Development and verification of the higher-order mode neutron flux calculation code HARMONY2.0  

作　　者：Er-Pin Zhang Zi-Ning Ni Nian-Biao Deng Jin-Sen Xie Yong Liu Tao Yu 

机构地区：[1]School of Nuclear Science and Technology,University of South China,Hengyang 421000,China [2]Key Laboratory of Advanced Nuclear Energy Design and Safety,Ministry of Education,Hengyang 421000,China [3]Science and Technology on Reactor System Design Technology Laboratory,Nuclear Power Institute of China,Chengdu 610213,China

出　　处：《Nuclear Science and Techniques》2025年第1期207-225,共19页核技术(英文)

基　　金：supported by the National Natural Science Foundation of China(No.U2267207);Science and Technology on Reactor System Design Technology Laboratory(No.KFKT-05-FWHTWU-2023004).

摘　　要：Higher-order modes of the neutron diffusion/transport equation can be used to study the temporal behavior of nuclear reactors and can be applied in modal analysis, transient analysis, and online monitoring of the reactor core. Both the deterministic method and the Monte Carlo(MC) method can be used to solve the higher-order modes. However, MC method, compared to the deterministic method, faces challenges in terms of computational efficiency and α mode calculation stability, whereas the deterministic method encounters issues arising from homogenization-related geometric and energy spectra adaptation.Based on the higher-order mode diffusion calculation code HARMONY, we developed a new higher-order mode calculation code, HARMONY2.0, which retains the functionality of computing λ and α higher-order modes from HARMONY1.0, but enhances the ability to treat complex geometries and arbitrary energy spectra using the MC-deterministic hybrid two-step strategy. In HARMONY2.0, the mesh homogenized multigroup constants were obtained using OpenMC in the first step,and higher-order modes were then calculated with the mesh homogenized core diffusion model using the implicitly restarted Arnoldi method(IRAM), which was also adopted in the HARMONY1.0 code. In addition, to improve the calculation efficiency, particularly in large higher-order modes, event-driven parallelization/domain decomposition methods are embedded in the HARMONY2.0 code to accelerate the inner iteration of λ∕α mode using OpenMP. Furthermore, the higher-order modes of complex geometric models, such as Hoogenboom and ATR reactors for λ mode and the MUSE-4 experiment facility for the prompt α mode, were computed using diffusion theory.

关 键 词：Neutron diffusion equation Higher-order modes Global homogenization Two-step method DOMAIN 

分 类 号：TL329[核科学技术—核技术及应用]