Separation of plutonium from lanthanum by electrolysis in LiCl–KCl onto molten bismuth electrode

• Published in: Journal of nuclear materials Vol. 340; no. 2-3; pp. 266 - 270
• Main Authors: Serp, J., Lefebvre, P., Malmbeck, R., Rebizant, J., Vallet, P., Glatz, J.-P.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15-04-2005; Elsevier
• Subjects: Applied sciences; Controled nuclear fusion plants; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Fission nuclear power plants; Fuels; Installations for energy generation and conversion: thermal and electrical energy; Nuclear fuels; P0700; 28.41.Bm; 81.15.Pq; Anode; Phase composition; Electrolysis; Cathode; Eutectic; Concentration effect; Bismuth; Lanthanum; Plutonium; Thin film; Nuclear reactor
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/j.jnucmat.2004.12.004

This work presents a study on the electroseparation of plutonium from lanthanum using molten bismuth electrodes in LiCl–KCl eutectic at 733K. The reduction potentials of Pu3+ and La3+ ions were measured on a Bi thin film electrode using cyclic voltammetry (CV). A difference between the peak potentials for the formation of PuBi2 and LaBi2 of approximately 100mV was found. Separation tests were then carried out using different current densities and salt phase compositions between a plutonium rod anode and an unstirred molten Bi cathode in order to evaluate the efficiency of an electrolytic separation process. At a current density of 12mA/cm2/wt% (Pu3+), only Pu3+ ions are reduced into the molten Bi electrode, leaving La3+ ions in the salt melt. Similar results were found at two different Pu/La concentration ratios ([Pu]/[La]=4 and 10). At a current density of 26mA/cm2/wt% (Pu3+), co-reduction of Pu and La was observed as expected by the large negative potential of the Bi cathode during the separation test.