The Design Of Radiation Level Monitoring Device For The Ventilation Filter Frame Of Nuclear Power Plant

The ventilation filter system of nuclear power plant is an important safety system when nuclear power plant operating.In order to ensure the air purification effectiveness of the filter,it is necessary to replace the failed filter element regularly.Before replacing the filter element,the radiation level should be measured to confirm that there is no surface contamination on the frame.But currently measurement is conducted by people use radiation detection equipment,the method of man-measuring to check the ?/? contamination on the surface need in the special shielding environment,it is difficult to guarantee the distance between the detector and frame constant and measuring speed is not constantly when measuring,so that could not guarantee the reliability of the measurement data.At the same time,the efficiency of man-measuring is low,and there is a risk that the detection personnel are exposed to excessive radiation pollution.It has great research significance and application value to develop a special device which can automatically and quickly detect the radiation level of ventilation filter frame of nuclear power plant.This paper mainly carried out the mechanical structure design,the hardware circuit design of ?/? surface contamination detection,the hardware design of ?radiation detection device and the design of automatic measurement and control circuit,as well as the development of measurement and control software of the radiation level measurement device of the ventilation filter frame of nuclear power plant.The main achievements are as follows:1)design the mechanical device adopts steel frame structure,realizes the ventilation filter framework positioning,send the ventilation filter framework into the device automatically,?/? surface contamination measurement using 24 road surround type array probe structure,? rate measurement using drop center measurement structure,system stability,the frame transporting is convenient.2)based on the composite detector of plastic scintillator sprayed with Zn S(Ag)scintillation material,the ?/? pulse discrimination circuit was designed and developed,which realized the digital processing of ?/? surface contamination measurement output pulse.3)based on the use of cylindrical plastic scintillation detector,pulse shaping and amplitude-frequency conversion circuit were designed and developed,which realized the digital processing of the out pulse of vanguard radiation dose measurement.4)developed the single-chip microcomputer data acquisition and transmission control circuit,and realized the counting and output communication of the output digital pulse of ?/? surface contamination measurement and the output digital pulse of the whole radiation measurement.5)adopt four-point positioning structure,coordinate with synchronous belt andphotoelectric detection and positioning device to realize automatic alignment of the ventilation filter frame and entry and exit of the measurement room automatically.6)based on the industrial control computer hardware platform,the software of data acquisition and analysis is developed and realized by using Python language.