Method for simulating three-dimensional neutron flux of pressurized water reactor core based on axial expansion

Abstract

The invention discloses a method for simulating the three-dimensional neutron flux of a pressurized water reactor core based on axial expansion. The method comprises the following steps: firstly, dividing the three-dimensional pressurized water reactor core to be simulated into a plurality of layers along the axial direction, expanding the three-dimensional neutron angular flux for each layer, andapproximately simulating the axial change of the neutron flux by adopting a linear model in the axial direction; establishing a two-dimensional neutron transport model based on a characteristic linemethod in the radial direction according to the three-dimensional neutron flux after axial linear expansion; obtaining the relationship between the zero-order neutron angular flux and the first-orderneutron angular flux according to boundary conditions so as to simplify the two-dimensional neutron transport model established by the characteristic line method; and finally, solving the simplified two-dimensional neutron transport model along each layer from bottom to top in the axial direction to obtain neutron flux distribution of the three-dimensional pressurized water reactor core of each layer. Compared with the prior art, neutron leakage items generated by transverse integration in the two-dimensional neutron transport model and the one-dimensional neutron transport model are avoided,the solving stability is high, the method can be used for transport module calculation of a numerical reactor, and the stability of numerical simulation is improved.

Description

technical field [0001] The invention relates to the field of nuclear reactor core design and safety, in particular to a method for simulating three-dimensional neutron flux in a pressurized water reactor core based on axial expansion. Background technique [0002] With the continuous development of the nuclear power industry, in order to cope with the life extension and safety analysis of nuclear power plants, the accuracy and stability requirements for the numerical simulation of the pressurized water reactor core are getting higher and higher. In order to meet the accuracy and stability requirements of PWR numerical simulation, high-fidelity methods such as numerical reactor are more and more used in the numerical simulation of PWR. [0003] The high-fidelity method adopts the whole core to solve directly, and the number of calculated grids is large, and the calculation burden of the three-dimensional neutron transport model of the transport module is relatively large. At...

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Problems solved by technology

[0004] Due to the existence of the leakage term, the neutron source in the two-dimensional and one-dimensional numerical simulation process is negative, and the neutron flux in the process of calculating the one-dimensional neutron transport model and the two-dimensional neutron transport model will not meet the Negative values ​​of physical laws lead to divergence in numerical simulation calculations

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