The development of an ion exchange decontamination process for the removal of transuranics, specifically plutonium, from uranium oxide is of great importance to the nuclear complex. The decontamination efficiency of plutonium from uranium oxide in a nitric acid solution has been shown to vary based on the pH of the acid using different resins (Reillex HPQ Polymer and/or TEVA). This is possibly due to recontamination of the cleaned surface by residual Pu. During the decontamination process, uranium oxide is dissolved from the surface of the part, liberating undesirable plutonium oxide contamination from the surface. Increasing the pH of the solution into the basic region activates the vinyl pyridines in the resin to attract Pu ions onto the resin column and discriminate against uranium, which flows through the column. Decreasing the solution pH strips the Pu from the vinyl pyridines to be recovered.

Our study was designed to determine the distribution coefficients [KDs] which were calculated for the different resins. The KD is a ratio of analyte activity in the resin phase to the solution phase. A high KD indicates high removal of the actinide species from solution. Additionally, for the nitric acid dependency studies, the separation factors (S.F.) were computed. Very high S.F.s indicate that extraction of Pu is significantly better than U uptake and poor for very low S.F.s. These were calculated for both uranium and plutonium in nitric acid solution to determine the efficiency of various resins at certain pH to remove the residual contamination from solution.