[en] Using regression analysis, analytical models were obtained for the functional dependences of the density, the electrical conductivity, and the refractive index of solutions containing HNO₃ (0 to 3 moles/liter) and UO₂ (NO₃)₂ (0 to 2 moles/liter) in the temperature interval 25-40⁰C. The model errors were +-).07%, for the density, +/-1.5% for the electrical conductivity, and +/-0.02% for the refractive index. The possibility of obtaining the inverse dependences are demonstrated: for the acid and salt concentrations as a function of density, electrical conductivity and temperature, with model errors of +/-1%. These models may be used in methods for determining the composition of the given system for the results of measuring two properties at a known temperature. In this case, within the model error limits of +/-1%, concentrations may be determined on the order of 1-3 moles/liter in the presence of microcomponents with a total concentration up to 0.02 moles/liter

[en] Using regression analysis, analytical models have been obtained for the concentration dependence of density, electric conductivity and light refractive index of HNO₃ solution from 0 to 3 mol/l and of UO₂(NO₃)₂ solution from 0 to 2 mol/l in the temperature range from 25 to 40 deg C. The model errors made up for density +-0.07%, for electric conductivity +-1.5% and for light refractive index +-0.02%. The possibility to obtain the reverse dependences - for acid and salt concentrations as functions of density, electric conductivity and temperature with the model errors +-1% is also shown. The models can be used in the methods of the composition determination of the given system from the results of measurements of two properties at a known temperature. Then, in the limits of the model errors +-1%, the determination of concentration values of the order of 1 to 3 mol/l can be made in the presence of microcomponents at their summary concentration up to 0.02 mol/l

[en] Equations of dependences of acid and salt concentrations on two parameters (density, electric conductivity or viscosity) and temperature are obtained using the regression analysis according to the earlier data on properties of the system: nitric acid-alkali metal salt - water at different temperatures. Errors of definitions are evaluated using the multiparametric method along with permissible microcomponent amounts (about 1% of macrocomponent amount: acids and salts), effect of errors of measurement of solution parameters and correlation coefficients between parameters. Errors concentration determination constitute MRSE+-2-5 rel.% for the systems with alkaline metal salt representing one of macrocomponets

[en] The authors use regression analysis on previously accumulated data on properties of nitric acid-alkali metal salt-water systems at different temperatures to obtain equations for the dependences of the acid and salt concentrations on two parameters and temperature. The authors have estimated the error in determinations using the multiparameter method, the allowable amount of trace components, the effect of errors in the measurement of the solution parameters, and the correlation coefficients between the parameters