[en] The role of some physical-chemical and thermophysical properties of nitrogen tetroxide in the development of cavitation phenomena is considered. It is shown that the first stage of the reversible chemical reaction N₂O₄ reversible 2NO₂ proceeding in the cavitation zone, with heat absorption during dissociation, exerts a considerable influence on the pump cavitational characteristics. The conclusion is made that the improvement of cavitational properties due to the occurring thermodynamic processes can be expected only in the range of relatively great gradients of saturated vapor pressures as a function of the liquid temperature

[en] Some cases of nitrogen tetroxide and nitrine (the nitrogen tetroxide and nitrogen oxide mixture) transition into the metastable state are considered. The influence of some technological processes and NPP control operations on spontaneous superheated liquid boiling in the pipelines and at pump inlet as well as that of the produced gas-liquid mixture on the pump cavitational stoppage are pointed out. It is shown that in the case of eliminating the spontaneous liquid boiling cause, the pump restores its parameters to their original quantities

[en] Some characteristics of nitrine flow (nitrogen, tetroxide and nitrogen oxide mixture) in pipelines and pumps are considered. It is shown that in cavitation zone with dissociation of equilibrium N²O⁴ and NO mixture involving N²O³ solution in N²O⁴, chemical reactions proceed with heat requirement (kJ/kg); N²O⁴ reversible 2NO²-o24 (1), N²O⁴ reversible NO²+NO-527.6 (2). The role of each reaction in the process of the flow formation in cavitation zone is considered. As a result of more intensive volatility of N²O³ component, vapour phase in cavitation zone is enriched by NO, liquid phase in the vicinity of steam cavities is depleted by it, that involves drop in presure of liquid saturated vapours in this zone. Heat requirements for breakage of chemical bonds result in drop of flow temperature. It is shown, that as a result of the effect of these processes, the improvement of cavitation characteristics of pumps pumping nitrine is expected in comparison With pure N²O⁴. The improvement of pump cavitation qualities will be different depending on parameters of saturation

[en] The development of nuclear power in the USSR is impossible without effective fast breeders for reprocessing of nuclear fuel. In a gas-liquid direct cycle cooling circuit of energy conversion, the reliability of the pump operation markedly effects the reliability of the system as a whole. Suction head provision is a factor of reliable pump operation. The ejector circuit for providing additive suction head at the pump inlet is analysed. Active liquid for the ejector is extracted from the pump. Based on the energy balance in the pump-ejector system the formula of the relative positive suction head provided by the ejector at the pump inlet is obtained. It is shown that this value depends on the ejector and the pump characteristics as well as on such properties of liquid as heat capacity, density and pressure variation of liquid saturated vapour with changing temperature (dPs/dT), which form a nondimensional parameter PI=(dPs/dT)(1/rho Cp). The value of the latter parameter determines the level of the effect of liquid properties on the extra positive suction head provided by the e ector. The temperature dependence of PI parameter for water and nitrogen oxide is given. Calculations have revealed that in some cases the ejector not only produces additive positive suction head but also decreases it. That is due to liquid heating in the ejector and variation of vapour pressure

[en] The PUMA was designed on the basis of the technical project for the semi-industrial BRIG - 300 nuclear power station with nitrogen tetroxide N₂O₄. The various circuits, reliability of the installation in normal and accidental working and the purification of the coolant, are examined

[en] The methods of developing of extra suction heat at the inlet of a pump transferring liquid nitrogen tetroxide in a power plant circuit are analysed. The main attention is paid to comparison of supercooling system and ejector efficiencies at the pump inlet. A parameter K is obtained which includes liquid density, heat capacity and a derivative of vapour pressure with respect to temperature. This parameter is used as the criterion of efficiency comparison. The parameter K versus temperature for liquid nitrogen tetroxide and experimental data on the ejector efficiency for two liquid temperatures are given. The ejector is efficient only at low N₂O₄ temperatures in the range 280-300 K, the supercooling section is reasonable to be used in the range of temperatures 320 K and higher. But in service of NPP on nitrogen tetroxide the wide range of temperatures is possible: start-up and run-up of the circuit (280-300 K) or the operation with nominal or increased powers (310-380 K)

[en] Thermophysical properties of nitrogen tetroxide used as a coolant in a gas cooled nuclear reactor allow a high specific power density in the core, about 800 to 1200 kW/dm³. Good physical and thermophysical characteristics of the reactor are obtained only for a low volume fraction of coolant in the core, i.e. if the length of heat transfer is minimized. In consequence any deposit on the surface of heat transfer of fuel element is to be avoided. The main parts of the study programme for the use of nitrogen tetroxide as a coolant are the choice of corrosion resistant materials, optimization of coolant composition and inexpensive coolant purification methods

[en] Study on a dissolution rate of gases and gaseous mixtures by liquid is described. It is shown that the dissolution rate of pure gases is proportional to their Henry coefficient. The dissolution rate of the gaseous mixture is close to that of gas being part of the mixture which has the largest Henry coefficient. The effects of interface turbulence account for the increase of the dissolution rate of a weakly soluble gas in the mixture with a readily soluble gas. The study allows to evaluate some parameters in formed cavities or in moving gaseous bubbles in multicomponent mixtures (in particular, in dissociating nitrogen tetroxide and in solutions on the basis of nitrogen tetroxide). Studying of these processes is essential in connection with using the nitrine coolant containing dissolved gases, solubility coefficients of which in N₂O₄ are in the range from 2.948 kg/(m³xMPa) for N₂ and up to 1530 kg/(m₃xMPa) for NO

[en] The velocity of release of gases into a bubble and a cavity from liquid has been described. It is shown that at simultaneous desorption of several gases dissolved in liquid, into emerging bubble the contribution of each gas is proportional to its coefficient of solubility and is independent of concentration of these gases in liquid. For gases with solubility coefficients above 1000 kg/(m³xMPa), partial pressure readily reaches equilibrium. Nitric oxide dissolved in nitrogen tetroxide ranks among them. Alternatively, for gases with low solubility coefficients (for example, nitrogen in N₂O₄), partial pressure in the cavity (bubble) increases slowly. An effect of any gas on the desorption rate of another gas has not been observed. The study allows to evaluate some parameters in formed cavities or in moving gaseous bubbles in multicomponent mixtures (in particular, in dissociating nitrogen tetroxide and in solutions on the basis of nitrogen tetroxide)

[en] Consideration of gaseous impurities in NPP coolants, their sources and the levels of their content is made. The data on the content of gaseoUs impurities (N₂, N₂O and nitrogen oxide) in the nitrine coolant during the reactor loop plant operation are reported. The content of gaseous impurities N₂, N₂O and nitrogen oxide in the nitrine coolant is determined by the method of reaction gas chromatography. As can be seen from the obtained data, nitrogen oxide, N₂ and N₂O are distributed uniformly over the circuit of the plant. Increased content of gaseous impurities and nitrogen oxide is observed in steam-gas chamber of the primary circuit condenser. The obtained data can be used for development of recommendations on regulated content of gaseous impurities in the primary coolant circuit under operational conditions