Decontamination of radioruthenium from TRUEX Solvent

Abstract

A procedure has been developed for the decontamination of radioruthenium from the lean organic phase composed of a solution 0.2 M n-octyl(phenyl)-N,N-diisobutylcarbamoylmethylyphosphineoxide (CMPO) and 1.2 M tri-n-butylphosphate (TBP) in n-dodecane (n-DD), which was used for the partitioning of minor actinides from actual high active waste solution (155 GWd/Te). For this purpose, the stripping behavior of radioruthenium from 0.2 M CMPO–1.2 M TBP in n-DD was studied at 298 K by using various aqueous reagents and adsorbents. Among the different reagents investigated, the aqueous solution of sodium hydroxide and sodium carbonate and adsorbents such as neutral alumina and anion exchange resin (OH^- form) were identified as the promising candidates. Nearly 90–95% of radioruthenium was removed from the lean organic phase in seven contacts using sodium carbonate or sodium hydroxide solution. The residual radioactivity in the organic phase was removed by treatment with neutral alumina or anion exchange resin. The quality of the organic phase was ascertained by ²⁴¹Am(III) retention test.