If the selective recovery of the cesium fraction from HLW is required, the work flow involves the following operations:

• Combined extraction of Cs, Sr, An and REE by the UNEX-extractant (8 stages).

• Scrubbing of the extract with a solution of 0.5 M citric acid (1 stage).

• Stripping of Sr, An and REE by a solution of 0.5 M guanidine carbonate and 20 g/l DTPA (5 stages).

• Stripping of cesium by a solution containing 5 M HNO3 and 100 g/l acetamide (6 stages).

• Regeneration of the extractant by a 10 M HNO3 solution (3 stages).

• Regeneration of the extractant by a 0.1 M HNO3 solution (1 stage).

Figure 9.4 represents a work flow with selective withdrawal of cesium which has been proven under dynamic conditions at RI and Idaho National Laboratory.