Dynamic Response Analysis On Shaft Of Canned Pump Under Loss-of-Coolant Accident Condition

Nuclear power has many advantages and people demand for environment and energy is higher and higher in the future,nuclear power will become an important development direction for the future energy industry.Canned nuclear main pump is the key component of nuclear power plant,which is related to the safety of the whole nuclear power plant.The loss-of-coolant accident is the most serious accident in nuclear power plant.Studying the working conditions of canned nuclear main pump under the loss-of-coolant accident is conducive to taking corresponding safety measures to prevent nuclear accident.This paper takes the canned nuclear main pump as the research object.After removing the cooling cycle system,canned sleeve and canned motor and unnecessary small-sized holes and chamfers,it is reasonably simplified.The nuclear main pump shaft system is modeled by the finite element method.The modal analysis of the canned nuclear main pump shaft system was performed,and the first five critical speeds,the first six modal shapes,and mass unbalance response were calculated.The analysis results show that the shafting is stable.In this paper,the flow field simulation analysis of the full flow field calculation domain of the canned nuclear main pump under normal working conditions is first performed.The pre-processing stage includes processing of fluid domain creation,mesh division,turbulence model selection,and boundary conditions determination.In the numerical simulation stage,the maximum force of the impeller was 57.438 MPa,the maximum deformation of the impeller was 0.081785 mm,and when the vibration frequency is 7Hz,the canned nuclear main pump shaft system has the maximum amplitude and the maximum amplitude was 2.7253 mm.When analyzing the working characteristics of the canned nuclear main pump under the loss-of-coolant accident conditions,the loss-of-coolant accident is divided into three kinds of conditions:small break,medium break and large break.The break location is divided into the inlet section and the outlet section.The numerical simulations calculate the impeller stress,deformation,and vibration of the canned nuclear main pump shaft under various loss-of-coolant accident conditions.At the same time,the change of coolant flow rate under each condition is calculatedAnalysis and calculation results show that when a break occurs in the inlet section,the impeller force becomes smaller,and the vibration amplitude of the canned nuclear main pump shaft system decreases,and the larger the break area,the smaller the impeller force,the smaller the canned nuclear main pump shaft amplitude;when there is a break in the outlet section,the impeller force increases,and the amplitude of the canned nuclear main pump shaft increases,and the larger the area of the break,the smaller the impeller force increase,and the smaller the canned nuclear main pump shaft amplitude increase.The vibration of the canned nuclear main pump shaft system under different flow and rotation rate conditions is analyzed.The smaller the flow rate under the constant rotation rate condition,the smaller the amplitude of the canned nuclear main pump shaft system;the smaller the rotation rate under the constant flow rate condition,the larger the amplitude of the canned nuclear main pump shaft system.The analysis and research results in this paper not only provide a data basis for the dynamic response characteristics of the canned nuclear main pump shaft system under loss-of-coolant accident conditions,but also provide a reference for the choise of corresponding safety measures to prevent nuclear accidents.