Reactor core xenon concentration distribution prediction method based on intrinsic orthogonal decomposition

Abstract

The invention discloses a reactor core xenon concentration distribution prediction method based on intrinsic orthogonal decomposition. The method includes calculating reactor core xenon concentrationaccording to reactor core three-dimensional power distribution online reconstruction values at different time points; carrying out intrinsic orthogonal decomposition on the xenon concentration of thereactor core; fitting the expansion coefficient by taking time as an independent variable to obtain a function that the expansion coefficient changes along with time; extrapolating the expansion coefficient to obtain an expansion coefficient prediction value at a future time point; calculating a reactor core xenon concentration prediction value at a future time point in combination with an intrinsic orthogonal basis function; decomposing the xenon concentration of the reactor core by utilizing an intrinsic orthogonal decomposition technology, and expressing the xenon concentration of the reactor core in a form of summing an expansion coefficient changing along with a time variable and an intrinsic orthogonal basis function product changing along with a space variable, so that the calculation precision is ensured. Through fitting and extrapolation of the expansion coefficient changing along with the time variable, the calculation speed is also satisfied, and the online reconstruction algorithm of the reactor core power distribution under the working condition that the reactor core state is changing is realized.

Description

technical field [0001] The invention relates to the technical field of nuclear reactor core operation and safety, in particular to a prediction method for core xenon concentration distribution based on intrinsic orthogonal decomposition. Background technique [0002] Nuclear reactor core power distribution online monitoring system, also known as core neutron flux online monitoring system, is of great significance to ensure the safety of reactor core and improve the economic benefits of nuclear power plants; the realization of online monitoring of core power distribution usually requires the help of The real-time measurement results of the neutron detector inside or outside the reactor, combined with the neutron transport or diffusion equation, establishes the online reconstruction algorithm of the core power distribution, and calculates the three-dimensional continuous power distribution of the core or the online reconstruction of the neutron flux density in real time. struc...

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Problems solved by technology

[0006] In the steady-state condition of the core, the xenon concentration is usually an equilibrium value, and its fluctuation will not affect the online reconstruction algorithm of the steady-state power distribution that only considers the space variable; however, when considering the time variable and the core state Under changing operating conditions, the concentration of xenon will have an important impact on the online reconstruction algorithm and calculation results of the core power distribution

[0007] At present, no research has been reported on this aspect. Therefore, it is necessary to study a method for predicting the xenon concentration distribution in the core, which is used to calculate the online reconstruction of the core power distribution under the condition that the time variable is considered and the core state is changing. algorithm

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