Controlling the concentration of oxygen in the PbBi alloy by changing the composition of the gas

Coolant PbBi is a key component of the concept of the reactor cooled by liquid heavy metal of the IV generation. The study of the chemical interaction of PbBi with metal materials within the reactor is an important area in the development of the reactor with this refrigerant. The refrigerant reaches in the reactor temperatures higher than 500 grad C and is key to ensure protection from corrosion even under these conditions. This protection of steel parts against corrosion is based on maintaining the oxide layers on the surface of these parts. The composition and stability of these layers is very sensitive to the concentration present of oxygen - at high concentration leads to the oxidation of the refrigerant; at too low a concentration is not a layer of oxides of the stable. Changes in the concentration of oxygen in the system can be implemented in different ways, in this study it was used the method of dosing the gas with varying oxygen content in the cover gas above the surface of the alloy PbBi. The aim of this work was to verify the applicability of this method for small systems of laboratory size and mastering automatic control of oxygen concentration feedback of data measured by the sensor concentration of oxygen directly in the alloy. (authors)