A fluid-solid coupling analysis method for nuclear reactor fuel melt migration behavior

Abstract

A fluid-solid coupling analysis method for nuclear reactor fuel melt migration behavior, the steps are as follows: 1. Initially model the reactor nuclear fuel, and use particles to form each component of the nuclear fuel; 2. Advance a time step determined by the stability condition; 3. For fluid particles, explicitly calculate the gravity term, viscosity term, surface tension term and drag force term in the momentum conservation equation to obtain the estimated velocity and position; 4. Implicitly calculate the pressure gradient term of the fluid particle to correct the velocity and position ;5. Calculate the drag force term and gravity term of solid particles on the fluid-solid coupling interface; 6. Retrieve the interaction between solid particles, use the friction model to control, and move the solid particles to the calculated position; 7. Output the results and push forward time step until the end of the simulation. This method can simulate all phenomena in the migration behavior, fully consider the fluid-solid coupling and the interaction between solids, and the calculation is in line with the physical essence and has extremely high accuracy.

Description

technical field [0001] The invention relates to the technical field of research on the migration behavior of the melt when the nuclear fuel is melted in a serious accident of a nuclear power plant, in particular to a fluid-solid coupling analysis method for the migration behavior of the melt of the nuclear reactor fuel. Background technique [0002] During the operation of the nuclear reactor fuel, if the coolant in the primary circuit cannot export the heat out of the core in time due to some accident, the temperature of the fuel will continue to rise, especially after the coolant boiling develops to film boiling, the core fuel The heat transfer of the reactor deteriorates sharply, and the fuel temperature rises sharply until it reaches the melting point of some materials, and the fuel will melt, resulting in a serious accident of core melting. The conditions for the melting of nuclear reactor fuel and how the resulting melt migrates in the core are of great significance to...

AI Technical Summary

Problems solved by technology

At present, some existing mechanism analysis programs (such as MELCOR and SCDAP / RELAP5, etc.) for the analysis and simulation results of these problems are relatively rough, mainly because the core melt During the migration process, unmelted fuel particles, etc. will be entrained and moved by the melt, and there are also interactions between these entrained discrete solids, which makes the problem more complicated, and the melt has a large free surface when it flows, And the deformation is obvious, which makes the traditional grid method have to face the inherent defect of grid distortion, making the calculation results less accurate

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