TAILIEUCHUNG - A role of electrons in zirconium oxidation

This process periodically speeds up the corrosion of the zirconium cladding in the aqueous coolant due to the breakaway of the dense part of oxide scale when its thickness reaches 2 mkm. It is shown that the electronic resistivity of zirconia is not limiting the zirconium oxidation at working temperatures. | A role of electrons in zirconium oxidation EPJ Nuclear Sci. Technol. 3 19 2017 Nuclear Sciences . Alekseev and . Shimkevich published by EDP Sciences 2017 amp Technologies DOI epjn 2017014 Available online at http REGULAR ARTICLE A role of electrons in zirconium oxidation Pavel N. Alekseev and Alexander L. Shimkevich NRC Kurchatov Institute 1 Kurchatov Sq. Moscow 123182 Russia Received 22 April 2016 Received in final form 26 April 2017 Accepted 29 May 2017 Abstract. Growing the oxide scale on the zirconium cladding of fuel elements in pressured-water reactors PWR is caused by the current of oxygen anions off the waterside to the metal through the layer of zirconia and by the strictly equal inverse electronic current. This process periodically speeds up the corrosion of the zirconium cladding in the aqueous coolant due to the breakaway of the dense part of oxide scale when its thickness reaches 2 mkm. It is shown that the electronic resistivity of zirconia is not limiting the zirconium oxidation at working temperatures. For gaining this limitation a metal of lesser valence than zirconium has to be added to this oxide scale up to 15 . Then oxygen vacancies arise in the complex zirconia increase its band-gap and thus sharply decrease the electronic conductivity and form the solid oxide electrolyte whose growth is inhibited in contact with water at working temperatures of PWR. 1 Introduction is carried out by generating electrons on the interface Zr O ZrO2 x over the reaction 1 by their passing Zirconium alloys are used for fuel cladding in pressured- through oxide scale to the interface ZrO2 H2O for water reactors PWR thanks to a low capture cross- disintegrating water over the reaction 2 and by diffusion section of thermal neutrons the good corrosion resistance of oxygen anion back to the metal through two different in water at high temperatures and to the mechanical oxide layers see Fig. 1 for oxidizing zirconium over the properties 1 .

• Năng lượng
• Pressured water reactors
• Equal inverse electronic
• Solid oxide electrolyte
• Oxidation of zirconium alloys
• Role of electrons