Chauvin, D.

Leichtle, D.

Pinna, T.

English

KITopen

KIT – The Research University in the Helmholtz Association www.kit.eduRadiological Protection Design Considerations for DEMOD. Leichtlea, D. Chauvinb, T. Pinnaca Karlsruhe Institute of Technology (KIT), Karlsruhe, GermanybEUROfusion – Programme Management Unit, Garching, GermanycENEA, FSN Deparatment, Frascati, ItalyD. Leichtle, Radiological Protection Design Considerations for DEMOISFNT-15September 2023, Las Palmas de Gran CanariaMotivationPrinciples of Radiological ProtectionApproach to Radiological Protection in the Design PhaseRadiological Protection Design GuidelineConclusions2Content12 Sep 2023D. Leichtle, Radiological Protection Design Considerations for DEMOISFNT-15September 2023, Las Palmas de Gran CanariaITER will be the first operating fusion facility under nuclear regulation. Lessons learnt from safety implementation and licensing.Radiological protection objectives are key challenges consideringplant performance, safety and regulatory constraints.High neutron/gamma radiation fields from various distributed sources, high inventories of Tritium and radioactive substances.Underestimation of radiological protection issues based on preliminary andincomplete design data.Design for shielding provisions complicated by evolving plant/system design.Radiological protection objectives and radiation induced issues arepotential (safety) design driversRequires evolving nuclear design process with ALARA integration at earlydesign phase.3Motivation12 Sep 2023D. Leichtle, Radiological Protection Design Considerations for DEMOISFNT-15September 2023, Las Palmas de Gran Canaria12 Sep 20234Principles of Radiological ProtectionD. Leichtle, Radiological Protection Design Considerations for DEMOISFNT-15September 2023, Las Palmas de Gran Canaria5Principles of Radiological Protection12 Sep 2023Source-related and in all exposure situationsJustificationAny decision which alters the radiation exposure situation should do more good than harm.OptimizationThe likelihood of incurring exposures, the number of people exposed, and the magnitude of their individual doses should all be kept as low as reasonably achievable, taking into account economic and societal factors.Individual-related and in planned exposure situationsLimitationThe total dose to any individual from regulated sources in planned exposure situations (other than medical exposure of patients) should not exceed the appropriate limits.D. Leichtle, Radiological Protection Design Considerations for DEMOISFNT-15September 2023, Las Palmas de Gran Canaria6Towards a Comprehensive RP Programme12 Sep 2023Comprehensive administrative and technical measures to design, operate, maintain and dismantle the facility from a radiological protectionperspective.Basis to identify, minimize and limit radiation hazards and exposure toionizing radiation.Covers the full project life-cycle from design to decommissioning. Develop and implement at (early) design phase.Provide sound basis to implement principles of radiological protectioninto organisational and technical processes.D. Leichtle, Radiological Protection Design Considerations for DEMOISFNT-15September 2023, Las Palmas de Gran CanariaExternal radiation exposure from various sourcesFusion plasmaActivated structuresActivated liquids (water, PbLi)Activated dustActivated corrosion productsRadiological wasteRadiation sources from monitoring, diagnostics, H&CDRadonInternal radiation exposure from air-borne sourcesTritiumActivated dustActivated corrosion productsHazards of Exposure to Ionizing Radiation7 12 Sep 2023D. Leichtle, Radiological Protection Design Considerations for DEMOISFNT-15September 2023, Las Palmas de Gran Canaria12 Sep 20238Approach to Radiological Protectionin the Design PhaseD. Leichtle, Radiological Protection Design Considerations for DEMOISFNT-15September 2023, Las Palmas de Gran Canaria9Relevant DEMO ObjectivesStakeholder requirements define DEMO plant performanceobjectives, such asDemonstration of electricity production: typically 300 MWe.Extrapolability of availability (DEMO 30%) to commercial FPP: e.g. 60-90%.Estimation of future full life-cylce economic potential of FPP.Similarly, favourable safety and environmental protection is to bedemonstrated, such asSafety functions are maintained in all situations.Exposure to hazards are controlled, kept below limits and as low asreasonably achievable.12 Sep 2023Radiological protection is implemented through the safety function„Limitiation of exposure to ionizing radiation“D. Leichtle, Radiological Protection Design Considerations for DEMOISFNT-15September 2023, Las Palmas de Gran Canaria10Radiological Protection at Design Stage12 Sep 2023Normal operation inherently covers preventive maintenance and inspection (M&I) activities to operate and maintain the facility in safe conditions.Design for Maintenance (as plant driver)Few key elements specifically relevant for Radiological ProtectionRisk and hazard identificationInventory of radiation sources incl. activation sourcesRadiation and contamination mapping.Maintenance strategyMaintenance inventoriesMaintenance types (preventive, incl. inspections, corrective and logistics)Radiological protection design guideline and ALARA design processD. Leichtle, Radiological Protection Design Considerations for DEMOISFNT-15September 2023, Las Palmas de Gran Canaria11Design Implementation of RP Objectives12 Sep 2023Radiological protection is a challenge …Impact on plant performance, integration, maintenance, safety, licensing …Complexity of exposure scenarios (sources, configurations, work places …)Requirements affect DEMO plant across PBSPlant and functional breakdown structure for identification of transversal functions withdedicated requirements, contraints and interfaces.Maintenance Plant availabilityMaterials Material choices (outside civil works)Nuclear Integration Radiation protection issuesVacuum Vacuum needs (outside fuel cycle)Tritium Tritium related issues (outside fuel cycle and breeding blanket)DEMO Transversal FunctionsRadiological protection design is a highly transversal activityD. Leichtle, Radiological Protection Design Considerations for DEMOISFNT-15September 2023, Las Palmas de Gran Canaria12RP: Maintenance Strategy12 Sep 2023Starting point: Maintenance inventoryMaintenance items: based on DEMO PBS and SSC listMaintenance environment: room book data, plant layout (GBS)Definition of Maintenance StrategyPreventive Maintenance: any planned and predefined activity aiming to maintain the function of a SSC at the high level of required performance, quality and safety.Corrective Maintenance: any unplanned (and undefined) activity due to failure, aiming to restore the function of the failed SSC at the high level of required performance, quality and safety.D. Leichtle, Radiological Protection Design Considerations for DEMOISFNT-15September 2023, Las Palmas de Gran Canaria13RP: Nuclear Integration12 Sep 2023Starting point: Protection requirements, inventories, shieldingarchitectureInvestment and occupational exposure protectionInventories of radiation source terms (including activation sources), SSC withshielding performancesDefinition of generic shielding architecture (tokamak, nuclear building)Nuclear design supportNuclear analyses (including V&V) in support of plant architecture and systemdesignIntegration of radiological protection design activities in design processesRadiological protection design guideline and ALARA design processD. Leichtle, Radiological Protection Design Considerations for DEMOISFNT-15September 2023, Las Palmas de Gran Canaria14Radiological Protection&Shielding Requirements12 Sep 2023Generic Safety RequirementsRequirement 81: Design for radiation protectionIdentification and control of radiation sourceSelection of materials to minimize activation ALARPAccess control and further prevention/mitigation of exposureRadiological zoningRequirement 5: Radiation protection in designEstablishment of acceptable limits consistent with regulatoryrequirementsRequirement 9: Proven engineering practicesDesign of safety important components according tonational/international codes and standards.D. Leichtle, Radiological Protection Design Considerations for DEMOISFNT-15September 2023, Las Palmas de Gran Canaria15DEMO Radiological Protection Req.12 Sep 2023Dose limitsRadiological zoningD. Leichtle, Radiological Protection Design Considerations for DEMOISFNT-15September 2023, Las Palmas de Gran Canaria12 Sep 202316Radiological Protection Design GuidelineD. Leichtle, Radiological Protection Design Considerations for DEMOISFNT-15September 2023, Las Palmas de Gran Canaria17 12 Sep 2023Preliminary Items of a DEMO RPD Guideline Purpose of the guidelineIntroducing a Radiological Protectionpolicy to raise awareness, stipulatecommitment to responsibilities and tosupport the general safety culture.Defining relevant high level design principles/recommendations and activities.Prepare for a formalized ALARA design process.Radiological Protection Design GuidelineDesign principlesGlobal shieldingapproachSource controlShieldingprioritiesMaterial choicesRecommendationsDesign activitiesNuclearanalysesDesign changeand controlDesign reviewandconfigurationcontrolALARA processMaintenance planRadiation mappingORE methodologyDose reductionfactorsSelectioncriteriaRP policy Safety/regulatory constraintsD. Leichtle, Radiological Protection Design Considerations for DEMOISFNT-15September 2023, Las Palmas de Gran Canaria18General Aspects for Integrated Shielding Design12 Sep 2023Identification of all relevant radiation source terms: particle, energy, source strength, location, distribution …Protection priorities and hierarchyShielding from the source(s)Improve weak shield capabilities of the primary shieldsApply primary shields to (potentially) all radiation source termsD. Leichtle, Radiological Protection Design Considerations for DEMOISFNT-15September 2023, Las Palmas de Gran Canaria19General Aspects for Integrated Shielding Design12 Sep 2023Streaming and leakage mitigation, moderation, absorption, material tailoring and optimization.Shielding of port systems to reduce radiation levels inside the maintenance area.And concurrently: reduce the radiation cross talk and backscattering by enhanced absorption.Use of reduced activation materials.Permanent and temporary shields (during interventions)D. Leichtle, Radiological Protection Design Considerations for DEMOISFNT-15September 2023, Las Palmas de Gran Canaria20Shield Design Issues at DEMO Tokamak Shield12 Sep 2023Ports (and port plugs) contribute to the overall shielding objectives of the primary shield assembly.Assembly gaps between Blanket Segments.Number/size of ports and port openingsManufacturing, assembly and maintenance tolerancesShielding imperfections due to gaps, penetrations, backfilling, etc.D. Leichtle, Radiological Protection Design Considerations for DEMOISFNT-15September 2023, Las Palmas de Gran Canaria21Some Generic Design Recommendations12 Sep 2023Design for Maintainability with Radiological Protection background… start in conceptual design.… provide respective design margins.… focus on „shielding functions“ and „control of radiation sources“ concurrently.… consider „safety design“ broader, include Radiological Protection.… simplify, optimize and standardize design solutions to improvereliability (decrease maintenance needs).… include stakeholders (systems, transverse functions, …) in the design process.D. Leichtle, Radiological Protection Design Considerations for DEMOISFNT-15September 2023, Las Palmas de Gran Canaria22ALARA Design Implementation12 Sep 2023Practical ALARA implementation byContinuous, predictive and iterative process;Decision-aiding techniques to find the optimized protection solution;Suitable objective means to demonstrate and justify the correct implementation.Pre-requisites and inputsRAMI assessment and Maintenance&Inspection needs (as available)Maintenance plans/activities with hands-on work effortsFacility zoning and radiation mapping (room book data)Possible dose reduction factorsD. Leichtle, Radiological Protection Design Considerations for DEMOISFNT-15September 2023, Las Palmas de Gran Canaria23ALARA Design Implementation12 Sep 2023ALARA process involvesEvaluation of the exposure situation and selection of appropriate dose constraintsIdentification of protection options (or dose reduction factors)Analysis of options and selection of best option under prevailing circumstancesImplementation of selected optionFeedback from design and operations (RoX)D. Leichtle, Radiological Protection Design Considerations for DEMOISFNT-15September 2023, Las Palmas de Gran Canaria24DEMO RP status12 Sep 2023Radiological ProtectionRequirementsSystem EngineeringMaintenancePreliminary ORE assessmentsInventories, radiation sourcesRadwasteNeutronicsRadiation transport and activationRoom bookRemote HandlingSafetySystem DesignPlant ArchitectureD. Leichtle, Radiological Protection Design Considerations for DEMOISFNT-15September 2023, Las Palmas de Gran Canaria12 Sep 202325ConclusionsD. Leichtle, Radiological Protection Design Considerations for DEMOISFNT-15September 2023, Las Palmas de Gran Canaria26ConclusionsRadiological Protection (RP) is a major design driver for fusion facilities due toits global and transversal function and challenging design constraints.Its successful integration supports public acceptance of nuclear fusiontechnology.Implementation of technical and administrative measures at early design phaseis instrumental for a qualified life-cycle RP Programme.EU DEMO project addresses RP design via dedicated Transversal Functions. Nuclear design issues are adressed in a system engineering approach.Main elements are identified and progressively developed. Preliminary RP design guideline and ALARA process are in preparation.12 Sep 2023D. Leichtle, Radiological Protection Design Considerations for DEMOISFNT-15September 2023, Las Palmas de Gran Canaria27Thank you for your attention!AcknowledgementSuggestions/Ideas: C. Bachmann, U. Fischer, G. Federici, J. Elbez Uzan, P. CortesPictures/Data: Courtesy of C. Gliss, C. Bachmann and EUROfusion project12 Sep 2023“This work has been carried out within the framework of the EUROfusion Consortium, funded by the European Union via the Euratom Research and Training Programme (Grant Agreement No 101052200 — EUROfusion). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Commission. Neither the European Union nor the European Commission can be held responsible for them.”

Radiological Protection Design Considerations for DEMO

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Radiological Protection Design Considerations for DEMO

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