Steam Oxidation Behavior of FeCrAl Cladding

In order to better understand the high temperature steam oxidation behavior ofFeCrAl FeCrAl alloys, this study addressed two topics. The first is continuing to evaluate the effect of alloy composition on performance of commercial and laboratory-made candidate FeCrAl alloys. For a few optimized compositions, this includes the performance of commercially-made tubing where it is clear that dropping the Cr content from 20% to 10–13% reduces the maximum operating temperature in steamSteam by ~50 °C. The second addresses more realistic accident conditions. Model FeCrAl compositions that were exposed in ~300 °C water for 1 year were subsequently “ramp” tested in steam at 5 °C/min to 1500 °C to assess the effect of the Fe-rich oxide formed in water on the subsequent steam oxidation resistance. For Fe-18Cr-3Al+Y, the 1 year exposures in three different LWR water chemistries did not affect the ability to form alumina to 1500 °C. However, for marginal alloys Fe-13Cr-4Al and Fe-10Cr-5Al, some specimens began forming voluminous Fe-rich oxide at lower temperatures.