Secondary emissions from underwater plasma-arc cutting of stainless steel for nuclear decommissioning

Detailed properties and yields of gaseous and particulate emissions from underwater plasma-arc cutting of stainless steel 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