<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>
<periodOfReport>2004-01-22</periodOfReport>
<notSubjectToSection16>0</notSubjectToSection16>
    <issuer>
        <issuerCik>0000785186</issuerCik>
        <issuerName>DURATEK INC</issuerName>
        <issuerTradingSymbol>DRTK</issuerTradingSymbol>
</issuer>
<reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001216921</rptOwnerCik>
            <rptOwnerName>BIXBY WILLIS</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>10100 OLD COLUMBIA ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>COLUMBIA</rptOwnerCity>
            <rptOwnerState>MD</rptOwnerState>
            <rptOwnerZipCode>21046</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>0</isDirector>
<isOfficer>1</isOfficer>
<isTenPercentOwner>0</isTenPercentOwner>
<isOther>0</isOther>
<officerTitle>Vice President</officerTitle>
<otherText></otherText>
</reportingOwnerRelationship>
</reportingOwner>
<nonDerivativeTable></nonDerivativeTable>
<derivativeTable><derivativeTransaction><securityTitle><value>Common Stock Option</value>
</securityTitle>
<conversionOrExercisePrice><value>5.75</value>
</conversionOrExercisePrice>
<transactionDate><value>2004-01-22</value>
</transactionDate>
<transactionCoding><transactionFormType>4</transactionFormType>
<transactionCode>X</transactionCode>
<equitySwapInvolved>0</equitySwapInvolved>
</transactionCoding>
<transactionAmounts><transactionShares><value>3000</value>
</transactionShares>
<transactionPricePerShare><value>13.19</value>
</transactionPricePerShare>
<transactionAcquiredDisposedCode><value>D</value>
</transactionAcquiredDisposedCode>
</transactionAmounts>
<exerciseDate><value>2000-11-02</value>
</exerciseDate>
<expirationDate><value>2004-11-02</value>
</expirationDate>
<underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value>
</underlyingSecurityTitle>
<underlyingSecurityShares><value>3000</value>
</underlyingSecurityShares>
</underlyingSecurity>
<postTransactionAmounts><sharesOwnedFollowingTransaction><value>36000</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature><directOrIndirectOwnership><value>D</value>
</directOrIndirectOwnership>
</ownershipNature>
</derivativeTransaction>
<derivativeTransaction><securityTitle><value>Common Stock Option</value>
</securityTitle>
<conversionOrExercisePrice><value>5.75</value>
</conversionOrExercisePrice>
<transactionDate><value>2004-01-23</value>
</transactionDate>
<transactionCoding><transactionFormType>4</transactionFormType>
<transactionCode>X</transactionCode>
<equitySwapInvolved>0</equitySwapInvolved>
</transactionCoding>
<transactionAmounts><transactionShares><value>3000</value>
</transactionShares>
<transactionPricePerShare><value>13.4037</value>
</transactionPricePerShare>
<transactionAcquiredDisposedCode><value>D</value>
</transactionAcquiredDisposedCode>
</transactionAmounts>
<exerciseDate><value>2000-11-02</value>
</exerciseDate>
<expirationDate><value>2004-11-02</value>
</expirationDate>
<underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value>
</underlyingSecurityTitle>
<underlyingSecurityShares><value>3000</value>
</underlyingSecurityShares>
</underlyingSecurity>
<postTransactionAmounts><sharesOwnedFollowingTransaction><value>33000</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature><directOrIndirectOwnership><value>D</value>
</directOrIndirectOwnership>
</ownershipNature>
</derivativeTransaction>
</derivativeTable>
<footnotes></footnotes>
<ownerSignature><signatureName>/s/Willis W. Bixby</signatureName>
<signatureDate>2004-01-23</signatureDate>
</ownerSignature>
</ownershipDocument>

