Earthquake-simulator tests of head-mounted equipment in advanced nuclear reactors

Earthquake-simulator experiments were conducted on a scale-model of a base isolated reactor vessel including four representations of head-mounted equipment, with frequencies spanning 4.5 Hz to 27 Hz. Three recorded earthquake motions and one synthetic motion, all triplets, were used as inputs in the experiments. Dynamic responses of the head-mounted equipment, including displacements, accelerations, and strains, were measured in the experiments for three vessel support conditions: conventional, and seismically isolated using Single concave Friction Pendulum (SFP) bearings and Triple Friction Pendulum (TFP) bearings. Seismic isolation was effective at reducing equipment responses (accelerations, displacements, and strains) with respect to those in the conventionally supported vessel across a range of seismic inputs. The data generated in the tests provides insights into the benefits of seismically isolating equipment in nuclear reactors and the accuracies of numerical modelling approaches that can be expected in calculating seismic responses of such equipment.