Dynamic model and earthquake response of a hybrid isolated system with tuned inerter dampers for nuclear power plants

Abstract

Considering the benefits of tuned inerter damper (TID), a hybrid control system (TIDISO system) for third-generation NPPs consisting of an un-isolated outer containment structure, an isolated inner containment structure and a connecting TID system was proposed. First, governing equations of motion for the 3-degree-of-freedom (3DOF) model were derived and the seismic response variances of TIDISO system under white noise excitation were obtained. Next, an optimization study on inertance, frequency and damping parameters was conducted, and then simplified expressions were provided as a function of the various structural parameters for the optimal TID parameters. Through simulation comparisons, the accuracy of the expressions was further verified. Finally, a case study was conducted to demonstrate the proposed rapid-determining formula for optimal TID parameters and to estimate the effectiveness of the proposed TIDISO system under seismic waves. The results illustrate the proposed system is effective to suppress acceleration and story draft responses, especially for isolation displacement. Under artificial wave 1, the displacement of isolation layer has declined from 475 mm to 327 mm, nearly 32.7%.