HYDRODYNAMICS OF A COOLANT IN THE OUTLET SECTION OF A CASSETTE TYPE FUEL ASSEMBLY

The results of experimental studies of the hydrodynamics of a coolant in the outlet section of a cassette fuel assembly of the RITM reactor of a low-power nuclear power plant are presented. The purpose of the work was to study the redistribution of axial velocity and coolant fl ow rate at the outlet of the fuel rod bundle, behind the fuel assembly cap, near the coolant extraction pipe, and in the holes of the upper support plate. To achieve the goal, experiments were carried out on a research stand with an air working medium on a model of the outlet section of the fuel assembly, including the outlet fragment of the fuel rod bundle, the cap, the upper support plate with the coolant extraction pipe. When conducting research, the pneumometric method and the method of injection of a contrast impurity were used. An area covering the entire cross section of the model was chosen as the study area. The picture of the coolant fl ow is represented by cartograms of the distribution of axial velocity and coolant fl ow rate, as well as cartograms of the distribution of the contrast impurity. The experimental results can be used in the design of new active sections of RITM reactors. The resulting experimental base can be used for local validation of CFD programs and onedimensional thermal-hydraulic codes used to substantiate the thermal reliability of cores.
The results of experimental studies of the hydrodynamics of a coolant in the outlet section of a cassette fuel assembly of the RITM reactor of a low-power nuclear power plant are presented. The purpose of the work was to study the redistribution of axial velocity and coolant fl ow rate at the outlet of the fuel rod bundle, behind the fuel assembly cap, near the coolant extraction pipe, and in the holes of the upper support plate. To achieve the goal, experiments were carried out on a research stand with an air working medium on a model of the outlet section of the fuel assembly, including the outlet fragment of the fuel rod bundle, the cap, the upper support plate with the coolant extraction pipe. When conducting research, the pneumometric method and the method of injection of a contrast impurity were used. An area covering the entire cross section of the model was chosen as the study area. The picture of the coolant fl ow is represented by cartograms of the distribution of axial velocity and coolant fl ow rate, as well as cartograms of the distribution of the contrast impurity. The experimental results can be used in the design of new active sections of RITM reactors. The resulting experimental base can be used for local validation of CFD programs and onedimensional thermal-hydraulic codes used to substantiate the thermal reliability of cores.
Author:  S. M. Dmitriev, T. D. Demkina, A. A. Dobrov, D. V. Doronkov, D. S. Doronkova, A. N. Pronin, A. V. Ryazanov, D. N. Solntsev, and A. E. Khrobostov
Keywords:  nuclear reactor, core or active section, fuel cassette, fuel rod or element, spacer grid, cap or head, coolant extraction pipe, axial velocity, axial fl ow rate, contrast impurity
Page:  195