Low melting metals from the groups 13 and 14 of the periodic table and their alloys are considered as prospective media for reprocessing of spent nuclear fuels with short cooling time. The process is performed using a “liquid metal – molten salt” system. Thermodynamic calculations of separation factors (Θ) of “Ln/Ac” couples at a given temperature allow to range the metals into the following sequence in order of decreasing effectiveness of separation of 4f- and 5f-elements: Al&gt;Ga&gt;Sn&gt;Pb&gt;In&gt;Tl. Most technologically attractive are the metals that melt below the working temperature, which is typically in the range of 723–823 K. Relatively high melting point of Al limits its application in the separation processes. Eutectic alloys of Ga with Al, Sn or In are the most interesting, since their melting points are close to the room temperature. Metallic alloys have extremely high thermal and radiation stability which is necessary for nuclear wastes recycling and further disposal. For thermodynamic modeling and evaluation of separation factors of metals Me1 and Me2 the following equation was applied: ΘMe1/Me2 = 3F/(2.303RT)*(E*2 - E*1) + logγ1 - logγ2, where E*1, E*2, γ1, γ2 are the formal standard potentials of the metals in the salt melt and their activity coefficients in the alloy phase, respectively. In the present work the possibility of separation of “Pr/Nd” and “U/Nd” couples employing Ga-Sn eutectic alloys was studied. Experiments were conducted between 723-823 K. The results of thermodynamic modeling are in good agreement with the experimentally obtained values of Θ. Separation of Ln and An employing Ga-Sn alloy is possible. Lanthanides are accumulated in the salt phase, and actinides in the metal phase.

Thermodynamic modeling and experimental verification of f-elements separation employing Ga-Sn eutectic alloys

249th National Meeting (2015)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.