Mathematical model for predicting the vibration performance of a core barrel considering the interaction of seismic load and fluid force

Abstract

The integrity of core barrel greatly affects the secure operation of the reactor, especially under extreme condition such as earthquake. The excitation of fluid force and inertial force acting on the core barrel requires detailed analyses. Owing to the strong coupling between the inertial force and hydrodynamic pressure in the process of an earthquake, it is difficult to calculate the dynamic response performance of the core barrel in the reactor. On the basis of analyzing the dynamic vibration characteristics of the core barrel, combined with the potential flow theory of inviscid fluid, a mathematical model suitable for effectively calculating the response of the core barrel under earthquake and fluid load was established. Meanwhile, the mathematical model was validated by comparison with the finite element analyses. Using this model, the response of the core barrel under the actions of predefined sinusoidal ground motion and designed seismic spectrum were calculated. Specifically, the effects of height-width ratio and the gap between core barrel and reactor pressure vessel on the vibration behavior were observed.