Flow formation features at the inlet to the fuel catridge of a ritm snpp reactor

The article presents the results of an experimental study investigating features of coolant flow formation in the inlet section of a fuel assembly (FA) located in the cartridge core of a RITM SNPP reactor. The work aims to investigate the effect of various inlet design elements on the redistribution of the axial flow velocity. To this end, a series of experiments were carried out using a scale model, including structural elements of the inlet section between the calibration washer and the attachment of fuel rods to the diffuser, as well as the section of the fuel rod bundle between the absorbing and spacer grids. The studies were carried out using the pneumometric method in characteristic sections along the length of the model. Features of the coolant flow are visualized by cartograms of the axial velocity for the working medium flow. The results of the experiments were used to perform a hydraulic profiling of the FA inlet section. The obtained experimental database can be used to validate the LOGOS CFD program and clarify methods for the thermal-hydraulic calculation of cores in a cell approximation.