Geometric Size Measurement System Of UO₂ Core Based On Image Processing

In recent years,with the country’s emphasis on the development of nuclear power,the power generation of nuclear power has increased year by year.As a raw material for nuclear power reaction,nuclear fuel pellets are increasingly produced,and the requirements for various parameters of nuclear fuel pellets is becoming more and more strict.However,the existing methods for the detection efficiency and accuracy of some parameters can’t meet the requirements.In this paper,aiming at the shortcomings of low efficiency and complex flow of traditional measurement methods for the geometric dimensions of nuclear fuel pellets,an automatic measurement system for the geometric dimensions of nuclear fuel pellets based on image processing is designed and implemented.The main work accomplished in this paper is as follows:(1)Designed and built a nuclear fuel geometry measurement hardware system.According to the measurement characteristics,the hardware measurement platform structure is designed and the corresponding device layout is completed.According to the requirements of the technical indicators,the selection of hardware devices was carried out,and appropriate image sensors,optical lenses and light sources were selected through correlation calculation and analysis.(2)The software client of the automatic measurement system is designed and completed.In order to meet the needs of the actual system and improve the automation of the system,this paper designs five functional modules: login,data measurement,data calibration,data management and user management.Finally,it completes the development of the actual client software and realizes the automatic measurement mode.(3)Based on the image processing method,a fast measurement algorithm for the geometrical dimensions of the end face of nuclear fuel pellets was studied and implemented.In this paper,a new set of processing flow is designed for the characteristics of nuclear fuel end contour curve image,which is mainly divided into preprocessing,contour feature extraction and key point identification.The common image preprocessing methods are compared experimentally,and the appropriate processing methods are selected according to the effect.And improve the image processing speed by accurately cutting the outline of the image by scanning the line and column of the image.Based on the least squares method and iterative idea,a new way is to complete the identification of the key points of the end face contour of the nuclear fuel pellet,and the final geometric dimension data measurement is completed by dimension calibration.Finally,the system has been tested repeatedly for a long period of time and the error analysis of the measured data shows that the measurement accuracy of the system reaches ±5μm and the measurement speed is up to 4 seconds/block.At the same time,it has simple operation,complete function,stability and reliability in long-term operation,and can completely replace the existing manual measurement methods.The measurement system has the characteristics of non-contact,fast and high precision.It greatly improves the measurement efficiency of the geometric size of the nuclear fuel inspection site.