И з в е с т и я в у з о в • Я д е р н а я э н е р г е т и к а • № 4 • 2 0 1 7 127

No abstract

Analysis of corrosion processes has a major role in justifying the reliability and safety of developed nuclear reactors of a new generation with heavy liquid metal coolants. An approach has been developed which allows practical conclusions to be made with respect to the processes in the given metal-oxide system based on analyzing state diagrams for these systems in the "oxidation potential – temperature" coordinates. The proposed approach relies on a long-term experience of experimental and computational studies concerned with the interaction of various steel grades with molten lead and lead-bismuth, as well as with the transport of metal impurities within these molten metals. The oxidation potential of a metal-oxide system is measured in experimental studies using oxygen activity sensors developed and manufactured at IPPE. The applicability of the proposed approach to analyzing the processes of mass transport in iron-oxygen, lead-oxygen, sodium-oxygen, and iron-water vapor systems has been demonstrated.

The article considers the main methods for studying the process of oxidation of structural steels and evaluating their corrosion resistance in heavy liquid metal coolants (HLMC) under static and dynamic conditions. It is shown that the main disadvantage of these methods is the impossibility of evaluating the results in real time. The authors propose a new method for the experimental determination of the oxidation rate of steels in molten HLMCs, which makes it possible to measure the reaction rate without depressurizing the plant, by periodically injecting air doses of a known volume and monitoring its response time. As additional data in the research methodology, the results of a chemical-spectral analysis of the coolant and slags were provided after the experimental campaign completion as well as a metallographic analysis of steel samples to determine the oxide coating thickness and its comparison with the calculated value for the integral oxygen assimilation by the system. To implement the methodology, a laboratory facility was proposed, equipped with an oxygen thermodynamic activity (TDA) sensor of the RF-IPPE design. The sensor is certified by Gosstandart of Russia (certificate RU. 31.002 A No. 15464), registered in the State Register of Measuring Instruments (No. 25282-03) and approved for use in the Russian Federation.

И з в е с т и я в у з о в • Я д е р н а я э н е р г е т и к а • № 2 • 2 0 2 0 39