The results of experimental studies of the applicability of the float-discrete method for measuring the level of a heavy liquid-metal coolant (HLMC) using sealed magnetically controlled contacts as a ...sensitive element are presented. These contacts register the coolant level in the field of a permanent magnet located on the surface of a heavy liquid-metal coolant. The performance of such a level sensor was studied using a control tank with a lead-bismuth coolant under conditions close to natural ones. This method is simple, but its main problem is maintaining the integrity of sealed magnetically controlled contacts when exposed to high temperatures. The experiments were carried out using a float-discrete level sensor prototype on a high-temperature stand with a lead-bismuth coolant. The data collected during the processing of the results confirm with reliable accuracy the applicability of the float-discrete method for monitoring the level of a heavy liquid-metal coolant. An HLMC level measuring device operating according to this method makes it possible to monitor the level in tanks while maintaining the tightness of the circuit. Due to this, it is possible to abandon the currently common methods for determining the level of HLMC using electric contact level sensors in which the sealing of the circuit is impossible. This device can be used on various experimental stands with liquid-metal coolants as well as in reactor plants and accelerator-controlled systems in the temperature range of 210–230°C, for example MYRRHA. To ensure the operability of the level transmitter at higher temperatures, it is necessary to upgrade the reed switch cooling system.
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The article presents the results of experimental studies on the effect of circulation pump operating modes on the wear of a double reciprocating slit throttling hydrostatic bearing operating in a ...lead coolant environment. The experiments were conducted on a high-temperature circulation test bench at a lead coolant temperature of 420–450°C. Results were obtained for operation modes with a high number of start-stop cycles (approximately 100 cycles per 100 h of operation), sustained operation with a low number of start–stop cycles and nominal speeds of 1000–1100 rpm (not exceeding 8 cycles per 100 h of operation), with 25 start–stop cycles per 100 h, and at low pump speeds below nominal values of 600–700 rpm with a maximum of 8 start–stop cycles per 100 h of operation. Data on the wear of the bearing bush and shaft are presented in the article. Processing and analysis of the research results led to the conclusion that this type of bearing can be used in low-pressure axial pump systems only under conditions where the pump creates a head exceeding 1.1 m of liquid lead.
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 article presents data on the anatomical and physiological features of the newborns skin. It also considers the issues of pathogenesis of the diaper dermatitis. The main measures aimed at the ...prevention and treatment of diaper dermatitis in newborns are provided. The articles highlights the role of dexpanthenol-containing drugs in the external therapy of skin diseases in young children.
The experimental investigations performed at NGTU of the characteristics of the near-wall layer in the flow of a heavy liquid metal coolant as well as the influence of the regime parameters of the ...loop (velocity of liquid metal coolant over contact surfaces, thermodynamic activity of oxygen, coolant temperature, and circulation time) on the change of its operating characteristics – surface roughness of the structural material during prolonged contact with high-temperature coolant flow (lead, lead–bismuth) – are analyzed.
Models of experimental sites for research of processes tribology in heavy liquid metal coolant.
•The contact a pair of heavy liquid metal coolant for reactors on fast neutrons.•The hydrostatic ...bearings main circulation pumps.•Oxide coating and degree of wear of friction surfaces in heavy liquid metal coolant.
So far, there are plenty of works dedicated to studying the phenomenon of friction. However, there are none dedicated to functioning of contact pairs in heavy liquid-metal coolants for fast neutron, reactor installations (Kogaev and Drozdov, 1991; Modern Tribology, 2008; Drozdov et al., 1986).
At the Nizhny Novgorod State Technical University, such research is conducted in respect to friction, bearings of main circulating pumps, interaction of sheaths of neutron absorber rods with their covers, of the reactor control and safety system, refueling systems, and interaction of coolant flows with, channel borders. As a result of experimental studies, the characteristic of friction pairs in the heavy, liquid metal coolant shows the presence dependences of oxide film on structural materials of the wear.
The inapplicability of existing calculation methods for assessing the performance of the bearing nodes, in the heavy liquid metal coolant is shown.
Heat removal during transient processes in nuclear power installations and bench loops cooled by lead and lead-bismuth coolant is studied. It is shown that low-pressure heat-exchange equipment is ...effective. The studies were conducted in a non-isothermal loop with circulating of lead coolant at 450–500°C, average speed in the narrow section of the gap in longitudinal flow over the heat-exchange surface 0.1–1.05 m/sec, Peclet number 300–3300, and the oxygen thermodynamic activity in lead 1–10
–3
. The processes occurring in a non-isothermal liquid-metal loop with an experimental heat-exchange section model the dependence of the heat-exchange characteristics on impurity mass transfer in the loop.
Lead and cadmium migration was studied in the system: biologically active plant raw material-extract. Antioxidant activity and detoxication ability of the extracts of birch buds and leaves was ...studied in pattern experiments with rats.
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