Basic Study on Laser Ablation Surface Cleaning of Nuclear Facility

Abstract

An ultra short pulsed Nd:YAG laser was employed to study the ablation effects and laser beam transport in optical fibres. Using 13 µm Zn coated carbon steel as a target, the relationship between ablation rate and laser fluence was investigated, and optimal processing conditions were determined. The laser induced products consisted of vapour and liquid particles. It was found that a smaller incident laser angle was more suitable for protecting the focusing lens from the pollution of the ablated products. The collection rate of the ablated products almost reached 100%. Additionally, a laser beam of over 5·6 W in power with a transportation rate of nearly 90% was output at the end of a 20 m long optical fibre. By this output power, a Zn coating of the same thickness could be completely ablated. A decontamination factor was introduced to estimate the cleaning effects of laser ablation, and satisfactory cleaning was obtained