<?xml version="1.0"?><ownershipDocument><schemaVersion>X0201</schemaVersion>    <documentType>3/A</documentType><periodOfReport>2003-04-28</periodOfReport><dateOfOriginalSubmission>2003-05-12</dateOfOriginalSubmission><noSecuritiesOwned>0</noSecuritiesOwned><issuer><issuerCik>0001065059</issuerCik><issuerName>USEC INC</issuerName>        <issuerTradingSymbol>USU</issuerTradingSymbol></issuer><reportingOwner><reportingOwnerId><rptOwnerCik>0001183262</rptOwnerCik><rptOwnerName>GREEN RONALD F</rptOwnerName></reportingOwnerId><reportingOwnerAddress><rptOwnerStreet1>6903 ROCKLEDGE DRIVE</rptOwnerStreet1><rptOwnerStreet2></rptOwnerStreet2><rptOwnerCity>BETHESDA</rptOwnerCity><rptOwnerState>MD</rptOwnerState><rptOwnerZipCode>20817</rptOwnerZipCode><rptOwnerStateDescription></rptOwnerStateDescription></reportingOwnerAddress><reportingOwnerRelationship><isDirector>0</isDirector><isOfficer>1</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther><officerTitle>Senior Vice President</officerTitle></reportingOwnerRelationship></reportingOwner><nonDerivativeTable><nonDerivativeHolding><securityTitle><value>Common Stock</value></securityTitle><postTransactionAmounts><sharesOwnedFollowingTransaction><value>8000</value><footnoteId id="F1" /></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership></ownershipNature></nonDerivativeHolding></nonDerivativeTable><footnotes><footnote id="F1">In the original Form 3 filed on May 12, 2003, this number was erroneously stated as 5,000 shares.</footnote></footnotes><remarks>This is an amendment and restatement of the original Form 3 filed on May 12, 2003.</remarks><ownerSignature><signatureName>Ronald F. Green</signatureName><signatureDate>2003-08-15</signatureDate></ownerSignature></ownershipDocument>

