Fluid-solid coupling analysis method for migration behavior of nuclear reactor fuel molten melt

Abstract

A fluid-solid coupling analysis method for a migration behavior of nuclear reactor fuel molten melt comprises the following steps: 1, carrying out initial modeling on a nuclear fuel of a reactor, and forming each component of the nuclear fuel by using particles; 2, advancing a time step length determined by a stability condition; 3, for fluid particles, explicitly calculating a gravity item, a viscosity item, a surface tension item and a drag force item in the momentum conservation equation to obtain an estimated speed and an estimated position; 4, implicitly calculating a pressure gradient item, a correction speed and a position of a fluid particle; 5, calculating a drag force item and a gravity item of solid particles on the fluid-solid coupling interface; 6, searching interaction among the solid particles, controlling by adopting a friction force model, and moving the solid particles to a calculation position; and 7, outputting a result, and advancing a time step until simulation is finished. All phenomena in the migration behavior can be simulated, the fluid-solid coupling effect and the interaction between solids are fully considered, calculation conforms to the physical essence, and extremely high accuracy is achieved.

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 in a nuclear power plant, and in particular relates 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 melting of the fuel will occur, resulting in the occurrence of a serious accident of core melting. The conditions for the melting of nuclear reactor fuel and how the resulting melt mig...

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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