Data on the Akkuyu NPP operating experience in the conditions of devastating earthquakes in Turkey on February 6, 2023 are presented. In accordance with the response of the Akkuyu NPP personnel to earthquakes, approaches to organizing personnel actions during seismic impacts in accordance with local regulatory documents in force at that time are considered. An overview of international experience in regulatory regulation regarding the response of NPP personnel to earthquakes and a comparison with Russian approaches is given. Regulatory and organizational gaps have been identified in terms of staff response both in the local regulatory documents of Akkuyu Nuclear JSC and in the Russian regulatory documents in force at the NPP. The analysis of countries with a developed nuclear industry confirms the need for clear and flexible response procedures, even in case of seismic impacts that have not reached the design level. In order to eliminate the identified organizational problems, activities are developed and implemented to finalize the local regulations «Actions for the implementation of preventive measures in case of a threat of emergency situations at the Akkuyu NPP site» by including activities for the response and actions of personnel. Activities are proposed to improve seismic monitoring at the site which for the first time established an urgent notification mechanism for recorded seismic fluctuations with ground acceleration ≥0.01g at the Akkuyu NPP
or in a city of mass residence of personnel within one hour after the event. Engineering and organizational activities are proposed to increase the level of safety of personnel and equipment. It is noted that the Russian federal standards
NP-064-17, which focus on consideration of impact parameters during design and operation, do not cover aspects of responding to low- and medium-intensity seismic events. The need to refine the regulatory framework by supplementing the norms of NP-064-17 in terms of formalizing the levels of response and notification of personnel in such seismic events is justified, which will standardize the actions of personnel and prevent unjustified risks.

The article contains information about the radiation situation and radiation doses of the population, as well as occupational exposure in 2022 in the territories served by the FMBA of Russia. The radiation situation and radiation doses of the population due to the natural and technogenically altered radiation background are analyzed. Data on the exposure of personnel of groups A and B of enterprises, including nuclear power plants, are presented. In none of the controlled regions there was any excess of the maximum permissible levels of radioactive contamination of air and water in open reservoirs in the sanitary protection zone and the observation zone. The distribution of the number of personnel working with ionizing radiation sources or exposed to ionizing radiation by dose intervals for individual radiation doses, as well as the value of the collective dose, is given. The main number of 58 965 personnel (67.5%) received radiation doses up to 1 mSv. The external and internal irradiation of personnel of domestic nuclear power plants is analyzed, for which data on averages, medians, modes, standard deviations, quantiles, coefficients of variation of effective doses and collective doses are provided. Compared to 2017, the collective doses of most nuclear power plants have decreased slightly. The average dose has not changed significantly for most nuclear power plants compared to 2017. Information is provided on the structure, number of X-ray radiological procedures by types and groups of organs, collective and average radiation dose of patients for various procedures in 2022 in the territories serviced by the FMBA of Russia. The quantitative ratio is dominated by chest organ fluorograms. The structure of medical exposure of patients in 2022 is given. Computer tomography makes the largest contribution to the total dose – 75.01%, with
a contribution of 6.25% in terms of the number of procedures. Data on radiation situation and radiation dose in the Russian Federation obtained in 2022 are compared with similar data for other years.

This scientific article discusses the problem of the positive void reactivity effect for reactors operating in the fast neutron spectrum, in particular for the VVER-SKD reactor. The relevance of the study is due to the need to ensure the safety of these reactors in the conditions of out-of-design accidents. The research focuses on the MTIR-SKD reactor application as an experimental platform for peer analysis. It is shown that changing the composition of the fuel and reflectors makes it possible to obtain a void reactivity effect of a different sign. It is assumed that a negative void reactivity effect will be implemented to ensure safety at the first stage of work with the reactor, and later it may be changed to a positive one. In the first part of the work calculations of neutron balances are carried out, revealing the mechanisms of the void reactivity effect formation. The results show that the steel reflector and the plutonium-240 isotope significantly affect the positive void reactivity effect. Options to achieve negative and zero void reactivity effect also being discussed as well as achieving a positive effect using high-carbon plutonium which eliminates the risk of uncontrolled reactor overclocking. The results obtained can serve as a basis for justifying the safe operation of the VVER-SKD reactor with a positive void reactivity effect. This work has both scientific and practical significance for the development and design of safe new generation nuclear reactors that provide reliable reactivity control in various operating conditions.

One of the methods of improving the reliability of nuclear power facilities is to increase the efficiency of the loop cooling system for reactor-power equipment (RPE) of nuclear power plants (NPP). The most important element of the loop cooling system is the evaporative cooling tower (ECT). The effectiveness of its work very much depends on the climatic situation, when operating in the southern, tropical conditions of the Russian Federation and abroad, especially in conditions of global warming and the development of the atmospheric greenhouse effect. To compensate the climatic factor of standard convection cooling tower operation, it is possible to additionally introduce cooling powers in the form of small-sized, highly efficient fan cooling towers with forced cooling. Based on the existing design solutions, to ensure the stable operation of the RPE cooling system, it is necessary to install 10-15 fan cooling towers near one evaporative cooling tower. There is a need to develop separate foundations and carry out special earthworks for each fan cooling tower. In addition to the above, fan cooling tower is a system with the potential to modernize equipment (sprinklers, motors, impellers, water traps), which can lead to an increase in constant or dynamic (mainly vibrating loads from fan operation), reducing the bearing capacity of the foundation. In order to avoid a decrease in bearing capacity, as well as its overload, it is necessary to take measures to strengthen it in accordance with regulatory and technical requirements. As part of this work, the loads acting on the fan cooling tower foundation are collected, its design scheme is developed. Based on the literary review, two alternative options to strengthen the fan cooling tower foundation are proposed to ensure a promising upgrade of equipment with increased weight. Based on the analysis of the developed computational and analytical model, it is determined that the loads from the center of the foundation, due to the proposed options to strengthen the fan cooling foundation, are redistributed along the edges, reducing the maximum load by 5 times. It is shown that the second option of mesh reinforcement benefits economically compared to the first option (reinforcement with high-quality, rolling elements), reducing the cost of foundation development by 1.2 times.

A calculated estimate of the neutron-physical characteristics of a light-water reactor core with a changing neutron spectrum is presented. The software tool DESNA-7 neutron physics module, designed for three-dimensional modelling of the core in a two-group approximation, is used. The calculation of the neutron-physical cross sections is carried out in the software tool SAPHIR-95.1. Fuel assembly models with guide channels for the placement of absorbing elements or mobile displacers is developed forming two cores with the same thermal power and different ways of regulating reactivity: boron and spectral (with partial boron). To compensate the excess reactivity partially, gadolinium fuel rods in the form of Gd₂O₃ with a concentration of 5% by weight are used. Uranium oxide with natural content of U⁵ is used as the material for the displacers. The two methods of displacer extraction are considered: linear displacement during the campaign and complete extraction of displacers (stationary from the beginning of the campaign) on day 326. They do not lead to a significant change in the critical concentration of boric acid. It is shown that the use of spectral regulation makes it possible to reduce the concentration of boric acid in the coolant by 35 percent. It is shown that the reactivity coefficients in terms of temperature of fuel and coolant, and density of coolant increase modulo during the campaign, maintaining their sign. The value of the reactivity coefficient for the concentration of boric acid in the first reactor circuit, depending on the water-uranium ratio, decreases modulo. The maximum value of the axial power peaking factor in the core with spectral regulation is 1.6. The possibility of using absorbing rods placed in the fuel assembly guide channels as emergency protection devices is considered. 

Traditionally, when conducting neutron physics calculations in cases where the moderator is a steam + water system, the effect of vaporization, for example, in boiling reactors of the BWR type, is taken into account homogeneously by reducing the density of water in accordance with the proportion of steam. The paper attempts to investigate the effect of the heterogenic structure of water + vapor bubbles on the neutron-physical characteristics of the fuel assemblies of the BWR reactor. To create the model, data from the OECD/NEA Burnup Credit Criticality Benchmark Phase IIIB are used. The research is carried out using the SERPENT-2 software package which allows randomly scattering spheres of various radii filled with various materials in different areas of the reactor core. The calculations are performed using the JEFF-3.1.1 library. The dependence of the observed effect on the radii of steam bubbles and on the proportion of steam in the coolant is investigated. It is found that the differences for homogeneous and heterogeneous fuel assembly models can be up to 0.3% in the value of Kinf, which is significantly higher than the accuracy with which calculations are performed (~0.01%). It is shown that α decreases with increasing vapor bubble size when compared with the homogeneous model. Thus, a change in the neutron spectrum is justified, which affects the change in the multiplication coefficient. A calculating study of the void effect revealed that discrepancies reach 8% when considering models with different vapor contents and identical vapor bubble sizes. This value is important for the correct interpretation of the reactivity power effect in fuel optimization problems. In particular, it is relevant to justify the introduction of new fuels.

As part of the work to prepare for the decommissioning of nuclear energy facilities, the first, most time-consuming and economically costly item in the scope of the measures being carried out is the removal of accumulated radioactive waste (spent nuclear fuel, radioactive substances, nuclear materials) from the production sites of decommissioned facilities. This event is associated with solving issues related to the definition of safe technology and the development of projects for the extraction of waste from storage facilities, premises, and technological equipment for nuclear energy facilities. One of the particular tasks of preparing RADON's storage facilities for decommissioning is the removal of accumulated radioactive waste from storage facilities that were filled with molten bitumen during conservation. The complexity of the task lies in the fact that currently there is no developed and tested technology for separating the bitumen component directly from waste, with further waste disposal from storage. Possible methods of handling bituminous radioactive waste located in a storage facility located at the nuclear waste storage facility of the Nizhny Novgorod branch of FSUE RADON are presented, the advantages and disadvantages of each of the described methods, and problematic issues related to solving this problem are outlined. The relevance of the topic under consideration in the framework of the program for the rehabilitation of "nuclear heritage" facilities is to gain experience in designing, developing safe methods and practical solutions for the extraction of bitumen solid radioactive waste from storage facilities of this type in modern conditions. It is concluded that it is necessary to carry out research and development work to develop a technology for the extraction of bitumen solid radioactive waste

The article considers the issue of the use of protective polymer coatings for the long-term protection of various surfaces from radioactive contamination at nuclear power plants and other radiation-hazardous facilities. The analysis of regulatory documents regulating the procedure to confirm newly developed technologies to safety requirements in the field of atomic energy use has been carried out. The paper shows the insufficiency of available solutions and the disadvantages of known polymer compositions, which negatively affect the possibility of their use of sealing roofs of near-surface radioactive waste storage facilities. An original technology of sealing the roof of the storage facility and a recipe to prepare a protective polymer composition has been developed and tested in the conditions of near-surface storage facilities for solid radioactive waste at the Novovoronezh NPP. The method of sealing the roofs of radioactive waste storage facilities and other radiation-hazardous facilities includes: pretreatment of the sealed surface by applying two protective layers of different compositions (the first layer is a primer–insulating, based on water-dispersion paint with localizing additives, the second layer is easily deactivated, based on nitro-epoxy enamel); coating the surface with a protective sealing composition EGAiB. To apply and form the first preparatory layer, a composition based on a water-dispersion paint with additives of carboxylic acid and piperazine is used. To form the second pretreatment layer, EP-51 type nitroepoxide enamel is used. EGAiB sealing composition based on epoxy resin of the VD EPEP-72 type, is used to form the main protective layer, glycidine ether of polyatomic alcohols serves as a modifier; paraffin chloride HP–110 is used as a flame retardant; tertiary aminophenol is used as a hardener; acetone is used as a solvent according to State Standard 2768-84. The test results confirmed high performance and the prospects for further research in this direction. Based on the results of tests and verification of the operational and technological properties of composite materials (based on PVB, epoxy resins), it was found that polymer compositions based on polyvinylbuteral and epoxy resins can be recommended for use on roofs with concrete-asphalt coatings of near-surface radwaste storages.

The research relevance lies in the active development in Russian Federation of a dual-component nuclear power system based on a closed nuclear fuel cycle (NFC) incorporating both competitive thermal and fast neutron reactors. Among the considered approaches to spent nuclear fuel (SNF) management from fast reactors is the deployment of a plant located on the site of a Nuclear Power Plant (NPP). The aim of this study is to develop a methodology for assessing the microeconomic competitiveness of fast reactor NPPs with taking into account capital, operational, and decommissioning costs associated with the construction and operation of the reactors and the on-site plant. Calculations of the levelized cost of electricity, the total cost of SNF reprocessing and fuel assembly fabrication as well as the return on investment in both the NPP and the on-site plant (used to substantiate the choice of the discount rate), are conducted using an enhanced proprietary model developed by the authors and based on recommendations of UNIDO experts. The reference case involves a nuclear power plant comprising two fast reactors, each with an installed electrical capacity of W=1200 MW (with parameters similar to those of the BR-1200 design), and a co-located on-site plant responsible for both SNF reprocessing and the fabrication of fuel assemblies for annual reactor refueling. The study quantifies the annual demand for fuel and SNF reprocessing for the reactors operating within a closed NFC. The cost of electricity from a nuclear power plant and the total cost of SNF processing and fuel assembly fabrication are determined for a given set of economic parameters of an on-site plant depending on the discount rate. The analysis demonstrates that, even under scenarios involving high capital expenditures for the on-site plant —resulting in total SNF reprocessing and fuel fabrication costs of up to 8,000 $/kg of heavy metal – the LCOE remains economically viable at approximately 60 $/MW*h, provided the discount rate does not exceed 5 %/year.

The article presents the experience of teaching mathematical disciplines using neuropedagogical methods and tools at the VETI NRNU MEPhI to students focused on working in the nuclear industry. The authors consider the frame as a modern neuropedagogical tool that allows future nuclear industry workers to master professional disciplines. The authors describe how frames can be used when studying the «Functions of several variables» topic as processes that depend on several variables simultaneously are often used in the nuclear industry to ensure the operation and safety of nuclear power plants. The topic is studied in the first year, and its knowledge is in demand in all courses when studying professional disciplines, writing term papers and theses, competitive works on nuclear topics and in further professional activities.

Nuclear energy as one of the electricity key sources continues to be at the center of public and scientific discussion. The object of this research is nuclear energy, and the subject is the impact of modern social changes on its development. In the context of global challenges such as climate change, energy security and the transition to sustainable energy sources, the nuclear power industry is facing new challenges and opportunities that require careful analysis. The relevance of the topic is due to the fact that in recent decades there has been a significant change in public opinion regarding nuclear energy. On the one hand, growing concerns about nuclear safety and environmental impacts cast doubt on the feasibility of using nuclear energy. On the other hand, the need to reduce carbon emissions and ensure energy independence opens up new horizons for nuclear energy. In this context it is important to understand how social changes such as increased environmental awareness, changing consumer preferences and the development of new technologies affect the future of nuclear energy. The scientific novelty lies in the study of the relationship between nuclear energy and social change, which makes it possible to identify key factors contributing to or hindering its development. This research not only expands existing knowledge in the field of nuclear energy, but also provides new perspectives for its integration into modern energy systems. The purpose of this research is to study the impact of modern social changes on the prospects for the development of nuclear energy. To achieve these goals, various research methods are used including statistical data analysis, expert interviews, surveys, case studies, and modeling. These methods allow for a deeper understanding of the current state of nuclear energy as well as to identify social changes affecting attitudes towards it.