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

The results of an experimental investigation of the changes occurring in the properties of heat-exchanger material and the thermal conductivity as a result of non-soluble aerosol deposition on heat-exchange surfaces of the passive system removing heat from the containment during severe accidents at NPP are reported. As the investigations showed, the deposited aerosol does not significantly influence

The results of a simulation, performed using the code ATHLET/BIPR-VVER (Russia, Germany), of tests on connecting a single main circulation pump (MCP) unit with three operating units during operation of VVER-1200 at 26% normal power level are presented. A comparison of the calculation and experiment showed the accuracy of the computational model to be satisfactory. Modeling is sufficient from the stand-point

In the course of a controllable thermonuclear fusion reaction the state of the plasma in the reactor must be monitored. Neutron diagnostics can provide some parameters of the plasma in the thermonuclear reactor. In the present work, the neutron diagnostics of the equatorial port of the ITER is checked by means of Monte Carlo modeling of seven external fast-neutron spectrometers based on solid stilbene

A series of works was conducted on determining the coefficient of heat transfer in a bundle of heat-exchange tubes in transverse flow of lead in the base oxygen regime and with oxygen concentration on the saturation line. The object of investigation was an experimental model consisting of a horizontal bundle of six rows of smooth tubes with four tubes per row. The investigation was conducted with sub-

In the decommissioning of the campus B at VNIINM located in a dense residential area in Moscow special attention was devoted to radiation monitoring. For this, the automated radiation monitoring system (ARMS) and mobile-ARMS were involved, the former during decommissioning and the latter during the most critical work; additional measurements were performed in the ventilation channel over 168 days.

The mathematical models implemented in the CABARET-SC1 code are described and the code validation results characterizing its potential in the description of key processes influencing hydrogen propagation in the reactor containment in the course of a severe accident are presented. Agreement with experimental data was achieved by refining the computational grids and adding a radiative heat-transfer model

The design of updated sources of neutrons from the composition of the State Primary Special Standard of units of neutron flux density and neutron fluence for nuclear-physics facilities, GET 51–17, whose upper bound of the reproduction range is raised several-fold as a result of the use of a better neutron generator – NG-10M, is described. The principles and methods of reproducing the neutron flux density

The population dose loads from the radioactive cloud and at residential sites in the contaminated area weredetermined. The dose was determined according to 131–135I, 137Cs, 90Sr, and 60Co. The adjacent uninhabited Dunai Peninsula, Ussuriiskii Zaliv, Primorskii Krai, and China’s Heilongjiang boundary province were considered. The effective dose of external irradiation on Dunai Peninsula was the highest

The results of experiments on the clarification of solution simulators obtainable by means of dynamic crossflow filtration during the reprocessing of mixed uranium-plutonium nitride spent fuel are presented. The experiments were performed using full-scale, dynamic, cross-fl ow filtration stands at the RT-1 radiochemical plant at the Mayak Production Association. It is shown that this method yields

The maximum coolant temperature in the VVR-Ts MAK-2 loop facility for the production of 99Mo was analyzed. The calculations showed that adequate accuracy and temperature 96.3°C are attained using more than 106 grid elements. Taking into account the temperature dependence of the thermal conductivity of the uranium-containing layer increases the maximum temperature in this layer by more than 10%. When

Experiments performed at the Mayak Production Assiciation to determine the 232U content in spent BN-600 fuel are analyzed. Calculations show that to within the limits of error the concentration largely agrees with the measured value, which makes it possible to use the calculations for a preliminary assessment of the 232U content in batches of uranium regenerated from reprocessed spent BN-600 FA.

The design of the TUK-109T large-size container developed at the All-Russia Research Institute of Experimental Physics (VNIIEF) for transporting ampuls with bundles of spent fuel pins is described. The results of full-scale tests and three-dimensional simulation modeling for strength validation for mechanical actions occurring under normal operating conditions and during emergencies are presented.

The operating time of the IBR-2 reactor depends on the fuel life. Currently, an IBR-2 run is formed at the cost of adding fresh FAs into the core without any reshuffling of the FA. In spite of its technological simplicity, this approach results in suboptimal fuel use because of high burnup non-uniformity. In the present work we propose optimizing a reactor fuel run by reshuffling FA during the run

The circulation flow in a centrifuge during enrichment of isotopic mixtures of heavy gases is determined. Nickel tetraphosphine Ni(PF3)4 was used as the working substance to study the hydraulic and separative characteristics of a centrifuge. The relative circulation parameter m characterizing the efficiency of the multiplication of the primary effect is determined by comparing the computed dependences

The results of an analysis of the thermal impact of the circulating cooling water discharged after cooling equipment in the Kalinin NPP on the thermic regime of the cooling reservoir and the climate in the littoral areas are presented. The impact was evaluated by comparing the hydrometeorological characteristics before the commissioning of the nuclear plant (1971–1983) and during its operation at full

The exportation of fast reactors under an international nuclear weapons non-proliferation regime is discussed. Russian sodium fast-reactor technology has been successfully demonstrated and is in the commercialization stage. Fast reactors with lead as coolant are being developed in Project Breakthrough. In this connection, the possibility of exporting fast reactors becomes logical. The main criterion

The trajectory of a radioactive cloud formed above the Dunai Peninsula, Ussuriiskii Zaliv, Primorskii Krai, and the border area of China as a result of a nuclear accident in Bukhta Chazma in 1985 was reconstructed. The population–cloud contact time and the radioactive fallout density of the primary dose-forming radionuclides are estimated and the obtained results are compared with the admissible norms

The SKP-KhOT system for measuring subcriticality, making it possible to determine Keff of jackets with spent FA VVER-1000 during normal operation as well as design basis and beyond-design basis accidents, has been installed in the KhOT-1 storage facility at the Mining and Chemical Combine. The results of its tests have been recognized as positive; the design basis subcriticality of the studied jackets

The automated system ASCRO developed and adopted in the nuclear industry for monitoring radiation conditions and on-site monitoring of subsoil status is continually improving, and the Rosatom State Corporation is continually expanding the sphere of activity of these systems. In the present article, the experience gained in the implementation of on-site monitoring of subsoil status in 2017 and the principles

The influence of the active-element characteristics on the efficiency of a cadmium-vapor laser pumped by uranium fission fragments was studied experimentally. The 441.6 nm laser radiation of the cadmium ion was studied. An aluminum tube with diameter ~15 mm and an inner coating of U3O8 with thickness 3 mg/cm2 served as the active element. The neutron source was the BARS-6 pulsed, fast, aperiodic, self-extinguishing

An approach to developing the NPP system with the lowest integral risk determined according to the entire life cycle and the conjugate infrastructure is studied. The search for the optimal power series of reactors for the developing NPP system is formalized and presented as a multicriterion optimization problem: reduction of harm from various risk factors and construction cost for the specified system

The results of the verification of a model of the IVG.1M reactor based on experiments performed in 1990 and 2017 are reported. Startups of the reactor which are associated with its emergence into a critical state and measured values of the power, neutron flux density, and efficiency of the CPS [control and protection system] components were chosen for verification The isotopic composition of the fuel

Dinitrogen oxide N2O (nitrogen hemioxide) is one of the harmful components of the off-gases during the reprocessing of spent nitride fuel. It enters the gas phase during the dissolution of nitride fuel in nitric acid and denitration of high-activity raffinate or the bottom solution from the evaporation of intermediate-level wastes. The preferred method of neutralizing it is high-temperature catalytic

It is proposed that the cost of production of titanium sponge can be lowered by replacing the expensive and environmentally hazardous Mg-thermal conversion process by hydrogen reduction of titanium tetrachloride. The Kroll process, which is mainly used to produce titanium, is costly, which determines the high cost of titanium sponge. The reprocessing of titanium sponge into ingots requires large amounts

To study the characteristics of the mass transfer of noncondensable gases in the primary loop of the nuclear icebreaker reactors, models of the core and the up-core space were developed using the Relap5 (USA) and Fluent (USA) codes and modeling of interphase mass transfer and transport of the gas phase by the water coolant was performed on these sections. Spatial non-uniformity of the content of undissolved

An alert indicating the formation of salt deposits in the pipelines of oil and gas production complexes reduces the financial losses associated with the removal of these deposits and the loss of production. A method of taking into account the presence of the native radionuclide 232Th and its decay product 208Tl in the deposits is proposed for performing radiation diagnostics of pipelines. The appearance

The purpose of this work is to compare industrial trials of modernized intermediate SPP-500-1 moisture separators-heaters of the K-500-65/3000 turbines in the No. 4 unit of the Leningrad NPP and the No. 1 unit of the Smolensk NPP. It was found that the distribution of the separated moisture along the perimeter and height of the steam space at the egress from the separation units is uniform in both

A classification by form and fraction of production turnovers with U–9%Mo fuel is made. The technology developed at the Institute of Physics and Power Engineering allowing unconditioned fuel rods and recovered material to be dissolved in a 10% solution of sodium hydroxide at temperatures 75–100°C is examined. The process developed for the Novosibirsk Chemical Concentrates Plant for extracting U–9%Mo

A variant of a gas cleanup system for the vitrification of liquid radwaste is proposed. The characteristics of the gas flow formed upon inclusion of liquid high-level waste in borosilicate glass are examined. Two approaches to a gas cleanup system for radwaste vitrification are analyzed. A validated choice of gas cleanup equipment is made. The proposed gas cleanup system provides an efficient and compact

Refined initial data are presented for retrospective prediction and analysis of the radiation conditions in Primorskii Krai after a nuclear accident on a nuclear submarine on August 10, 1985 in Bukhta Chazhma. The initial and boundary conditions are substantiated, including sources of radioactive contamination of the environment, emission intensity of the determining dose-generating radionuclides,

The possibilities of minimizing the volume of waste are examined for the reprocessing of spent nuclear fuel from VVER-1000 and the matrix material for high-level wastes. The analysis takes into account the designbasis isotopic composition of VVER-1000 spent fuel and the current normative base in the sphere of waste management. It is shown that deep underground disposal of radioactive wastes cannot

The results of studies of the kinetics of radiation-induced optical absorption spectra of commercially produced glasses LPX-100 and -200 (Lemer Pax Co., France) after γ-irradiation to 1 MGy in the wavelength range 320–1000 nm are reported. The restoration of light transmission was monitored for 120 days. The linear coefficients of attenuation of γ-radiation by glasses were measured using a KRONA-II-04

The purpose of this work is to analyze the use of detecting materials in radiation monitors as well as the replacement of widely used 3H-based neutron counters by neutron-detection scintillation technology. The replacement of helium counters is a consequence of two factors: the lack of 3He and widespread use of 3He-based counters in safety equipment, such as volumetric neutron detectors. Selection

Ion sources based on Penning discharge cells are now widely used in small-size pulsed neutron generators of geophysical well-logging apparatus. The operating efficiency of the apparatus is associated with the amplitude and time parameters of the neutron pulse of the generator, which depend on the gas pressure, geometry of the electrode systems, and other factors. Therefore it is necessary to investigate

Neutronics measurements are regularly conducted during operation in order to evaluate the physical characteristics of the core. A nonstandard reactimeter connected to a backup neutron detector is used to perform the measurements. A calculation of the reactivity on the basis of the indications of a single detector results in distortion of the true value of the reactivity because of spatial effects.

The results of experimental studies of the effect of the magnetic field of the well casing on the operation of the gas-filled neutron tube used in the logging equipment are reported. The operation of the ion source was evaluated in terms of the parameters of the pulsed currents of charged particles recorded at the target of the neutron tube. Analysis shows that a longitudinal magnetic field, as compared

As part of the work on eliminating the nuclear legacy temporary storage facilities for high-level solid wastes were opened, radiometric inspection of the wastes was performed, wastes were sorted, control rods of ship reactors were identified in the wastes and removed, and spectrometric determination of the induced activity in each rod was made. Forty-four rods with activity totaling 1.35·1013 Bq were

The dose loads from the natural and technogenic background to the population living in the vicinity of NPP with VVER-1200 in Kaliningrad Oblast were estimated on the basis of radioecological inspection data. The average yearly effective population irradiation dose from natural and technogenic radionuclides present in the environment is equal to 2.42 mSv. The population radiation impact from atmospheric

An analytical expression is obtained for the dependence of the maximum separative power of a centrifuge on the rotor length taking the feed flow into account. It is shown that the maximum separative power of a centrifuge is a nonlinear function of the rotor length.

The reasons for the appearance of alternating deviations of the parameters in transient regimes, which negatively impact the resource characteristics of ship reactors, are investigated. A definitive physical mechanism and certain key phenomena responsible for the appearance and evolutionary character of the deviations of the defining parameters are revealed on the basis of qualitative analysis confirmed

The behavior of mixed uranium-plutonium nitride fuel and uranium nitride was studied by means of thermogravimetry at high temperatures (to 2173 K) in a helium flow. The mass loss of the nitride samples was found in the low temperature range (<1773 K), which is not associated with decomposition of uranium or plutonium mononitrides. The mass loss occurs in two stages and is accompanied by the release

The purpose of this work is to investigate the sorption of americium from model solutions of liquid radwastes using modified solid-phase extracting agents based on TODGA as an alternative method of additional purification of liquid radwaste by removing transuranium elements by means of alkali precipitation. The kinetic parameters of uranium and americium sorption from highly saline weakly acidic (pH

The main results of experimental validation of the operability of passive core cooling systems of nextgeneration VVER are presented. It is shown that the residual heat release can be removed in 24 h on account of the operation of the second-stage water-storage system and the passive heat-removal system. As part of the validation of VVER-TOI passive safety systems the thermophysical properties of boric

The objectives and problems of modeling systems in developing nuclear thermionic power plants for use in space are discussed. The basic data of the modeling codes and systems developed in the process of creating the Enisei SNPS are presented. The principles of safe integration of a control digital computer into the control circuit of NPP are described and the results of experiments on the development

The economic expediency of re-enrichment of depleted uranium with the possibility of subsequent disposal of secondary waste is evaluated. Three variants of bringing depleted uranium as a raw material into the production of natural-uranium equivalent and enrichment of uranium product are examined. Methods are proposed for evaluating the expediency of producing a natural-uranium equivalent from depleted

When fuel rods melt during a severe accident, the movement of the structural and fuel materials along fuel assemblies can be spatially non-uniform, so that a three-dimensional thermohydraulic model is implemented in the EVKLID/V2 code as part of the HYDRA-IBRAE/LM module. The transport of the same sets of components and their mixtures as in the one-dimensional version of the HYDRA-IBRAE/LM module can

Using an experimental stand for studying the solubility of fluorides, measurements were performed at 550–700°C with step 50°C and the solubility of plutonium and americium trifluorides in melt with molar composition 73LiF–27BeF2 was calculated. Previously, such measurements were not performed for plutonium and americium trifluoride. The temperature dependence of the solubility of plutonium and americium