia “cracks” @ 750 C).C).

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UFUF66 Properties Properties

UFUF66 + 2H + 2H22O O UO UO22FF22 + 4HF + 4HF

Any UFAny UF66 leak into air will react with moisture leak into air will react with moisture

and appear as a white cloudand appear as a white cloud

When cooled to ambient temperatures, UFWhen cooled to ambient temperatures, UF66 is a is a

solid at atmospheric pressures.solid at atmospheric pressures.

UFUF66 cylinders are under a slight vacuum when cylinders are under a slight vacuum when

allowed to reach ambient temperatures.allowed to reach ambient temperatures.

Any cylinder leak would tend to “self-seal” Any cylinder leak would tend to “self-seal” through the formation of UOthrough the formation of UO22FF22 at the leak. at the leak.

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ConversionConversion

Gore Oklahoma USA (closed)Gore Oklahoma USA (closed)

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ConversionConversion

Uranium Hexafluoride Conversion FacilitiesUranium Hexafluoride Conversion Facilities

CountryCountry OwnerOwner PlantPlant CapacityCapacity (MTU/year)(MTU/year)

RussiaRussia Minatom Minatom AngarskAngarsk 20,000 20,000 United StatesUnited States HoneywellHoneywell Metropolis, IllinoisMetropolis, Illinois 14,000 14,000 FranceFrance COMURHEX COMURHEX Pierrelatte 1Pierrelatte 1 14,000 14,000 CanadaCanada CamecoCameco Port Hope, OntarioPort Hope, Ontario 10,500 10,500 United KingdomUnited Kingdom BNFBNF Springfields, LancashireSpringfields, Lancashire 6,000 6,000 RussiaRussia MinatomMinatom EkaterinburgEkaterinburg 4,000 4,000 ChinaChina CNNCCNNC LanzhouLanzhou 400 400 FranceFrance COMURHEX COMURHEX Pierrelatte 2Pierrelatte 2 350 350 BrazilBrazil IPENIPEN São PauloSão Paulo 9090TotalTotal 69,34069,340