Impact of fecral oxide composition on severe accident progression in MELCOR

Experimental studies have shown that the composition of the oxide layer forming on FeCrAl surface depends strongly on the temperature of the environment, with varying fractions of aluminum, chromium, and iron oxides forming under different conditions.In this work, multiple oxide compositions were incorporated into MELCOR simulations for evaluation of their impact on cladding degradation. The weight fractions of aluminum, chromium, and iron oxides were derived from published experimental data, serving as basis for modifications of the material model.Simulations of a representative Loss of Coolant Accident scenario show that these changes significantly affect cladding temperature evolution, oxidation progression, and hydrogen generation. These results highlight the need to account for environmentally dependent behavior when modeling advanced cladding materials in integral codes.