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  • 1 The University of Tokyo Nuclear Engineering Research Laboratory Tokai-mura 319-11 Ibaraki-ken Japan
  • 2 Japan Atomic Energy Research Institute Department of Fuel Cycle Safety Research Tokai-mura 319-11 Ibaraki-ken Japan
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The coextraction equilibrium of technetium(VII) and uranium(VI) from nictric acid solution was studied in a system involvingn-octyl(phenyl)-N,N-diisobutylcarbamoylmethyl phosphine oxide (CMPO) in decalin. Stoichiometry of technetium, uranium and CMPO in the Tc-U-CMPO complex was obtained from the distribution data by slope analysis. The results indicated that the enhanced extraction of technetium was caused by the formation of UO2NO3TcO4·nCMPO (wheren=2 and/or 3). It was found that this coextraction of technetium with uranium was well explained by using ion exchange reaction between UO2(NO3)2·2CMPO complex and TcO 4 .