THE REMOVAL OF ACTINIDE ELEMENTS FROM HIGH LEVEL RADIOACTIVE WASTE BY TRIALKYL PHOSPHINE OXIDE (TRPO) EXTRACTION——THE STRIPPING OF ACTINIDE ELEMENTS FROM LOADED TRPO ORGANIC PHASE

The stripping behavior of actinide elements loaded in 30% TRPO-kerosene solution with nitric acid,oxalic acid and sodium carbonate solution is studied and stripping parameters are given. Americium and lanthanide elements can be effectively stripped with 5-6mol/l nitric acid,but at higher nitric acid concentration third phase would appear. More than 99% neptunium and plutonium could be recovered in two times stripping by 0. 5 mol/l oxalic acid with crossflow. Uranium is stripped with sodium carbonate. The cross contamination between the three fractions are very little. A proposed flowsheet for the removal of actinide elements from high level radioactive waste by TRPO extraction is presented.