Guzel Kh. Sharipzyanova

The article is devoted to the problem of improving the operational performance of nuclear reactor systems, the relevance of which increases with the development of scientific, technical and technological progress. One of the conditions for the successful use of ceramic materials as absorbing elements for thermal neutron reactors is a detailed study of their microstructure and operational properties. Ceramics based on hafnates and oxides of rare earth elements under certain conditions shows high heat resistance and radiation resistance, therefore, in order to achieve optimal regulatory operational characteristics of the materials used, it is extremely important to control the conditions for obtaining complex oxide ceramics, which allows obtaining single-phase structures with high density and an ideal fluorite lattice in these conditions. Such an approach to solving the problem at the design stage not only improves the absorbing properties of materials, but also significantly increases their service life under high temperatures and neutron irradiation. Research shows that adding certain rare earth metal oxides improves the mechanical properties of materials, making them more durable and efficient. Further development of this area opens up new horizons for improving the safety and efficiency of nuclear power. The materials of the article are of interest in modernizing technological processes of nuclear technologies at the design and initial development stage, as well as in training highly qualified specialists and ordinary readers. The results obtained in the course of complex studies require further understanding. The results of the studies also showed that dysprosium hafnate, like other materials with a disordered structure, have high radiation resistance. It has been established that a change in composition determines synthesis, and the use of various methods allows obtaining materials with differentiated properties, which directly affects the physical and operational characteristics.

With the opening of new horizons in nuclear energy, especially in the context of the development of third-generation reactors and their improved versions, the requirements for safety and environmental sustainability of nuclear technologies have increased significantly. An important aspect of these requirements is the efficient functioning of materials for absorber elements, which play a key role in monitoring and regulating the nuclear reaction. Absorbers ensure the possibility of reliable reaction control, reducing risks and complying with environmental protection standards. Hafnates are one of the most promising grades of materials for use in new reactors. These compounds are characterized by high neutron absorption capacity and stable physicochemical properties at high temperatures. One of the main advantages of titanates is their ability to create effective structures that can quickly respond to changes in reactor operating conditions. This allows them to retain their characteristics even at high temperatures and radiation exposure. The advantages of using gadolinium as a burnable absorber, which can increase the initial fuel load and expand the reactor core, as well as the energy release field, are considered. The article presents the results of an experimental study of the corrosion resistance of gadolinium titanate obtained by a mechanochemical method. The tests are carried out in an autoclave at high temperatures and pressure, with measurements of changes in samples during heat treatment. The data obtained increase the efficiency of using additional material. The conclusion is made on the need to develop technologies for mass production of absorbing elements, as well as improving the quality control and reducing the costs of manufacture. It is noted that the development of new materials based on complex oxide ceramics of rare earth elements requires solving problems associated with the introduction into mass production, quality improvement and production costs reduction.

Introduction. This paper investigates the influence of deformation thermocyclic treatment (DCT) and subsequent normalizing on the mechanical properties and microstructure of low-carbon Steel 10. Low-carbon steels are widely used in engineering due to its high ductility; however, traditional heat treatment methods have a limited effect on its strength. Steel 10, with slightly increased carbon content, is more susceptible to heat treatment, which allows for optimizing the balance between strength and ductility. The purpose of the work is to determine the optimal parameters of DCT and normalizing for achieving the best combination of mechanical properties of sheet steel Steel 10. In this work, Steel 10 samples, produced by OJSC “NKMC”, were studied. The methods of investigation include the analysis of the chemical composition using an emission spectrometer ARL 4460. Samples were subjected to cyclic forging (DCT) on a hydraulic press, followed by rolling to a thickness of 3 mm. Mechanical properties (tensile strength, yield strength, elongation, and reduction of area) were determined using a testing machine Instron 3369. Results and Discussion. The results showed that DCT leads to grain refinement and texture reduction, which improves ductility. The optimal normalizing temperature is 900°C, providing the best combination of strength and ductility for both conventionally treated and DCT-treated steel. At the same time, DCT slightly increases the strength but significantly increases the elongation (by 15 %) and the reduction of area (by 11%). Subsequent normalizing of the DCT-steel significantly increases ductility (by more than 50 %) and reduces strength. The data obtained allow for optimizing the technological process to achieve the desired balance of properties.

Dysprosium molybdate powder was prepared by the mechanochemical method from a stoichiometric mixture of molybdenum oxide and dysprosium oxide. The XRF, TEM and SEM methods showed that during mechanochemical treatment for 30 minutes, due to mechanochemical reactions between the initial powders, a fine powder of the Dy2MoO6 compound containing up to 8% Dy2(MoO4)3 was formed. The technological properties (fluidity, compactibility) of the mechanosynthesized dysprosium molybdenum powder, as well as its microstructure after sintering, have been investigated.