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

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

9. AT-1 Dismantling of high active cells
Cells are 7m high

10. AT-1 Operational 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-1 Operational 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-1 General 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. BR3 Layout
Steam generator
Re-fuelling pond
Spent fuel pond
RPV

16. BR3 Project Summary 1987: reactor shut down
1991: decontamination of the Primary Loop
: dismantling highly active internals(2 sets)
- dismantling of contaminated loops and equipment
- thorough Decontamination of metallic pieces
: removal and dismantling of the RPV
2000-date: decontamination of steam generator, dismantling of reactor loops, concrete
2009: final completion

17. BR3 RPV Removal De-couple RPV from primary loop
Lift RPV into re-fuelling pond
Re-instate pond integrity
Cutting of RPV

18. BR3 RPV 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. BR3 Operational 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. BR3 Operational 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. BR3 General 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
Windscale Advanced Gas-Cooled Reactor (WAGR) operated from 1963 to It was the prototype for the UK's commercial AGR reactor programme. Following shut-down and removal of the fuel, it was decided that WAGR should be dismantled as a demonstration project. A new store has been constructed adjacent to WAGR for intermediate level wastes (ILW) arising from the decommissioning.
Dismantling work is progressing in a "top-down" manner. To date, approximately one third of the core structures within the pressure vessel have been dismantled and the project is on schedule to complete core dismantling operations by The waste is being grouted in Nirex approved concrete boxes, which are either stored as intermediate level waste in the purpose-built store adjacent to the reactor or sent to Drigg for disposal as low level waste.
Dismantling of the core will be complete by 2007, although some further clearance work necessary to put the plant in a suitable condition for long term care and maintenance means that the formal completion of the project is scheduled at At this point, the objective of demonstrating dismantling capability will have been achieved. The volume of ILW requiring packaging and disposal is considerably reduced if the activity in the concrete bioshield is allowed to decay to LLW levels, so it is proposed to defer dismantling of the bioshield and reactor building until about Other related buildings will be dismantled as they become redundant.
The total cost of the WAGR project (up to and including core and pressure vessel removal) is estimated at £80M, of which £8M was the cost of the remote dismantling machine.

25. WAGR Layout 3 Te. Transfer hoist and slew beams RDM Upper housing
Maintenance Cell
RDM Upper housing
Sentencing Cell
Reactor core and pressure vessel
3 Te. Transfer hoist and slew beams
Upper loading cell
Lower loading cell
Concreting cell
This slide shows the current condition of the facility.
The operating floor, fuel pipes and reactor top dome have been removed.
The heat exchangers (boilers) have been removed and two of their concrete bioshields modified to create a waste route.
The waste packaging building has been built alongside the containment building.
The main tool installed to dismantle the Reactor is a Remote Dismantling Machine - which encompasses a remotely operated 3te crane and a manipulator deployment system.

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
: dismantling and
removal of core components
Total cost €55M
Windscale Advanced Gas-Cooled Reactor (WAGR) operated from 1963 to It was the prototype for the UK's commercial AGR reactor programme. Following shut-down and removal of the fuel, it was decided that WAGR should be dismantled as a demonstration project. A new store has been constructed adjacent to WAGR for intermediate level wastes (ILW) arising from the decommissioning.
Dismantling work is progressing in a "top-down" manner. To date, approximately one third of the core structures within the pressure vessel have been dismantled and the project is on schedule to complete core dismantling operations by The waste is being grouted in Nirex approved concrete boxes, which are either stored as intermediate level waste in the purpose-built store adjacent to the reactor or sent to Drigg for disposal as low level waste.
Dismantling of the core will be complete by 2007, although some further clearance work necessary to put the plant in a suitable condition for long term care and maintenance means that the formal completion of the project is scheduled at At this point, the objective of demonstrating dismantling capability will have been achieved. The volume of ILW requiring packaging and disposal is considerably reduced if the activity in the concrete bioshield is allowed to decay to LLW levels, so it is proposed to defer dismantling of the bioshield and reactor building until about Other related buildings will be dismantled as they become redundant.
The total cost of the WAGR project (up to and including core and pressure vessel removal) is estimated at £80M, of which £8M was the cost of the remote dismantling machine.

27. Remote Dismantling Machine
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
This slide shows the Remote Dismantling Machine in more detail.
The two tooling deployment systems, 3Te transfer hoist and manipulator mast can be clearly seen.
The 3Te hoist with it’s system of rotating beams is used to deploy tools into the reactor vault and move waste into the waste route.
The manipulator mast and manipulator deploy the various tools into the reactor vault to release reactor components. To date it has only been used in the Loop Tube campaign.

28. WAGR Operational 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. WAGR General learning points
Relationship with stakeholders
good housekeeping
efficient waste packing