Study of corrosion mechanism of new zircaloys (original) (raw)
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Corrosion Behavior of Zirconium Alloy Nuclear Fuel Cladding
MRS Proceedings, 1989
ABSTRACTZircaloy−2 and −4 are used as nuclear fuel cladding. Both alloys are more than ninety-eight percent zirconium and are corrosion resistant to various media. Electrochemical measurements using polarization techniques have been made on these alloys in aqueous media with a pH of 8.5 and varying ionic concentration (1X and 10X) at temperatures of 22°C and 95°C. Results showed that under the test conditions of the study these alloys passivated and had negligible corrosion rates, but there were some variations in passivation due to surface preparation and some crevice corrosion was observed. Data are presented and discussed in terms of passivity, breakdown potential and susceptibility to localized corrosion.
This paper includes continuous results of long-time corrosion tests of Zr alloys, being a part of the "Corrosion of Zr alloys " project (in the frame of CEZ, Czech republic). The results confirm a poor corrosion resistance of ZrlNb alloys in a water environment exhibiting a higher Li concentration, a poor corrosion resistance of Zry-4 type alloys in a steam environment at temperatures exceeding 450 °C. On the other hand the results confirm very good corrosion properties of ZrlNb in steam, Zry-4 Improved in 400 °C steam and ZIRLO alloy in a 360 °C higher Li water environment.
Multi-Elemental Coatings on Zirconium Alloy for Corrosion Resistance Improvement
Coatings
Zirconium alloys are commonly used as a cladding material for fuel elements in nuclear reactors. This application is connected with zirconium alloy’s good resistance to water corrosion and radiation resistance under normal working conditions. In the case of severe accident conditions, the possibly very fast oxidation of zirconium alloys in steam or/and air atmosphere may result in the intense generation of hydrogen and explosion of the hydrogen oxide mixture. The development of a solution to minimize the aforementioned risk is of interest. One of the actual concepts is to improve the oxidation resistance of Zr alloy cladding with protective coatings. This study aimed to develop, form, and investigate new coatings for zirconium alloy Zry-2. Multi-elemental Physical Vapour Deposition (PVD) coatings with Cr, Si, and Zr were considered for Institute of Nuclear Chemistry and Technology) INCT as corrosion protective coatings for nuclear fuel claddings. Heat treatment at 850–1100 °C/argon,...