Demonstration facility for producing uranous nitrate with hydrogen in presence of Pt/ZrO₂ catalyst on 70L scale per batch

The recovery of plutonium and uranium from spent nuclear fuel employing PUREX process involves coextraction of Pu(lV) and U(Vl) from nitric acid into diluted tri-n-butyl phosphate (TBP) followed by selective partitioning of plutonium into an aqueous stream by reducing Pu(IV) to Pu(lll). This reduction step is achieved by the addition of uranous nitrate produced by electrolytic reduction of uranyl nitrate. Though the electrolytic reduction unit is simple to operate, it is difficult to achieve more than 65% conversion. In order to accomplish near total conversion with fast kinetics, catalytic chemical reduction process has been developed, alternative to electrolytic reduction process for the production of uranous nitrate. Operation of the facility at 5 bar involves simple design of equipment and systems. In addition, procedures for emptying and refilling of cylinders are also easier. Using Pt/ZrO₂ catalyst, 3 runs were carried out at 5 bar by maintaining a C/U ratio of 1:500 and near total conversion was obtained in 40 min. More than 10 runs were taken in the pressure range of 35-5 bar and the process was demonstrated on 70L scale. The substrate ZrO₂ was found to be stable. All the produced uranous nitrate was deployed for partitioning process at reprocessing plant