Abstract. The VVER-1200 (V-491) reactor is a water-cooled power reactor, the design of which provides for higher fuel and coolant operating parameters compared to the VVER-1000 (V-320) reactor. For long-term and trouble-free operation of the reactor, the fuel is modified by adding various homogeneous compounds and heterogeneous inclusions. Uranium-gadolinium fuel in a homogeneous design with axial profiling of fuel elements has received practical application. The possibility of heterogeneous use of Gd₂O₃, ZrB₂, Am₂O₃ and other burnable and alloying additives is being investigated. Such additives make it possible to maintain the thermal conductivity of the fuel at the level of conventional oxide fuel. The studied modifications show satisfactory behavior under irradiation at extremely high temperatures and burnup. However, the issues of radiation safety when handling both fresh and spent fuel remain less studied. In this work, a computational assessment of the neutron component of the radiation characteristics of a UO₂ composition with a heterogeneous variant of the localization of ^natGd₂O₃ and Am₂O₃ microcapsules was carried out. This design option does not impair the thermal conductivity of the fuel and has a positive effect on the nuclear physical and thermophysical properties of the fuel. Americium has been studied not only as a possible alternative to Gd, but also from the perspective of its possible utilization in thermal reactors. The influence of Am on the photon component of the radiation characteristics of fresh fuel is considered. It is concluded that the radiation safety of fresh and irradiated products containing Am should be achieved primarily by solving problems of protection from photon radiation. The research is carried out to develop procedures and regulations for handling new fuel during its manufacture and after irradiation in the reactor. The studies were carried out using verified calculation codes of the MCNP 6.2 and Nedis 2m programs.

Modeling of dry deposition of radioactive aerosols in the Arctic regions of the Far North is presented using a model of dry deposition of aerosols on heterogeneous underlying surfaces, which takes into account the influence of the size and density of aerosol particles, surface roughness characteristics and dynamic friction velocity, determined based on parameterization of the boundary and surface layers in the used version of the WRF-ARW model. Estimates of contamination of the earth's surface with radioactive aerosols with particle sizes of 0.1, 1 and 10 microns in the Arctic regions of the Far North (territories of Yamal Peninsula and Kola Peninsula) with heterogeneous underlying surfaces under real meteorological conditions in summer and winter periods have been obtained. It is shown that contamination of the earth's surface with radioactive aerosols in the Yamal and Kola Peninsulas depends on the size of aerosol particles and the types of the underlying surface in summer and winter. The greatest heterogeneity of contamination of the territory and its dependence on the type of underlying surface is observed for particles less than 1 micron, and for large particles, the determining factors are the terrain and meteorological conditions at the time of release. The results of numerical modeling will reduce the uncertainty of estimates of contamination of the area with radioactive aerosols and increase their reliability in the interests of analyzing and ensuring public safety, including the environmental impact of radioactive aerosols generated at nuclear energy facilities that are operated and will be used in the Arctic regions of the Far North.

The costs of ensuring the protection of modern nuclear engineering installations account for a significant proportion (20-30%) of the total cost of construction.  Therefore, optimization of the composition of radiation protection materials is an important direction for minimizing protection costs while maintaining high performance indicators. Natural resources, the deposits of which are located near these facilities, make a significant contribution to reducing the cost of construction of nuclear power facilities. In modern radiation technologies, composite radiation protective materials (REM) with a matrix of glass, polymers, cement and other materials play a key role. The inclusion of various fillers in the matrix makes it possible to design the optimal composition of REM for specific irradiation conditions determined by the isotopic composition of radioactive contamination. Both natural materials and industrial waste can be used as fillers, which helps to solve the problem of their disposal. This article presents the results of computational and experimental studies of samples of natural minerals from the northern part of Vietnam. This research is part of a comprehensive project that has been implemented at the Department of Nuclear Power Plants and Renewable Energy of the Ural Federal University (UrFU) for more than 10 years. The project is aimed at studying the radiation-protective properties of natural minerals and industrial waste in order to assess their potential applicability as part of building materials for the protection of nuclear power plants. To study the calculation of the radiation-protective properties of minerals, the sample density was determined by the Archimedes method using the MH-300A density meter, the chemical composition was determined using X-ray fluorescence analysis in the laboratory of the Egyptian Nuclear Materials Administration (Cairo), the XCOM database was used. Experimental investigation of the shielding properties of the samples was carried out using the Robotron spectrometric installation. The results of the study of natural materials revealed samples of stones that can be used as a concrete filler in the construction of nuclear power plants and other nuclear power facilities in Vietnam, as well as clay for the manufacture of radiation protection blocks for prefabricated protection.

The construction of new nuclear power plants under the NPP-2006 project required Leningradsky Metallichesky Zavod (LMZ) to implement an electronic and hydraulic turbine regulation and protection system (TRPS) in the design of a large capacity condensing turbine K-1200-6,8/50, based on the experience, design and circuit solutions for a similar system of a high-speed turbine-analogue K-1000-60-3000 manufactured by LMZ. Despite the preservation of the turbine layout in relation to the turbine-analogue (2LP module + HP module + 2LP module), the turbine control concept through the TRPS and the available references at the stage of commissioning of the Novovoronezh NPP-2 power units (before the power unit was turned on to the grid), as experience has shown, there were cases of incorrect operation of the TRPS due to the ambiguity of the assembly or hidden inconsistencies. The elimination of the causes of incorrect operation of hydraulic assemblies is often directly related to the search for the root cause "from the inside", i.e. disassembly of equipment is required. The presented article shows cases of incorrect operation of the TRPS and ways to solve them from the experience of commissioning on a high-capacity turbine K-1200-6,8/50 with a brief description of the problematic TRPS hydraulic components, the amount of refinement of structural elements. The experience of commissioning described in this article is still relevant today due to regular scheduled preventive repairs at commissioned power units of the NPP-2006 project, during which a routine audit of the hydraulic elements of the steam distribution organs is carried out, as well as a pre-start check of the interaction of the hydraulic and electronic parts of the TRPS. In addition, the commissioning of nuclear power plants with turbine K-1200-6,8/50 is currently underway abroad (in People's Republic of Bangladesh) where the described experience can be applied on occasion.

This paper presents multipoint kinetics of the VVER-1200 nuclear reactor model determined under the Avery coupled reactors formulation. Different numbers, from two to twenty, of axial nodes are modelled in MATLAB. For a more precise description of the transient’s nature, this model was extended by Mann’s thermal hydraulic model. Within the frame of Mann’s approach, one fuel node is adjacent to two coolant nodes. For daily maneuvering modes space-dependent xenon oscillations are considered and the Axial Xenon Oscillation Index is introduced. This paper also introduces the novel nodal mathematical model of the boron acid which is coupled with thermal hydraulic model by coolant mass flow rate. The computational results show that the accuracy of the proposed model is more than satisfactory, and general assumptions about transients align with their physical definitions. This research contributes to the advancement of the point-like nuclear reactor modeling for further improvement of the automatic power controller design.

In the Russian Federation the requirements for aging (life) management of pipelines which in the designs of nuclear power plant (hereinafter - NPP) units in accordance with the federal norms and rules in the field of nuclear energy use to the elements of 1, 2 and 3 safety classes, are established in NP-096-15. One of the most “dangerous” loading factors for dynamically loaded pipelines of NPPs is vibration loads as for real structures of NPP pipelines the values of corrosion-erosion wear are not high due to the use of corrosion-resistant steels and limitation of the flowing medium velocity (according to NP-068-05 water velocity is up to 5 m/s, and steam and gas is up to 60 m/s).
The issues of aging management of dynamically loaded pipelines are considered. The use of calculation-experimental
method is proposed to determine the stress-strain state of the pipeline under vibration impact in order to determine the damageability under cyclically repeated loads. It is recommended to use the values of accumulated and ultimate damage rather than standardized frequencies or vibration amplitudes as a resource characteristic under vibration loading of the pipeline.

The ability to carry the load during transients without achieving the operating conditions of the safety and emergency control action of the reactor is called the dynamic stability of the NPP power unit. Water level control in steam generators RU VVER-1200 (V-392M) is carried out to maintain a balance between steam removal, purging and water supply. A change in the water level in the steam generator caused by transients can lead to the achievement of technological protection and blocking settings, followed by the shutdown of the main circulation pump and a reduction in load. An analysis of the commissioning tests of the Novovoronezh, Leningrad and Belorussian NPP power units, as well as the shutdowns of the main equipment due to changes in the level in the steam generators, allowed us to identify possible ways to increase the dynamic stability of the VVER-1200 power units. Maintaining the nominal water level in the steam generator makes it possible to prevent steam from entering the turbine with an increased humidity of more than 1%. There are real perspectives for VVER-1200 power units dynamic stability improving by upgrading the shut-off valves at the steam generator power supply unit with increased performance and appropriate adjustments to the water level settings in the steam generator. Increasing the dynamic stability of the VVER-1200 power units will make a significant additional contribution to the economic attractiveness of the improved nuclear power plant design of domestic design.

Atomic cities, Russian cities where enterprises related to the production and industrial use of nuclear energy are concentrated, are chosen as the object of research in this article. The authors will include in this list the cities of location of nuclear power plants and closed administrative territorial formations of the nuclear industry. Currently, more than 2.35 million people live in the cities where the State Atomic Energy Corporation «Rosatom» operates. The development of these territories as a framework for the development of our entire country is one of the important tasks of ROSATOM. The subject area of the study is to recreate and support the identity of the so-called “corporate image” of public areas of atomic cities (parks, squares, recreation areas). The article proposes to do this by equipping the designated places with small architectural forms of the architectural style common to all atomic cities (in the form of a peaceful atom, cooling towers, reactor, etc.). The objective of the study is to propose a design solution that will revive the traditions lost over time in terms of creating a unified architectural image of parks and public gardens in the cities where ROSATOM is present, while increasing the comfort of urban public spaces in these cities. The main methods of research are theoretical analysis of scientific literature on the problems of creating and improving the image of territories, systematization of the available material, its graphic visualization and others. The main result of the study is the justification of the feasibility of developing models of small architectural forms (benches, garbage bins, vases, entrance areas, lampposts, bicycle parking lots, etc.), the appearance and shape of which can identify the belonging of a park (public garden) to the city of presence of a nuclear power facility. This, in turn, will revive the unified appearance of urban spaces of atomic cities, and will have a positive impact on the growth of the level of attractiveness for tourist traffic and on the comfort of public spaces for the local population.

The article presents the experience of applying the ecosystem approach in the higher education system when building a university development strategy that ensures the training of personnel with the competencies necessary to achieve the country's technological sovereignty, ready for rapid learning and adaptation in a changing external environment, capable of developing technologies. The authors present the basic principles of implementing the ecosystem approach in practice of National Research Nuclear University «MEPhI», and also identify the key results obtained in the application of the ecosystem approach based on changes in educational, research, innovation, organizational and managerial processes