Simulation Investigation of Fluorine Cold Plasma Interaction with Cobalt Oxide as an Etchant for Decontamination Metal Waste

Abstract

Fluorine cold plasmas are recognized as effective dry processing techniques for removing surface contaminants with high bond energy. Among the radionuclides, 58Co and 60Co pose significant challenges. The removal of Co isotopes from contaminated metal surfaces is a key focus in developing metal surface cleaning processes. This study aimed to investigate the plasma reaction resulting from the discharge of a dielectric barrier in fluorine gas. This plasma was interacting with a Cobalt oxide film on the surface of stainless steel 304 through experimental observation and simulation study. It was observed that the Cobalt oxide transformed into a powdered form after exposure to plasma irradiation, enabling easy separation from the base metal surface. The efficiency of clearance from the metal surface depends on the generation of fluorine (F) radicals within the plasma. To identify the crucial parameters influencing plasma formation and optimization, the plasma created using CF4 etching gas was simulated using Comsol Multiphysics software. The simulation study reports there are optimal values for voltage, frequency, and the distance between the two electrodes, which enhance cleaning speed. In addition, increasing the temperature will speed up the etching process

Keywords

• fluorine cold plasma
• metal decontamination
• plasma etching
• cobalt oxide
• comsol multiphysics software