# Research on the Multi-Angle Seismic Spectrum Response Law of Auxiliary Feedwater Electric Pumps
###### Abstract
[16] utilized spectrum analysis techniques to scrutinize vibrations in the auxiliary feedwater electric pump of HPR1000, identifying deviations from standard performance. [PERSON] et al. [17] conducted harmonic response analyses on an auxiliary feedwater pump rotor subjected to seismic forces, deriving relationship curves between impeller displacement and excitation frequency through numerical simulations. [PERSON] et al. [18] conducted both on-site tests and numerical calculations on an auxiliary electric feedwater pump, devising strategies to enhance its operational reliability. [PERSON] et al. [19] utilized a dual-method approach, employing fluid dynamics theory calculations and computational fluid dynamics (CFD) modeling analysis to conduct a comparative evaluation of the comprehensive performance of the auxiliary feedwater system pump under accident conditions. Their analysis involved summarizing the unique characteristics identified through each method. These varied approaches collectively contribute to advancing the understanding of auxiliary feedwater electric pumps' seismic behavior and reliability. The seismic input direction significantly influences the seismic analysis of nuclear pumps, as the response characteristics within the structure vary based on this input direction. Researchers have diligently explored this aspect: [PERSON] et al. [20] conducted seismic response analysis of a coolant pump using the multiple input direction response spectrum method, investigating its most favorable and unfavorable input directions. [PERSON] et al. [21] performed seismic analyses on a dynamic model of a vertical centrifugal pump in different directions, determining that the 45\({}^{\circ}\) to 75\({}^{\circ}\) region of the model should align with the direction of frequent earthquakes. [PERSON] et al. [22] conducted seismic response analyses on a nuclear main pump using the response spectrum method, focusing on key components. They analyzed displacement and stress responses under multiple input angles. [PERSON] et al. [23] carried out a multi-angle reaction spectrum analysis of the rotor's key position in a horizontal waste heat discharge pump. [PERSON] et al. [24] conducted a sensitivity analysis of the spectral input angle and stiffness of a coolant pump. These investigations collectively contribute to a deeper understanding of the optimal seismic input directions for various types of nuclear pumps. The auxiliary feedwater electric pump commonly adopts a horizontal multi-stage centrifugal structure, introducing complexity to its structural dynamic characteristics. Consequently, there arises a need to explore the seismic response characteristics in various directions. Despite extensive scholarly research on the seismic performance and vibration characteristics of this pump, the response patterns under seismic excitations in different directions remain unclear. To address this gap, this paper concentrates on a representative auxiliary feedwater electric pump by leveraging the finite element method. Through modal analysis, the study comprehensively examines the response patterns of the pump under seismic spectra input from multiple angles. The research findings hold substantial significance in elucidating the response characteristics of the auxiliary feedwater electric pump and enhancing its overall seismic performance. Moreover, these insights can offer valuable guidance for optimizing the design and installation layout of similar horizontal multi-stage centrifugal pumps.