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Electrochemical behavior of plutonium fluoride species in LiF-CaF2 eutectic melt

Claquesin, Julien and Lemoine, Olivier and Gibilaro, Mathieu and Massot, Laurent and Chamelot, Pierre and Bourges, Gilles Electrochemical behavior of plutonium fluoride species in LiF-CaF2 eutectic melt. (2019) Electrochimica Acta, 301. 80-86. ISSN 0013-4686

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Official URL: https://doi.org/10.1016/j.electacta.2019.01.169

Abstract

The electrochemical behavior of plutonium fluoride species was investigated in molten LiF-CaF2 medium in the 1093–1153 K temperature range with PuF4 additions. A preliminary thermodynamic study supposed a Pu(IV) carboreduction into Pu(III) and that Pu(III) reduction into metal proceeds in one step. Then, an electrochemical study was carried out on an inert electrode (tungsten) and confirmed the thermodynamic predictions: Pu(IV) is spontaneously reduced into Pu(III) in presence of carbon and Pu(III) is directly reduced into Pu(0): Pu(III) + 3e− = Pu(0). Moreover, Pu(III) reduction mechanism is a diffusion controlled process. Diffusion coefficients were calculated at different temperatures and obey to an Arrhenius' type law with an activation energy of 63 3 kJ mol−1. The standard potential of Pu(III)/Pu(0) was determined at 1113 K and is found to be −4.61 V vs. F2 (gaz)/F−. This value permitted to calculate activity coefficients for several molalities.

Item Type:Article
HAL Id:hal-02284130
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Commissariat à l'Energie Atomique et aux énergies alternatives - CEA (FRANCE)
French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UT3 (FRANCE)
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Deposited On:11 Sep 2019 12:48

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