Research On Force Performance And Quality Control Of Dome Overall Lifting In Nuclear Power Station

The dome hoisting of nuclear island reactor plant is one of the five major milestones in the whole process of nuclear power plant construction.The successful completion of the hoisting marks the end of the main project of nuclear island reactor plant and the shift of the focus of nuclear power plant construction to the installation of main equipment.It is difficult to arrange the lifting points and adjust the level of the lower part of the dome,to guarantee the welding quality at high altitude,to meet the requirements of the first-class nuclear equipment,and to have a long construction period.The application of dome integral hoisting technology can realize the rational arrangement of hoisting points in the integral hoisting of large-span space ribbed steel plate shell structure,so as to achieve the goal of uniform and coordinated force.This paper uses finite element software to optimize the position and angle of lifting point in the process of integral lifting of dome.At the same time,a new type of detachable lifting lug connection mode is proposed,and the mechanical analysis of its connection performance is carried out by using finite element software ANSYS.The main contents of this paper are as follows:(1)SAP2000 is used to optimize the number of lifting points and lifting angle during the whole lifting process of the dome of nuclear power plant.The results show that the deformation value at the edge of the dome steel lining decreases gradually with the increase of the number of suspension cables;when the number of suspension cables is fixed,the deformation value at the edge of the dome steel lining increases gradually with the increase of the inclination angle of the suspension cables.Considering the difficulty of construction during hoisting,it is suggested that the number of slings should be 12 and the inclination should be 60 degrees.(2)In order to improve the convenience of lifting lug in construction,a new type of detachable bolt connection method is proposed for the connection performance of lifting lug and dome steel lining.Based on the stress state of lifting lug and the theory of material mechanics,the calculation method of lifting lug is established,and the design process of lifting lug is put forward.(3)The finite element analysis software ANSYS is used to simulate the new type of assembled lug connection,and to study its mechanical properties.The results show that the new type of lug connection can meet the strength requirements under the lifting tension.The maximum stress values of lug plate,lug bottom plate and bolt are 234.4 MPa,234.8 MPa and 887.59 MPa,respectively,which are all small.The correctness of the design method proposed in this paper is verified by the corresponding yield strength of steel.(4)Taking the integral lifting of the dome of a nuclear power plant as an example,this paper expounds the control methods of the lifting rig,the lower part of the dome and the size of the upper part of the steel lining of the reactor plant,and probes into the preparatory work and error control measures for each stage of the integral lifting of the dome,so as to ensure the smooth lifting and installation of the dome.