Abstract:Traditional thermal hydraulic system procedures are not sufficient for simulation calculation and safety analysis of offshore reactors.By adding an additional force model to the momentum equation and modifying the program model coordinates based on the influence of the sway on the various control bodies of the system,the program is developed twice.The second loop small stack is simplified and designed,and the sway amplitude and period are analyzed.On the influence of hydraulic characteristics of ocean small piles.The simulation and analysis of the two-size break accidents show that the sway will cause periodic changes in the flow and have a phase difference.The periodic additional force caused by the sway when breaking will compensate or superimpose the original flow.