Authors & Affiliations
Osipov A.A., Ivanov K.D.
A.I. Leypunsky Institute for Physics and Power Engineering, Obninsk, Russia
Osipov A.A. – Researcher. Contacts: 1, pl. Bondarenko, Obninsk, Kaluga region, Russia, 249033. Tel.: +7 (910) 526-74-71; e-mail:&
Ivanov K.D. – Leading Researcher, Dr. Sci. (Tech.).
Abstract
Liquid metals are currently used as coolants in reactor plants for various purposes. It turned out that for normal operation of such installations it is necessary to ensure a reduced content of oxygen impurities in the coolant. This is especially true for installations with heavy liquid metal coolants (HLMC) based on lead or lead-bismuth melts. To monitor oxygen in these systems, electrochemical sensors have become widespread, using oxygen-saturated liquid metals as reference electrodes. When using liquid metals as coolants, as well as when using them in sensors of the thermodynamic activity of oxygen, the question arises about the equilibrium composition of the oxide in contact with this liquid metal. In the standard approach, it is believed that when a liquid metal is saturated with oxygen, an oxide of stoichiometric composition is formed, but it is well known that the compositions of oxides can depend on the partial pressure of oxygen and are characterized by a wide range of homogeneity. This article outlines an approach to calculating the compositions of nonstoichiometric oxides in equilibrium with the liquid metal – oxygen system under the assumption that the isobaric-isothermal potential of oxide formation can be described by a parabolic dependence on the composition. The work considers a method for determining the composition of a non-stoichiometric oxide in equilibrium with a metal melt. This method is based on the use of reference oxides to construct a parabolic dependence and the conditions for achieving a minimum of this dependence. Using the Pb-O and Bi-O systems as an example, it is shown that the composition of lead and bismuth oxides in equilibrium with the metal is enriched in the metal component and weakly depends on the activity of the metal.
Keywords
liquid metal, dilute solution, non-stoichiometric oxide, thermodynamic activity, oxygen, saturation
Article Text (PDF, in Russian)
UDC 544.3:536.7
Problems of Atomic Science and Technology. Series: Nuclear and Reactor Constants, 2024, no. 1, 1:14