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Preparing a decommissioning project

Preparing a decommissioning project. H. Sterner E. Thurow Energiewerke Nord GmbH. H. Sterner; E. Thurow, EWN, chapter 1. Company EWN View of the Greifswald NPP Site. Company EWN Basic data on the reactor units. Company EWN Dismantling project. Project Facts Objective: green field

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Preparing a decommissioning project

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

  2. Company EWNView of the Greifswald NPP Site

  3. Company EWNBasic data on the reactor units

  4. Company EWNDismantling project Project Facts Objective: green field site reuse Duration: 1995 – 2012 Dismantling Masses: 1.800 Mio Mg Spent Fuel: 5037 elements

  5. Company EWNState of dismantling/disposal unrestricted material suspected/contaminated material (turbine hall) (reactor building) (other places) (09/2002) Mg

  6. Company EWNSite reuse - vision

  7. Preparing a decommissioning project Contents of presentation Introductory Remarks 1.1 Fundamentals 1.2 Project analysis 1.3 Technical concept 1.4 Decommissioning plan 1.5 Licensing aspects 1.6 Financial aspects 1.7 Social aspects

  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

  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

  10. Basic considerations • Decommissioning strategy • Financing • Technical • Waste Management • Fuel Management • Social

  11. Boundary conditions political: • acceptance by authority and public • legal/licensing constrictions • specific local conditions technical: • plant and site conditions • plant design • availability of fuel storages • waste management possibilities and disposal options

  12. Boundary conditions financial: • availability of budget • cash flow social: • personnel age and competence • personnel strategy • integration in project • privatisation strategy

  13. Project objectives • implementation of project • minimum risk • as cheap as possible (i.e. generally also as fast as possible) • socially acceptable

  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

  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

  16. Project analysis Objectives of 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)

  17. Project analysis Main issues of the project analysis • spent fuel management (and fresh fuel if present) • waste management • dismantling strategy • mass flow logistic • post operation • personnel strategy • site reuse options

  18. Project analysis Result of the project analysis • main dependencies between project activities • mile stones and overall project life time • key decision plan (with arguments)

  19. Project analysis Example:Key decisions by EWN • 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

  20. Project analysis

  21. operation post operational phase decommissioning variant 2 1 establishsafe enclosure complete immediate dismantling safe enclosure completedismantling Decommissioning variants

  22. Decommissioning variants operational licence decommissioning licence realisation post safe dismantling operation operation enclosure safe enclosure variant 1: safe enclosure 3-5 a 2-3 a ~ 30 a 12 - 14 a planning 4 a post immediate operation dismantling operation variant 2: immediate dismantling 3-5 a 12 - 14 a shutdown

  23. Decommissioning variants Safe enclosure - advantage: • activity reduction by radioactive decay • timely postponement of investments • progress in decontamination technique

  24. Decommissioning variants Safe enclosure - disadvantage: • 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

  25. Project analysis

  26. Dismantling controlled area unit 1 Transport steam generator No. 5 from the steam generator room via reactor hall to the interim storage

  27. Dismantling in the steam generator room unit 1

  28. Project analysis

  29. ISN – cross section storage for spent fuel and interim/decay storage for radioactive material storage area 20.000m² dimension l. 240m x w. 140m x h. 18m halls 1-7 radioactive material: - 20‘-containers- cast iron containers - concrete containers - steel containers - casks (cast iron) - large components hall 8 spent fuel in CASTOR casks masses halls 1-7 approx. 110.000Mg hall 8 585Mg (heavy metal)

  30. Interim Storage North

  31. Project analysis

  32. Site reuse

  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

  34. Technical conceptEWN table of content • Introduction • Site and buildings description • Present status • Decommissioning and dismantling activities • Decontamination methods • Emissions • Material flow and waste management • Radiological protection • Declassification • Necessary new installations and systems • Fire protection • Workers protection • Plant security • Infrastructure • Safety case • Environmental impact assessment

  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

  36. Technical conceptEWN - main direction of dismantling

  37. Technical conceptPlant 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.)

  38. Technical conceptCategorisation by radiological classes • Category I - unrestricted material • Category II - suspected material (an eventual contamination cannot be excluded) • Category III - contaminated material

  39. Technical conceptCategorisation by radiological classes EWN - example Estimated masses for different contamination categories in the turbine hall units 1 – 4 Category I unrestricted material ca. 45 % Category II suspected material ca. 53 % Category III contaminated material ca. 2 %

  40. Technical conceptClassification of systems I Systems necessary for nuclear safety and radiation protection II Systems necessary for industrial safety and operation III Not necessary systems

  41. Technical concept WWER 440 - classification of systems

  42. Technical conceptWaste and material management • Fuel • Operational waste • Dismantled material

  43. 235 252 unit 5 unit 4 unit 3 unit 2 unit 1 Fuel 0 0 245 0 584 0 578 221 3 pool (defect) Reactor 349 0 349 0 0 0 0 0 313 0 C - 30 252 in 3 CASTOR 440/84 in the unit 3/4 Wet Storage ZLN C - 30 CASTOR 2398 4547 Interim Storage 235 Sale (1996) Technical conceptEWN - fuel management 1990 1999

  44. Technical conceptEWN - waste management

  45. Plant Greifswald site 1.800.000 Mg Category I Not contaminated Ca. 1.235.000 Mg Category II and III Potentially contaminated Ca. 565.000 Mg Concrete and plant parts Ca. 94.000 Mg Plant parts TH 1 – 6, IH 6 Ca. 50.000 Mg Building structures Ca. 1.185.000 Mg Remaining building structures Ca. 471.000 Mg Technical conceptEWN - material management

  46. Technical conceptProject structuring • Different structures depending on point of view • Work breakdown • Responsibility • Objects • Type of work • Phases

  47. Technical conceptEWN - Work breakdown

  48. Decommissioning planContent and structure • Comprehensive Project Management • Licensing Process • Characterisation of the facility • (dose mapping and inventory classification) • Safety assessment • Criticality assessment • Radiation Protection and Monitoring • Environmental impact assessment • Waste Management • Decontamination • Dismantling and demolition • Remote dismantling • Engineering support • Quality Assurance and Quality control • Physical Protection • Site adaptation and development • Public relation

  49. ER First issue in 1994 Issue Index one year later ER1 Licensing concept for decommissioning/dismantling of units 1 - 6 2 ER2 Radiation protection concept 2 ER3 Site operation 4 ER4 Incident analyses 2 ER5 Fire protection concept 2 ER6 Intervention in contaminated building structures under controlled area conditions 3 ER7 Reconstruction/new construction of the complex of central active workshop/melting facility 3 ER8 General dismantling plan 1 ER9 Material flow/release measurement concept 1 ER10 Decontamination concept 2 ER11 Disposal of damaged fuel elements 1 ER12 Physical protection 3 ER13 Remote dismantling of reactor pressure vessels 1 to 5 2 ER14 Clearing of tube storages for activated components 1 ER15 Disposal of absorber sections and shielding assemblies 2 Decommissioning planEWN – Explanatory reports

  50. Decommissioning plan • Initial for operation license • Updating during operation • Final for decommissioning license • Ultimate after project termination

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