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RETURN OF EXPERIENCE

RETURN OF EXPERIENCE. Valerie Drake UKAEA. VA Drake, UKAEA, Chapter 13. Four European pilot projects. Other Major European projects. AT-1 (Marcoule, France) . AT-1 General Description. Pilot plant for reprocessing fast breeder reactor fuel shut down 1979. fission product solution.

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RETURN OF EXPERIENCE

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  1. RETURN OF EXPERIENCE Valerie Drake UKAEA VA Drake, UKAEA, Chapter 13

  2. Four European pilot projects

  3. Other Major European projects

  4. AT-1 (Marcoule, France)

  5. AT-1 General Description • Pilot plant for reprocessing fast breeder reactor fuel • shut down 1979 fission product solution Spent fuel storage Chop and leach Fuel dissolution 1st extraction cycle 2nd and 3rd extraction cycle 4th U/Pu separation cycle U and Pu concentration Plutonium oxide (PuO2) Uranyl nitrate solution

  6. AT-1Project Summary • decommissioned between 1984 and 2001 in five stages: • alpha cells • small beta-gamma cells • high active cells using ATENA • storage and fission product cells • final clean-up and dismantling

  7. Rremoval of solid wastes Gaseous wastes ventilation HA Washing of the fission product storage tank Storage of thefission product solutions cell 910 cells 908/909 911 911 Fuel dissolution – cleansing of the gaseous effluents 1st extraction cycle cell 904 Casks arrival Spent fuel storage Chop and leach Solution filtration cell 901 Cell 902 cell 903 Uranyl nitrate solution 911 Oxalic precipitation calcination U and Pu concentration 2nd and 3rd extraction cycle 4th U/Pu separation cycle Plutonioum oxide (PuO2) cell 900 cell 905 cell 952 cells 950/951 Cell 906 911 Transfersiphon mist traps Liquid effluents storage cell 911 cell 907 AT-1 Flowsheet

  8. AT-1ATENA • Remote dismantling machine with power manipulator • 6 metre articulated arm • high reliability • site specific design

  9. AT-1Dismantling of high active cells

  10. AT-1Operational lessons learned(1) • The working environment should not be used to test unqualified equipment (RD 500) • ‘Dropping’ dismantled waste into the cells spreads contamination • Shot-blasting of walls proved lengthy and gave rise to secondary waste • Need to consider the effect of project time scales on ageing equipment/ systems

  11. AT-1Operational lessons learned(2) • Financial incentives to minimise waste production • Computer modelling of operations • Cell cleanliness • Use of standard equipment - availability of spare parts • Cutting of sheet metal using explosive cords • Dismantling and cutting using the ATENA machine

  12. AT-1General learning points • Good Post Operational Clean Out (POCO) on plant closure • Dismantle early and rapidly (time = money) • Commence manual work as soon as possible

  13. BR3 (Mol, Belgium)

  14. BR3 General Description • Type: Pressurized Water Reactor (Westinghouse) • Power: 40.9 MWth, 10.5 MWe (net) • Started in 1962, shut down in 1987 • Served as training center for future NPP operators and as test bed for advanced PWR fuel

  15. Re-fuelling pond Steam generator Spent fuel pond RPV BR3 Layout

  16. BR3Project Summary • 1987: reactor shut down • 1991: decontamination of the Primary Loop • 1991-95: dismantling highly active internals(2 sets) - dismantling of contaminated loops and equipment - thorough Decontamination of metallic pieces • 1999-2000: removal and dismantling of the RPV • 2000-date: decontamination of steam generator, dismantling of reactor loops, concrete • 2009: final completion

  17. BR3RPV Removal • De-couple RPV from primary loop • Lift RPV into re-fuelling pond • Re-instate pond integrity • Cutting of RPV

  18. BR3RPV Dismantling Cylindrical shell: Cut into 9 rings using horizontal milling cutter (tangential steps). Flange: Cut with Band Saw Rings: Cut with Band Saw into segments Band Saw Turntable Milling Cutter

  19. BR3Operational lessons learned(1) • “As built” drawings are not always correct • Mechanical methods used to decontaminate concrete is prone to spread of contamination • Effect on visibility from particulates and insulation

  20. BR3Operational lessons learned(2) • Development of dose assessment tool(VISIPLAN) • 80% reduction in radioactive waste volumes by decontamination(MEDOC process) • Use of full scale mock-ups for remote work • Use of proven technology • Shielding benefits of underwater cutting

  21. ALARA planning & optimisation BR3 VISIPLAN model

  22. BR3General learning points • Decontaminate plant early after shut down • Importance of setting-up waste routes • Importance of planning

  23. WAGR (Windscale, UK)

  24. WAGR General Description • Type: Advanced Gas cooled Reactor • Power: 33 MW(e) • Started in 1963, shut down in 1981 • Served as prototype for UK reactor development

  25. 3 Te. Transfer hoist and slew beams RDM Upper housing Sentencing Cell Upper loading cell Maintenance Cell Lower loading cell Concreting cell Reactor core and pressure vessel WAGR Layout

  26. WAGR Project Summary • 1981: reactor shut down • 1993: remote dismantling machine installed • 1993: waste route complete • 1994: removal and disposal of 4 heat exchangers • 1999-2006: dismantling and removal of core components • Total cost €55M

  27. Upper Housing Lower housing Shield floor Turntables Fixed beam 3 Te Hoist Slew Beam Manipulator Mast Pressure vessel 8 Te. Hoist Sentencing cell slew beam Sentencing cell carousel floor Remote Dismantling Machine

  28. WAGROperational lessons learned • Deployment difficulties with some remote tooling • Simple tooling, thoroughly tested is best • Develop contingency solutions • Consider effect of equipment on environmental systems

  29. WAGRGeneral learning points • Relationship with stakeholders • good housekeeping • efficient waste packing

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