Activation energy determination and kinetic modeling of thorium oxide dissolution in nitric acid/ hydrofluoric acid system: Influence of fluoride ion on ThO 2 dissolution

Keshtkar, Asghar; Abbasizadeh, Saeed

doi:10.1016/j.pnucene.2016.09.008

Cited by 15 publications

(1 citation statement)

References 26 publications

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“…There are several approaches for studying the behavior of fluid solid interaction. The shrinking core model (SCM) is the most suited method for studying the dissolution behavior of solids-liquid system [24][25][26][27][28][29]. In order to establish the kinetic and the rate-controlling step for the dissolution of UO 2 sintered pellets using nitric acid solution, the experimental data could be analyzed according to the SCM.…”

Section: Dissolution Kinetics Modelmentioning

confidence: 99%

Recycling Scrap from Un-Irradiated Nuclear Fuel by HNO3 Leaching

2020

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The work describes the wet chemical route process to recover and recycle a defective un-irradiated uranium dioxide sintered pellets. The optimal conditions of the un-irradiated UO 2 sintered pellets dissolution in Nitric acid solutions has been examined. The effects of acid concentration, contact time and temperature on dissolution action have been studied. The samples were exposed to leaching over a range of nitric acid concentrations 2-8 mol/L and temperatures from 20 to 70 °C. The stoichiometry of the dissolution reaction depends on the acidity of the solution. The shrinking core model (product diffusion control model and chemical reaction control model) was used to correlate the experimental results. Kinetics study shows that the chemical reaction model controls the dissolution of UO 2 sintered pellets in nitric acid solution. The average value of apparent activation energy estimated from the temperature effect of the chemical reaction was found to be about 101.40 kJ/ mol. The optimal conditions to dissolve the UO 2 sintered pellets in nitric acid solution have been proposed.

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