A shaking table test for an evaluation of seismic behavior of 480 V MCC

► We perform a shaking table test for electric cabinet. ► We examine an amplification ratio of electric cabinet. ► We examine a failure capacities of electric cabinet. ► A seismic fragility of electric cabinet is evaluated. In this study, a seismic behavior of the electrical cabinet system in Nuclear Power Plants (NPPs) was evaluated by the shaking table test. A 480 V Motor Control Center (MCC) was selected for the shaking table test, and a real MCC cabinet for the Korea Nuclear Power Plant site was rented from a manufacturing company. For the shaking table tests, three kinds of seismic input motions were used, which were a US NRC Reg. guide 1.60 design spectrum, a UHS spectrum and Floor Response Spectrum of PAB 165′ at the Ulchin NPP site. The UHS input motion was particularly selected for an evaluation of high frequency seismic effects. The PGA levels for the shaking table test were scheduled from 0.2 g to 3.0 g in order to assess the real seismic capacity of the electrical cabinet system. For the evaluation of the structural seismic amplification effects, three directional accelerations were measured at three points outside of the cabinet system, and regarding incabinet response amplification, accelerations were measured at two points where electrical equipment such as relay were mounted. The seismic amplification effect is determined on the outside and the inside of a cabinet as input seismic motion, and compared to the results which were calculated by analytical method based on NUREG/CR-5203. Finally, with the seismic fragility evaluation for the 480 V MCC cabinet, the previous seismic result from a seismic PSA report in Korea is found to be slightly conservative.