Investigation of Coolant Flow in an RITM-Reactor Fuel Cassette

The results of coolant flow investigations of a fuel rod bundle of an RITM-reactor fuel cassette for a small nuclear power plant are reported. The purpose of this work is to investigate the redistribution of the axial and transverse flow velocities as well as the axial coolant flow rate behind a spacer grid. For this purpose, experiments were performed on an aerodynamic stand using a scale model of a fuel rod bundle of an FA. A region with characteristic type cells was chosen for investigation. The coolant flow is represented by cartograms of the distribution of the transverse and axial velocities as well as by graphical plots of the distribution of the axial velocity and flow rate through the characteristic types of cells. The resulting experimental database can be used to verify modern CFD programs as well as programs for performing cell-by-cell thermohydraulic calculations of a core.