Belgoprocess started the industrial decommissioning of the main process building of the former EURO-CHEMIC reprocessing plant in 1990, after completion of a pilot project in which two buildings were emptied and decontaminated to background levels. The remaining structures were demolished and the concrete debris was disposed of as industrial waste and green field conditions restored.
Decommissioning involves the removal and decontamination of equipment from each cell, the decontamination of the cell walls, ceilings and floors, and the dismantling of the ventilation system. These activities are followed by a complete monitoring in order to obtain the unconditional release of the remaining structures.
In the earlier days, concrete walls with limited in depth contamination, were decontaminated using commercially available pneumatic hand scabblers. In addition, 3-headed, 5-headed and 7-headed hand-operated floor scabblers have been used. The pneumatic powered machines have adapted dust extraction systems around the scabbier heads. To improve the working conditions for the operators, and to increase capacity, scabblers have been progressively automised.
Operation efficiency was significantly improved when shaving machines were introduced, using a diamond tipped rotary head, designed to give a smooth surface finish, which is easier to measure. The use of these machines resulted in a higher efficiency and a 30% reduction of secondary waste production. It also reduced the physical load to the operators due to the absence of machine vibration.
The paper gives an overview of the specific efforts that have been put in improving the techniques for the decontamination of concrete surfaces at the decommissioning of the Eurochemic reprocessing plant in Dessel, Belgium.