Analysis method of early deformation of nuclear reactor fuel based on particle method

Abstract

A method for analyzing early deformation of nuclear reactor fuel based on a particle method, the main steps are as follows: 1. Establish a geometric model, set particle physical properties and mechanical parameters; 2. Establish a particle neighbor domain; 3. Calculate solid boundary particles based on boundary conditions and a solid collision model External force load; 4. Calculate temperature and calculate thermal expansion strain based on thermal expansion model; 5. Calculate plastic strain and elastic stress-strain of continuous medium particles in solid based on elastic model, elastic-plastic model and plastic model; 6. Determine whether fracture occurs and update particles 7. Output calculation results. This method can analyze the early deformation behavior of nuclear reactor fuel in severe accidents; based on the particle method, it can effectively avoid the grid distortion problem existing in the grid method; this method is a pure Lagrangian nuclear method, which can effectively avoid stress-strain analysis Tensile instability in the process.

Description

technical field [0001] The invention relates to the technical field of early deformation research of fuel in serious accidents of nuclear reactors, in particular to a method for analyzing early deformation of nuclear reactor fuel based on a particle method. Background technique [0002] When an accident occurs in a nuclear power plant, if the core of the nuclear reactor is not sufficiently cooled, the state of the fuel will deviate from the normal operating conditions, and the rise in temperature will cause thermal expansion of the core structural materials and the fuel, which will cause the fuel to deform as a whole and withstand additional stress. The deformation of the fuel changes the shape and flow area of ​​the coolant passage, which affects the effect of subsequent emergency cooling measures. In addition, the injection of emergency water and other measures will generate external force loads on the core structure and fuel. In this case, the fuel at high temperature is...

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Problems solved by technology

In the field of marine research, the particle method has been successfully applied to the study of the interaction between elastic structural materials and ocean waves, but there are few studies on the application of complex situations in severe accidents in nuclear reactors

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