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  • Author or Editor: G. Santhosh x
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Abstract  

Ammonium dinitramide (ADN) prills were prepared by emulsion crystallization and characterized by optical microscopic, thermogravimetric (TG) and differential scanning calorimetric (DSC) techniques. The isothermal and non-isothermal decomposition kinetics of ADN prills were studied by TG. The differential isoconversional method of Friedman (FR) and integral isoconversional method of Vyazovkin were used to investigate the dependence of activation energy (E a) with conversion (α) and the results were compared with literature data. The dependence of activation energy was also derived from isothermal data. A strong dependence of E a with α is observed for the ADN prills. All the methods showed an initial increase in E a up to α=∼0.2 and later decreases over the rest of conversion. The apparent E a values of FR method are higher than that of Vyazovkin method up to α=∼0.45. The calculated mean E a values by FR, Vyazovkin and standard isoconversional method for α between 0.05 and 0.95 were 211.0, 203.9 and 156.9 kJ mol−1, respectively.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: P. Govindan, S. Sukumar, K. Vijayan, G. Santhosh Kumar, S. Ganesh, Pradeep Sharma, K. Dhamodharan, R. Subba Rao, M. Venkataraman, and R. Natarajan

Abstract  

A novel method has been developed for recovery of plutonium and uranium from carbonate wash solutions generated during solvent wash process involved in the reprocessing of high burn up FBTR fuel. The proposed method involves a selective coprecipitation of Pu and U by adding ammonium hydroxide to the pre acidified carbonate wash solution. Substantial removal of DBP by successive steps of coprecipitation, completely eliminates the possibility of undesired solid formation which is mainly due to the presence of high content of DBP. By adopting this method, an excellent decontamination factor for DBP has been achieved without any crud/solid formation. Phosphate content in the final oxide product meets the product specifications. Flowsheet condition necessary for the recovery process for plutonium from the aqueous carbonate solution is formulated and adopted in the CORAL facility.

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