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DEVELOPMENT AND MANUFACTURING OF A FACILITY FOR THE DECONTAMINATION BY ELECTRO-ETCHING AND APPLICATION TO ALPHA RADIOACTIVE WASTE FROM THE "RM2" INSTALLATION

Objective

The "RM2" installation is a disaffected laboratory for post-irradiation fuel examination operated from 1967 to 1982 at Fontenay-aux-Roses. This project is aimed at the industrial-scale testing of a new drum-type nitric acid electro-etching process to be used for RM2 waste decontamination.

The innovative nature of this project lies in the decategorization of plutonium bearing waste. At present in France, only surface storage sites are available for nuclear waste. These sites can only accept beta-gamma waste with little or no alpha contamination.

The prevailing radiological conditions are as follows:

specific alpha contamination: 3.7E3 to 3.7E5 Bq/g;
dose rates: 10 mGy/h to 1 Gy/h.

This industrial decategorization process for alpha-bearing waste can be applied wherever necessary in the European Community (reactor decommissioning to Stage 3, decommissioning of research laboratories or fuel reprocessing plants). The end result will be a net reduction of waste volumes for underground waste storage.

The radioactive waste will be removed from the RM2 installation at a rate of 700 kg per month beginning in December 1991 and conditioned in special 200 l stainless steel drums which will be placed in waste drums and transferred to the Saclay waste treatment centre in type B casks for decontamination. Before the transfer to Saclay, the drum activity will be carefully measured by an automatic neutron counter. After decontamination, the waste will be reconditioned for transfer to the ANDRA facility.

The potential benefit is that, by thorough decontamination, 7 tons of metal waste provided for underground storage could be accepted for definitive surface storage. This would considerably reduce the total cost of this operation.
An electroetching decontamination device for radioactive waste has been designed and manufactured. It is a copy of industrial electrodeposit techniques for bolts, for instance. Some minor improvements were implemented: most of copper electric current bars were replaced by stainless steel bars; the main drum metal is titanium; some control devices were added; the electric current direction was reversed.

The device has treated 3 x 200 kg of waste to date at the RM2 installation, a disaffected laboratory for post irradiation fuel examination.
WORK PROGRAMME

1. Waste characterization and conditioning

2. Adaptation of the electro-etching decontamination process

2.1. Design and manufacture of the decontamination device
2.2.Implementation and commissioning testing of the device

3. Preliminary decontamination tests on radioactive components

4. Industrial decontamination of 7 tons of radioactive waste

5. Analysis of results

6. Generation of specific data

Coordinator

Commissariat à l'Energie Atomique (CEA)
Address
Centre D'études Nucléaires De La Vallée Du Rhône Cité De Marcoule
30205 Bagnols-sur-cèze
France