Decontamination of radioactive metal surfaces by electrocoagulation

[Display omitted] •It is feasible to apply the electrocoagulation (EC) process to decontaminate steel contaminated with U.•Contaminated metal is used as the sacrificial anode and the cathode Ti.•Decontamination efficiency depends on geometry, dimensions and surface conditions of the metal.•The grease or dust presence on the metal surface reduces the treatment efficiency.•Iron hydroxides formed in the EC process carry to U to the sludges. The decontamination of noncompactable radioactive wastes, such as tools and equipment, aims to reduce the waste volume to be conditioned and stored. The electrocoagulation (EC) application in the decontamination of noncompactable radioactive waste from stainless steel containing uranium, was studied to evaluate its technical viability. The first studies were carried out with stainless steel plates coated with WO3 to simulate a fixed contamination and to determine the best tungsten removal conditions via EC considering pH, electrolyte support, distance between the electrodes, cell potential and counter-electrode material. The best removal conditions for WO3 were applied to plates contaminated with UO2(NO3)2 to evaluate the viability of the EC decontamination process. Uranium removal efficiencies of 90% were obtained in 1 h, at pH of 1, 2.4 V and 1 cm of distance between anode / cathode in a circular array. The EC process, under the previously obtained conditions, was applied to two metallic pieces contaminated with U. It proved feasible to decontaminate metallic pieces through the EC process, thus being able to obtain up to 90% U removal efficiency; however, it is important that the surfaces of the parts are free of grease and dust.