Effects of NiCl2 and FeCl2 additives on the anodic dissolution behaviours of Inconel 600 in molten LiCl–KCl salts

Abstract

The anodic dissolution behaviour of Inconel 600 must be elucidated to design an efficient decontamination process for used nuclear steam generator tubes with radioactive nuclide depositions in their surface microcracks. We investigated the effects of NiCl2 and FeCl2 additives in LiCl–KCl eutectic salts on the microstructural changes in Inconel 600 during electrolytic decontamination. A Cr–Fe depletion layer formed on Inconel 600 via Ni reduction at the position where alloying elements oxidised. In the FeCl2-added salt, the selective dissolution of active alloying elements through the grain boundary produced a cavity-cluster layer whose shape was changed using applied electrochemical methods.