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The particularities of the experimental investigation of the hydrodynamics of the fl ow parts of heat-exchange equipment and reactor facilities that are associated with the design of the experimental sections, performing experiments on them, and processing the experimental data are examined. Specifi c practical recommendations for increasing the determination accuracy of the hydrodynamic parameters, cost reduction of the experimental work, and reduction of the expenditures on materials are given. The recommendations can be used to validate the heat-exchange equipment, reactor facilities with a fast neutron spectrum, and VVER.Obtaining experimental data on the hydrodynamic parameters of the fl ow parts of reactor facilities is one of the conditions for reliable and effi cient operation.The aim of the present work is to examine the design particularities of the experimental sections and perform and process the results of experimental investigations of the hydrodynamic parameters of the fl ow parts of reactor facilities and heat-exchange equipment [1][2][3][4][5].In some cases, individual complex fragments of the fl ow part are investigated in the experimental process of design validation of natural reactor facilities. For example, in distributing manifold systems of reactor facilities the core, arranged at the exit from a manifold, is simulated by a pipe bundle of relatively short length with throttling diaphragms placed in the exit part. The coeffi cient of hydraulic resistance ζ of the diaphragms is a complicated function of the Reynolds number. So, for the ratio f = 0.26 of the fl ow section of the diaphragm to the fl ow section of the tube, a distinct minimum of the coeffi cient of hydraulic resistance is characteristic for the transition from laminar to turbulent; it increases by a factor of 1.4 with Reynolds number in the tube increasing from 1·10 4 to 16·10 4 (Fig. 1). The use of a simulator could lead to a larger error in the determination of the fl ow profi le at the exit from the manifold in the presence of a large nonuniformity at its entry. To increase the accuracy with which the indicated profi le is determined in the experiment, it is suggested that throttling diaphragms with Reynolds number in the tubes for which the fl ow regime of the working medium has a relatively weak effect on its value be used.The investigation of the coeffi cient of hydraulic resistance of the complicated fl ow parts of reactor facilities with relative large energy losses to pumping of the incompressible working medium using a compressible working medium in the experiments is always associated an uncertainty in transferring the data to reactor facilities. This is due to the change in the density of the compressible working medium along the fl ow part of the experimental section, which is used to determine the coeffi cient of hydraulic resistance. The larger the head losses during pumping of the compressible working medium along the fl ow part of the experimental section, the larger the changes in the density of the working me...

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