Plutonium chemical properties in NaCl-KCl and CaCl2 at 1073 K

The electrochemical properties of plutonium have been studied in molten equimolar NaCl/KCl and CaCl2 at 1073 K by cyclic voltammetry. The respective standard potentials of Pu(III)/Pu redox couple, -2.54 V and -2.51 V (versus Cl-/Cl-2 reference electrode), led to the calculation of the activity coefficients of Pu(III) in each electrolyte. In CaCl2 the complexation of Pu(III) ions is lower and the voltage gap between Pu(III)/Pu redox system and the solvent limit is higher. Use of these results to construct potential-pO(2-) diagrams for plutonium at 1073 K gives a rational overview of plutonium properties in these media. (c) 2005 Elsevier B.V. All rights reserved.