Study of distribution of nitrous acid in tributyl phosphate (30%) - nitric acid - uranyl nitrate system

In partitioning step of PUREX process separation of uranium and plutonium from each other is done by selectively reducing Pu(IV) to poorly extractable Pu(III) by means of a reducing agent or by in-situ reduction (electrochemical reduction). In presence of nitrous acid oxidation occurs and thus to scavenge nitrous acid hydrazine is used as holding reductant in aqueous medium. In literature distribution of nitrous acid below 0.95 M nitric acid system is not available and hence its exact behaviour with respect to electrolytic partitioning cannot be predicted. In the present study efforts are made to investigate its distribution behavior in TBP (30%) -nitric acid -uranyl nitrate system during electrolytic partitioning. The results reported in this paper will be utilized for mathematical modeling and simulation of partitioning contactors. (author)