Nodal expansion method based reduced-order model for control rod movement

Abstract

Control rod movement is one of the main considerations for nuclear reactor safety analysis, whose accuracy simulation requires a significant amount of computing time. In this paper, combined with the proper orthogonal method (POD) and least square method (LSM), a novel reduced-order method based on the nodal expansion method (RO-NEM) is proposed to reduce the consumption of computational resources. Based on the snapshots obtained from NEM, the reduced-order model constructed by RO-NEM can predict the neutron flux distribution at the unknown state efficiently. Results from typical benchmark problem demonstrate that the proposed RO-NEM can accurately and efficiently obtain neutron distribution. Global POD (GPOD) and local POD (LPOD) methods for selecting snapshots to generate POD basis are compared in this work. Results show that LPOD has better calculation accuracy and efficiency than GPOD. This work provides new perspectives and directions for improving the efficiency of numerical calculations in nuclear reactor engineering.