The Design Of Graphite Coating Thickness Meter For Nuclear Fuel Rod Cladding Tube

In the production of nuclear fuel assemblies,graphite is needed to coat the inner wall of zirconium tubes of nuclear fuel rod cladding tubes.The thickness of graphite layer directly affects the reliability and safety of nuclear fuel blocks.The research on the thickness of graphite coating on the inner wall of zirconium tube has penetrated many disciplines,such as weak signal detection technology,non-destructive detection technology,nuclear radiation detection technology,sensor technology,computer control technology and so on.According to the principle of backscattering of beta rays,a beta backscattering thickness gauge is designed.The thickness gauge uses STM32F407,a high-performance processor developed by ST Company,as its control core.The sensor uses LND of America and G-M tube 76011 produced by INC Company.It is a mica window.The main contents of this paper include the following aspects:(1)The research status,development trend and research significance of the beta backscatter thickness gauge;(2)The principle of beta thickness measurement and the model of beta backscatter thickness measurement instrument are designed according to the principle;(3)Choose the appropriate device,and explain its characteristics and application methods.Then design the hardware circuit of the beta backscatter thickness gauge,clarify the design idea of the hardware circuit,describe in detail the composition of the main circuit and simulation results,mainly including the peripheral circuit of STM32F407 single chip computer,signal conditioning circuit,communication circuit;(4)The software design platform Keil uVIsion5 of the thickness gauge system is introduced,and the main program module,data acquisition module,communication module and OLED display module are designed.The whole software system adopts modular structure design,and other functional modules are invoked by the main program.Independent function to run;(5)The monitoring interface of the upper computer of the beta backscatter thickness gauge is designed.After communicating with the lower computer,the functions of data acquisition,real-time display,data storage and report derivation are realized;(6)Set up anexperimental platform,carry out experimental research,compare the measured thickness of graphite coating with the standard thickness,and improve the accuracy as far as possible.Through the design of hardware and software system,the detection function of beta backscatter thickness gauge is finally realized.In this paper,an experimental device of beta backscatter thickness gauge is designed and tested.The results achieved the expected purpose and proved the feasibility of the thickness gauge.The research on the production process of nuclear fuel rod cladding tube in nuclear industry has important practical significance.