Izvestiya vuzov. Yadernaya Energetika

The peer-reviewed scientific and technology journal. ISSN: 0204-3327

Computational and Experimental Study of Stability of Natural Circulation of Light-Water Supercritical Coolant in a Closed Loop

12/10/2025 2025 - #04 Thermal physics and thermal hydraulics

Sedov A.A. Pustovalov S.B. Polyakov P.S. Simonov S.S. Frolov A.A. Zaryugin D.G.

DOI: https://doi.org/10.26583/npe.2025.4.04

UDC: 621.039; 621.039.524.441; 621.039.526

Within the framework of this paper, validation of the analytical solution of the system of thermal-hydraulic equations using experimental data obtained at natural circulation (NC) of light-water coolant at supercritical parameters (SC-water) is considered. At present, an experimental thermal-hydraulic stand ‘Multipurpose non-reactor VVER-SCP loop’ has been created and put into operation at SRC ‘Kurchatov Institute’. One of the elements of the stand is a closed loop with a SC-water NC. As a result of literature data analysis, a number of criteria, correlations, formulas and approximations are selected, which were further used in the analytical solution of the system of equations. The main types of thermal-hydraulic instability that can occur in closed loops with SC-water NCs are considered. Formulas for determining the coolant flow rate depending on the heater power, the maximum achievable flow rate and the maximum permissible input power, as well as the enthalpy difference of the coolant in the heater at the maximum flow rate have been obtained for a closed loop with SC-water at NC and used in the analytical solution of the equations. Criteria for the occurrence of thermal-hydraulic instability in the considered system were obtained. Experimental results on heat transfer and hydrodynamics in the heated cylindrical channel, as well as the dynamics of the whole circuit, including power and flow characteristics, have been obtained. The formulas proposed by the authors are validated for NC conditions of SC-water using experimental data. The difference in the calculated determination of the thermal-hydraulic instability onset boundary according to the obtained analytical formulas in comparison with the experimental data does not exceed 5 %. The obtained results should be taken into account when forming initial technical requirements for operation of reactor plants with light-water SCW coolant in the mode of natural circulation in nominal mode or in case of normal operation disturbance.

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natural circulation of light-water coolant closed circuit thermohydraulic processes thermohydraulic instability supercritical pressure SCP- natural circulation circuit

Link for citing the article: Sedov A.A., Pustovalov S.B., Polyakov P.S., Simonov S.S., Frolov A.A., Zaryugin D.G. Computational and Experimental Study of Stability of Natural Circulation of Light-Water Supercritical Coolant in a Closed Loop. Izvestiya vuzov. Yadernaya Energetika. 2025, no. 4, pp. 44-62; DOI: https://doi.org/10.26583/npe.2025.4.04 (in Russian).

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