Modelling Material Effects on Flow-Accelerated Corrosion in Primary CANDU Coolant and Secondary Reactor Feed-Water

Abstract

The effects of chromium content on flow-accelerated corrosion (FAC) of carbon steel have been predicted very well by including a passivating layer, which is a chromium-dependent diffusion barrier at the metal-oxide interface. By adjusting the properties of the chromium-dependent layer, described with a Passivation Parameter (PP), we can predict the FAC of carbon steel of different chromium contents in typical reactor feed-water environments (140ºC and neutral or ammoniated chemistry). The model and an appropriate PP are also applied to the environment typical of carbon-steel feeders in the primary coolant of a CANDU reactor (310ºC and lithiated chemistry). The model predicts FAC rate very well (with a deviation of 10% or less) in both situations.