Multi-scale and multi-physical field coupling analysis method for cladding behavior in serious accident of reactor

Abstract

The invention discloses a multi-scale and multi-physical field coupling analysis method for cladding behaviors in a serious accident of a reactor. The method comprises the following steps: 1, establishing calculation models under different scales; 2, developing a coupling interface module to realize data transmission between models; 3, the nuclear reactor system analysis software calculates a steady-state operation condition and defines an initial condition; 4, starting transient accident process simulation by the nuclear reactor system analysis software; 5, after the state parameters of the lower grid plate are obtained, the coupling interface module 1 is called to transmit data; 6, respectively carrying out calculation by adopting Fluent, Abaqus and a one-dimensional cladding oxidation model; 7, if the calculation results in the step 6 are converged, calling the coupling interface module 1 and the nuclear reactor system analysis software to continuously run, otherwise, calling the coupling interface module 2, and repeating the steps 6 and 7; and 8, if the calculation time is greater than the termination time, terminating the calculation. Otherwise, calculating the next time step length, and repeating the steps 5-8. The method is of great significance to severe accident process prediction and analysis.

Description

technical field [0001] The invention relates to the field of nuclear reactor safety analysis methods, in particular to a multi-scale and multi-physical field coupling analysis method for cladding behavior in severe reactor accidents. Background technique [0002] During a severe accident in a nuclear reactor, the cladding temperature rises rapidly. Under the action of factors such as the internal pressure of the air gap and the deformation and extrusion of the fuel pellets, the cladding bulges and deforms during this process, which reduces the area of ​​the coolant flow channel and further deteriorates the heat transfer. As the temperature of the cladding further increases, a violent oxidation reaction between the cladding and water vapor will occur, and the chemical heat released during the process will accelerate the temperature rise of the core, and at the same time generate a brittle oxide phase, which will reduce the mechanical properties of the cladding. When the clad...

AI Technical Summary

Problems solved by technology

This method cannot consider the coupling effects of cladding deformation, channel blockage, oxidation phase transition, chemical reaction heat release, etc., and requires a large number of modifications to the empirical coefficients in the model to achieve the expected simulation results, which is not universal

So far, no relevant reports have been found to propose a reasonable solution to this problem. Therefore, the development of multi-scale and multi-physics coupling analysis methods for cladding behavior in severe reactor accidents is of great significance for the prediction and analysis of severe accident processes.

Images