STUDY OF ELECTROCHEMICAL BREAKDOWN OF ANO DIC OXIDE-FILMS ON ZIRCONIUM - APPLICATION TO DECONTAMINATION

Zircaloy-LF constitutes the jacket material of the fuel elements. In o rder to decontaminate radioactive isotopes trapped in the zirconia fil m, electrochemical cracking is used in a nitric acid environment to pr oduce the fracture and scaling of the oxide film. The physicochemical conditions of cracking are determined, as well as the role played by i nternal stresses in the layer. This work is completed by surface analy ses (SEM) and by impedance measurements in order to determine the evol ution of the film resistance during cracking.