Corrosion Resistance of Dysprosium Titanate Powders and Pellets in the Model Environment of the WWER-1000 Coolant

Abstract

The results of autoclave tests of corrosion resistance of dysprosium titanate powders and pellets in the model environment and the parameters of the primary coolant of the WWER-1000 reactor are presented. During exposure in autoclave for up to 500 h, powders are characterized by the decrease in weight, which does not exceed 0.5%, and weight increase depends on powder density. Pellets with the highest density (7.1–7.2 g/cm³) are most corrosion resistant and with the density of 5.74–5.79 g/cm³ powders corrode with the monotonous weight growth under increasing exposure in the autoclave. After 2300 h of autoclaving, the average increase was approx. 156 mg/dm² (0.3%). The change in the powders and pellets phase composition of dysprosium titanate after corrosion tests was not detected. Studies of the conditions of defective models of absorbing elements after autoclave tests retain their integrity without changing the linear dimensions. After cutting the absorber elements models, the powders were freely removed from the cladding. The change in the powders’ phase composition also was not revealed.