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1
RETURN OF EXPERIENCE
Valerie Drake
UKAEA
VA Drake, UKAEA, Chapter 13
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Four European pilot projects
Name ofinstallation
Type ofInstallation
PlaceCountry
AT1 Pilot reprocessingplant
La HagueFrance
BR3 PWR plant MolBelgium
KRB BWR plant GundremmingenGermany
WAGR AGR plant WindscaleU.K.
3
Other Major European projects
Name ofinstallation
Type ofInstallation
PlaceCountry
KGR 8 PWR type units GreifswaldGermany
NPP A-1 HWGCRexperimental andpower prototype
JaslovskeSlovak Republic
4
AT-1 (Marcoule, France)
5
AT-1 General Description
• Pilot plant for reprocessing fast breeder reactor fuel
• shut down 1979 fission product solution
Chop and leach
Fuel dissolution
Spent fuel storage
Uranyl nitrate solution
Plutonium oxide (PuO2)
U and Pu concentration
4th U/Pu separation
cycle
2nd and 3rd extraction
cycle
1st extraction cycle
6
AT-1Project Summary
• decommissioned between 1984 and 2001 in five stages:
alpha cellssmall beta-gamma cellshigh active cells using ATENAstorage and fission product cellsfinal clean-up and dismantling
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AT-1 Flowsheet
Storage of the fission product
solutions
1st extraction
cycle
cell 904
cell 900
cell 901
Gaseous wastes ventilation HA
cell 903Cell 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 908/909cell 910
Rremoval of solid wastes
Uranyl nitrate solution
Plutonioum oxide (PuO2)
Cell 906cells 950/951cell 952cell 905
cell 907cell 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
911911
911
911
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
BR3 Layout
Steam generator
Re-fuelling pond
Spent fuel pond
RPV
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
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BR3RPV Dismantling
Milling Cutter
Turntable
Band Saw
Cylindrical shell: Cut into 9 rings using horizontal milling cutter (tangential steps).Flange: Cut with Band Saw Rings: Cut with Band Saw into segments
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)
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• Type: Advanced Gas cooled Reactor
• Power: 33 MW(e)
• Started in 1963, shut down in 1981
• Served as prototype for UK reactor development
WAGR General Description
25
WAGR Layout
Maintenance Cell
RDM Upper housingSentencing Cell
Reactor core and pressure vessel
3 Te. Transfer hoist and slew beams
Upper loading cell
Lower loading cell
Concreting cell
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
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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
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