Removal of Metal Oxide Layers as a Dry Decontamination Technique Utilizing Bead Reaction and Thermal Quenching by Dry Ice Blasting

A new removal method for metal oxide layers formed on steel surfaces was developed as a dry decontamination technique for radioactively contaminated metal waste. In this method, surface oxide layers formed on metal wastes are fused with glass flux and the resulting hot glass layers are removed by thermal quenching using dry ice blasting. After optimization of operating conditions in each process, removal tests were carried out using oxidized stainless and carbon steel samples, which were prepared in boiling water reactor conditions. The experimental results indicated that the surface oxide layers were fused into the glass flux such as borax by a bead reaction and successfully removed by dry ice blasting. Energy dispersive X-ray analysis confirmed that no oxide layer remained on the oxidized steel samples after treatment by the present method.