Nuclear Reactor Core Big Stud Peak Clipping Of The Flange Thread Structure Research And Optimization

Nuclear reactor core is a place for nuclear reactions, its external large stud bolt connection structure is an important connection in nuclear reactor components, its design quality directly affects the nuclear reactor safety, reliability and life. The main function of big stud bolt connection structure in the working process is locking and sealing, it also will be affected by the role of the high pressure, vibration and other external factors, since the first nuclear reactor was established in 1942, the study of big stud connection structure has been closely watched. The main failure mode of the big stud connecting is gluing, gluing makes the big screw thread serious damaged broken rupture,its leads to replace the damaged big stud when nuclear reactor need replace nuclear fuel that spend more time and lots of labor. The more time may cause the danger of nuclear leak. In order to meet the needs of the development of the nuclear industry, human need find a new thread structure to solve the problem of thread gluing.The main reason of big stub’s gluing is the stress uneven distribution on the thread, under the action of pressure which lead to the largest stress of thread gluing is more likely to occur the thread gluing for a long time. In order to solve the phenomena of thread gluing and to improve efficiency of replacing the nuclear reactor fuel, commissioned by the Nuclear Power Institute of China to research and optimize its thread structure.This article takes a nuclear reactor’s big stud bolt of M310 as the object, and the same type of reactors large stud bolt connection structure be investigated to determine its main failure mode is galling, the stress distribution on the thread inequality is one of the main causes of gluing. According to the cause of thread gluing, this paper proposes a solution :the reducing the peak of threads stress, the reducing the peak of threads stress is to cut the secondary standard thread and the object is a single thread. Firstly, this article looking for axial force and every thread of relations in the ordinary bolt and nut only under the axial force and find the compatibility equation of deformation. It can be used to build the mathematical model about the value of the axial cutting quantityxm of large stud bolt, and then established the optimization equation according to mathematical model and the size of standard big stud bolts and nuts. Under the above conditions, used the optimization toolbox of MATLAB software to solve the axial cutting quantityxm about the reducing the peak of threads stress of nut. After compared the results about stress analysis of the standard flange bolts and the reducing the peak of threads stress bolt and nut and verify the possibility of the reducing the peak of threads stress thread by Ansys soft. Meanwhile, this article analyze the machining error and machining method in the process of production and describes in details the productive process of the reducing the peak of threads stress of thread 5.220 M ? that provide the theory and practice basic about the reducing the peak of threads stress of thread.This article verify the feasibility of the reducing the peak of threads stress thread structure by theoretical analysis and simulated experiment and produce the reducing the peak of threads stress 5.220 M ? nut, that provides reliable reality basis for using in the nuclear reactor and promote the development of the nuclear industry.