There is a growing interest in laser radioactive decontamination of metal
surfaces. It offers advantages over conventional methods: improved safety,
reduction of secondary waste, reduced waste volume, acceptable cost. The
main mechanism of cleaning by lasers is ablation. Apulsed TEACO2 laser was
used in this work for surface cleaning in order to show that ablation of
metal surfaces is possible even at relatively low pulse energies, and to
suggest that it could be competitive with other lasers because of much
higher energy efficiencies. A brief theoretical analysis was made before the
experiments. The laser beam was focused using a KBr-lens onto a surface
contaminated with 137 Cs (b-, t1/2 = 30.17 y). Three different metals were
used: stainless steel, copper and aluminium. The ablated material was pumped
out in an air atmosphere and transferred to a filter. The presence of
activity on the filter was shown by a germanium detector-multichannel
analyzer. The activity levels were measured by a GM counter. The calculated
decontamination factors and collection factors showed that ablation occurs
with a relatively high efficiency of decontamination. This investigation
suggests that decontamination using a CO2 laser should be seriously
considered.
Experimental Investigations on Fusion Cutting Stainless Steel with Fiber and CO2 Laser Beams