Loose Parts Location Analysis And Mass Estimation System In NPP And Their LabVIEW Implementations

Nuclear power as a kind of mature technology of clean energy, has a broad perspective in ourcountry. Nuclear has many advantages compared with coal power and wind power, etc.But itsexistence of potential safety hazard is very large. There are thousands of components in the lightwater reactor coolant system of nuclear power plant. Considering the influence of the water, it isdifficult to ensure that all components are not loose or fall off. However, the appearance of looseparts in the NPP means that the plant safety performance is decreasing. Therefore, in order tomonitoring and diagnosis the loose parts which maybe appeared in the primary circuit, the looseparts monitoring system must be installed in the primary circuit of nuclear power plants. LooseParts Monitoring System or LPMS for short, as one of the important systems of nuclear power plant,which can provide important guarantee for nuclear reactors’ safe, stable and economic operation.At present, the development of foreign plant loose parts monitoring system has a strong vitality,showing a good application prospect. The study of the loose parts monitoring system for nuclearpower plants in China started relatively late, the technology is also not enough strong. Therefore, ithas very important significance to actively research the looseness fault diagnosis technology whichcan ensure the safety and reliability operation plant, and further development and improve theintelligent level of diagnosis.Based on the Major National Science and Technology Program“Research on the Prototype of Loose Part Ponitoring in Puclear Power Plant (No. KYZ193612003)“and“Public Tehnology and Social Development Project in Zhejiang Province(No.2012C23017)”.Loose parts location methods and mass estimation method are studied in the thesis. And proposedthe loose parts localization method based on continuous wavelet transform and Hilbert envelopeand the method of impact mass estimation of loose parts, it’s realized based on Lab VIEW.In the experimental data acquisition part of the thesis, it expounds the background noisecollecting plate impact experiments and boiler experimental platform of the experiment process.The build process of plate impact experiments and Boiler background noise experiment areexpounded. Including: experiment purpose, experiment contents, experiment equipment, theexperimental steps, etc. We complete the two experiments’ data collection. And analyzed thebackground noise data of boiler, which provided a data basis for the further Proposed loose partslocalization and mass estimation.This thesis combines with time-frequency analysis,and proposes a loose parts localizationmethod based on CWT and Hilbert envelope. In this method,the impact signal is analyzed by using the continuous wavelet transformation, and obtain the signal in the frequency zone, then adopt themethod of calculating the Hilbert envelope maximum of impact signal to determine the impactsignal arrival time, and applied to grid localization. And we made a simulation experiment to verifiythis method, the results show that this method has strong anti-interference capacity and highlocating accuracy. Meanwhile, this thesis also analyzes the principle and characteristic of theexisting mass estimation method. In view of the defect of those methods,we propose a massestimation method based on wavelet energy spectrum. In this method, wavelet energy spectrummethod is used to make estimation for different impact mass, and the linear interpolation method isused to establish the scale peak function, then by this function to realize mass estimation.And wemade a simulation experiment to verifiy this method, the results show that the method hascharacteristics of small estimation errors and good consistency, strong anti-interference capacity.In this thesis, different algorithms of time difference of arrival(TDOA),including theaccumulation method based on CWT,the root mean square method based on CWT, Hilbertenvelope method based on CWT and the Look-up table positioning program of grid locationmethod are realized by the LabVIEW programming. And we combine the two modules to becomeloose pieces positioning analysis system.And we made a simulation experiment to debug andverifiy the system，and according to the experimental results，the merits and faults of the threearrival time estimation methods are analyzed and compared.At last, This thesis based on the newmethod proposed in the first few chapters of this article.we designed and developed LPMSprinciple prototype based on LabVIEW.And this system implemented the functions like loose partonline monitoring,loose part location,mass estimation,etc.