A model of the relationship between the oxidation parameters of zirconium alloys in water steam at 1000°C and the alloy composition. II. Model selection, comparison with experiment

In the framework of the previously developed model for the oxidation of zirconium alloys in water stream during the LOCA (Loss of Coolant Accident), the role of each element in the alloy composition in the oxidation kinetics is estimated. The contribution of each component to oxidation resistance was determined by the method of solving the “inverse problem”. Algorithm, flowchart, tables of step-by-step solution of “inverse” and “direct” problems, and the results of calculations of the parabolic oxidation constant K and the time t to transition to the linear stage of oxidation for each alloy are presented. The contribution of each alloying and impurity element to the oxidation resistance of the alloy is determined by the stoichiometric coefficients and corresponds to the thermodynamic sequence of the formation of oxides of these elements in water vapor at 1000°C. The thermodynamic meaning of the parameters included in the kinetic equations is determined, which are proportional to the standard formation energy ∆Gi of the oxide of the corresponding alloy component.