The Structure System Design And Research Of The Multi Bolt Tension Machine

At the end of each fuel cycle in the Pressurized water reactor,It is necessary to open the reactor pressure vessel head in order to load the nuclear fuel.When closing the head,the tightening force of the bolt is applied by the Multi bolt tension machine to obtain a good seal.Because of the big bolt,the large tightening force,the narrow working environment,and the high radiation,Bolt tension in this condition become more difficulty.The high pressure vessel requests to provide the bigger bolt pretightening force,but the narrow working space has limited the size of the bolt pretightening force tool.This become one of the main contradiction in the design of the pretightening force tool.Besides,the Multi bolt tension machine of the reactor pressure vessel is monopolized by foreign countries,and there is no a case of engineering practice in China.After studying the application example and engineering problems of the Multi bolt tension machine abroad,the author finish the design of mechanical structure and control system for the hydraulic machine in this article.The main research contents of this paper are as follows:1)analyzed the present situation of bolt tension machine and the trend at home and abroad in detail,and the significance of this research is elaborated;2)studied the bolt tension data of the steam generator in practice,and created Functional relation between the absolute tensioning and the residual tensioning;3)According to the pressure vessel flange seal requirements,calculate the bolt tightening force and design the hydraulic system parameters;4)study the interface dimensions of the working space about the bolt tension machine,construct the mechanical structural layout,and design the whole mechanical structure drawing of the Multi Bolt Tension Machine;5)grope the automatic and visual control concept of bolt tension machine,and design the control scheme of hydraulic tension and tension measurement;Finally,this paper designed the whole machine structure of Multi bolt tension machine,which had compact structure and reasonable layout.The feasibility of hydraulic design is proved by checking the hydraulic pressure.Based on the process control and visualization software,the automatic control program and the design of the control picture are completed.At the same time,structure is verified by finite element analysis of structure strength.Finally solved the problem of narrow working space and high hydraulic pressure,and made a positive contribution to the application of the Multi bolt tension machine.