Feasibility of clearance level electrolytic decontamination of simulated radioactive Ni-based alloy.

• Clearance level of radioactive metal waste by electrolytic decontamination assessed. • LiCl-KCl eutectic-4 wt.% NiCl 2 with max. 8 wt.% CoCl 2 electrolyte at 500 °C used. • For Co conc.< 167 ppm, 3 decontamination cycles required to meet clearance level. • Electrolytic decontamination can be used to treat nuclear waste. Many countries are in the process of decommissioning their nuclear power plants. These power plants contain valuable metals, including Inconel alloys, which are often only contaminated on the surface. Metals are typically decontaminated using laser ablation. However, electrolytic decontamination is a simpler and less expensive solution. Our investigation aimed to develop a method for decontaminating Inconel alloy contaminated with Co to clearance level for recycling and reuse. This study focused on the electrolytic decontamination of Ni-0.2 wt.% Co alloy, identified as a potential replacement for the radioactively contaminated material. Molten LiCl-KCl-NiCl 2 -CoCl 2 (500 °C) was used as the electrolyte in the experiments and the potential recyclability of the used electrolyte was examined. In the absence of CoCl 2 in the electrolyte, the decontamination factor is 1.38E8 after the third cycle of electrolytic decontamination. Considering that the decontamination factor corresponding to the clearance level is 1.27E7, three cycles of electrolytic decontamination are considered to be sufficient. Additionally, an investigation of the possibility of recycling the used electrolyte showed that the solidified products formed after vacuum distillation were LiCl, KCl, and Co oxide with traces of Ni oxide. ICP analysis of the LiCl and KCl collected after vacuum distillation revealed that the concentration of Co was less than 0.1 ppm, which suggests that the used electrolyte can be recycled. These findings are expected to offer valuable insights into the electrolytic decontamination process, its limitations, and potential applications in the processing of nuclear waste. [Display omitted] [ABSTRACT FROM AUTHOR]