Collaborative development and testing of Russian technologies for the decontamination of Idaho chemical processing plant high-activity liquid waste

A collaborative research effort between Russian and United States scientists is underway to demonstrate the applicability of Russian technologies for the decontamination of liquid, high-activity wastes stored at the Idaho Chemical Processing Plant. Solvent extraction technologies currently under development at the V. G. Khlopin Radium Institute include a chlorinated cobalt dicarbollide-based cesium and strontium partitioning process and a phosphine oxide derivative based process to partition actinides, rare earth elements and technetium. Both technologies are applicable to acidic waste solutions. Dynamic (counter-current) tests were performed in a hot cell at the Khlopin Radium Institute using both cobalt dicarbollide and phosphine oxide processes and simulated waste with radionuclides added. Excellent recovery of all targeted radionuclides was demonstrated. Batch (cross-current) tests were performed in a hot cell at the Idaho National Engineering Laboratory on actual, radioactive-waste samples to verify results obtained at the Khlopin Radium Institute. Distribution coefficients obtained from the-tests using actual waste were in close agreement with those measured in the dynamic tests. Demonstration of both solvent extraction processes in 2 cm diameter centrifugal contactors will be performed in late 1995 using simulated waste.