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 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

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

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

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

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

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

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

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

BR3 (Mol, Belgium)

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

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

BR3 Project 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

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

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

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

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

ALARA planning & optimisation BR3 VISIPLAN model

BR3 General learning points Decontaminate plant early after shut down Importance of setting-up waste routes Importance of planning

WAGR (Windscale, UK)

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 1981. 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 2007. 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 2010. 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 2040. 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.

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.

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 Windscale Advanced Gas-Cooled Reactor (WAGR) operated from 1963 to 1981. 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 2007. 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 2010. 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 2040. 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.

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.

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

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