Corrosion issues in nuclear fuel reprocessing plants

Abstract: In spent fuel reprocessing plants, various nitric media are met throughout the PUREX process that leads to the separation of fission products, uranium and plutonium. Structural materials for the equipment are mainly austenitic stainless steels and zirconium. They are protected by a stable passive layer in nitric acid. At first, corrosion mechanisms of stainless steels are presented. Special attention is paid to the cathodic reactions that are specific to nitric media. Secondly, the mechanism of passivity and the behaviour of zirconium are described.