Hot test of trialkyl phosphine oxide (TRPO) for removing actinides from highly saline high-level liquid waste (HLLW)

The TRPO process for partitioning of actinides from Chinese high saline HLL W was studied. A hot test was carried out in a countercurrent mode with act ual HLLW by using a miniature centrifugal contactor set. This highly saline HLLW was obtained from a reprocessing plant. The 30%(v/v) TRPO-kerosene wa s used as extractant. The feed solution was the 2.7 times diluted HLLW and its HNO3 concentration was 1.08 mol/L. The results of the hot test were ver y attractive. Actinides as well as Tc-99 were effectively separated from th e HLLW by TRPO extraction. The decontamination factors (D.F) for total alph a and 99Tc activities are 588 and 125 respectively. Am, Np/Pu, and U were w ell stripped by 5.5 mol/L HNO3, 0.6 mol/L H2C2O4 and 5% Na2CO3, respectivel y. Their separation was very efficient, and cross contamination was very lo w. After partitioning the HLLW become a non-alpha waste.