Erosion behaviour of turbine rotor blades installed in the Krsko nuclear power plant

Abstract

Turbines installed in nuclear power plants operate with wet steam. The flow of wet steam causes the erosion of the last stage rotor blades, and can cause a considerable damage to the condensing steam turbines. This paper reviews the results of many years of monitoring and researching of the behaviour of the erosion process and its mechanism for rotor blades of 664 MW turbine installed in Krsko nuclear power plant. On the basis of the results obtained and behaviour of the erosion process, the erosion rate for rotor blades material and a simplified model for their service life is estimated. The rotor blade erosion process was divided into three characteristic regions of erosion: the first incubation region showed no evident damage to the blade material, the second region with the maximum erosion rate and the third one with the lowest erosion. It was established that the rotor blades during their service life mostly operate in the third region with a lower rate of erosion. On the basis of the obtained behaviour of the rotor blades erosion process and a simplified model and calculation their service life of 290,000 h has been estimated, which is longer than it was expected.