Lead-bismuth Coolant Research Articles

Numerical Study on Characteristics of Lead-Bismuth Lubricated Hydrodynamic Bearing Considering Non-Condensable Gas

Lead-Bismuth Eutectic (LBE) is an interesting candidate as a coolant for Generation IV nuclear power plants. Lead-bismuth lubricated radial guide bearing is the key component of the mechanical pump in a lead-bismuth coolant system. In this paper, the transient calculation model of multiphase lubrication flow field of journal bearing is established by using Singhal full cavitation model and structured dynamic grid technique. Due to the saturated vapors of LBE being very low, the effects of different Non-Condensable Gas (NCG) contents on the characteristics of lead-bismuth lubricated journal bearing systems were analyzed. The results show that the NCG content has an obvious influence on the working state of the bearing. With the increase in NCG content, the bearing load capacity decreases. Under the same load, with the increase in NCG content, the eccentricity of the static equilibrium position will be larger, which will increase the risk of bearing contact with the bearing bush. Moreover, the increase of NCG content will lead to the increase of tangential oil film force work, which is helpful to improve rotor stability.

Vibration response analysis of mobile liquid Pb-Bi micro-reactors under transportation with liquid sloshing

Mobile micro-reactors, which used the liquid lead–bismuth eutectic (LBE) as coolants, providing energy to remote regions had become a popular topic in nuclear energy due to their desirable characteristics, including inherent safety and modularity. However, the liquid sloshing effect in a reactor may exhibit fluid–structure interaction (FSI) coupling effects, which could have a significant impact on the relevant internal systems. And the ratio of coolant in liquid to solid form was correlated with the duration of heat dissipation. This paper aimed to investigate the liquid sloshing effect in a micro-reactor that was subject to vehicle vibrations, the objective was to provide recommendations for transportation scenarios involving various liquid sloshing. To achieve this, a full-vehicle dynamic model of the system was developed using multi-body dynamics. Additionally, MATLAB simulation software was utilized to simulate the road roughness loadings that the micro-reactor may encounter during transportation. Moreover, a finite element numerical model of the Mobile Micro-reactor had been developed in order to simulate the sloshing effect that occurred during transportation, the numerical models presented in this study were validated by comparing them with a previously-verified Housner model that involved a cylindrical tank. This study investigated the sloshing effects of the Mobile Micro-reactor under different liquid–solid ratios of coolant, internal component lengths, and liquid surface heights. The results indicated that the internal components within the reactor vessel can alleviate the sloshing effect. The solid ratios of liquid lead–bismuth coolant and the liquid surface height during transportation had an impact on the sloshing effect. These findings provided valuable insights for studying the sloshing response of on-board reactors during liquid sloshing transportation.

A study of thermophysical and physicochemical characteristic of the KALLA experiment facility

Activities are currently underway across the world to build heavy liquid metal-cooled reactors. For example, the ALFRED and BREST-OD-300 reactor designs use lead coolant, while the MYRRHA and SVBR-100 reactors use lead–bismuth coolant. The high corrosive and erosive activity of the coolant requires control of oxygen concentration and flow velocity. Due to the complex geometry of the reactors cooling circuit flow, numerical simulation methods are used extensively to justify the operation modes for liquid metal coolants. Correct justification of the complex oxygen transport processes in liquid metals requires the detailed physicochemical computational model, which takes into account the major reactions of oxygen with the coolant and the structural materials.This paper presents a physicochemical model, which includes the following processes: erosion, growth, and dissolution of the two-layer oxide film, precipitation and dissolution of metal oxides in the circuit with subsequent deposition in a filter, and inflow of oxygen by the mass exchanger. The physicochemical model was implemented using the model of passive scalar, which allows simulating the impurity transport in the coolant.Capabilities of the presented model are demonstrated based on the results of investigating thermohydraulic and physicochemical processes at the KALLA laboratory experimental facility. The duration of the simulation is 1000 hr.The spatial distributions of metal oxides concentrations, areas of enhanced erosive activity, as well as mass of oxides deposited in the filter and the amount of oxygen entering the circuit have been obtained. The surface distribution of the oxide film thickness on the test facility surfaces contacting the coolant has also been calculated.Accounting for thermocouples and the manufacturing technology made it possible to improve the accuracy of calculating the thermohydraulic characteristics of the coolant flow compared to earlier studies.

A Comparative Study of the EP823 Steel Corrosion Resistance in Lead and Lead-Bismuth Coolants

A Comparative Study of the EP823 Steel Corrosion Resistance in Lead and Lead-Bismuth Coolants

Electrochemical Sensors for Controlling Oxygen Content and Corrosion Processes in Lead-Bismuth Eutectic Coolant-State of the Art.

Controlling oxygen content in the primary circuit of nuclear reactors is one of the key tasks needed to ensure the safe operation of nuclear power plants where lead-bismuth eutectic alloy (LBE) is used as a coolant. If the oxygen concentration is low, active corrosion of structural materials takes place; upon increase in oxygen content, slag accumulates due to the formation of lead oxide. The generally accepted method of measuring the oxygen content in LBE is currently potentiometry. The sensors for measuring oxygen activity (electrochemical oxygen sensors) are galvanic cells with two electrodes (lead-bismuth coolant serves as working electrode) separated by a solid electrolyte. Control of corrosion and slag accumulation processes in circuits exploring LBE as a coolant is also based on data obtained by electrochemical oxygen sensors. The disadvantages of this approach are the low efficiency and low sensitivity of control. The alternative, Impedance Spectroscopy (EIS) Sensors, are proposed for Real-Time Corrosion Monitoring in LBE system. Currently their applicability in static LBE at temperatures up to 600 °C is shown.

Calculation of stationary thermal detonation wave in the multiphase system “water drops, surrounded by steam films, in continuous molten lead”

A mathematical model of a thermal detonation wave in a multiphase system “water droplets in vapor shells located in a high-temperature heavy metal melt”, which can form after a rupture of the heat exchange tube of steam generator of a fast neutron reactor with a liquid lead or lead-bismuth coolant, is proposed. The model is based on the equations of the mechanics of multiphase systems. Interphase heat transfer and friction are described by well-known correlations validated on numerous experimental data. The key mechanism of thermal detonation wave propagation is the fragmentation of water droplets in the shock wave front. Fragmentation is carried out due to the difference in the velocities of drops and melt, which occurs on the shock wave due to the difference in their densities. The propagation velocity of a thermal detonation wave is determined by calculation of the Hugoniot adiabat. The parameters on the leading shock wave are calculated from relations expressing the laws of conservation of mass, momentum, and energy of a multiphase mixture. The calculated pressure distribution behind the shock wave has a maximum near the shock wave plane. The calculation results revealed that the thermal equilibrium of the phases is achieved much later than their velocity equilibrium.

Point Defect Model for the kinetics of oxide film growth on the surface of T91 steel in contact with lead–bismuth eutectic

Point Defect Model (PDM) has been successfully employed for aqueous solutions to describe the rate of surface corrosion of structural materials. In this work, the adaptation of PDM for the case of lead–bismuth coolant is developed. The necessary modifications in the set of electrochemical reactions and in the model of electrostatic potential distribution in the oxide film are made. Parameters of the proposed model, PDM_PB, are optimized using the experimental data for T91 grade steel. The obtained adaptation of PDM shows applicability to the case of lead and lead–bismuth coolants which is of critical importance for the next-generation fast-neutron reactors.

Experimental study of using microwave reflex-radar level gauges for liquid metal coolants

The article presents the results of work aimed at solving the problem of measuring the coolant level in miscellaneous tanks of liquid-metal-cooled reactor plants, mainly of an integral layout with a free level of the primary coolant. The choice of relevant measuring means and methods is limited by the extreme parameters of the liquid metal coolant (LMC) and operating conditions. Traditional measuring means are practically unsuitable; therefore, measuring the HLMC level is a complex technical task. Based on this review, they propose and describe a method of pulsed microwave reflectometry as the most promising in terms of combining the characteristics of reliability, accuracy and ease of use. The results of the experimental study demonstrated the efficiency of the level gauge, which worked according to this method, for measuring the level of lead-bismuth coolant in the control tank under conditions close to natural ones. An analysis of the results confirmed the possibility of using this method to control the level of melts of various metals as applied to HLMC reactor plants. Using the device for measuring the level, which works according to the proposed method, it is possible to control the level of melt of various metals in tanks in real time without the need to move various parts of the sensitive element of the level gauge while maintaining the tightness of the circuit. This device is applicable for various nuclear power plants, accelerator-controlled systems, research reactors and experimental facilities with liquid metal coolants.

Demonstration of the model of physicochemical processes in heavy liquid metal cooled reactors in an example of the THEADES experiment simulation

Activities have been currently underway across the world to build heavy liquid metal-cooled reactors. Thus, for example, the ALFRED and BREST-OD-300 reactor designs use lead coolant, while the MYRRHA and CLEAR-I reactors use lead–bismuth coolant. The high corrosive and erosive activity of the coolant requires regulations oxygen concentration (1 ÷ 4E-6 wt.%) and flow velocity (0.5 ÷ 2.5 m/s). Due to the complex geometry of the reactor circulation circuit flow paths, numerical simulation methods are used extensively to justify scheduled modes of operation for liquid metal coolants. Correct justification of the complex oxygen transport processes in liquid metals requires the respective physicochemical computation model, which takes into account the main reactions of oxygen with the coolant and the structural materials.This paper presents a physicochemical model, which includes the following processes: erosion, growth, and dissolution of the two-layer oxide film, coagulation and dissolution of metal oxides in the circuit with subsequent deposition on filtering elements, and inflow from mass transfer apparatuses. StarCCM+, a commercial CFD code, was used as the tool in this study. The physicochemical model was implemented using models of passive impurities, which are used to simulate oxygen transport in the circulation circuit.Capabilities of the presented model were demonstrated based on the results of investigating thermohydraulic and physicochemical processes obtained at the THEADES experimental facility. The duration of the simulation was 1000 h.The distributions of impurity concentrations, increased erosive activity areas, as well as the total amount of oxides deposited on filter and the amount of oxygen entering the circuit have been obtained as a result of the calculations. The surface distribution of the oxide film thickness on the test facility surfaces contacting the coolant has also been calculated. These data can be extrapolated to reactor elements that operate under conditions that are similar to the considered experiment. For example, fuel assemblies.Simulation of thermocouples, as well as taking into account manufacturing technology made it possible to improve the accuracy of calculating the flow’s thermohydraulic characteristics as compared to earlier studies.

КОМПЛЕКС ЭКСПЕРИМЕНТАЛЬНЫХ СТЕНДОВ ДЛЯ ПРОЕКТИРОВАНИЯ И БЕЗОПАСНОСТИ БЫСТРЫХ РЕАКТОРОВ С ЖИДКОМЕТАЛЛИЧЕСКИМИ ТЕПЛОНОСИТЕЛЯМИ

To substantiate the safety and characteristics of fast reactors with liquid metal coolants, a complex of more than 20 stands of various profiles and purposes, well equipped with modern measuring instruments, including hydrodynamic, thermohydraulic and technological stands, has been created at SSC RF - IPPE. In addition, JSC “SSC RF - IPPE” has a complex of fast physical stands, including two critical stands - BFS-1 and the world's largest physical stand BFS-2. The article presents the characteristics and the possibility of stands designed for research in the field of hydrodynamics, heat transfer and coolant technology in support of design solutions, safety improvement and testing of equipment elements and assemblies of operating and planned installations with fast reactors with sodium, lead and lead-bismuth coolants, as well as for accelerator-controlled systems and thermonuclear fusion, low-power nuclear power plants for space: - Hydrodynamic stands - “SGDI” (air), “V-2” (air), “SGI” (water), “V-200” (water), “GDK” (air). - Thermal-hydraulic liquid metal stands - “6B” (Na, Na-K), “AR-1” (Na, Na-K), “Pluton” (Na), “SPRUT” (Na, Na-K, Pb, Pb-Bi, water). - Technological liquid metal stands - “Protva-1” (Na), “Protva-2” (Na), “PUSHM” (Na), “Armatura” (Na), “IK-MT” (Na), “SID” (Na), “BTS” (Na), “TT-1M” (Pb), “TT-2M” (Pb-Bi), “LIS-M” (Li). A large-scale sodium test stands “SAZ” is under construction, which allows testing full-scale prototypes of equipment and its elements to substantiate existing and future projects of fast sodium reactors. The BFS complex of physical stands is the world's only experimental tool for full-scale modeling of the cores of nuclear reactors of various types (of any composition, geometry and configuration). The materials and construction of the stands allow simulating the core, breeding zones, reflectors and in-core shielding, as well as elements of fuel cycles and storage facilities for spent nuclear fuel and radioactive waste. Reactor materials of the stands (metallic plutonium, oxide and metallic highly enriched uranium with enrichment of 36% and 90% in uranium-235, hundreds of tons of fertile materials, construction materials, various coolants) make it possible to assemble both complex full-scale models of fast reactors, and benchmarks, experiments for which are carried out to correct neutron-physical constants and improve computational methods.

ИССЛЕДОВАНИЕ МЕХАНИЗМА ШЛАКОНАКОПЛЕНИЯ В КОНТУРАХ СО СВИНЕЦСОДЕРЖАЩИМИ ТЕПЛОНОСИТЕЛЯМИ И ЕГО ПРЕДОТВРАЩЕНИЕ ВЫСОКОТЕМПЕРАТУРНОЙ ОБРАБОТКОЙ СМЕСЯМИ ВОДОРОДА И ВОДЯНОГО ПАРА

The results of computational and experimental studies of the properties of lead and lead-bismuth coolants and the mechanism of physicochemical processes occurring in their circulation circuits explain the reasons for the formation of slag deposits based on lead oxide. First of all, this is the uncontrolled interaction of lead and lead-bismuth coolants with gaseous oxygen, which, along with nitrogen, is one of the main components of air. Slag deposits are based on lead oxides, but they also contain a significant amount of unoxidized lead (and bismuth in the case of using a lead-bismuth coolant) bound by a lead oxide framework into a single structure, as well as a small amount of components of construction materials (iron , chrome, nickel). The formation of slags in the circulation loop with a lead-containing coolant has a negative effect on its operation: the flow cross-sections are narrowed; heat transfer surfaces are blocked; the normal operation of pipeline fittings is disrupted. To minimize slag accumulation, it is necessary to limit the contact of the coolant with air oxygen, avoid draining the coolant from the circulation circuit, control whether the circulation circuit is in a depressurized state both during research and during non-working periods, when heating and filling the circuits with a coolant, create and maintain a vacuum. The best way to prevent slag accumulation is periodic hydrogen cleaning of the circuit with gas mixtures "hydrogen - water vapor - inert gas". The greatest cleaning efficiency is achieved when gas mixtures are introduced directly into the coolant flow using gas injection devices. Mechanical devices with moving parts, ejectors, nozzle nozzles can act as gas injection devices.

ПОВЕРХНОСТНОЕ НАТЯЖЕНИЕ ЭВТЕКТИЧЕСКОГО РАСПЛАВА Pb44,6Bi55,4 В АТМОСФЕРЕ ВОЗДУХА

In the 1950s liquid lead and the lead-bismuth eutectic alloy (Pb45Bi55) were considered candidates for their use as coolants for nuclear power systems in the USSR and the USA. At the same time, the alloy (Pb45Bi55), first proposed by A.I. Leypunsky, was chosen as a coolant for the nuclear submarine “Alpha”, which was ahead of its time in terms of its tactical and technical data. However, in 1968, one of them suffered a severe radiation accident caused by the melting of fuel elements in the core of an onboard nuclear reactor due to the precipitation of oxides from the coolant and their accumulation, which blocked the pipeline cross-section and sharply worsened the cooling of the reactor, which led to its failure. In fact, the primary cause of the accident was a lack of knowledge about the physicochemical and technological properties of the lead-bismuth coolant. Thus, the main disadvantage of the Pb45Bi55 coolant is its corrosiveness to structural materials used in the nuclear power plant. But it has been found that corrosion by liquid lead alloys can be reduced by adjusting the oxygen level in the coolant. For example, the corrosion rate of martensitic steel at 770 K in a Pb45Bi55 flowing coolant without oxygen is about 1 mm per year, but it can be reduced to 0.01 mm per year, i.e. 100 times, if oxygen is dissolved in Pb45Bi55 coolant and its mass concentration is maintained at the level of 0.01 ppm. The observed effect is explained by the protection provided by the oxide layer formed on the steel surface of the pipeline. Thus, for a deeper understanding of the phenomena occurring at the boundaries of the liquid metal “coolants - gases” section, it remains relevant to study the processes of formation and destruction of the protective oxide layer and its behavior in coolant fluids, especially from the point of view of long-term operation of nuclear power plants. In this regard, data on the surface tension of the “coolant - gas” interphase boundaries are of great scientific and practical importance. In this connection, the present work sets the task of experimentally studying the influence of atmospheric air on the surface tension of Pb45Bi55 eutectic melt. Measurements of the surface tension of the eutectic melt Pb44,6Bi55,4 prepared by the authors were carried out in a non-stop mode sequentially, under static vacuum and atmospheric air, on the same surface. About three hundred experimental points obtained in this work made it possible to describe the dynamics of the surface tension changing process depending on the time of exposure of the coolant surface in vacuum and atmospheric air. It is shown that in comparison with the results obtained by the authors by the large lying drop method in a static vacuum, in the first 10 minutes from the beginning of the exposure of the eutectic melt in atmospheric air at a pressure of about 300 mmHg), the surface tension of the eutectic Pb44.6Bi55.4 decreases by 55 mN/m and more, which is an order of magnitude higher than the total error (2 %) of our measurements.

Investigations of regularities in the accumulation of hydrogen-reduced slags in circulation circuits with lead-containing coolants

The paper presents a computational analysis of regularities in the accumulation of slags during the interaction of lead and lead-bismuth coolants with oxygen gas. Oxidation of lead-containing coolants will cause the formation of lead oxide, while the formation of bismuth oxide is unlikely. Dosed supply of oxidizing gas to lead-containing coolants makes it possible to oxidize, selectively, chromium and nickel to their oxides without the slag formation from solid lead oxide. Regularities were studied which are involved in the lead oxide formation during the interaction of lead-containing coolants with oxygen gas. It has been found that, in the process of interacting with oxygen gas, a lead-bismuth alloy is oxidized 1.7 times as intensively as lead, this being explained by the presence of bismuth in the alloy. Bismuth is oxidized more intensively than both lead and the lead-bismuth alloy. The inert gas overpressure during depressurization does not prevent air oxygen from entering the circuit, and the dependence of the nitrogen and oxygen flow into the circuit on the argon flow out of the loop is close to linear regardless of the circuit state (cold, without coolant; heated, without coolant; heated, with circulating coolant). Oxygen is a chemically active impurity and is absorbed by the circuit; it is therefore important to control nitrogen in the gas spaces of the reactor and research plant circuits with lead-containing coolants. This will make it possible to signal, in a timely manner, the ingress of oxygen into the circuit and to take measures required to avoid or reduce the scale of the slag formation from lead oxides.

Corrosion Behavior and Surface Treatment of Cladding Materials Used in High-Temperature Lead-Bismuth Eutectic Alloy: A Review

Liquid metal fast reactors were considered to be the most promising solution to meet the enormous energy demand in the future. However, corrosion phenomenon caused by the liquid metal, especially in high-temperature lead-bismuth coolant, has greatly hindered the commercialization of the advanced Generation-IV nuclear system. This review discussed current research on the corrosion resistance of structural materials (such as EP823, T91, ODS, and authentic steels) in high-temperature liquid metal served as reactor coolants. The current corrosion resistance evaluation has proved that even for the excellent performance of EP823, the structural material selected in pressurized water reactor is not the ideal material for operation in the high-temperature lead-bismuth eutectic (LBE). Furthermore, the latest coating technologies that are expected to be applied to cladding materials for coolant system were extensively discussed, including Al-containing coatings, ceramic coatings, oxide coatings, amorphous coatings and high-entropy alloy coatings. The detailed comparison summarized the corrosion morphology and corrosion products of various coatings in LBE. This review not only provided a systematic understanding of the corrosion phenomena, but also demonstrated that coating technology is an effective method to solve the corrosion issues of the advanced next-generation reactors.

Simulating the Production of Medical Radioisotopes in a Fast Thorium-Cycle ADS with SERPENT

Radiopharmaceuticals are used in nuclear medicine for diagnostic or therapeutic acts. The short decay half-lives of medical radioisotopes, especially those used for diagnostics, imply that they should be produced continuously and transported as quickly as possible to the medical units where they are used. Neutron-rich medical radioisotopes are generally produced in research reactors, like technetium-99m, lutetium-177, holmium-166 and iodine-131. On the other hand, proton-rich radioisotopes are produced via reactions with charged particles from accelerators like fluorine-18, gallium-67, iodine-123 and thallium-201. Beside this, innovative nuclear reactors are advocated as solutions to the issues of nuclear waste production and proliferation threats. Fast neutron, thorium-cycle and accelerator-driven subcritical (ADS) reactors are some of the most promising of them, proposed as safer fuel breeders and “waste burners”. This article examines the use of a fast thorium-cycle ADS with liquid lead-bismuth eutectic coolant for the production of molybdenum-99/technetium-99m and lutetium-177. Burnup simulation has been made with the Monte-Carlo (MC) code SERPENT. It is demonstrated that MC codes can advantageously be used to determine the optimal irradiation time for a given radioisotope in a realistic reactor core. It is also shown that fast thorium-cycle ADS is an economical option for the production of medical radioisotopes.

On Corrosion Properties of Ceramic Materials for Pump Friction Pairs in Lead–Bismuth Environment

We consider the results of studies on the choice of material of the lower radial bearing of the pump designed to circulate lead–bismuth coolant. The circulation of the liquid coolant is provided by a vertical axial pump having a “long” shaft. In this design, it is necessary to provide for the lower bearing the lubrication carried out with lead–bismuth coolant. Having analyzed the operating conditions of the axial pump, we decided to carry out the lower bearing in accordance with the scheme of a hydrodynamic sliding bearing. The materials of friction pairs in such a bearing must withstand the stresses arising from the operation of the pump, as well as the aggressive conditions of the coolant. Nonmetallic materials—ceramics and carbon-based composite materials—were selected on the basis of the study of published data for experimental research on the corrosion and heat resistance in the lead–bismuth environment.

Research on slipper bearings of pumps of reactor systems with lead-bismuth coolant at relatively low temperatures

The academic focus of the article relates to nuclear power engineering, reactor plants (RP) with heavy liquid metal coolant (HLMC) – lead and eutectic lead-bismuth. The article’s purpose is to set out the goals and objectives of the research of slipper bearings for HLMC transfer pumps and to identify the problems of design and operation under these conditions based on the available experience. This experience applies both to energy reactors with high HLMC temperatures (400-550°C), and partly to acceleration-controlled systems and research reactors with HLMC temperature of about 200-350°C. The choice of the type of slippper bearing is justified for further researches of its operability in conditions of low HLMC temperatures.

The development and application of digital refueling mock-up for China initiative accelerator driven system

The refueling procedure in China initiative Accelerator Driven System (CiADS) is extremely complex, since there are some complicated structures in the coupling system, and the liquid lead-bismuth coolant turns the dynamic refueling process into the opaque experience. Building a real-scale physical mock-up system for the simulation of refueling procedure had always been considered as an effective way. However, the refueling design of CiADS will demand frequent changes in the preliminary design stage, which makes the approach time-consuming, not economic, and lack of flexibility. Another reason making this method not appropriate is that the refueling procedure will always accompany by the radioactive process and the release of airborne radionuclide, which will cause the possibly potential risks to the workers in nuclear reactor building. Considering these situations, Institute of Modern Physics, Chinese Academy of Sciences (IMPCAS) has developed an immersive virtual reality based digital refueling mock-up for the project of CiADS. The proposed refueling simulation system has some attractive features, including the real-time visualization for the automatic refueling simulation, feedforward and feedback control to the digital refueling mock-up, the interference and collision detection in the simulation process, and the sequential optimization and reliability assessment method in the refueling procedure, which can meet the requirement of frequent changes, and evaluate the refueling scenario both quantitatively and qualitatively.

МОДЕЛИРОВАНИЕ ТЕПЛОПЕРЕДАЧИ В КАНАЛАХ КРУГЛОЙ ФОРМЫ МАШИН НЕПРЕРЫВНОГО ЛИТЬЯ ЗАГОТОВОК С ПЕРСПЕКТИВНЫМ СВИНЦОВО-ВИСМУТОВЫМ КРИСТАЛЛИЗАТОРОМ

As part of the search for new areas of application of liquid metal coolants, their use for cooling crystallizers of steel in continuous casting machines instead of water has been proposed. This solution will reduce energy costs in the production of steel due to the implementation of the steam-power cycle with the generation of electricity. This article describes the results of the justification of the optimal liquid metal coolant and the modeling of cooling of a round crystallizer channel by it. It is shown that the eutectic alloy of lead with bismuth, which was successfully used as a coolant for ship reactors in the Soviet Union, is best suited to solve this problem. A comparative simulation of cooling of hardened steel in a round channel with a lead-bismuth eutectic with temperatures of 180 °C and 450 °C and water with a temperature of 20 °C revealed that replacing water with a liquid metal coolant practically does not reduce the efficiency of steel production. The greatest heat flux is removed from the steel crystallizer at a temperature of lead-bismuth eutectic at the inlet of the steel crystallizer equal to 180 °C. The temperature of the lead-bismuth eutectic at the outlet of the steel crystallizer reaches 400 °C, which is sufficient to generate electricity in the steam-power cycle. The choice in favor of modeling in comparison with the experiment was made in accordance with current trends in cost reduction due to the use of computer-based calculation tools. It is advisable to continue research to select the wall material and determine the optimal shape of the cooling channels of the crystallizer for maximum intensification of heat transfer between hardening steel and lead-bismuth coolant.

РАЗРАБОТКА И ОБОСНОВАНИЕ КОНСТРУКЦИЙ МАССООБМЕННЫХ АППАРАТОВ ДЛЯ РЕГУЛИРОВАНИЯ ОКИСЛИТЕЛЬНОГО ПОТЕНЦИАЛА В СВИНЦОВО-ВИСМУТОВОМ ТЕПЛОНОСИТЕЛЕ РЕАКТОРНЫХ УСТАНОВОК НОВОГО ПОКОЛЕНИЯ

In a lead-bismuth heat carrier, to ensure the conditions for the formation and maintenance of protective oxide films on the surfaces of structural elements in contact with the heat carrier, it is necessary to regulate the dosage of dissolved oxygen into the heat carrier. In the absence of feeding the lead-bismuth heat carrier with dissolved oxygen, the oxidative potential of the heat carrier can decrease to values at which the development of corrosion and erosion processes begins. A solid - phase method for regulating the oxidizing potential in a lead-bismuth heat carrier, which is implemented using mass transfer devices, has been developed and justified at the SSC RF-FEI. The authors of this paper develop various structures of mass transfer devices for use in research installations with lead-bismuth coolant, as well as in advanced reactor installations of the new generation, in which the lead-bismuth melt is considered as a primary coolant. The article presents the results of the development and justification of mass transfer devices that can be used to regulate the oxide potential in the lead-bismuth coolant of a new generation of reactor plants.