Sequential distillation of fission-produced radioiodine and radioruthenium from sulfuric acid solutions

Fission-produced I-131 and Ru-103 radionuclides have been separated sequentially by distillation from H2SO4 of controlled chemical composition. The thermal-neutron irradiated uranium trioxide targets were digested in 2M NaOH solution and then, the supernatant solution was acidified to 20\% H2SO4 with addition of a few drops of H2O2 Solution. On boiling for 3.5 hours, greater than or equal to99.99\% I-131 was volatilized, passed through 3M H2SO4 traps, and then collected in 0.1M NaOH + 0.01\% Na2S2O3 solution with a recovery yield of 73.6\%. The product radionuclide had high radiochemical and radionuclidic purities. After separation of I-131, the fission-product solution was acidified to 40\% H2SO4 acid containing KMnO4 as an oxidant and boiled for 40 minutes. Ruthenium nuclides were volatilized and collected in 0.1M NaOH solution. Gamma-ray spectrometry showed that the separation and the recovery yields of 103Ru were greater than or equal to99.99 and 65\%, respectively, with similar to92\% radionuclidic purity, measured immediately after separation. The radionuclides of I-132 and Rh-106 were the main contaminants detected in the obtained Ru-103 product solution.