1 Preparing a decommissioning project H. Sterner E. Thurow Energiewerke Nord GmbH H. Sterner; E. Thurow, EWN, chapter 1

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  • 1 Preparing a decommissioning project H. Sterner E. Thurow Energiewerke Nord GmbH H. Sterner; E. Thurow, EWN, chapter 1
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  • 2 Company EWN View of the Greifswald NPP Site
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  • 3 Company EWN Basic data on the reactor units
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  • 4 Company EWN Dismantling project Project Facts Objective:green field site reuse Duration:1995 2012 Dismantling Masses:1.800 Mio Mg Spent Fuel:5037 elements
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  • 5 Company EWN State of dismantling/disposal unrestricted material suspected/contaminated material (turbine hall) (reactor building) (other places) (09/2002) Mg
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  • 6 Company EWN Site reuse - vision
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  • 7 Preparing a decommissioning project Introductory Remarks 1.1Fundamentals 1.2Project analysis 1.3Technical concept 1.4Decommissioning plan 1.5Licensing aspects 1.6Financial aspects 1.7Social aspects Contents of presentation
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  • 8 Introduction Decommissioning reasons achieving of planned designed life time less actual life time than planned high maintenance and operational costs future costs can not be calculated safety uncertainties material aging incident political decision
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  • 9 Introduction Decommissioning final phase in life-cycle of nuclear facility objective:exemption / removal from regulatory control activities:decontamination, dismantling, demolition, fuel/waste/material disposal..... consideration: health and safety of personnel and public, preservation of environment
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  • 10 Basic considerations Decommissioning strategy Financing Technical Waste Management Fuel Management Social
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  • 11 Boundary conditions acceptance by authority and public legal/licensing constrictions specific local conditions political : technical : plant and site conditions plant design availability of fuel storages waste management possibilities and disposal options
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  • 12 Boundary conditions financial : availability of budget cash flow personnel age and competence personnel strategy integration in project privatisation strategy social :
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  • 13 Project objectives implementation of project minimum risk as cheap as possible (i.e. generally also as fast as possible) socially acceptable
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  • 14 Project objectives Example of derived criteria fulfilment of safety criteria minimum costs maximum use of own personnel and local companies site reuse know-how transfer privatisation
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  • 15 Project objectives Safety criteria guarantee nuclear safety - undercriticality - cooling guarantee appropriate radiation protection - limit dose commitment (ALARA) conventional workers safety release of radioactivity below licensed levels
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  • 16 Project analysis evaluation of the project under all boundary conditions, considering feasible alternatives determination of main project tasks and necessary investments determination of main conditions and basic time schedule determination of requirements on personnel (qualification and number) Objectives of project analysis
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  • 17 Project analysis spent fuel management (and fresh fuel if present) waste management dismantling strategy mass flow logistic post operation personnel strategy site reuse options Main issues of the project analysis
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  • 18 Project analysis main dependencies between project activities mile stones and overall project life time key decision plan (with arguments) Result of the project analysis
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  • 19 Project analysis direct dismantling instead of safe enclosure necessity of a new dry spent fuel storage necessity of an interim storage with treatment capabilities for radioactive material from dismantling due to lack of final disposal capacities license for decommissioning and dismantling instead of operation license prolongation preferable project realisation by own staff instead of contractors site reuse for industrial activities instead of green field Example:Key decisions by EWN
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  • 20 Project analysis
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  • 21 Decommissioning variants operation post operational phase decommissioning variant establish safe enclosure safe enclosure complete dismantling complete immediate dismantling 1 2
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  • 22 Decommissioning variants planning 4 a ~ 30 a12 - 14 a operational licencedecommissioning licence safe enclosure operation 3-5 a2-3 a variant 1: safe enclosure post operation realisation safe enclosure operation 3-5 a12 - 14 a variant 2: immediate dismantling post operation immediate dismantling shutdown
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  • 23 Decommissioning variants activity reduction by radioactive decay timely postponement of investments progress in decontamination technique Safe enclosure - advantage:
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  • 24 Decommissioning variants qualified plant personnel is not available possible negative effects on public extensive backfitting necessary safe enclosure dismantling technical infrastructure is not usable radiological problems due to decay of Co-60 Safe enclosure - disadvantage:
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  • 25 Project analysis
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  • 26 Dismantling controlled area unit 1 Transport steam generator No. 5 from the steam generator room via reactor hall to the interim storage
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  • 27 Dismantling in the steam generator room unit 1
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  • 28 Project analysis
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  • 29 ISN cross section storage for spent fuel and interim/decay storage for radioactive material storage area 20.000m dimension l. 240m x w. 140m x h. 18m halls 1-7radioactive material: - 20-containers - cast iron containers - concrete containers - steel containers - casks (cast iron) - large components hall 8spent fuel in CASTOR casks masseshalls 1-7approx. 110.000Mg hall 8585Mg (heavy metal)
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  • 30 Interim Storage North
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  • 31 Project analysis
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  • 32 Site reuse
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  • 33 Technical concept General main issues main decommissioning and dismantling steps dismantling principles operational waste management categorisation of systems/buildings/areas by radiological classes inventory mass flow logistic (from dismantling) main items of partial plant adaptation main items of investments (new equipment) special dismantling and disposal concept for highly activated components safe post operation, evaluation of the residual life time of old equipment possibilities to reduce operational costs
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  • 34 Technical concept EWN table of content 1.Introduction 2.Site and buildings description 3.Present status 4.Decommissioning and dismantling activities 5.Decontamination methods 6.Emissions 7.Material flow and waste management 8.Radiological protection 9.Declassification 10.Necessary new installations and systems 11.Fire protection 12.Workers protection 13.Plant security 14.Infrastructure 15.Safety case 16.Environmental impact assessment
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  • 35 Technical concept EWN - dismantling principles as large components / parts as possible for treatment in our warm workshop or interim storage dismantling planning on system basic, execution on room basis start in unit 5; low contamination / radiation dose from low to high contamination / radiation dose use market equipment in situ decontamination only for dose reduction
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  • 36 Technical concept EWN - main direction of dismantling
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  • 37 Technical concept Plant inventory Systems and other components on a room-by-room basis Masses and material types (on a room- and system-basis) Contamination in rooms and systems (including estimation of contamination penetration in concrete structures) Dose rates, including ambient rates in rooms, hot spots, and at large components Hazardous materials (Asbestos, PCB etc.)
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  • 38 Technical concept Categorisation by radiological classes Category I- unrestricted material Category II- suspected material (an eventual contamination cannot be excluded) Category III- contaminated material
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  • 39 Technical concept Categorisation by radiological classes EWN - example Estimated masses for different contamination categories in the turbine hall units 1 4 Category Iunrestricted material ca. 45 % Category IIsuspected materialca. 53 % Category IIIcontaminated materialca. 2 %
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  • 40 Technical concept Classification of systems ISystems necessary for nuclear safety and radiation protection IISystems necessary for industrial safety and operation IIINot necessary systems
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  • 41 Technical concept WWER 440 - classification of systems SystemUnit System Category Remarks Post Operation Preparation Safe Enclosure Safe Enclosure ventilation for reactor- and auxiliary building 1, 2, 3, 4III Capacity reduction, Adaptation and/or Installation of new Ventilation systems water cleaning system 2 (SVO-2) 1/2 3/4 III water cleaning system 3 (SVO-3) including sew

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