In the frame of the decommissioning of nuclear facilities, many cutting techniques have been studied in different configurations, in order to qualify the performance of the tools implemented and also the quantity and characteristics of the wastes and secondary emissions produced. The present paper, calling the operational conditions of each tool, presents a synthesis of the results obtained from the suspension or airborne release point of view. The knowledge of the suspension fraction of radioactive aerosol contamination is needed for the safety analysis of nuclear installation and for the radioprotection of workers as well. This synthesis shows that the suspension fraction can vary over several orders of magnitude according to the configurations studied and provides relevant information for the dismantlers.
Several experiments have been carried out with a Nd-YAG laser as a future dismantling cutting tool. At the beginning, industrial lasers could cut only small thicknesses due their small power (1 kW) but now, with the rise in industrial power (8 kW), it is possible to cut plates up to 100 mm thickness. This technique is practical with the use of optical fibers which allow to maintain the laser generator in a non-radioactive zone. This paper provides a synthesis of the measurements of aerosols and gases produced in different configurations (cutting in air and underwater) and some comparisons with other cutting tools.
Detailed properties and yields of gaseous and particulate emissions from underwater plasma-arc cutting of stainless stell have been measured as part of an interlaboratory programme to assess the repeatability of the cutting process and secondary emissions. 20 mm and 40 mm thick specimens of 304 stainless steel were cut with argon/nitrogen gas at water depths of 0.5 and 1.0 m. Good repeatability was obtained. Aerosol particles evolved were significantly enriched in Mn and to a lesser extent in Cr but reduced in Ni and Co. Size distributions and concentrations of these particles were measured. Fine particles collected in the water were shown to be partially dissolved by acidity caused by absorption of nitrogen oxides in the water. Emissions of NO and H2 were also quantified
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