Agents and Processes Design for TRU Elements Back Extraction in TRPO Process

To reduce the long-term risk of the high-level liquid waste (HLLW) and the waste disposal cost, transuranium (TRU) elements should be removed from HLLW. A so-called TRPO process has been developed by Chinese scientists to partition HLLW. In this process, the extractant, trialkyl phosphine oxide (TRPO), is able to extract TRU elements into organic phase completely, which makes the treatment and disposal of raffinate HLLW much easier. However, the treatment of extracted TRU elements in organic phase, in return, becomes new troublesome issue. Generally, there are three promising ways to treat the extracted TRU elements: (1)transmutation; (2)conditioning; (3)recycling U+Pu in Purex-TRPO Integrated Process. In any of the three ways, the back extraction agents and processes play significant roles. In this paper, the investigations on back extraction agents for TRU elements, such as TTHA, DTPA, AHA, HEDPA, DOGA, and carbonates are introduced. The corresponding back extraction processes and experimental results are reviewed.

Hot test of partitioning strontium from high-level liquid waste (HLLW) by dicyclohexano-18crown-6 (DCH18C6)

The crown ether strontium extraction(CESE) process for partitioning strontium from HLLW was studied. A hot test was carried out in a counter current mode with genuine HLLW by using a miniature centrifugal contactor set. 0.1 mol/L DCH18C6 in 1-octanol was used as extractant. The feed solution was the HLLW raffinate of TRPO process after removing TRU elements. Acidity of the feed was 1.45 mol/L HNO