REMOVAL OF ACTINIDE ELEMENTS FROM HIGH LEVEL RADIOACTIVE WASTE BY TRIALKYLPHOSPHINE OXIDE (TRPO)--THE STRIPPING OF ACTINIDE ELEMENTS FROM LOADED ORGANIC PHASE

Stripping behaviors of 30% TRPO-kerosene organic phase containing actinide elements in nitric acid, oxalic acid and sodium carbonate solutions were studied. The conditions for stripping actinide elements were given. The 5-6 mol/L nitric acid of concentration can effectively reextract americium and lanthanide, but third phase would be generated if nitric acid concentration is over high. Two times of stripping with 0. 5 mol/L oxalic acid in crossflow can recover more than 99% of neptunium and plutonium, and 5% sodium carbonate can reextract uranium. The cross contamination in these three groups is very little. A flowsheet of TRPO process for removing actinides from high level waste solution is proposed.