Experimental Study on Accelerated Corrosion Uranium-water Vapor by Thermogravimetry

The experimental study on uranium corrosion was carried out over a range of 50~90 ℃ and 32%~86% relative humidity by thermogravimetry (TG). The corrosion degree of uranium-water vapor reaction was evaluated by weighing sample weight gain at appropriate intervals. Under above experimental conditions, the characteristic of uranium corrosion was observed and its kinetics was also discussed. The results indicate that there are three stages in the uranium-water vapor oxidation reaction at various temperatures. First, there is an initial reaction stage followed by the corrosion rate tends to be slow down after the first corrosion stage. At the third stage, the corrosion reaction presents to be a linear reaction with a stable oxidation reaction rate constant. The dynamics curves on the rear part of linear reaction stage are fitted, and the activation energy deduced is about 42.899 kJ·mol~(-1 ) at RH=74.7%. Uranium-water vapor reaction is faster at higher temperatures. The effect of relative humidity on the uranium-water (reaction) is about the same as that of temperature in the range of 70~90 ℃, but the (further) study on the effect of (rela)tive humidity below 60 ℃ is necessary.