Study On Acceleration Sensing System Of Fretting Wear Of Steam Generator Heat Transfer Tube

As a low-carbon,efficient and stable clean energy,nuclear power is an important way to solve environmental pollution and energy shortages.Nuclear power security is an main factor restricting its development,which is stressed as the top priority in the construction of nuclear power plant by the country leader.PWR nuclear power plant is now the main development direction of nuclear power plants.However,the fretting wear problem of steam generator tubes(SGT)in the PWR nuclear power plant seriously threat the safe operation of nuclear power plants.Reasonable assessment of SGT fretting damage plays an important role in steam generator health monitoring,SGT structure design optimization and SGT service life prediction.To obtain the radial acceleration in the fluid environment of SGT,the installed acceleration sensor has requirement in heat resistance,pressure resistance and waterproofness.From the sensor technology point of view,the working environment has strict requirements on the size of acceleration sensor,which is difficult for the traditional sensor detection technology.Fiber-optic F-P acceleration sensor technology has the advantages of simple structure,small volume,high precision,anti-electromagnetic interference,long distance measurement and so on,which is suitable for the fretting damage monitoring of SGT.Therefore,this article developed fiber-optic F-P acceleration sensor based on double-ended fixed beam and the non-scanning correlation fiber-optic F-P sensor demodulation system,which achieved the high-speed high-precision fretting damage monitoring,optimize the design of SGT.This article built the mathematical theory model of non-scanning correlation F-P sensor demodulation,which was used to simulate and analyze the influence of light source noise and F-P cavity tilt deformation.The structure of light path in the fiber-optic F-P sensor was designed.The acceleration sensor based on double-ended fixed beam was designed and optimized in mechanical structure,which sensitivity,natural frequency and other performance parameters were analyzed.The design of optical demodulation module in fiber-optic F-P demodulation system,hardware and software systems were accomplished.To weaken the noise and ensure high-speed stable demodulation,the experiments of bent multi-mode fiber around different diameter cylinder was designed to solve the light spectrum glitches caused by SLD coupling mode-mode interference.By analyzing the lateral tilt deformation of the optical wedge,the production process of optical wedge was optimized to improve the measurement accuracy.The power and filter circuits were optimized by designing hardware.The circuit control system based on FPGA was adapted to realize the high-speed collection,processing and transmission of sensor signal.The fiber-optic F-P demodulator was built to complete the debugging and testing the function module,including Linear array CCD driver,active filter circuit,USB communication and so on.Then,the entire acceleration sensor system was carried out to vibration testing and calibration,which shows that the demodulation range of system is 11.687?m~21.308?m with the accuracy of 4.7nm and the acceleration accuracy of 0.38 g.The high pressure fluid environment experiment was carried out to verify that the sensor can work stablely in the steam generator environment for long time.