The Study On Data Processing For Ultrasonic Nondestructive Testing Of RRV

With the development of economy, energy becomes the primary problem to be solved. Developing nuclear energy is a very good way to solve the problem of energy. Nuclear reactor pressure vessel is an extremely important equipment in nuclear power plant. To ensure the quality of nuclear reactor pressure vessel, and further ensure nuclear plant working securely and normally, nuclear reactor pressure vessel must be tested roundly. Ultrasonic nondestructive detection technology is a kind of common nondestructive detection technology. It is used widely, because ultrasonic nondes- tructive detection has the advantages of strong penetrability, defects detection sensitivity, high accurate orientation and low cost. So it is used in nondestructive detection of nuclear reactor pressure vessel in this paper. Meanwhile, echo signal of ultrasonic nondestructive testing contains all content of a ultrasonic detection, so to process the echo signal of the ultrasonic nondestructive detection is an important and also a key step in ultrasonic detection process. Therefore signal processing for ultrasonic nondestructive detection of nuclear reactor pressure vessel is studied in this paper.Firstly, this paper discusses the development course and explores the frontier of ultrasonic nondestructive detection technology. According to structure and characteristics of the nuclear reactor pressure vessel, identify the objects and contents to be tested, give a specific system design scheme, and analyzed the echo signal. Secondly, the method of ultrasonic signal de-noising is studied. Several existing method of signal de-noising are compared and analyzed, an improved threshold value de-noising algorithm is adopted. For the actual features of the pressure vessel, putting the soft and the hard thresholding de-noising method together can better realize signal de-noising processing. And the ultrasonic signal is simulated in MATLAB, the de-noi- sing effect is better and is to the benefit of the subsequent signal analysis and processing. For the storage and transmission of data, this paper study Embedded Zero-tree Wavelets and improve this arithmetic. While considering in the one-dimens- ional space, data compression only reduce signal redundancy, cannot reduce spatial signals redundancy. This paper puts forward that signal is transferred in the spaces. Then in the experiment environment of MATLAB the two-dimensional space signal has a compressed simulation using the improved Embedded Zero-tree Wavelets, and acquired better compression efficiency.In the end of the paper, according to the system function, the software system of the ultrasonic nondestructive detection for the nuclear reactor pressure vessel is designed completely. Visual Studio 2005 is selected as the software development environment. VC++ and MATLAB7.1 joint programming complete the design of the main interface, parameter settings module,the data processing module and the database module.