Abstract
Disposal of nuclear wastes containing long-lived alpha emitters is a matter of great environmental concern. At this Centre, solvent extraction and extraction chromatographic studies are in progress with CMPO (Octyl(phenyl)N,N-diisobutylcarbamoylmethyl phosphine oxide) as the main extractant for the removal of actinides from Purex high active aqueous raffinate waste (HAW) and high level waste concentrate (HLW) solutions. Batch extraction studies with HAW solutions reveal that after two contacts with 0.2 M CMPO + 1.2 M TBP in dodecane, its alpha activity reduces to approx0.2% of initial value. The CMPO loaded actinides are efficiently stripped with suitable reagents. Mixer settler experiments in progress confirm these results. Extraction chromatographic studies with CMPO impregnated Chromosorb-102 (CAC) column show higher uptakes of actinides and lanthanides as compared to other metal ions and the capacity in terms of Nd(III) is 18 mg/g of CAC at 3 M HNO3 for less than 1% breakthrough. The results indicate that CMPO based extraction chromatographic techniques have great potential for application in the removal of actinides from Purex waste streams.
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