Investigation On Modular Construction Lifting Technology Of Steel Plate Concrete Structure In CAP1400 Nuclear Power Plant

With the adjustment of China's energy structure and the increasingly mature nuclear power technology,the second-generation nuclear power construction technology has gradually retired from the domestic nuclear power construction stage.And it replaced by the third-generation nuclear power plants which are safer,with larger installed capacity and higher economy.As a representative of China's third-generation nuclear power,State Nuclear Power Demonstration Plant CAP1400 nuclear power plant,which bases on AP1000 technique,is an important link in the localization and autonomy of China's nuclear power.Its modular construction concept is the trend of future construction technology development of nuclear power plants.SC Structure(Steel plate-concrete Structure)shielding wall used in CAP 1400 nuclear power plant is an innovation of the reference compost AP1000.But there is no mature experience can be used for reference.SC shielding wall structure is a large diameter(diameter 47.97m)annular double-layer flexible structure,with large weight,small overall stiffness,easy to appear inelastic deformation in the lifting process.And its final assembly accuracy requirement is very high,which brings great difficulty to the construction.In order to meet the needs of module construction,this paper divided the SC structure into different module forms according to the characteristics of SC structure.With the help of modeling software TEKLA,finite element software ANSYS,calculation software Midas Gen etc,the modular lifting of SC structure is analyzed from the aspects of center of gravity check,structural reinforcement,lifting fixture design,rigging selection and so on.1.Through analysis of the structure itself,considering the technological relationship with CV(containment vessel,steel vessel,belongs to nuclear safety mechanical equipment)structure,combined with the related requirements of manufacturing and construction,SC shielding wall can be divided into non-closed composite module and whole circle module.2.Hoisting simulate is performed for the not closed combination module in free situation,the anti-deformation lifting equipment itself,and the combination module with anti-deformation equipment.The result shows that with the hoisting anti-deformation equipment,combination module hoisting deformation can be effectively controlled.And the deformation can meet the needs of the design and construction.At the same time,because of the designed two-stage balance beam,the interference between the gravity center of the combined module and the CV structure can be effectively solved.And the selection of sling can be completed according to the force situation.3.The whole circle module is modeled and analyzed.It's found that the gravity center does not coincide with the geometric center.The problem can be solved by setting counterweight reinforcement.After balancing,the number of hoisting Settings is compared and analyzed.The results shows that the scheme of determining 32 upper chord hoisting points and 64 lower chord hoisting points is a better choice.On this basis,the lifting deformation of the whole circle module is simulated and analyzed.It is found that the radial and annular deformation of SC structure was small,and there is a certain deflection in the direction of eccentricity and counterweight.The ratio of total deflection to diameter is 1/269,and the total deformation is small,meeting the requirements.Through the comparison and analysis of different hoisting equipment,the truss trapezoidal pipe scheme is the best.Analyze is performed on the dislocation of lifting point deeply,part suspension cable failure and even distributed load in this scheme.The result shows that part components should be strengthened to ensure stiffness,strength and stability of the structure meeting the requirements of lifting.Through the above studies,the modular hoisting problem of CAP 1400 shielding wall is solved from a technical perspective.For different modular,different solutions are prepared.It will be a reference for the modular construction of subsequent nuclear power plant.And it will contribute to push the localization and independence of nuclear power plants in China.