Effect of Chromium, Vanadium, Al₂O₃–Cr, and Al₂O₃-V Coatings on the Strength of Uranium Dioxide Granules

Abstract

The strength properties of uranium dioxide particles coated with chromium, vanadium, Al₂O₃–Cr, and Al₂O₃–V are tested by diametrical compression between two parallels planes in the temperature range from 20 to 900 ⁰С. It is shown that the strength of particles depends on the coating thickness and material, strength of the fuel core (kernel), loading rate, and test temperature. The particle strength grows with an increase in coating thickness and test temperature, reaching its maximum at 700 to 900 ⁰С. The coating fracture pattern changes from intercrystalline rupture (20–150 ⁰С) to ductile fracture (650–900 ⁰С). Methods are proposed for both statistical processing of test results and probabilistic particle strength assessment. It is shown that the strength of coated particles is well described by the Weibull probabilistic dependence, which makes it possible to predict the fracture of particles at any load. The particle strength versus load has been probabilistically estimated at different temperature values.