Determination of the activity coefficient of Am in liquid Al by electrochemical methods

The activity coefficient of americium in liquid aluminium has been determined by electrochemical methods. To the author’s knowledge, this is the first time this value is published in the open literature. For radiation safety reasons only 100 mg of this highly radioactive element were permitted to be manipulated inside the glove-box. Hence an “ad hoc” experimental set-up, which allows working with small amounts of solvent, has been designed. The Am(III) solution has been prepared by direct AmO2 dissolution into CaCl2–NaCl; the conversion into its chloride form has been achieved by carbochlorination (Cl2 + C) at 600 °C. Cyclic voltammetry technique, performed in the obtained CaCl2–NaCl–AmCl3 solution, has allowed a first estimation for the logarithm of the activity coefficient, being equal to logγAm(Al)=-6.7±1logγAm(Al)=-6.7±1 at 700 °C.