Study On Portable RPV Steels Irradiation Embrittlement Detection System Based On Barkhausen Noise

Reactor Pressure Vessel is the core component of the pressurized water reactor nuclear power plan.Its unchangeability makes its working life directly determines the life of nuclear power plants,and embrittlement is the root cause of various performance changes of RPV.Therefore,it is very important to evaluate the degree of radiation embrittlement damage of RPV steel.Based on Barkhausen noise detection technology,a portable testing system for radiation embrittlement of portable nuclear reactor pressure vessel was designed to predict the lifetime of nuclear power station to achieve double benefit of safety and economy.Based on TMS320F28335,a portable testing system for radiation embrittlement of pressure vessel is built,including excitation module,power amplifier toamplify excitation signal and sensor toreceived Barkhausen noise signal,conditioning module to amplifying the millivolt-level Barkhausen noise signal and filteringinvalid noise,serial communication module,power module,LCD display module.Then we design and debug software including sinusoidal signal excitation controllable frequency amplitude signal,acquisition of ADC unit,FIR filtering of Barkhausen signal characteristic value calculation andLCD screen serial communication and correct display.The reliability of the testing system is verified,and the experiments of two simulated steel specimens of thermal aging and proton irradiation are carried out.The amplitude,root mean square,envelope half width,envelope area,center width and magnetic hardness coefficient of Barkhausen noise signal are obtained.Results show that the center width of the thermal aging specimen increases with the length of the treatment,and then decreases,and the magnetic hardness coefficient does not a have certain rule;The characteristic value of the center width of the proton irradiation specimen is to be discussed and the magnetic hardness coefficient increases with increasing injection volume.The results of this study can provide a basis for evaluating the damage degree of irradiated embrittlement of RPV steel.