Research on numerical calculation of reactor neutron noise in frequency domain and time domain

Abstract

The theoretical calculation of neutron noise plays an important role in interpreting experiments and providing abnormal directivity information in the reactor. Therefore, it is necessary to study the numerical calculation methods of reactor neutron noise in frequency domain and time domain. Based on the theoretical framework of the Galerkin finite element method, this work derives the specific equations of reactor neutron noise in frequency domain and time domain, and then the neutron noise of a small core configuration under helium bubble perturbation was calculated. With the change of the perturbation flow of the helium bubble source, that is, the change of the characteristics of the noise source, the deviation of the calculated results of the neutron noise in frequency domain and time domain also changes sequentially and presents a nonlinear relationship with the noise source.