Research Of The Bolt Assembly Machine And Preload Technology Of RPV

With the development of China's energy consumption demand increases rapidly,as a clean and security energy,nuclear power has become one of the most important energy developing direction in China recently.As nuclear power equipments progress fast,the Fukushima nuclear power plant accident sounded an alarm,making China consider the safety of nuclear power.Considering the safety and reliability of which,the state has launched the research and development task of the fourth generation.As one of the core equipments–reactor pressure vessel(RPV)–supplier,China First Heavy Industry has established the "national key project of RPV” research group.Based on the " national key project of RPV”,the paper chooses the main bolt assembly and disassembly,as well as preload technology of RPV as the study object.In order to solve the problem that the thread surface is easy to be damaged during the installation and disassembly of the main bolt,the main influencing factors in the process of assembling and dismantling the main bolt are determined by theoretical analysis and the relative test: weight and rotational torque.Based on the key parameters of the test,weight and the rotational torque as the design basis,the core of the target product main bolt assembly and disassembly equipment is designed: weight compensation machine and bolt rotating device.At the same time,according to the requirements of the use of two devices,the design of a set of special stability and control system to optimize the main bolt assembly and disassembly equipment design.Aiming at the problem of high preloading force and high preloading precision of the target product,a bolt assembly device is studied.Through studying the advanced bolt preloading technology at home and abroad,the core structure of the cylinder component and the tension nut assembly are analyzed and compared.Considering the product space structure,reliability and other factors,to determine the use of single cylinder and rotary stretch nut mature structure as the target product bolt tensile machine structure core.By using the method of finite element analysis and theoretical calculation,a design method of Single stud tension machine is clarified.Aiming at the problem that the bolt number of the target RPV is large and the preload precision is difficult to control,the whole preload process is simulated by finite elementanalysis.The control method of the three preload uniformity of the bolt of the RPV is mastered by the relevant preload test.The principle of setting the preload gradient at each level is described.The design method of the main bolt assembly and disassembly and preloading equipment of the nuclear reactor and the preloading uniformity control method of the main bolt group have been successfully applied to the manufacture of four generations of RPV,this has made positive contribution to the development of nuclear power industry in China.