Demonstration of an Improved Total Partitioning Process for High Level Liquid Waste Using Annular Centrifugal Contactors

High level liquid waste (HLLW) produced from the reprocessing of the spent nuclear fuel still contains moderate amounts of uranium, transuranium (TRU) actinides, Sr-90, Cs-137, etc., and thus constitutes a permanent hazard to the environment. The partitioning and transmutation (P&T) strategy has increasingly attracted interest for the safe treatment and disposal of HLLW, in which the partitioning of HLLW is one of the critical technical issues. An improved total partitioning process, including a TRPO (tri-alkylphosphine oxide) process for the removal of actinides, a CESE (crown ether strontium extraction) process for the removal of Sr, and a calixcrown ether extraction process for the removal of Cs, has been developed to treat Chinese HLLW at the Institute of Nuclear and New Energy Technology (INET), Tsinghua University, China. A demonstration test of the improved total partitioning process was carried out using 74-stage 10-mm-dia annular centrifugal contactors and simulated HLLW. The test results showed that the decontamination factors were >1.2 x 10(6), 4600, and 7500 for Nd, Sr, and Cs, respectively. In the test, Nd was used to simulate Am. During the test, 74-stage 10-mm-dia annular centrifugal contactors worked stable continuously with no stage failing or interruption of the operation.