The Possibilities of Acoustic Emission Method for Detection of Flow Accelerated Corrosion

Authors : Koula Václav, Dráb Martin

Company : ZD Rpety - DAKEL
Country : Czech Republic

Topic :

FAC prediction tools
Non-Destructive Examination methods
Inspection methods

ABSTRACT :

The text presents possibilities for the detection of the flow accelerated corrosion (FAC) using the method of acoustic emission on power plant steam-piping with steam pressure of 1.5 - 60 MPa and temperatures up to cca 300 ºC. A continuous AE signal sampling at the frequency of 2 MHz allows to use the current methods of signal analysis. AE signals were acquired both on steam-piping in the virgin state (without the FAC process) and on places with the running FAC process already confirmed (by measuring of the steam-piping wall thickness). Data analysis discovered the STV parameter, which allows the indication of the FAC process during the power plant operation. Based on that a special-purpose STV analyzer with very simple handling, allowing immediate evaluation of the acquired data, was designed and constructed. Its usage allows searching for steam-piping sections with the running FAC process during the power plant operation. That helps refining the plans for time-consuming and expensive measurement of the wall thickness of the steam-piping segments during the operational shutdowns of the power plant blocks. It is possible to maintain periodical measurements in places of already running FAC and that way to monitor the FAC trend. Described procedures help reducing the costs for identification of the steam-piping sections with the running FAC and increase the safety of power plants operation.