The dynamic responses of three storied auxiliary building of a nuclear power plant (NPP) constructed with a monolithic reinforced concrete shear wall are investigated in this study. The dynamic characterization is weighed through a shake table test and evaluated the efficiency of various structural modeling systems for evaluating seismic responses. The shear wall was subjected to a collaborative research round-robin analysis conducted by the Korea Atomic Energy Research Institute to forecast seismic responses of the auxiliary building in the NPP using a shake table test. The shake table test was performed with five different levels of intensity measures of the base excitation to obtain acceleration responses from different positions of the building in one horizontal direction (front-back). The main motivation of this study is to develop a nonlinear numerical model and examine the efficiency of various modeling approaches for evaluating the performance under seismic loading. Three numerical modeling approaches, i.e., multi-layer shell element modeling (MLSM), fiber beam-column element modeling (FBCM), and beam-truss element modeling (BTM), are generated to simulate the seismic response behaviors of the auxiliary building structure. Modal analysis, floor response spectra, acceleration amplification factor along with height, and story shear force of the building are compared as they are critical responses for evaluating the seismic vulnerability of the structure. The comparison shows that all the nonlinear numerical modeling approaches, i.e., MLSM, FBCM, and BTM, can predict the complex behavior of a shear wall system for low earthquake level, but for high earthquake level, MLSM shows better agreement with the shake table experiment. So, it is recommended to use MLSM modeling for nonlinear analysis with an earthquake intensity measure of 1 g or more.