Research On Passive Residual Heat Removal System Based On 1d-3d Coupling Method

When a nuclear power plant occurs an accident,it often leads to grave consequences such as core meltdown because the residual heat in core could not be recovered in time.In order to improve the safety of reactor,more and more power plants are equipped with passive residual heat removal system.The secondary side passive residual heat removal system cools steam from the steam generator through the residual heat removal heat exchanger,which takes away the core heat indirectly.The system relies on the driving force generated by passive means such as density difference and height difference to establish natural circulation,which greatly increases the inherent safety of nuclear power plant and reduces the investment cost of safety facilities.At present,the system has been used in many types of nuclear power plants.This paper take the secondary passive residual heat removal system as the research object.Firstly,we use self programming method to complete one-dimensional modeling of steam generator based on C # language.Then we verify the model in steady state and transient state,and the results accord with the practice.Secondly,for the three-dimensional calculation of the residual heat removal heat exchanger,we use the FLUENT software to obtain the parameters and flow field distribution in the heat exchange tube,after that we verify the accuracy of the model under different working conditions.Finally,this paper introduces the external control methods of one-dimensional and three-dimensional computing,and programs the coupling program based on C # language.Then we use the one-dimensional and three-dimensional coupling calculation method to simulate the operation of the whole passive residual heat removal system,and analyze the variation rules of the system operating parameters under different conditions.The coupling calculation method in this paper combines the advantages of onedimensional calculation and three-dimensional calculation,which can not only ensure the calculation speed,but also improve the calculation accuracy and obtain the flow field distribution of key equipment.This method provides a new idea for the simulation calculation of passive residual heat removal system,and provides the reference value for the design and optimization of the system and related equipment.