Abstract
This work aims at simulating steam Zircaloy clad interaction in a wide range of temperatures extending to those expected in severe accident conditions of nuclear power plant light water reactors. The equations governing interaction variables for a two-layer (α-oxide) and three-layer (α-β-oxide) structure are analytically solved for a semi-infinite and for a finite metal thickness. This method has great computational advantages (small calculation time with no divergence problem) compared with the numerical solution methods, and it can be accurately applied at high temperatures and for finite metal thickness compared to published parabolic correlations, which yield large deviations from experimental data at these conditions. Variables such as oxidation rates, steam consumption, hydrogen generation, and heat released due to oxidation are very important in identifying reactor core degradation scenarios. We thus focused on predicting them as accurately as possible. The predicted oxidation rates at constant temperatures and under constant heating rates are compared with available experimental data for Zircaloy-4, and good agreements were observed. The results reflect the importance of the oxidation heat generation as a heat source in severe accidents knowing that the reactor core contains large quantities of structural metals.