Investigation of the components nature and concentration influence on carbon dioxide equilibrium in the system CaCl2-Na2CO3-NaOH-H2O by potentiometric titration

The modern thermal power plants equipment requires strict deposits control on the surfaces. Such deposits are formed from impurities entering the cycle with water, the amount of which has significantly increased at modern powerful thermal power plants. At the modern level of the coolant water treatment, it is possible to exclude most of the impurities responsible for salt deposition. Analysis of various types of the sediments has shown that carbonate deposits are an integral part of them. Modern research methods (potentiometric titration in combination with methods of mathematical modelling) for carbonate, silicate, phosphate water systems have shown the existence of phase-unstable states leading to salt deposition during the coolant circulation. In this article, the carbonate system CaCl2-Na2CO3-NaOH-H2O was studied by potentiometric titration with a glass indicator electrode. The influence of the components nature (Li2CO3, Na2CO3, Ca2CO3, LiOH, NaOH, KOH, CaCl2, MgCl2) and the conditions for the existence of phase-unstable systems with varying concentrations of these components were studied. It is known that organic phosphonates are effective inhibitors of deposits in the carbonate system. In this paper, the action of two compounds of the specified class is considered. The concentration limits of their inhibitory action have been determined.

Marine integral water cooled reactors with steam-condensate process in the primary circuit

Одним из путей улучшения массо-габаритных характеристик судовых водоохлаждаемых реакторов интегрального типа с естественной циркуляцией теплоносителя является реализация пароконденсатного цикла в первом контуре, при котором насыщенный пар с высокой степенью сухости генерируется непосредственно в активной зоне и затем конденсируется в парогенера­торе, отдавая тепло рабочему телу второго контура. Тепловыделяющий канал активной зоны с непосредственной генерацией насыщенного пара состоит из кольцевого твэла и установленной в его полости нетепловыделяющей трубки с навивкой для закрутки потока теплоносителя. Закрутка потока внутри твэла предотвращает кризис кипения на его внутренней поверхности (на наружной поверхности твэла имеет место закризисный режим теплоотдачи), что обеспечивает допустимые значения температур топлива и оболочек твэла при достаточно высокой плотности энерговыделений, характерных для активных зон судовых реакторов. В статье описаны особенности теплогидравлического расчета каналов активной зоны, парогенератора-конденсатора и контура естественной циркуляции интегрального реактора с пароконденсатным циклом в первом контуре. Представлены результаты расчета характеристик реакторов тепловой мощностью 150 и 25 МВт. Показано, что размеры интегральных реакторов с естественной циркуляцией теплоносителя при реализации пароконденсатного цикла в первом контуре не превышают размеры характерные для интегральных водоохлаждаемых реакторов с принудительной циркуляцией теплоносителя, предназначенных к использованию на объектах морской техники. One of the ways to improve the weight and size characteristics of integrated water-cooled reactors with natural coolant circulation is to implement a steam condensate cycle in the primary circuit, in which dry saturated steam is generated directly in the core and then condenses in the steam generator. The fuel channel of the core with the direct generation of saturated steam consists of an annular fuel rod and a non-fuel pipe installed in its cavity with a winding for swirling the coolant flow. The swirling of the flow inside the fuel element prevents a burn up its internal surface (there is a post-crisis heat transfer regime on the external surface of the fuel element), which ensures acceptable temperatures of the fuel and its cladding at a sufficiently high energy density typical for marine reactor core. The article discusses the features of thermal-hydraulic calculations of the core channel, steam generator – condenser and natural circulation circuit of integral type reactor with the steam-condensate cycle in the primary circuit. It is presents the characteristics of marine reactors with a thermal capacity of 150 and 25 MW. It is shown that size of the marine integrated reactors with natural coolant circulation and a steam condensate cycle in the primary circuit is similar to size of reactor with enforced coolant circulation.

A Coolant Circulation Cooling System Combining Aluminum Plates and Copper Rods for Li-Ion Battery Pack

The spontaneous combustion of electric vehicles occurs frequently, and the main reason is the thermal runaway of a lithium-ion battery. In order to prevent the heat that is produced in the use of a lithium-ion battery out of control, this study proposed a coolant circulation cooling system, that is, the heat generated by the lithium-ion battery is transferred to heat sinks through aluminum plates and copper rods, and then dissipated through the coolant. Based on a CALB-LB5F73 LiFePO4 battery pack, experiments with the coolant circulation cooling system were conducted to study the temperature rise characteristics at different ambient temperatures. The temperature of the battery pack was still close to the upper limit of permitted temperature when the ambient temperature reached 313 K. Further improvement, increasing the diameter of copper rod of the system was proposed to enhance heat dissipation and simulations with this scheme were completed. The findings show that the cooling system can clearly reduce the temperature of a lithium-ion battery pack and control the temperature within the safe temperature range.

On the experimental lead-cooled installation

Extensive experience in operating nuclear power plants convincingly proves that fast liquid metal cooled reactors are among the most promising. The advantages of using liquid lead coolants in nuclear power industry are shown. In Russia, lately, much attention has been paid to the natural safety of fast reactors. At the stage of testing materials for components of reactor plants, a number of problems arose for basic systems. An experimental lead-cooled installation was developed for testing large structures, continuous monitoring and maintaining specified technical parameters. For reliable coolant circulation (lead coolant circulation speed up to 200 kg/s), a magnetohydrodynamic pump (MHD pump) has been developed, which is distinguished by high efficiency and reliability, it is also ease in operation and maintenance. Currently, the experimental setup is successfully used in scientific research of materials for RU BREST-OD-300. All its systems showed high reliability, maintainability and the possibility of further modernization.

Regulation of the temperature in the ampoule channel with natural circulation of coolant

It has been shown by calculations that it is possible to extend considerably the capabilities for control of temperature conditions in an ampoule channel with natural coolant circulation, using the proposed hydraulic circuit layout, on samples during irradiation in the SM-3 reactor reflector cell by changing the circulation circuit geometry through the arrangement of a bypass heat removal line formed in the upper part above the flow limiter as compared to control only by changing the thermal conductivity of the gas gap in the channel body (through changing the gas pressure or composition). The ampoule channel test conditions, layout and simulation model for thermal-hydraulic analysis using the RELAP5/MOD3.2 code are presented. An investigation was conducted to study the effects of the bypass cooling circuit on the temperature conditions during irradiation of samples in an ampoule channel. The bypass flow rate change is achieved by varying the passage area of the flow limiter orifice. Options have been considered for filling the channel body gas gap with helium and a helium mixture. The calculation showed that the heat removed by the bypass line could reach 40% of the total heat released in the channel. With helium used in the channel body gap, the temperature conditions during irradiation are adjusted in a broader range (200–330 °С) than with a gas mixture of a lower thermal conductivity (279–330 °С), the major temperature variation taking place with the flow limiter orifice area being less than 0.2–0.3 cm2. Any further increase in the flow limiter orifice area does not lead to a major temperature change in the coolant flowing about the samples.