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  <xs:element id="bwxt_DefinedContributionPlanVestingPeriodForEmployerMatchingContributions" abstract="false" name="DefinedContributionPlanVestingPeriodForEmployerMatchingContributions" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <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_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRateToDetermineInterestCost" abstract="false" name="DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRateToDetermineInterestCost" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:percentItemType"/>
  <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_CommingledAndMutualFundsMember" abstract="true" name="CommingledAndMutualFundsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="bwxt_DiversifiedCreditMember" abstract="true" name="DiversifiedCreditMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="bwxt_FixedIncomeExcludingUSGovernmentSecuritiesMember" abstract="true" name="FixedIncomeExcludingUSGovernmentSecuritiesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="bwxt_PartnershipsWithSecurityHoldingsMember" abstract="true" name="PartnershipsWithSecurityHoldingsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <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_OtherAssetCategoryMember" abstract="true" name="OtherAssetCategoryMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <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_DefinedBenefitPlanAlternativeInvestmentsFairValueofPlanAssets" abstract="false" name="DefinedBenefitPlanAlternativeInvestmentsFairValueofPlanAssets" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="bwxt_CapitalStockTable" abstract="true" name="CapitalStockTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="bwxt_ShareRepurchaseProgramMember" abstract="true" name="ShareRepurchaseProgramMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="bwxt_CapitalStockLineItems" abstract="true" name="CapitalStockLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="bwxt_TwentyTwentyOmnibusIncentivePlanMember" abstract="true" name="TwentyTwentyOmnibusIncentivePlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="bwxt_TwoThousandAndTenLongTermIncentivePlanMember" abstract="true" name="TwoThousandAndTenLongTermIncentivePlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="bwxt_TwoThousandTwelveLongTermIncentivePlanMember" abstract="true" name="TwoThousandTwelveLongTermIncentivePlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1: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_CashSettledPerformanceSharesMember" abstract="true" name="CashSettledPerformanceSharesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <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_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardExpirationPeriodMaximum" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardExpirationPeriodMaximum" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="bwxt_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedPerformancePeriod" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedPerformancePeriod" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="bwxt_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsNonvestedWeightedAverageFairValue" abstract="false" name="SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsNonvestedWeightedAverageFairValue" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:perShareItemType"/>
  <xs:element id="bwxt_SharebasedCompensationArrangementbySharebasedPaymentAwardWeightedAverageVesting" abstract="false" name="SharebasedCompensationArrangementbySharebasedPaymentAwardWeightedAverageVesting" 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_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdjustmentToAssumedVestingWeightedAverageGrantDateFairValue" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdjustmentToAssumedVestingWeightedAverageGrantDateFairValue" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:perShareItemType"/>
  <xs:element id="bwxt_ContingenciesAndCommitmentsTable" abstract="true" name="ContingenciesAndCommitmentsTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="bwxt_EnvironmentalMattersMember" abstract="true" name="EnvironmentalMattersMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="bwxt_ContingenciesAndCommitmentsLineItems" abstract="true" name="ContingenciesAndCommitmentsLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="bwxt_NumberOfFormerNuclearFuelProcessingFacilities" abstract="false" name="NumberOfFormerNuclearFuelProcessingFacilities" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <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_EnvironmentalRemediationExpenseStatementOfIncomeOrComprehensiveIncomeExtensibleEnumerationNotDisclosedFlag" abstract="false" name="EnvironmentalRemediationExpenseStatementOfIncomeOrComprehensiveIncomeExtensibleEnumerationNotDisclosedFlag" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="bwxt_EnvironmentalLossContingencyStatementOfFinancialPositionExtensibleEnumerationNotDisclosedFlag" abstract="false" name="EnvironmentalLossContingencyStatementOfFinancialPositionExtensibleEnumerationNotDisclosedFlag" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="bwxt_TwoUtilityCustomersMember" abstract="true" name="TwoUtilityCustomersMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="bwxt_USGovernmentMember" abstract="true" name="USGovernmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="bwxt_DebtSecuritiesAvailableForSaleAndEquitySecuritiesFVNIAmortizedCost" abstract="false" name="DebtSecuritiesAvailableForSaleAndEquitySecuritiesFVNIAmortizedCost" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" 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_DebtSecuritiesTradingAndEquitySecuritiesAccumulatedGrossUnrealizedLossBeforeTax" abstract="false" name="DebtSecuritiesTradingAndEquitySecuritiesAccumulatedGrossUnrealizedLossBeforeTax" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="bwxt_DebtSecuritiesAvailableForSaleAndEquitySecuritiesFVNI" abstract="false" name="DebtSecuritiesAvailableForSaleAndEquitySecuritiesFVNI" 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_CostsAndExpensesAdjusted" abstract="false" name="CostsAndExpensesAdjusted" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="bwxt_OperatingIncomeLossAdjusted" abstract="false" name="OperatingIncomeLossAdjusted" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <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_NuclearComponentProgramMember" abstract="true" name="NuclearComponentProgramMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <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_CommercialOperationsMember" abstract="true" name="CommercialOperationsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="bwxt_NuclearManufacturingMember" abstract="true" name="NuclearManufacturingMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="bwxt_NuclearServicesandEngineeringMember" abstract="true" name="NuclearServicesandEngineeringMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
</xs:schema>
