Effects of surface treatments and temperature on the oxidation behavior of 308L stainless steel cladding in hydrogenated high-temperature water.

• Ground surface has higher oxidation resistance than mechanically polished surface. • A fine-grained layer favors formation of dense oxide film with high Cr/Fe ratio. • Highly network Cr-bearing δ-ferrite improves the oxidation resistance. • Thermally activation enhanced self-diffusion of Cr in ferrite inhibits oxidation. • The ferrite-affected oxidation zone expands with the increase in temperature. The properties of the oxide films grown on 308 L SS cladding with various surface treatments and temperatures in simulated PWR primary water are studied. The thickness of the inner oxide layer increases with the decrease of the surface roughness. The high oxidation resistance of the ground surface is due to the thicker fine-grained layer with high dislocations density and subgrain boundaries in the near-surface. The ferrite-affected oxidation zone (FAOZ) expands with the increase in temperature, resulting from the thermally activated self-diffusion of Cr in ferrite. The effects of surface states, ferrite and temperature on oxidation performance of 308 L SS cladding are discussed. [ABSTRACT FROM AUTHOR]