Treatment of metal waste by melting
The Centraco foundry unit treats short-lived low-to-intermediate-level radioactive metal waste and materials produced by nuclear installations.
Examples of metal waste and materials treated at Centraco include valves, pipes, metal tools, miscellaneous metal items from maintenance or decommissioning, etc.
The Centraco facility is equipped with a cutting shop for large components. It handles components up to 19 metres in length, and weighing 200 tonnes, such as heat exchangers or fuel pool storage racks, without the need for prior treatment by stakeholders.
After sorting and adjusting to the correct size, the metal waste is melted in the induction furnace, which has a capacity of four tonnes. Once a temperature of 1,500°C has been reached, the molten material is poured into a casting ladle. The molten metal in the ladle can then be poured into an ingot mould containing steel liners, to produce the final package form, known as an ingot. The melting unit enables waste volumes to be reduced by a factor of between six and ten, and also allows precise physical/chemical and radiological characterisation of packages sent for storage.
The final residues of melting (slag, dust and refractories) and the ingots are conditioned in accordance with agreements with ANDRA. They are reassigned to producers in proportion to the weight and activity of the incoming waste, after deduction of any recycled materials.
Where possible, and depending on the metallurgical quality of the molten material, part of the waste can be recycled as radiological shielding, produced using a centrifuge. The shielding is then integrated into concrete containers for conditioning of ion exchange resins.
The recycled steel is deducted from the final residues reassigned to producers.
Cyclife France is authorised to treat low-level radioactive waste from foreign producers at the Centraco site, under nuclear safety conditions that are identical to those applicable to the treatment of French waste. Final waste is returned to the producing country after treatment.
The Centraco melting unit has approval to melt 3,500 tonnes of metal waste per year.
Since it entered service, the melting unit has melted more than 23,500 tonnes of metal waste (as of the end of 2018).
Large-size metal waste
To meet its customers' requirements, Cyclife France has designed a treatment solution for large metal components (up to 19 metres in length and with a mass of up to 200 tonnes) originating from the maintenance or dismantling of nuclear facilities.
The capabilities of the Centraco racks and large components treatment shop are as follows:
- receipt of items via specific channels,
- cutting up using the diamond wire technique, by milling, or using a clamp/shear, and adjustment to the correct size,
- automatic metallurgical sorting using magnets, eddy current separation, or a trommel screen,
- routing of items adjusted to the dimensions of the furnace to the Centraco melting unit,
- conditioning of waste that does not comply with the specifications of the Centraco furnace for dispatch to ANDRA.
Recovery of metal waste
Cyclife France is able to fabricate manufactured products which meet the needs of nuclear industry operators, and can investigate the fabrication of any other type of recovered product, in consultation with its customers.
Cyclife France performs the following services using melted metal waste:
- tube manufacture via centrifugation,
- cleaning and preparation of obtained parts (cooling, cutting and shot blasting),
- assembly and fabrication of final products,
- preparation of products for dispatch.