Study On The Detection And Analysis Of Loose Parts In Nuclear Power Plants

Based on the National Natural Science Foundation of China (51175466) "Study on weak impact signal detection and extraction", the study on detection of loose parts in Nuclear Power Plants, estimation of loose parts’ mass and location of loose parts are carried out.Chapter Ⅰ:The background and significance of the detection and related research of loose parts in Nuclear Power Plants are illustrated and the function and characteristics of Loose Parts Monitoring System (LPMS) are introduced. And the research status of mass estimation and location analysis of loose parts are illustrated at the same time. Finally research content and frme of thesis are proposed.Chapter Ⅱ:The extraction method of impact signal based on EVA is proposed. By comparing the spectrum distribution of background noise and impact signal, the algorithm principle is elaborated. The feasibility of the algorithm is verified by experiments and the results are not affected by the pulse signal.Chapter Ⅲ:The relationship between the mass of the loose parts and the spectrum distribution of the impact signal is analyzed. Feature extraction method on the base of geometric segmentation is presented, and the value is set as the input of the random forest regression model, the output is the quality of the loose part. The accurate mass estimation of the method is shown by the experimental resultsChapter Ⅳ:Based on triangle localization method and kernel density estimation algorithm, a new method for lacating loose parts on the base of multiple sensors is proposed. The problem that the triangle localization method has multiple intersections under multiple sensor conditions is avoided. As detection results of each sensor are integrated effectively, more accurate location is achieved.Chapter Ⅴ:The design scheme of loose part detection and analysis system based on Matlab GUI is introduced. And a prototype system containing three modules of detection, mass estimation and location is developed.Chapter Ⅵ:The research contents of this paper are summarized, and the future research directions are prospected.