Deformation Analysis And Control Measures Of AP1000 Nuclear Power Plant Structure Module

AP1000 advanced pressurized water reactor nuclear power technology has been successfully used in China.The nuclear power plant has been built and operated concurrently,and is ready for batch construction.The typical feature of AP1000 nuclear power plant construction process is modular construction,which is to split or assemble part of the building structure or mechanical equipment to form a number of modules,and concurrently construct the module prefabrication and site construction,which can greatly shorten the construction period and effectively guarantee the quality.However,modular construction brings convenience,but also increases the difficulty of the construction process,such as module deformation is difficult to control,lifting risk significantly increased.In order to solve these problems,the constructors need to accurately grasp the construction difficulties,summarize and feedback the previous engineering practices,constantly explore and innovate,and develop new technologies and new methods to meet the needs of the project.Based on the example of CA20 structure module in AP1000 power project,the deformation problem in module construction is studied in detail in this paper.By using the methods and means of quality management,factors such as personnel,machinery,materials,methods and environment are analyzed and improved,and different control methods are adopted in the following stages by taking advantage of the process characteristics of module construction.In assembling stage,vertical assembling is used instead of horizontal assembling,anti-deformation and rigid fixing measures are adopted to weld seam,and deformation is controlled by determining reasonable welding parameters and welding sequence.In addition,measuring and monitoring methods are introduced to control plane positioning,vertical deformation and settlement in time.In the hoisting stage,the stress and strain of the module body in hoisting are numerically simulated by FEM(Finite Element Method),and the vulnerable parts are strengthened.By using the Body-balance method,the module is balanced and analyzed,and the adjustment method is introduced.The lifting capacity and technological parameters of the crane are checked to ensure the safety and stability of the lifting.In addition,some matters needing attention in the process of module hoisting are introduced.In the concrete pouring stage,the mix proportion of SCC(Self-compacting concrete)is determined by experiments.The deformation of modular steel plate during pouring process is calculated and analyzed to ensure that the deformation value is within the allowable range.Taking the concrete pouring principle of "integral pouring,once to done",this paper describes the construction sequence,layered thickness and control measures of integral pouring,especially takes targeted reinforcement measures for weak parts such as single-sided steel plate wall,in order to effectively control module deformation and meet the conditions of installation and operation of follow-up equipment.This paper hopes to summarize some anti-deformation construction methods suitable for module construction process by studying and analyzing the causes of deformation and reinforcement measures of module construction in nuclear power plant,so as to improve the quality control ability of large-scale structural module construction,provide some help for other similar projects,and provide methods for subsequent more scientific and effective construction of large-scale structural module.