Experimental determination of a flow's mass velocity and enthalpy by the section of water-cooled nuclear reactors models

Аuthors

Basov A. V., Boltenko E. A., Davydov M. V., Kononenko I. V.

Joint Stock Company «Electrogorsk Research and Engineering Center on NPP safety» (JSC «EREC»), Saint Constantine str., 6, Electrogorsk, Moscow region, 142530 Russia

Abstract

The article presents a review of the works carried out in EREC on the study of the flow structure in the models of fuel assemblies by the isokinetic sampling method. The experiments were performed on models of fuel assemblies related to the RBMK, VVER reactors and assem- blies with twisted simulators. The article presents the studies of the flow structure at isothermal and non-isothermal coolant flows in various types of models, and describes the features of the isokinetic sampling method for various types of assemblies. A modified method of isokinetic sampling is presented. To perform measurements in complex profile assemblies sampling cells were preliminary being formed by lengthening the simulators’ walls and replacing liquid boundaries of the cells under study by the impenetrable walls within the limits of the cells, being formed, from the assembly active outlet to the controlling section. The sampling cells were being formed by installing output grid in the controlling section. The results of water flow rates (ve- locities) measuring in all cells of the assembly with swirled simulators are described. Relative unbalance of water flow through the assembly, defined as Δ = (ΣGcell — Gassembly)/ Gassembly, was of 6–10%. The difference of 30–50% between the average velocities in the cells and the average velocity in the assembly is quite significant. The article presents some results of the mass velocity and enthalpy of single-phase and two-phase flows distribution in both unheated and fullscale electrically heated model of nineteen-rod bundle of the RBMK-1000 fuel assemblies.

Keywords:

isokinetic sampling, models of fuel assemblies, output grid.

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