A universal formula for high-order added mass of reactor core barrel with lower core plate immersed in fluid

The high-order mode has non negligible influence on the flow induced vibration response of the core barrel, which requires accurately capturing its high-order added mass. In this regard, a theoretical model of high-order added mass for core barrel with lower core plate was developed. To fulfill this, the governing equations of this intrinsic fluid-structure interaction were first derived based on Galerkin method and potential flow theory. Then, some hypotheses were introduced to simplify the mathematical expressions and solutions. Based on these assumptions and governing equations, the hydraulic pressure exerted on the façade of core barrel was given. The calculation of the added mass of a certain high-order mode was proposed through the integration of hydraulic pressure. Compared with the finite element results, it indicates that the added masses calculated by our model are applicable. Consequently, the parameters such as thickness of lower core plate, core barrel thickness and radius ratio of core barrel to reactor pressure vessel were analyzed, so as to explore the variation rule of added mass. This contribution offered a concise formula to facilitate relevant engineering applications.