Stable and accurate reactor physics thermotechnical coupling calculating method

Abstract

A stable and accurate reactor physics thermotechnical coupling calculating method can simultaneously obtain statuses of a neutronics field, a fluid field and a heat transfer field; all variables are simultaneously updated in an iteration process, so the method has better value stability when compared with a conventional coupling method; the method uses a simultaneous time-space neutron diffusion equation and a thermotechnical equation discrete equation to obtain a novel nonlinear equation group with larger scale; using a Newton iterative method to resolve values of the novel nonlinear equation group, wherein the Newton iterative method needs to calculate a Jacobian matrix of the equation group in each iteration step, so physics thermotechnical coupling calculation is difficult. The novel method builds a value relation between the diffusion equation and thermotechnical equation, and explicit calculation can provide the Jacobian matrix, so problems caused by approximation calculation f the Jacobian matrix can be prevented; in addition, the novel method inherits Newton method characteristics, and hopes to provide 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...

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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

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