Stainless steels corrosion modelling in nitric acid in presence of oxidizing ions

Delgado, S.*; Giganon, A.*; Irisawa, Eriko ; Igarashi, Takahiro  ; Kato, Chiaki   

The sustainability of nuclear fuel reprocessing plants hinges on effectively predicting and managing corrosion, particularly of stainless steels (SS) in contact with nitric acid and oxidizing ions. The corrosion process is influenced by two main factors: the stability of oxidizing ions in nitric acid, determined by their redox reactions with nitric species, and the direct corrosion reactions of these ions with SS. A corrosion model incorporating these factors has been developed, using data from experiments and simulations with various oxidizing pairs like Np(VI)/Np(V), Pu(VI)/Pu(IV), and others. These simulations highlight how redox reaction kinetics and corrosion rates impact the degradation of SS in nuclear plants.