<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019f13bf-2286-7f03-b6f0-04bd7f21a425,g:1a23a885-fde5-4dc5-9bc3-bacf939c53d5-->
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:din="http://www.deepisolationnuclear.com/20260630" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:dtr-types="http://www.xbrl.org/dtr/type/2024-01-31" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" attributeFormDefault="unqualified" elementFormDefault="qualified" targetNamespace="http://www.deepisolationnuclear.com/20260630">
  <xs:import namespace="http://fasb.org/srt/2026" schemaLocation="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd"/>
  <xs:import namespace="http://fasb.org/us-gaap/2026" schemaLocation="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd"/>
  <xs:import namespace="http://www.xbrl.org/2003/instance" schemaLocation="http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd"/>
  <xs:import namespace="http://www.xbrl.org/2003/linkbase" schemaLocation="http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd"/>
  <xs:import namespace="http://www.xbrl.org/dtr/type/2024-01-31" schemaLocation="https://www.xbrl.org/dtr/type/2024-01-31/types.xsd"/>
  <xs:import namespace="http://xbrl.org/2005/xbrldt" schemaLocation="http://www.xbrl.org/2005/xbrldt-2005.xsd"/>
  <xs:import namespace="http://xbrl.sec.gov/country/2026" schemaLocation="https://xbrl.sec.gov/country/2026/country-2026.xsd"/>
  <xs:import namespace="http://xbrl.sec.gov/dei/2026" schemaLocation="https://xbrl.sec.gov/dei/2026/dei-2026.xsd"/>
  <xs:import namespace="http://xbrl.sec.gov/ecd/2026" schemaLocation="https://xbrl.sec.gov/ecd/2026/ecd-2026.xsd"/>
  <xs:annotation>
    <xs:appinfo>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="din-20260630_pre.xml" xlink:role="http://www.xbrl.org/2003/role/presentationLinkbaseRef" xlink:type="simple"/>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="din-20260630_def.xml" xlink:role="http://www.xbrl.org/2003/role/definitionLinkbaseRef" xlink:type="simple"/>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="din-20260630_lab.xml" xlink:role="http://www.xbrl.org/2003/role/labelLinkbaseRef" xlink:type="simple"/>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="din-20260630_cal.xml" xlink:role="http://www.xbrl.org/2003/role/calculationLinkbaseRef" xlink:type="simple"/>
      <link:roleType id="Cover" roleURI="http://www.deepisolationnuclear.com/role/Cover">
        <link:definition>0000001 - Document - Cover</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CondensedConsolidatedBalanceSheets" roleURI="http://www.deepisolationnuclear.com/role/CondensedConsolidatedBalanceSheets">
        <link:definition>9952151 - Statement - Condensed Consolidated Balance Sheets</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CondensedConsolidatedBalanceSheetsParentheticals" roleURI="http://www.deepisolationnuclear.com/role/CondensedConsolidatedBalanceSheetsParentheticals">
        <link:definition>9952152 - Statement - Condensed Consolidated Balance Sheets (Parentheticals)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CondensedConsolidatedStatementsofOperationsandComprehensiveLoss" roleURI="http://www.deepisolationnuclear.com/role/CondensedConsolidatedStatementsofOperationsandComprehensiveLoss">
        <link:definition>9952153 - Statement - Condensed Consolidated Statements of Operations and Comprehensive Loss</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CondensedConsolidatedStatementsofChangesinStockholdersEquity" roleURI="http://www.deepisolationnuclear.com/role/CondensedConsolidatedStatementsofChangesinStockholdersEquity">
        <link:definition>9952154 - Statement - Condensed Consolidated Statements of Changes in Stockholders&#8217; Equity</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CondensedConsolidatedStatementsofCashFlows" roleURI="http://www.deepisolationnuclear.com/role/CondensedConsolidatedStatementsofCashFlows">
        <link:definition>9952155 - Statement - Condensed Consolidated Statements of Cash Flows</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="NatureofOperations" roleURI="http://www.deepisolationnuclear.com/role/NatureofOperations">
        <link:definition>9952156 - Disclosure - Nature of Operations</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="BasisofPresentationandSummaryofSignificantAccountingPolicies" roleURI="http://www.deepisolationnuclear.com/role/BasisofPresentationandSummaryofSignificantAccountingPolicies">
        <link:definition>9952157 - Disclosure - Basis of Presentation and Summary of Significant Accounting Policies</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ReverseMerger" roleURI="http://www.deepisolationnuclear.com/role/ReverseMerger">
        <link:definition>9952158 - Disclosure - Reverse Merger</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RevenueRecognition" roleURI="http://www.deepisolationnuclear.com/role/RevenueRecognition">
        <link:definition>9952159 - Disclosure - Revenue Recognition</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="PropertyPlantandEquipmentNet" roleURI="http://www.deepisolationnuclear.com/role/PropertyPlantandEquipmentNet">
        <link:definition>9952160 - Disclosure - Property, Plant and Equipment, Net</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="IntangibleAssets" roleURI="http://www.deepisolationnuclear.com/role/IntangibleAssets">
        <link:definition>9952161 - Disclosure - Intangible Assets</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="StockholdersEquity" roleURI="http://www.deepisolationnuclear.com/role/StockholdersEquity">
        <link:definition>9952162 - Disclosure - Stockholders' Equity</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="Leases" roleURI="http://www.deepisolationnuclear.com/role/Leases">
        <link:definition>9952163 - Disclosure - Leases</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="AccruedExpenses" roleURI="http://www.deepisolationnuclear.com/role/AccruedExpenses">
        <link:definition>9952164 - Disclosure - Accrued Expenses</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RelatedPartyTransactions" roleURI="http://www.deepisolationnuclear.com/role/RelatedPartyTransactions">
        <link:definition>9952165 - Disclosure - Related Party Transactions</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="IncomeTax" roleURI="http://www.deepisolationnuclear.com/role/IncomeTax">
        <link:definition>9952166 - Disclosure - Income Tax</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="EmployeeBenefits401kPlan" roleURI="http://www.deepisolationnuclear.com/role/EmployeeBenefits401kPlan">
        <link:definition>9952167 - Disclosure - Employee Benefits &#8211; 401(k) Plan</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="StockBasedCompensation" roleURI="http://www.deepisolationnuclear.com/role/StockBasedCompensation">
        <link:definition>9952168 - Disclosure - Stock-Based Compensation</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LossPerCommonShare" roleURI="http://www.deepisolationnuclear.com/role/LossPerCommonShare">
        <link:definition>9952169 - Disclosure - Loss Per Common Share</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SegmentReporting" roleURI="http://www.deepisolationnuclear.com/role/SegmentReporting">
        <link:definition>9952170 - Disclosure - Segment Reporting</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CommitmentsandContingencies" roleURI="http://www.deepisolationnuclear.com/role/CommitmentsandContingencies">
        <link:definition>9952171 - Disclosure - Commitments and Contingencies</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SubsequentEvents" roleURI="http://www.deepisolationnuclear.com/role/SubsequentEvents">
        <link:definition>9952172 - Disclosure - Subsequent Events</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="BasisofPresentationandSummaryofSignificantAccountingPoliciesPolicies" roleURI="http://www.deepisolationnuclear.com/role/BasisofPresentationandSummaryofSignificantAccountingPoliciesPolicies">
        <link:definition>9955511 - Disclosure - Basis of Presentation and Summary of Significant Accounting Policies (Policies)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ReverseMergerTables" roleURI="http://www.deepisolationnuclear.com/role/ReverseMergerTables">
        <link:definition>9955512 - Disclosure - Reverse Merger (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RevenueRecognitionTables" roleURI="http://www.deepisolationnuclear.com/role/RevenueRecognitionTables">
        <link:definition>9955513 - Disclosure - Revenue Recognition (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="PropertyPlantandEquipmentNetTables" roleURI="http://www.deepisolationnuclear.com/role/PropertyPlantandEquipmentNetTables">
        <link:definition>9955514 - Disclosure - Property, Plant and Equipment, Net (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="IntangibleAssetsTables" roleURI="http://www.deepisolationnuclear.com/role/IntangibleAssetsTables">
        <link:definition>9955515 - Disclosure - Intangible Assets (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LeasesTables" roleURI="http://www.deepisolationnuclear.com/role/LeasesTables">
        <link:definition>9955516 - Disclosure - Leases (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="AccruedExpensesTables" roleURI="http://www.deepisolationnuclear.com/role/AccruedExpensesTables">
        <link:definition>9955517 - Disclosure - Accrued Expenses (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RelatedPartyTransactionsTables" roleURI="http://www.deepisolationnuclear.com/role/RelatedPartyTransactionsTables">
        <link:definition>9955518 - Disclosure - Related Party Transactions (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="StockBasedCompensationTables" roleURI="http://www.deepisolationnuclear.com/role/StockBasedCompensationTables">
        <link:definition>9955519 - Disclosure - Stock-Based Compensation (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LossPerCommonShareTables" roleURI="http://www.deepisolationnuclear.com/role/LossPerCommonShareTables">
        <link:definition>9955520 - Disclosure - Loss Per Common Share (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SegmentReportingTables" roleURI="http://www.deepisolationnuclear.com/role/SegmentReportingTables">
        <link:definition>9955521 - Disclosure - Segment Reporting (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="NatureofOperationsDetails" roleURI="http://www.deepisolationnuclear.com/role/NatureofOperationsDetails">
        <link:definition>9955522 - Disclosure - Nature of Operations (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="BasisofPresentationandSummaryofSignificantAccountingPoliciesDetails" roleURI="http://www.deepisolationnuclear.com/role/BasisofPresentationandSummaryofSignificantAccountingPoliciesDetails">
        <link:definition>9955523 - Disclosure - Basis of Presentation and Summary of Significant Accounting Policies (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ReverseMergerNarrativeDetails" roleURI="http://www.deepisolationnuclear.com/role/ReverseMergerNarrativeDetails">
        <link:definition>9955524 - Disclosure - Reverse Merger - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ReverseMergerScheduleofNumberofSharesofCommonStockIssuedandOutstandingDetails" roleURI="http://www.deepisolationnuclear.com/role/ReverseMergerScheduleofNumberofSharesofCommonStockIssuedandOutstandingDetails">
        <link:definition>9955525 - Disclosure - Reverse Merger - Schedule of Number of Shares of Common Stock Issued and Outstanding (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RevenueRecognitionScheduleofRevenuebyContractTypeDetails" roleURI="http://www.deepisolationnuclear.com/role/RevenueRecognitionScheduleofRevenuebyContractTypeDetails">
        <link:definition>9955526 - Disclosure - Revenue Recognition - Schedule of Revenue by Contract Type (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RevenueRecognitionNarrativeDetails" roleURI="http://www.deepisolationnuclear.com/role/RevenueRecognitionNarrativeDetails">
        <link:definition>9955527 - Disclosure - Revenue Recognition - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RevenueRecognitionScheduleofChangesinContractAssetsDetails" roleURI="http://www.deepisolationnuclear.com/role/RevenueRecognitionScheduleofChangesinContractAssetsDetails">
        <link:definition>9955528 - Disclosure - Revenue Recognition - Schedule of Changes in Contract Assets (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RevenueRecognitionScheduleofAllowanceforCreditLossesDetails" roleURI="http://www.deepisolationnuclear.com/role/RevenueRecognitionScheduleofAllowanceforCreditLossesDetails">
        <link:definition>9955529 - Disclosure - Revenue Recognition - Schedule of Allowance for Credit Losses (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="PropertyPlantandEquipmentNetScheduleofPropertyPlantandEquipmentNetDetails" roleURI="http://www.deepisolationnuclear.com/role/PropertyPlantandEquipmentNetScheduleofPropertyPlantandEquipmentNetDetails">
        <link:definition>9955530 - Disclosure - Property, Plant and Equipment, Net - Schedule of Property, Plant and Equipment, Net (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="PropertyPlantandEquipmentNetNarrativeDetails" roleURI="http://www.deepisolationnuclear.com/role/PropertyPlantandEquipmentNetNarrativeDetails">
        <link:definition>9955531 - Disclosure - Property, Plant and Equipment, Net - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="IntangibleAssetsScheduleofIntangibleAssetsDetails" roleURI="http://www.deepisolationnuclear.com/role/IntangibleAssetsScheduleofIntangibleAssetsDetails">
        <link:definition>9955532 - Disclosure - Intangible Assets - Schedule of Intangible Assets (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="IntangibleAssetsNarrativeDetails" roleURI="http://www.deepisolationnuclear.com/role/IntangibleAssetsNarrativeDetails">
        <link:definition>9955533 - Disclosure - Intangible Assets - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="IntangibleAssetsScheduleofExpectedFutureAmortizationforOurDefiniteLivedIntangibleAssetsDetails" roleURI="http://www.deepisolationnuclear.com/role/IntangibleAssetsScheduleofExpectedFutureAmortizationforOurDefiniteLivedIntangibleAssetsDetails">
        <link:definition>9955534 - Disclosure - Intangible Assets - Schedule of Expected Future Amortization for Our Definite-Lived Intangible Assets (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="StockholdersEquityDetails" roleURI="http://www.deepisolationnuclear.com/role/StockholdersEquityDetails">
        <link:definition>9955535 - Disclosure - Stockholders' Equity (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LeasesScheduleofLeaseCostDetails" roleURI="http://www.deepisolationnuclear.com/role/LeasesScheduleofLeaseCostDetails">
        <link:definition>9955536 - Disclosure - Leases - Schedule of Lease Cost (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LeasesScheduleofSupplementalInformationDetails" roleURI="http://www.deepisolationnuclear.com/role/LeasesScheduleofSupplementalInformationDetails">
        <link:definition>9955537 - Disclosure - Leases - Schedule of Supplemental Information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LeasesScheduleofFutureMinimumLeasePaymentsDetails" roleURI="http://www.deepisolationnuclear.com/role/LeasesScheduleofFutureMinimumLeasePaymentsDetails">
        <link:definition>9955538 - Disclosure - Leases - Schedule of Future Minimum Lease Payments (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LeasesScheduleofFutureMinimumLeasePaymentsDetails_1" roleURI="http://www.deepisolationnuclear.com/role/LeasesScheduleofFutureMinimumLeasePaymentsDetails_1">
        <link:definition>9955538 - Disclosure - Leases - Schedule of Future Minimum Lease Payments (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LeasesScheduleofSupplementalCashFlowandOtherInformationDetails" roleURI="http://www.deepisolationnuclear.com/role/LeasesScheduleofSupplementalCashFlowandOtherInformationDetails">
        <link:definition>9955539 - Disclosure - Leases - Schedule of Supplemental Cash Flow and Other Information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="AccruedExpensesScheduleofAccruedExpensesDetails" roleURI="http://www.deepisolationnuclear.com/role/AccruedExpensesScheduleofAccruedExpensesDetails">
        <link:definition>9955540 - Disclosure - Accrued Expenses - Schedule of Accrued Expenses (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RelatedPartyTransactionsNarrativeDetails" roleURI="http://www.deepisolationnuclear.com/role/RelatedPartyTransactionsNarrativeDetails">
        <link:definition>9955541 - Disclosure - Related Party Transactions - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="RelatedPartyTransactionsScheduleofRelatedPartyActivitiesDetails" roleURI="http://www.deepisolationnuclear.com/role/RelatedPartyTransactionsScheduleofRelatedPartyActivitiesDetails">
        <link:definition>9955542 - Disclosure - Related Party Transactions - Schedule of Related Party Activities (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="IncomeTaxNarrativeDetails" roleURI="http://www.deepisolationnuclear.com/role/IncomeTaxNarrativeDetails">
        <link:definition>9955543 - Disclosure - Income Tax - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="EmployeeBenefits401kPlanDetails" roleURI="http://www.deepisolationnuclear.com/role/EmployeeBenefits401kPlanDetails">
        <link:definition>9955544 - Disclosure - Employee Benefits &#8211; 401(k) Plan (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="StockBasedCompensationNarrativeDetails" roleURI="http://www.deepisolationnuclear.com/role/StockBasedCompensationNarrativeDetails">
        <link:definition>9955545 - Disclosure - Stock-Based Compensation - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="StockBasedCompensationScheduleofStockOptionsDetails" roleURI="http://www.deepisolationnuclear.com/role/StockBasedCompensationScheduleofStockOptionsDetails">
        <link:definition>9955546 - Disclosure - Stock-Based Compensation - Schedule of Stock Options (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="StockBasedCompensationScheduleofFairValueofOptionsGrantedBasedonAssumptionsDetails" roleURI="http://www.deepisolationnuclear.com/role/StockBasedCompensationScheduleofFairValueofOptionsGrantedBasedonAssumptionsDetails">
        <link:definition>9955547 - Disclosure - Stock-Based Compensation - Schedule of Fair Value of Options Granted Based on Assumptions (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="StockBasedCompensationScheduleoftheCompanysRSUActivityDetails" roleURI="http://www.deepisolationnuclear.com/role/StockBasedCompensationScheduleoftheCompanysRSUActivityDetails">
        <link:definition>9955548 - Disclosure - Stock-Based Compensation - Schedule of the Company&#8217;s RSU Activity (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LossPerCommonShareScheduleofLossAndAverageShareAmountsUsedToComputeBothBasicAndDilutedEarningsPerShareDetails" roleURI="http://www.deepisolationnuclear.com/role/LossPerCommonShareScheduleofLossAndAverageShareAmountsUsedToComputeBothBasicAndDilutedEarningsPerShareDetails">
        <link:definition>9955549 - Disclosure - Loss Per Common Share - Schedule of Loss And Average Share Amounts Used To Compute Both Basic And Diluted Earnings Per Share (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LossPerCommonShareScheduleofAntidilutiveSecuritiesDetails" roleURI="http://www.deepisolationnuclear.com/role/LossPerCommonShareScheduleofAntidilutiveSecuritiesDetails">
        <link:definition>9955550 - Disclosure - Loss Per Common Share - Schedule of Anti-dilutive Securities (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SegmentReportingNarrativeDetails" roleURI="http://www.deepisolationnuclear.com/role/SegmentReportingNarrativeDetails">
        <link:definition>9955551 - Disclosure - Segment Reporting - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SegmentReportingScheduleofIncomeStatementsbySegmentSignificantSegmentExpensesandSegmentAssetsDetails" roleURI="http://www.deepisolationnuclear.com/role/SegmentReportingScheduleofIncomeStatementsbySegmentSignificantSegmentExpensesandSegmentAssetsDetails">
        <link:definition>9955552 - Disclosure - Segment Reporting - Schedule of Income Statements by Segment, Significant Segment Expenses, and Segment Assets (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SegmentReportingScheduleofNetSalesbyGeographicAreaDetails" roleURI="http://www.deepisolationnuclear.com/role/SegmentReportingScheduleofNetSalesbyGeographicAreaDetails">
        <link:definition>9955553 - Disclosure - Segment Reporting - Schedule of Net Sales by Geographic Area (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SegmentReportingScheduleofLongLivedAssetsbyGeographicAreaDetails" roleURI="http://www.deepisolationnuclear.com/role/SegmentReportingScheduleofLongLivedAssetsbyGeographicAreaDetails">
        <link:definition>9955554 - Disclosure - Segment Reporting - Schedule of Long-Lived Assets by Geographic Area (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SegmentReportingScheduleofCustomerConcentrationRiskDetails" roleURI="http://www.deepisolationnuclear.com/role/SegmentReportingScheduleofCustomerConcentrationRiskDetails">
        <link:definition>9955555 - Disclosure - Segment Reporting - Schedule of Customer Concentration Risk (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
    </xs:appinfo>
  </xs:annotation>
  <xs:element id="din_SeriesAConvertiblePreferredStockMember" abstract="true" name="SeriesAConvertiblePreferredStockMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="din_SeriesAPrimeConvertiblePreferredStockMember" abstract="true" name="SeriesAPrimeConvertiblePreferredStockMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="din_StockIssuedDuringPeriodSharesStockOptionsExercisedAndDistributionOfRestrictedStock" abstract="false" name="StockIssuedDuringPeriodSharesStockOptionsExercisedAndDistributionOfRestrictedStock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="din_StockIssuedDuringPeriodValueStockOptionsExercisedAndDistributionOfRestrictedStock" abstract="false" name="StockIssuedDuringPeriodValueStockOptionsExercisedAndDistributionOfRestrictedStock" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="din_IncreaseDecreaseInAccountsReceivableAllowanceForCreditLoss" abstract="false" name="IncreaseDecreaseInAccountsReceivableAllowanceForCreditLoss" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="din_ReverseMergerTextBlock" abstract="false" name="ReverseMergerTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="din_ScheduleOfAllowanceForCreditLossesForContractAssetTableTextBlock" abstract="false" name="ScheduleOfAllowanceForCreditLossesForContractAssetTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="din_BasisofPresentationandSummaryofSignificantAccountingPoliciesDetailsTable" abstract="true" name="BasisofPresentationandSummaryofSignificantAccountingPoliciesDetailsTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="din_NumberOfIdentifiableAssets" abstract="false" name="NumberOfIdentifiableAssets" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="din_RecognizedTaxBenefitPercentage" abstract="false" name="RecognizedTaxBenefitPercentage" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="din_FairValuePercentage" abstract="false" name="FairValuePercentage" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="din_ReverseMergerDetailsTable" abstract="true" name="ReverseMergerDetailsTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="din_StockholdersMember" abstract="true" name="StockholdersMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="din_TwoThousandEighteenIncentivePlanMember" abstract="true" name="TwoThousandEighteenIncentivePlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="din_TwoThousandTwentyFivePlanMember" abstract="true" name="TwoThousandTwentyFivePlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="din_PrivatePlacementOfferingMember" abstract="true" name="PrivatePlacementOfferingMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="din_AWarrantsMember" abstract="true" name="AWarrantsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="din_BWarrantsMember" abstract="true" name="BWarrantsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="din_ReverseMergerDetailsLineItems" abstract="true" name="ReverseMergerDetailsLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="din_CommonStockHeldByStockholders" abstract="false" name="CommonStockHeldByStockholders" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="din_InitialOfferingCost" abstract="false" name="InitialOfferingCost" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="din_ReverseMergerScheduleofNumberofSharesofCommonStockIssuedandOutstandingDetailsTable" abstract="true" name="ReverseMergerScheduleofNumberofSharesofCommonStockIssuedandOutstandingDetailsTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="din_DeepIsolationConvertedToDeepIsolationNuclearStockMember" abstract="true" name="DeepIsolationConvertedToDeepIsolationNuclearStockMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="din_IssuedInOfferingMember" abstract="true" name="IssuedInOfferingMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="din_AspenOutstandingPriorToMergerMember" abstract="true" name="AspenOutstandingPriorToMergerMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="din_AdvisorSharesMember" abstract="true" name="AdvisorSharesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="din_GrantRevenueMember" abstract="true" name="GrantRevenueMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="din_RemediationAdministrativeAndConsultingServicesAndOtherRevenueMember" abstract="true" name="RemediationAdministrativeAndConsultingServicesAndOtherRevenueMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="din_ContractWithCustomerAssetRevenueRecognizedButNotYetBilled" abstract="false" name="ContractWithCustomerAssetRevenueRecognizedButNotYetBilled" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="din_BilledAndTransferredToReceivables" abstract="false" name="BilledAndTransferredToReceivables" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="din_AccountsReceivableAllowanceForCreditLossWriteoffAfterRecovery" abstract="false" name="AccountsReceivableAllowanceForCreditLossWriteoffAfterRecovery" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="din_IntangibleAssetsDetailsTable" abstract="true" name="IntangibleAssetsDetailsTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="din_StockholdersEquityDetailsTable" abstract="true" name="StockholdersEquityDetailsTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="din_A2018PlanMember" abstract="true" name="A2018PlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="din_AssumedOptionsMember" abstract="true" name="AssumedOptionsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="din_StockholdersEquityDetailsLineItems" abstract="true" name="StockholdersEquityDetailsLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="din_CommonStockVotingRightsNumberOfVotesPerEachShare" abstract="false" name="CommonStockVotingRightsNumberOfVotesPerEachShare" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="din_ClassOfWarrantOrRightExercised" abstract="false" name="ClassOfWarrantOrRightExercised" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="din_RightOfUseAssetsObtainedInExchangeForLeaseObligationsAbstract" abstract="true" name="RightOfUseAssetsObtainedInExchangeForLeaseObligationsAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="din_AccruedLegalFeesCurrent" abstract="false" name="AccruedLegalFeesCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="din_AccruedResearchAndDevelopmentExpensesCurrent" abstract="false" name="AccruedResearchAndDevelopmentExpensesCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="din_AccruedFranchiseTaxesCurrent" abstract="false" name="AccruedFranchiseTaxesCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="din_AccruedSubcontractorCostCurrent" abstract="false" name="AccruedSubcontractorCostCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="din_AccruedPropertyPlantAndEquipmentCurrent" abstract="false" name="AccruedPropertyPlantAndEquipmentCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="din_DBDCMember" abstract="true" name="DBDCMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="din_NACMember" abstract="true" name="NACMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="din_DFIMember" abstract="true" name="DFIMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="din_RelatedPartyReceivablesRollForward" abstract="true" name="RelatedPartyReceivablesRollForward" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="din_RelatedPartyPayablesRollForward" abstract="true" name="RelatedPartyPayablesRollForward" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="din_IncentiveStockOptionsMember" abstract="true" name="IncentiveStockOptionsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="din_PerformanceStockUnitsMember" abstract="true" name="PerformanceStockUnitsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="din_PercentageOfStockOptionsGranted" abstract="false" name="PercentageOfStockOptionsGranted" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="din_PecentageOfIncentiveStockOptionsGrantedToStockholder" abstract="false" name="PecentageOfIncentiveStockOptionsGrantedToStockholder" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="din_PercentageOfISOGrantedToNonStockholder" abstract="false" name="PercentageOfISOGrantedToNonStockholder" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="din_PercentageOfFairMarketValueAtTimeOfGrant" abstract="false" name="PercentageOfFairMarketValueAtTimeOfGrant" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="din_CommonStockIncreaseInCapitalSharesReservedForFutureIssuance" abstract="false" name="CommonStockIncreaseInCapitalSharesReservedForFutureIssuance" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="din_FourCustomersMember" abstract="true" name="FourCustomersMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="din_DeepIsolationUSEMEAMember" abstract="true" name="DeepIsolationUSEMEAMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="din_FreestoneMember" abstract="true" name="FreestoneMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="din_U.S.DepartmentOfEnergyMember" abstract="true" name="U.S.DepartmentOfEnergyMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="din_U.S.TradeAndDevelopmentAgencyMember" abstract="true" name="U.S.TradeAndDevelopmentAgencyMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="din_CPCCOMember" abstract="true" name="CPCCOMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="din_OkloMember" abstract="true" name="OkloMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="din_H2CFormerlyWRPSMember" abstract="true" name="H2CFormerlyWRPSMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
</xs:schema>
