A Stable and Accurate Calculation Method for Reactor Physical Thermal Engineering Coupling

Abstract

A stable and accurate coupling calculation method of reactor physics and thermal engineering is a method to simultaneously obtain the state of neutronics field, fluid field and heat transfer field during the solution process. Since all variables are updated at the same time during the iterative process, this method Compared with the traditional coupling method, it has better numerical stability. This method obtains a new larger-scale nonlinear equation system through the simultaneous space-time electron diffusion equation and the discrete equation of the thermal equation. For this equation system, Newton iteration is applied method to solve numerically, because the Newton iterative method needs to calculate the Accord ratio matrix of the equation system at each iterative step, it is difficult to calculate the coupling of physical and thermal engineering, this method explicitly calculates by establishing the numerical connection between the diffusion equation and the thermal The Accord ratio matrix is ​​obtained to avoid the problems caused by the approximate calculation of the Accord matrix. At the same time, this method inherits the characteristics of the Newton method and is expected to have a faster convergence speed.

Description

technical field [0001] The invention relates to the technical field of reactor core design and safety analysis, in particular to a stable and accurate calculation method for reactor physics, heat and engineering coupling, which is called a full coupling method. Background technique [0002] The reactor is a complex system coupled with multiple physical fields. Due to its complexity, a relatively independent discipline has been formed for each physical field. Among them, nuclear reactor physical analysis and nuclear reactor thermal analysis are two important areas of reactor design and safety analysis. [0003] The so-called physical thermal engineering coupling means that there are feedback effects among the physical parameters in the reactor, and these feedback effects will be more significant when a transient safety accident occurs in the reactor, so the accurate consideration of these feedback effects requires the coupling analysis of physical thermal engineering calculat...

AI Technical Summary

Problems solved by technology

[0005] The biggest advantage of the existing physics-thermal-engineering coupling method is that it is easy to implement, because it hardly requires program redevelopment. However, due to the nature of this "loosely coupled" algorithm, its convergence speed is limited. To obtain a high convergence accuracy As a result, a large number of physical thermal engineering iterations is required, so it is necessary to balance the calculation accuracy and computational efficiency. In addition, the existing coupling methods also have the problem of calculation oscillation or even divergence in some cases. Although by adding physical thermal engineering coupling The damping factor between calculations can significantly alleviate this phenomenon, but it still cannot jump out of the "code coupling" ideological framework, and the physical equations and thermal equations are still solved by decoupling

Images