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Electromagnetic-Acoustic System

#1048


Development of Electromagnetic-Acoustic System for Non-Destructive Testing of Cooling Systems of Nuclear Reactors

Tech Area / Field

  • FIR-NSS/Nuclear Safety and Safeguarding/Fission Reactors

Status
3 Approved without Funding

Registration date
28.07.1997

Leading Institute
Moscow State University, Russia, Moscow

Supporting institutes

  • Physico-Technical Institute / Ural Branch, Russia, Udmurtia, Izhevsk\nMoscow State University / Department of Acoustics, Russia, Moscow\nMoscow State University / Department of Low Temperature Physics and Superconductivity, Russia, Moscow\nAll-Russian Research Institute for Nuclear Power Plant Operation, Russia, Moscow\nNIIIT (Pulse Techniques), Russia, Moscow

Collaborators

  • University of Illinois At Urbana-Champaign / Department of Physics, USA, IL, Urbana\nTohoku University / Institute of Fluid Science (IFS), Japan, Sendai\nFraunhofer Institute Zerstörungsfreie Prüfverfahren, Germany, Saarbrücken\nOsaka University / Graduate School of Engineering, Japan, Osaka

Project summary

In the framework of this project it is proposed to study the possibilities of practical application of a method of electromagnetic generation of acoustic waves in a metal for the task of non-destructive control and diagnostics of conditions of constructive elements of nuclear reactors, in particular, those of cooling systems of steam generators.

Since nuclear power plants (NPP) represent a source of enhanced danger of radioactive environmental contamination, the enhanced safety of these plants is required. Despite of the fact that materials and constructions used in NPP initially possess high capacity to withstand corrosion and radiation, their characteristics degrade in the process of exploitation due to the influence of a series of technogenic factors. These are, first of all, high density of fluxes of penetrating radiation, high temperature, aggressive media. Therefore, the condition of the constructive elements of nuclear reactors needs to be monitored regularly. Methods used for this purpose include X-ray defectoscopy, luminescence hydraulics, a mechanoplastic method, an electromagnetic (inductive) method, and an acoustic (ultrasound) method. Data obtained with these different methods complement each other, the latter two, however, possess the best capabilities for the tasks of diagnostics.

The method of electromagnetic-acoustic transformation (EMAT), which is proposed to develop in this project, combines the main advantages of the electromagnetic and acoustic methods. In particular, it is contactless (does not need a mechanical contact) like the inductive method, and it is non-local (capable to probe remote regions) like the acoustic one. Underlying the EMAT method is a phenomenon of mutual transformation of electromagnetic and acoustic waves in a metal in the presence of permanent magnetic field. This method permits to generate and register in a contactless way ultrasound oscillations in metallic constructions. These waves serve as a tool to search for and perform a remote probing of defects on both outer and inner surfaces of tubes or slabs, to carry out measurements of thickness, diagnostics of homogeneity of the metal and quality of a mechanical contact between the metal and a protecting coating, etc.

The final goal of the proposed project is to develop and build a measuring EMAT complex to be used for non-destructive testing of the cooling systems of nuclear reactors. Such a complex would include the following blocks: a set of electromagnetic-acoustic transducers, a high power generator of radio-pulses, sensitive preamplifiers of the received signals, a computer system for control, signal processing, and visualization of the received information. The construction and working regimes will be optimized through theoretical and experimental investigations. A package of computer programs for processing the results of measurements is suggested to develop. The laboratory experiments will be supplemented with the testing on elements of the real constructions of the cooling systems of nuclear reactors.

The project participants are interested in and welcome establishing cooperation with specialists from the US, the EU, and Japan, who deal with an applied research in the field of systems for non-destructive testing of NPPs constructive elements. The collaboration may consist in the exchange of scientific-technical information, thejoint solution of practical technical problems, the performance of expertise, and in other activities related to the problem of diagnostics of the cooling systems of nuclear power reactors.


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