The paper considers assessments of aquatic ecosystem state. The analysis of existing assessments in hydrochemistry is carried out, their advantages and disadvantages are revealed. The work proves the application of indicators of alkaline phosphatase and extracellular esterase to assess the status of aquatic ecosystems in the monitoring of surface land waters. 

The paper considers a functional linear equation with a shift in the radiation protection model for the transport of charged particles and ionizing radiation. The aim of the work is to study the questions of the existence and uniqueness of solutions for various cases that arise when the initial parameters of the model change. The analysis of the system accompanying the functional equation is carried out by linear algebra methods. For the case of the inequality to zero of the main determinant of the accompanying system, the correctness of the obtained solutions is shown; the functional equation has a unique solution. If the determinant vanishes, the problem is completely solved for cycles of length 2. The functional equation has no solutions if the determinant is zero and the rank of the extended matrix is 2. For the case of a joint system with a degenerate matrix, analytical formulas for the general solution of a homogeneous and inhomogeneous functional equation are obtained . These solutions depend on the coefficients of the initial equation, the initial function generating the cycle, and contain an arbitrarily chosen function. To eliminate the ambiguity that arises, one can go to a model with a non-degenerate matrix by changing the system of weight coefficients of the model equation, or use additional initial conditions.

The article shows that the segregation heterogeneity inherent in 10GN2MFA steel preforms causes the formation of sections enriched with alloying elements, impurities and nonmetallic inclusions, which leads to a pronounced structural heterogeneity and different tendency to recrystallize during pressure treatment, the formation of quenching structures, and hot cracks in the heat affected zones during the execution of the outer rollers during automatic submerged arc welding. Such behavior can also appears in the weld metal with increased heat input, and other deviations in technology that cause the formation of a large dendrite structure. 

It is established that if the original equations of hereditary viscoelasticity in the traditional form contained two independent viscoelastic operators corresponding to the axial and transverse creep strains, then the record in the components of the deviators of the state equations will already contain three different viscoelastic kernels defined by the compositions of the original two operators. These three operators can coincide up to a real factor only when the Harutyunyan hypothesis about the constancy of transverse deformation (i.e., the constancy of the Poisson's ratio) during creep is fulfilled. Body with a similar viscoelastic behavior are called quasi-elastic. Taking into account the results of studies, as well as the fact that until now only the creep kernel has been experimentally established under axial tension and the transverse creep kernel has never been defined, it is currently not possible to solve the problems of hereditary creep beyond the application of the Harutyunyan hypothesis. It is also obvious that the volumetric strain operator cannot be identical, since it is determined by the composition of the creep operators. The application by some authors in their studies of the hypothesis of the identity of the operator has no mathematical or physical grounds. In the case of nonlinear viscoelasticity (or viscoelastic plasticity), with sufficient accuracy for practice, one should simply linearize the equation of state using the secant module and reduce these problems to the case of linear viscoelasticity already studied in this article.

The article deals with development of modified finite element method for real-time calculations of virtual welding parameters and virtual welding joint geometric properties. The representation of welding joint as array of square-based columns, with movable horizontal separator between solid and molded parts, is shown. The development causes the result as opportunities for visualization of welding joint and its calculations. 

This work presents the results of numerical studies on the possibility of increasing the maximum safe using different kinds of fuel for sodium-cooled BN reactors. The purpose of this work is to study and detect fuel or fuel combination with the best technical and economic indicators and safety conditions for the BN-800 reactor plant which not only increases the economic indicators but also the efficiency of the entire pre-reactor cycle. For some time now, the problems associated with a decrease in the amount of U235 resulted in an increase in price and an increase in the amount of accumulated Pu initially achieved in the military industry. However, since the reprocessing of spent nuclear fuel (SNF) by WWER and RBMK, ways must be sought to compensate for these phenomena with the priority of reliable and safe operation of a nuclear facility. An indicator of reliable and safe operation of nuclear power plants in the case under consideration is SVRE (sodium void reactivity effect). Achieving high values of this value leads to a decrease in the secure operation of NPPs and forces us not only to find ways to increase the RF, but also ways that result in minimal values for SVRE with maximum RF. In the calculations aimed at the reduction of SVRE it is assumed that the minimum value of KW is KW ≥ 0,95. The paper examines the effects of several important factors on reactor performance and economic performance. These factors include the use of different fuels and fuel combinations, the geometric dimensions of the reactor, the distribution of enriched fuel in the core, and the change in specific fuel volume within allowable limits. The influence of geometrical dimensions on the SVRE is considered, the size of the core is changed due to a change in the specific heat release and the volume fraction of the fuel. In the core fuel is introduced which nuclei have no spectral dependence on the amount of sodium. 

The pare shoes the development cartogram of changes the natural frequencies of coolant pressure oscillation (NFCPO) in the reactor core to predict the conditions of growth the vibrations of fuel assemblies (FA) for WWER-1200. Determination of the average temperature and pressure of the coolant in the core in the nominal mode is carried out by applying the known calculation results obtained using the thermo hydraulic three-dimensional CFD model of the WWER-1200 reactor. It is shown that the coincidence of the NFCPO with the frequency of vibrations of the FA is possible only at certain values of pressure and temperature of the coolant and vibration amplification occurs only in the temperature range corresponding to the bandwidth relative to the detected value of the NFCPO. It is shown that it is possible to increase flexural vibrations of FA-2M at different stages of reactor start-up. 

The paper raises the question of increasing the sensitivity of NPP equipment diagnostics due to the increase of the overhaul period. It is proposed to use the principal component approach. The results of an experiment indicating an increase in sensitivity and selectivity through the use of the proposed method are presented.

The article considers the creation of a portable software and hardware complex for diagnostics of diesel generator sets of nuclear power plants to increase the sensitivity of diagnosis of diesel generator sets and conduct a comprehensive analysis of diagnostic parameters. The work provides a synthesis of a block diagram of a portable software and hardware complex for diagnostics of diesel generator units of nuclear power plants. 

The article studies the main tasks of quality management. It settles the importance of effective human resources management in the aspect of strategic development of an organization. It emphasizes the necessity of sustainable development model and lean production model as a basis of ecological and social safety in a modern organization by the example State Corporation «Rosatom». 

The paper analyzes economic, environmental and social problems that have a certain impact on the development of nuclear energy in the Federal Republic of Nigeria. It considers the political structure of the country, the demographic and religious characteristics of the population, the environment, the general state of the economy, agriculture and industry of Nigeria. Particular attention is paid to the oil industry of Nigeria as nowadays it is currently the most developed industry in the state which provides the country with OPEC membership. The work shows that the country lacks energy capacities for the sustainable development of the economy. To solve this problem hydroelectric power plants are being designed on the Niger River, as well as thermal power plants operating on gas produced in the Niger delta, the construction of nuclear power plants is planned. Currently, the country's population is 201 million people and its number continues to grow rapidly. Therefore, the government decides to put into operation two nuclear power plants for the further development of industry and agriculture. However, both the construction of the NPP and its operation are hindered by military conflicts that very often arise in Nigeria on a different basis: political, interfaith, interethnic and economic. It is quite difficult to carry out both the construction of radiation hazardous facilities and their operation in such conditions.There is a need to take increased security measures for physical protection of both specialists involved in the construction of radiation-hazardous facilities and directly the facilities themselves. 

The article discusses research materials on the application of new approaches to the formation of human resources for the nuclear industry as part of the early career guidance of schoolchildren. “Young Nuclear Expert”, a regional model for the early career guidance of schoolchildren, is developed based on an analysis of the current requirements for Rosatom employees, corporate values, the importance of the human factor in the safe operation of nuclear power plants, and the Concern’s recommendations. The events carried out by the chairs of VETI NRNU MEPhI to form universal competencies among younger students, their professional self-determination are highlighted.