Study On Acoustic Emission Detection Technique For Corrosion Behavior Of Nuclear Plant 304 Stainless Steel

With the rapid development of economy and society, the demand for energy is increasing sharply. As a kind of clean and safe energy source, nuclear power can greatly improve the global ecological environment and support sustainable development of human beings'society. When we enjoy the unprecedented enormous merits which the development of nuclear power brings to us, its security problem is also concerned by the international countries and even all the people throughout the world extraordinarily. The nuclear accidents bring challenges to the safe utilization of nuclear power. There are many factors can induce safety accidents of nuclear power plant operation and the key materials'corrosion failure of nuclear power is one of the most important factors. Therefore, the study about accurate and effective detection of key materials'corrosion failure of nuclear power has great economy benefits and social significance.Electrochemical detection technology is by far most widely used in the corrosion detection domain. It can inspect every kind of materials'corrosion failures accurately; however, this technology can only analyze the corrosion resistance, stage and types of metal materials qualitatively. Since the quantitative analysis can't be implemented, we can't analyze and evaluate the corrosion state in its entirety and there is a serious need for a more advanced detection technology to study the key materials'corrosion failure of nuclear power deeply and thoroughly. In this paper, a lot of corrosion experiments had been carried out to study the corrosion process of the 304 stainless steel based on the acoustic emission. The main content was as follows:1. By referring a great lot of literatures about corrosion detection of stainless steel, this paper analyzed the recent developments and security problem of nuclear power and studied the stainless steel main corrosion forms of nuclear power and mechanical, physical and electrochemical methods for corrosion detection.2. This paper studied the corrosion resistance of stainless steel materials based on the acoustic emission detection technology and made a contrast with electrochemical impedance spectroscopy detection results. In this paper, the AE parameters to evaluate the materials'corrosion resisting property was suggested firstly and the experiments showed that acoustic emission could evaluate the materials'corrosion resisting property accurately and effectively.3. This paper studied the stress corrosion process of stainless steel materials based on the acoustic emission detection technology and made a contrast with electrochemical noise detection results. It was the first to apply the average spectrum of acoustic emission signals to characterize different corrosion stages of stainless steel materials. The experiments showed that the characters of different corrosion stages were easy to distinguish.4. This paper studied the corrosion failure of the 304 stainless steel in slow-strain-rate tension based on the acoustic emission detection technology and made a contrast with electrochemical noise detection results. The experiments showed that the acoustic emission detection technology was sensitive to crack growth of stainless steel and it could detect the internal dynamic defects of stainless steel effectively.5. This paper applied the K-means cluster algorithms to make the cluster analysis of acoustic emission signals during corrosion process and abstracted the different kinds of acoustic emission signals'features by wavelet packet transform. And this paper implemented the type recognition of acoustic emission signal sources.