Study On The Analysis Method Of Containment External Water Tank Structure Strength

HPR1000 is the third generation nuclear power technology independently designed by China,Its passive containment heat removal system(PCS)is used for long-term heat removal of the inner containment under beyond design basis accident conditions,which is very important for the safety of nuclear power plant.As an important part of PCS system and heat exchange tank and arranged in the outer containment.,external water tank is the key facility to ensure the safety of nuclear power plant.Therefore,it is of great significance to study the analysis method of the external containment tank strength of the third generation nuclear power plant,which is a new type of structure.The overall outer containment model was established,including the containment shell,surrounding buildings and external water tank,and analyze the applicability of the integral steel reinforcement model.Analyze the chamfering model of the external water tank structure,and establish part of the pipeline and equipment model of the water tank.The overall model is divided into sections and the grid sensitivity is analyzed.Perform modal analysis on the outer containment and external water tank to obtain the vibration characteristics of the structure.The external water tank has a low natural frequency and is prone to vibration on the wall of the water tank.According to the relevant safety analysis report,the combination of abnormal operation and extreme environmental conditions is selected to analysis,which is the most serious condition for the external water tank structure.According to the theoretical and computational analysis results,the ground motion load in this combined condition should be simulated by the time history analysis method,the temperature load should be simulated by the coupling method.Discuss the influence of different loads on the structure,and determinant the boundary conditions of the combined load.Select safety guidelines according to relevant regulations.For the fluid-structure interaction system of the external tank,categorize fluid-structure interaction theory and methods,and the comparative analysis of fluid-solid coupling methods can be obtained.The two-way fluid-structure interaction calculation method can better analyze the interaction between fluid and solid in the external tank.It is verified by experiments that this method can better analyze the fluid oscillation characteristics and structural dynamic response,and is suitable for strength analysis of the external water tank.Finally,the structural strength calculation is carried out.The results show that the calculated stress and strain values of the external storage tank are less than the allowable value of the external storage tank structure under the conditions of El Centro ground motion,artificial ground motion and long-term ground motion coupled with temperature load respectively.The research method proposed in this paper suitable for structural strength analysis of external water tanks,and applied to the HPR1000 external water tank structure strength analysis.It can provide relevant reference for the safety design of external water tank of containment.