Sixty years of experience in mastering alkaline liquid metals jointly with industry institutes, the Academy of Sciences, and engineering design agencies developing Nuclear Power Facilities (NPF) has culminated in the development of the scientific foundations for their use in nuclear power and the scientific substantiation of the hydraulic parameters and highly efficient technological processes ensuring

The results of studies on the physical chemistry, mass transfer, and technology of alkali liquid-metal coolant are reported. The state of the coolant is determined by the interaction coolant-impurities-structural materials- protective gas. The impurity sources and their intensity were determined: sodium and sodium-potassium alloy – oxygen, hydrogen (tritium), carbon, products of corrosion of structural

Safety enhancement of NPP power units with water-moderated and -cooled reactors on the basis of installation of additional multifunctional low-power steam-turbine generators is studied. It is shown that the parameters of the primary and secondary loops change as the VVER-1000 reactor is cooled via the use of the residual heat in the core to generate steam that serves as the working body for a low-power

To the article “Excitation Functions of the Reactions Ag109 (p, n); Ag109(d, 2n); Ag107 (α, 2n+pn), and Yield of Cd109,” by P. P. Dmitriev, I. O. Konstantinov, and N. N. Krasnov, Vol. 22, No. 4, pp. 386–388, April, 1967.

Methods of calculating the nuclear reactor reactivity from the measured time-dependence of the neutron flux are discussed. It is noted that the corresponding problems for the direct and inverse equations of point kinetics in the approximation of a prompt-jump change of neutron flux are not equivalent, which is expressed in that the reactivity values in these problems do not coincide with one another

The saturation yield of the rhenium radioisotopes 186Re, 188Re, and 189Re on irradiation of a 186W target by the nuclei 4He, 3He, 1H, and 2H with energy 47, 25, 15.3, and 19 MeV, respectively, was measured by the activation method. The chosen energy of the accelerated particles made it possible to minimize the contribution of the activity of long-lived rhenium radioisotopes in the desired radionuclides

The hydraulic resistance of irregular fi ne packing is studied as a function of the process parameters for the rectification of metal hexafluorides. It is shown that the dependence of the hydraulic resistance of irregular fi ne packing on the rectification parameters coincides with the dependence presented in the literature but with different coefficients and exponential factors.

A quantitative assessment of the 131I activity in RBMK coolant as a function of the number of defective fuel pins and the distribution over a fuel run is presented. The 131I yield fraction is determined using a model based on the solution of the diffusion equation with empirical coefficients. This investigation was performed for a core-average FA whose power is a function of the burnup. It is shown

The design of a KGK-2 γ-ray dose rate detector is described. The basic characteristics of the detector are presented. The readings of a KGK-2 gas-filled ionization chamber detector and VED-2 secondary-electron emission detector during power startup of BR-K1 and BR-1M reactors are compared. It is shown that by using KGK-2 and VED-2 detectors in combination the γ-ray dose rate can be measured in the

The purpose of the present work is to analyze the long-term yearly average volumetric activity in the surface air and the yearly absorbed dose of β- and γ-radiation in the spread zone of continuous emissions from NPP. The particulars of the spreading of the emission radionuclides and the associated yearly absorbed radiation dose are determined. It is shown that the atmospheric volumetric activity of

A stand for inspecting experimental fuel pins in the cooling pool of the MIR.M1 reactor and methodological approaches to measuring the height and diameter of experimental fuel pins are described. The basic characteristics of the equipment used for performing measurements are described. The structural features of an experimental FA (EFA) and the test parameters of experimental fuel pins in an assembly

The basic regularities in the transmutation Np, Am, and Cm in a molten-salt burner reactor are examined on the basis of the results of neutronic calculations of an idealized infinite homogeneous medium consisting of metal halogenides with low atomic mass. It is shown that an optimal equilibrium regime for the transmutation of Np, Am, and Cm in a molten-salt burner reactor could exist. In this regime

Grid designs with mixing elements for VVER FA and experimental studies of their thermohydraulic and mass transfer characteristics are analyzed. The Novosibirsk Chemical Concentrates Plant and the Machine Building Plant manufacture the grids. Comparative assessments of the coolant mixing intensity, increase of the critical heat flux and critical power, and coefficient of hydraulic resistance are made

The observed differences of the neutron fluxes between experiments and calculations on passage of neutrons through thick layers of iron and steel are conditioning the use of better models for representing the scattering cross-sections and energy-angle distributions of neutrons in elastic and inelastic scattering. The effect of the NJOY99 and GRUCON prepared nuclear data for Fe, Cr, and Ni on Keff and

The behavior of radionuclides (Kr and Xe) and process gases (CO) in the vacuum-cesium channel of a thermionic converter reactor is modeled by solving Boltzmann’s equation numerically. Modeling techniques and a software system were developed in the course of this work. Series of calculations were performed for the variation of the initial flux of radionuclides, the dependence of the radionuclide flux

A method of calculating and optimizing a multi-flow cascade with a specified number of gas centrifuges in stages on cuts of their partial flows were developed. A special feature of the method is an iterative fitting of the separation coefficients of the gas centrifuges that depend on the feed flow and the division factor of the flow. A computational experiment was conducted on the separation of molybdenum

This article is devoted to model calculations of a lead-cooled reactor core performed using the EVKLID/V1 code. The ingress of water vapor into the core is modeled for the stationary state of the reactor at the rated power capacity. The change in the reactivity and power at different mass flow of water vapor is analyzed. Baseline calculations performed using the MCU-FR code were performed in order

The results of research on the influence of the chemical composition, cold-deformation, and irradiation temperature on the short-time mechanical properties of the austenitic stainless steels 08Kh18N10T, EI-847, EP-172, and ChS-68 after neutron irradiation in the BN-350 fast reactor to damaging dose 57–59 dpa in the range 400–490°C are reported. The investigation showed that high-temperature radiation

EdF’s idea of irradiating in Russian fast reactors fuel pins with recycled plutonium arose in February 2016 during a discussion with CEA of testing experimental FA in BN-600. EdF proposed to additionally irradiated several fuel pins fabricated using plutonium obtained after reprocessing of mixed fuel irradiated in PWR. In 2017, the studies with fabrication of full-scale FA were to expensive, so that

The operation of a high-temperature fuel rod with a fuel kernel consisting of uranium dioxide is accompanied by significant changes in the initial structure of the fuel – a multi-zone dioxide structure with different grain size and shape (growth of initially uniaxial grains, formation of a columnar structure) can form in the transverse section of the kernel. For low level of stress appearing in the

The CELSIST subchannel module is described. The results of the simulation of experiments on the flow of liquid metal coolant in model FA are presented: lead-bismuth eutectic alloy in a 19-rod FA on the THEADES stand (Karlsruhe Liquid Metal Laboratory, Germany), sodium in a 19-rod FA on the Bundle 2A FFM stand (ORNL, USA), sodium-potassium eutectic alloy in a 37-rod FA on the 6B stand (IPPE, Russia)

The absorbed dose rate of external γ-radiation from two sources of radiation – surface soil layer and subsurface phytomass of plants in stand grass – is calculated by different methods. The calculation of the absorbed dose rate based on integration of the dose attenuation function of a point source taking into account the dose accumulation factor was compared with the results of a Monte Carlo solution

The possibilities of burning americium from spent nuclear fuel of thermal reactors in the operating BN-800 are examined. It is shown that because of the small fission cross-section in the neutron spectrum of a fast reactor all of the americium cannot be directly converted into fission products. This can be done only by transmutation of americium into plutonium, which must be separated and directed

The radiation conditions at a ship repair yard in Bukhta Chazhma after a nuclear accident on a submarine on August 10, 1985 were reconstructed by means of hindcasting taking into account a 3D model of the enterprise and dose rate measurements during the first few days after the accident. The submarine presented the greatest danger during the first few days. The dose rate was equal to 1500–2500 mSv/h

The startup of a space nuclear power system is conducted after the space vehicle is put into its operational orbit. The reactor is in a deeply subcritical state, it is technically unfeasible to use a startup source of neutrons, and ground-based operator intervention is excluded. Since payload usage before the nuclear reactor starts is supported by storage batteries, the problem of reducing the startup

Radioactive wastes are formed during the production of uranium-plutonium nuclear fuel at enterprises. In the present article the concentration ranges for uranium, plutonium, and neptunium in liquid and cemented wastes corresponding to different radioactivity classes are determined. The concentration ranges are determined for wastes formed in the production of nitride fuel for the initial load, as well

The definition of the separation potential for multicomponent separation is analyzed. The possibility of introducing a particular separation potential together with the general separation potential for concrete setups is examined. An expression is obtained for the particular separation potential of a gas centrifuge.

The neutron fluxes of D–D and D–T tubes with sorbed and stuffed targets are compared. Calculations of the change of the neutron flux in generators when a tube of one type is replaced by a tube of a different type are presented. The influence of the atomic-molecular composition of the ion beam and the target material, the hydride stoichiometry, and the isotopic composition of the gas in the getter is

Work has been performed as part of the implementation of measures to reduce the hazard of irradiated graphite during the decommissioning of uranium-graphite nuclear reactors. Electrochemical decontamination is studied as a method of purifying the indicated wastes from radioactive contamination. The results of experiments on removing 60Co,134,137Cs, 154Eu, and 241Am from the surface of irradiated graphite

Analysis of the problems and potential of two nuclear technologies based on fusion reactions of light nuclei and fission of heavy nuclei shows the following. Independent large-scale development of each one will make it necessary to overcome still unsolved technological, materials science, environmental, and economic problems, raising the question of the expediency of further development of these energy

The development of any energy system, including nuclear, is a lengthy and multi-stage process. To evaluate the outlook, many significant factors outside the nuclear energy system and the uncertainty of future avenues of macroeconomic development must be taken into account. This task requires a multi-criteria approach to the analysis of the competitiveness of the technology using criteria that combine

A clinically available software method has been developed and tested for evaluating tumor dynamics according to size and physical density in adaptive radiation treatment of cancer patients for any cases of imaging of tumor borders, including fuzzy imaging of the tumor borders. The quantitative informativeness of the method is shown.

The results of studies of the intensification of heat-and-mass transfer and mixing of coolant are presented. Justification is given for the design, number, and arrangement of intermediate intensifier plate grids in combination with honeycomb spacer grids in the structural implementation of TVSA-T. The hydraulic and thermo-mechanical constraints of the design are taken into account. It is shown that

In the second half of the 1950s, when all resources of the Soviet Union were directed at making as fast as possible a nuclear bomb as a weapon of deterrence, scientists did not leave any stone unturned in their efforts to convince the managers of the Soviet nuclear project of the need to begin work on the peaceful use of atomic energy. The story of how a decision was made to create the world’s first

The kinetics of a pulsed booster controlled by a high-energy proton beam is examined as a promising source of powerful neutron pulses. A subcritical multiplying assembly based on plutonium dioxide with a reactivity modulator is considered as the pulsed booster. The pulsed booster intensifies neutron pulses generated in a non-multiplying target by the accelerator protons. The parameters of the neutron

An analytic solution is given for a system of first-order inhomogeneous linear differential equations describing the mass transfer of fission products in radioactive decay chains of arbitrary complexity and length by means of a system of an infinite number of working zones separated by radiation safety barriers. The computational procedure is implemented in the TARUSA system of computer codes, making

Some issues concerning the prevention of dangerous radiation exposure of the general public and providing insurance for spacecraft with next-generation nuclear reactors are examined. It is shown that the technical and organizational measures to meet the requirements of international and Russian documents will secure radiation safety for the general public when using spacecraft with nuclear reactors

The 14C emissions from NPP with RBMK-1000 and EGP-6 reactors as well as the yearly population irradiation dose due to these emissions are evaluated. A model is presented for calculating the population irradiation dose due to 14C emissions assuming an equilibrium 14C distribution between local food products and atmospheric air and absence of such an equilibrium for humans as a result of the consumption

Issues concerning the completeness and integrity of a strategy for the development of nuclear energy in Russia to 2050 and the prospects for the period to 2100 are examined. It is shown that questions concerning the final stages of the lifecycle and environmental aspects associated with the use of nuclear technologies are not duly reflected in the strategy. The authors believe that the strategy cannot

The chemical and structural properties of cement compounds, containing radwaste simulators, after exposure to γ-radiation and electrons to absorbed dose 100 MGy are examined. It is shown that the phase composition and surface morphology of samples of cement compounds do not change much and the chemical stability remains satisfactory.

The results of verification of the module for sodium aerosol behavior in moist air in an enclosure on experiments performed using the ATF facility (India) are reported. The computational results for the average diameter of aerosols suspended in air with different moisture content and initial mass concentration were compared with the experimental data. The sensitivity of the computational results to

This article contains information on the occupational external and internal radiation exposure in 2017 for organizations (including NPP) in areas served by the Russian Federal Medical Biological Agency. The parameters of the dose distribution were calculated: mode, median, average, standard deviation, quantile, and coefficient of variation. The distribution of the number of individuals working with

The possibilities of using partial neutron-transport equations, as compared with the classical system of equations, to estimate the temporal behavior of a fast reactor, for which computational studies have been performed on test models of the MET-1000 and MOX-1000 reactors developed as part of the Gen-IV project, are analyzed. The movement of the control rods was modeled as a reason for the appearance

A method of optimizing gas-centrifuge cascade systems for separating binary mixtures of isotopes is proposed. This method makes it possible to determine the optimal parameters of a system with an arbitrary scheme for connecting steps and cascades without performing preliminary calculations of each cascade. This method was used to perform calculations of two-cascade systems with different connection

The outcome of a project to integrate the business-process of computational validation of reactor equipment into a unified information space of an enterprise for the purpose of creating digital doppelgangers of nuclear power facilities is reported. The preparation time required for design documentation was reduced by implementing a program link between the Product Lifecycle Management (PLM) and Simulation

For technical and economic reasons, the technology for extracting platinoids from irradiated fuel is a complex problem. The purpose of the present work was to analyze the content of platinoids in the products of the technological scheme used for reprocessing spent fuel, the most called for methods of extracting platinoids, and the outlook for using platinoids. The problem of extracting platinoids cannot

An advanced version of the BERKUT-U/V2.1 code intended for modeling the behavior of fuel rods with oxide or nitride fuel in standard and emergency operating regimes of fast reactors with liquid-metal coolant is being developed at the Nuclear Safety Institute, Russian Academy of Sciences (IBRAE RAS), as part of the project Next-Generation Codes of Project Proryv (Breakthrough). The present work reports

It is shown that the technological scheme for fabricating uranium dioxide pellets is suitable for fabricating uranium-molybdenum pellets. It permits using the standard powder metallurgy methods to fabricate pellets from uranium-molybdenum powder obtained by thermocentrifugal atomization of ingots of uranium-molybdenum alloy. The proposed technology uses standard equipment operating in easily reproducible

An experimental study was performed of the influence of mixing intensifier-grids on the cooling of a 37-rod electrically heated TVS-2M model with top and bottom reflooding. It is shown that the mixing grids bring about a very small reduction of the maximum temperature of the rods and longer cooling time of the assembly. To cool the TVS-2M model, the starting temperature of the fuel-rod simulators and

The results of using the CONV-3D code to model incompressible fluid flows in round tubes in laminar, transient, and turbulent regimes are presented. The results of modeling with different Reynolds numbers are compared with the Poiseuille parabola and the Blasius formula. It is shown that the code satisfactorily models the flow of an incompressible fluid in laminar, transient, and turbulent regimes

The problems associated with the corrosion of steel in sodium are examined. Equations including the physical constants characterizing mass transfer in the sodium–steel–impurity system are presented. The solution of the system of equations makes it possible to calculate the distribution of the dissolved components and suspensions in sodium flow. The source of the dispersed phase in the coolant fl ow

It is shown that dialysis cells with a sedimentary membrane spontaneously forming from reaction products can be regarded as an effective method for reprocessing the radioactively contaminated liquid media. The studied cell was created on the basis of a commercially produced anisotropic microfiltration element made of fibrous polypropylene. The dialyzer operated in a regime of continuous purging of

The shape and size of the projection of the focal spot of an x-ray tube largely depend on the direction of the beam, which results in a spatial difference of the point spread function (PSF) of the imaging system. A model developed for determining the PSF at an arbitrary point of the radiation field is presented in this article. The input data for the model are the geometric parameters of the system

The characteristic operational features of different flowmeters and devices for measuring the coolant and feedwater flows in the loops of nuclear steam generating facilities (NSGF) currently operating in NPP are analyzed. A new design has been developed for labeled nuclear-magnetic flowmeter-relaxometers with a new flow measuring regime. This regime and other new structural solutions in the new devices

A method was developed for optimizing a cascade with two additional product streams, in which two components of intermediate mass are concentrated simultaneously. The solution of the optimization problem is based on variation of the cuts of partial flows of the cascade steps with large separation factors. A minimum of the total feed stream of the steps with specified concentration of the isotopes is

The status of development work on fuel pins with fast-reactor nitride fuel and a liquid-metal sublayer, which is being considered in Project Breakthrough (Project Proryv) together with fuel pins with a helium sub-layer, is presented. Such fuel pins are shown to have the potential to improve the core characteristics of the advanced high-power reactors BR-1200 and BN-1200. The basic results for the development

The purpose of this work is to develop a migration-dosimetric model of the formation of the irradiation of grassy plants in meadow biogeocenoses under constant radioactive fallout. The model makes it possible to calculate the volumetric activity of radionuclides in the atmospheric surface layer and the intensity of their deposition on the earth surface, the dynamics of the activity of radionuclides

It is shown that there exists an optimal thickness of a rubidium target, dependent on the proton energy at its ingress, for reaching a compromise between the maximum yield of 82Sr and a minimum relative yield of the impurities 83Sr and 85Sr. The optimal irradiation regime and holding time are determined for a target to chemical separation of strontium from it during operation with no accelerator downtime

One of the predicted disruptions in the normal functioning of steam generators in a lead-cooled reactor over a long period of operation is depressurization of the heat-exchange tubes. The most likely tube failure sites are the tube–spacer comb interfacing zones. The oscillatory motion of the tubes in the lead coolant makes it necessary to study the fretting of the tube material. We describe the structural

First-order perturbation theory for the multiplication coeffi cient based on the method of characteristics in the form used in the MCCG3D code is presented. Finite-difference analogs of the perturbation theory formulas are derived using the difference scheme of the MCCG3D code. Test calculations were performed. It is shown that the results obtained by perturbation theory and direct calculations converge