Corrosion-Rate-Law Considerations in Superheated Steam

Fuel cladding materials have been corrosion tested under heat-transfer conditions to superheated steam. Each datum point obtained represented an integrated corrosion response over a temperature gradient along the length of an electrically heated test specimen. An analytical model is developed by which these data may be treated to yield corrosion behavior at a given specific temperature. Corrosion rate laws in superheated steam are examined, and particular emphasis is given to the transition from nonlinear to linear rate control. It is argued, in the case of Incoloy-800^®, that the transition results in true steady-state linear control, thus allowing the model to be used to extrapolate the corrosion behavior of this alloy to long periods of time.