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  <xs:element id="bwxt_DeferredTaxAssetsLongTermContracts" abstract="false" name="DeferredTaxAssetsLongTermContracts" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="bwxt_AvailableForSaleDebtSecuritiesAndEquitySecuritiesFVNI" abstract="false" name="AvailableForSaleDebtSecuritiesAndEquitySecuritiesFVNI" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="bwxt_DefinedBenefitPlanPlanAssetsLevel3ReconciliationRealizedGain" abstract="false" name="DefinedBenefitPlanPlanAssetsLevel3ReconciliationRealizedGain" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="bwxt_PaymentTermsDomain" abstract="true" name="PaymentTermsDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="bwxt_ScheduleOfChangesInAccumulatedOtherComprehensiveIncomeLossTableTextBlock" abstract="false" name="ScheduleOfChangesInAccumulatedOtherComprehensiveIncomeLossTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:textBlockItemType"/>
  <xs:element id="bwxt_GovernmentCustomersMember" abstract="true" name="GovernmentCustomersMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="bwxt_SeniorNotesDue2029Member" abstract="true" name="SeniorNotesDue2029Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="bwxt_IncreaseDecreaseInPensionPostretirementAndAccruedEmployeeBenefits" abstract="false" name="IncreaseDecreaseInPensionPostretirementAndAccruedEmployeeBenefits" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="bwxt_DefinedContributionPlanVestingPeriodForEmployerMatchingContributions" abstract="false" name="DefinedContributionPlanVestingPeriodForEmployerMatchingContributions" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="bwxt_UraniumAndNuclearServicesMember" abstract="true" name="UraniumAndNuclearServicesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="bwxt_CashSettledRestrictedStockUnitMember" abstract="true" name="CashSettledRestrictedStockUnitMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="bwxt_DeferredTaxAssetsLeaseLiabilities" abstract="false" name="DeferredTaxAssetsLeaseLiabilities" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="bwxt_DefinedBenefitPlanPlansWithAssetsInExcessOfAccumulatedBenefitObligationAggregateProjectedBenefitObligation" abstract="false" name="DefinedBenefitPlanPlansWithAssetsInExcessOfAccumulatedBenefitObligationAggregateProjectedBenefitObligation" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="bwxt_DebtSecuritiesAvailableForSaleAndEquitySecuritiesFVNIAccumulatedGrossUnrealizedGainBeforeTax" abstract="false" name="DebtSecuritiesAvailableForSaleAndEquitySecuritiesFVNIAccumulatedGrossUnrealizedGainBeforeTax" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="bwxt_ThriftPlanAndMiiThriftPlanMember" abstract="true" name="ThriftPlanAndMiiThriftPlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="bwxt_AuditInformationAbstract" abstract="true" name="AuditInformationAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="bwxt_BasisOfPresentationAndSignificantAccountingPoliciesTable" abstract="true" name="BasisOfPresentationAndSignificantAccountingPoliciesTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="bwxt_DefinedBenefitPlanPlanAssetsLevel3ReconciliationTranslation" abstract="false" name="DefinedBenefitPlanPlanAssetsLevel3ReconciliationTranslation" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="bwxt_DeferredFinanceCostsRollForward" abstract="true" name="DeferredFinanceCostsRollForward" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="bwxt_DefinedBenefitPlanMarkToMarketAdjustment" abstract="false" name="DefinedBenefitPlanMarkToMarketAdjustment" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="bwxt_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedPerformancePeriod" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedPerformancePeriod" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="bwxt_DefinedBenefitPlanAmountsRecognizedInNetPeriodicBenefitCostAndOtherComprehensiveIncomeLoss" abstract="false" name="DefinedBenefitPlanAmountsRecognizedInNetPeriodicBenefitCostAndOtherComprehensiveIncomeLoss" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="bwxt_BasisOfPresentationAndSignificantAccountingPoliciesLineItems" abstract="true" name="BasisOfPresentationAndSignificantAccountingPoliciesLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="bwxt_LongTermInvestmentsExcludingInvestmentsInUnconsolidatedAffiliates" abstract="false" name="LongTermInvestmentsExcludingInvestmentsInUnconsolidatedAffiliates" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="bwxt_ScheduleOfResultsRelatedToEquityAccountedInvesteesLineItems" abstract="true" name="ScheduleOfResultsRelatedToEquityAccountedInvesteesLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="bwxt_MinimumPercentageOfFairMarketValueClosingPrice" abstract="false" name="MinimumPercentageOfFairMarketValueClosingPrice" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:percentItemType"/>
  <xs:element id="bwxt_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdjustmentToAssumedVesting" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdjustmentToAssumedVesting" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="bwxt_UsGovernmentSecuritiesMember" abstract="true" name="UsGovernmentSecuritiesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="bwxt_FiniteLivedIntangibleAssetsForeignCurrencyTranslationAndOtherGainLoss" abstract="false" name="FiniteLivedIntangibleAssetsForeignCurrencyTranslationAndOtherGainLoss" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="bwxt_LineOfCreditFacilityIncreaseInMaximumBorrowingCapacity" abstract="false" name="LineOfCreditFacilityIncreaseInMaximumBorrowingCapacity" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="bwxt_SeniorNotesDue2028Member" abstract="true" name="SeniorNotesDue2028Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="bwxt_FormerCreditFacilityMember" abstract="true" name="FormerCreditFacilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="bwxt_RisksAndUncertaintiesTextBlock" abstract="false" name="RisksAndUncertaintiesTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:textBlockItemType"/>
  <xs:element id="bwxt_AssetsForPlanBenefitsPrepaidPostretirementBenefitObligation" abstract="false" name="AssetsForPlanBenefitsPrepaidPostretirementBenefitObligation" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="bwxt_EquitySecuritiesAndCommingledMutualFundsMember" abstract="true" name="EquitySecuritiesAndCommingledMutualFundsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="bwxt_ResearchAndDevelopmentExpenseGross" abstract="false" name="ResearchAndDevelopmentExpenseGross" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="bwxt_OtherAssetCategoryMember" abstract="true" name="OtherAssetCategoryMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="bwxt_ScheduleOfAssetAllocationByAssetCategoryTableTextBlock" abstract="false" name="ScheduleOfAssetAllocationByAssetCategoryTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:textBlockItemType"/>
  <xs:element id="bwxt_NuclearServicesandEngineeringMember" abstract="true" name="NuclearServicesandEngineeringMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="bwxt_ThriftPlanMember" abstract="true" name="ThriftPlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="bwxt_CashHeldForDecommissioningOfFacilitiesMember" abstract="true" name="CashHeldForDecommissioningOfFacilitiesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="bwxt_FinancialAssuranceToPayExpectedCostOfDecommissioning" abstract="false" name="FinancialAssuranceToPayExpectedCostOfDecommissioning" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="bwxt_CashAndAccruedItemsMember" abstract="true" name="CashAndAccruedItemsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="bwxt_DebtInstrumentCovenantLeverageRatioFutureIncreaseMaximum" abstract="false" name="DebtInstrumentCovenantLeverageRatioFutureIncreaseMaximum" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="bwxt_ScheduleOfAmortizedAndUnamortizedIntangibleAssetsLineItems" abstract="true" name="ScheduleOfAmortizedAndUnamortizedIntangibleAssetsLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="bwxt_DepreciationDepletionAndAmortizationExcludingDiscontinuedOperation" abstract="false" name="DepreciationDepletionAndAmortizationExcludingDiscontinuedOperation" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="bwxt_TermOneMember" abstract="true" name="TermOneMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="bwxt_NumberOfFormerNuclearFuelProcessingFacilities" abstract="false" name="NumberOfFormerNuclearFuelProcessingFacilities" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="bwxt_ScheduleOfAmortizedAndUnamortizedIntangibleAssetsTable" abstract="true" name="ScheduleOfAmortizedAndUnamortizedIntangibleAssetsTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="bwxt_GovernmentOperationsSegmentMember" abstract="true" name="GovernmentOperationsSegmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="bwxt_LongTermDebtGrossExcludingCurrentMaturities" abstract="false" name="LongTermDebtGrossExcludingCurrentMaturities" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="bwxt_DefinedBenefitPlanPlansWithAssetsInExcessOfAccumulatedBenefitObligationAggregateFairValueOfPlanAssets" abstract="false" name="DefinedBenefitPlanPlansWithAssetsInExcessOfAccumulatedBenefitObligationAggregateFairValueOfPlanAssets" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="bwxt_BondsIssuedAndOutstanding" abstract="false" name="BondsIssuedAndOutstanding" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
</xs:schema>
