The study of hydrodynamic processes of a coolant flow in FA-KVADRAT PWR with various mixing spacer grids

Abstract

The article presents the results of experimental studies of the influence of different designs of mixing spacer grids on the coolant flow in FA-KVADRAT PWR. The investigations were carried out by simulating the coolant flow in the core on the experimental air stand being an aerodynamic open loop through which air is pumped. To measure the local hydrodynamic characteristics of the coolant flow, special pneumometric sensors were used for measuring the total velocity vector and the flow rate value. During the investigations of the local hydrodynamics of the coolant, transverse flow velocity, as well as the coolant flow rates in the cells of the experimental model FA-KVADRAT, was measured. The analysis of spatial distribution of projections of absolute flow velocity allowed studying and detailing the coolant flow pattern behind the mixing spacer grids with different designs of deflectors as well as selecting the optimal design of the deflector. The accumulated database on the coolant flow in FA-KVADRAT has formed the basis for engineering assessment of active zones’ structures of PWR. The results of experimental studies are used to verify CFD codes (in both foreign and domestic development) as well as programs for detailed cell-by-cell calculation of active zones in order to reduce conservatism when assessing heat engineering reliability.