Method for acquiring neutron angular flux density in nuclear fuel assembly

Abstract

The invention relates to a method for acquiring neutron angular flux density in a nuclear fuel assembly. The method comprises the following steps: 1, calculating value of a primary function; 2, calculating integral of the primary function and angle variable; 3, establishing a wavelet unwrapping equation in the assembly; 4, processing assembly boundary conditions; 5, calculating the neutron angular flux density; 6, establishing the wavelet unwrapping equation with allowance; 7, correcting the neutron angular flux density; and 8, judging whether the neutron angular flux density meets the precision demand or not. According to the invention, argument variable of neutron angular flux density is unwrapped by using a one-dimensional primary function to reduce the calculation scale. By means of adopting the assembly boundary unwrapping and the unwrapping within the assembly respectively, the fuel assembly boundary is unwrapped in areas to avoid calculation of redundancy unwrapping coefficient. As the neutron angular flux density and the allowance are respectively processed, two-time equal coupling scales are just calculated, so that the unwrapping order is relatively and simply improved. Under the premise that approximate computational accuracy is realized, the coupling coefficient is prevented from square increase along with precision improvement, and the calculating efficiency is improved.

Description

technical field [0001] The invention relates to the field of nuclear fuel assembly neutronics analysis methods, in particular to a method for obtaining nuclear fuel assembly neutron angular flux density. Background technique [0002] In order to ensure the safety of the reactor and improve the operating economy, it is necessary to improve the calculation accuracy of the nuclear fuel assembly parameters. Among them, obtaining the distribution of neutron angular flux density in the nuclear fuel assembly is one of the key links. With the complexity of nuclear fuel assembly design and the increase of computational requirements, the phenomenon of drastic variation of neutron angular flux density in some nuclear fuel assemblies was discovered [1] , thus exacerbating the difficulty of obtaining high-precision angular neutron flux density. [0003] Traditional neutron angular flux density acquisition methods are divided into spherical harmonic function method and discrete ordinate...

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Problems solved by technology

[0013] In order to solve the problems in the above-mentioned prior art, the object of the present invention is to provide a method for obtaining the neutron angular flux density of nuclear fuel assemblies. Insufficient flux density acquisition ability, and compared with traditional methods, the calculation efficiency is greatly improved, which has engineering practical value

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