A wet oxidation process for the destruction of organics from intermediate level radioactive wastes has been developed in parallel by AEA Technology for the treatment of reactor sludges from the Winfrith Steam Generating Heavy Water Reactor, and by Nuclear Electric for the treatment of spent organic ion exchange (IX) resins from their nuclear power stations. The process, which is based on catalysed reaction with hydrogen peroxide, has already been subject to experimental investigations up to 10-50 kg inactive resin batch using pilot scale plant for the above applications. The main objective of this programme is to demonstrate the feasibility of the wet oxidation technology on a range of real radioactive wastes by the design, construction and operation of a fully active mobile pilot plant (50-100 kg/day capacity).
A wet oxidation process for the destruction of organics from intermediate level radioactive wastes has been developed. The main objective of this project is to demonstrate the feasibility of the wet oxidation technology on a range of real radioactive wastes by the design, construction and operation of a fully active mobile pilot plant.

The worldwide literature survey and the assessment of candidate wastes in the United Kingdom has been completed. Comprehensive information on candidate European Community wastes has been obtained, and is currently being evaluated to establish the potential role of wet oxidation in its management. Experimental studies have concentrated on spent organic ion exchange (IX) resins, which have been identified as the major candidate waste type for treatment in the UK. Emphasis has been placed on determining the optimum catalyst requirements and pH control regime, which is necessary for process optimization and safety considerations. The appraisal of plant concepts has been completed, and the conclusions support the adoption of a semicontinous process. This will incorporate many of the features of the batch process, and allow a partially continuous waste feed combined with batch discharge of the product. Assessment of experimental results obtained from previous inactive treatment tests on organic containing wastes is being carried out.
Work programme:

The programme consists in the following tasks:
- analysis of literature data and assessment of candidate waste in UK and EC context
- evaluation of previous experimental results outside this CEC contract
- completion of wet oxidation experiments at small scale for both inactive and active conditions
- appraisal of alternative plant concepts
- evaluation of complete treatment schemes
- design, construction and operation of a mobile active wet oxidation pilot plant
- drawing-up of flow sheets
- analysis of safety and economic aspects

The key organic wastes identified for investigation include: IX resins from power reactor operation, decontamination liquors, mixed reactor sludges from WSGHWR, solvents and scintillants and cellulose containing soft wastes.