Thermodynamic quantities of actinides and rare earth elements in liquid bismuth and cadmium

Kurata, Masaki; Sakamura, Yoshiharu; Matsui, Tsuneo

doi:10.1016/0925-8388(95)01960-x

Cited by 83 publications

(56 citation statements)

References 6 publications

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“…The reduction peak potential is formed where approximately 0.54 V larger in the positive direction with respect to the potential at the solid W electrode. Many researchers have explained that the potential difference in the M + /M reaction exists because the activity coefficients of TRUs and REs, when reacted at the liquid electrode, are smaller than those at the solid electrode [34][35][36]. Accordingly, the activity can be thermodynamically calculated by using the potential difference that occurs in the process where the reduced metal reacts with the liquid Cd to form the M-Cd intermetallic compound.…”

Section: Analysis Of Peak I Cmentioning

confidence: 99%

Electrode Reactions of Nd3+/Nd Couple in LiCl-KCl-NdCl3 Solutions at Solid W and Liquid Cd Electrodes

Sim

Kim²,

Paek

et al. 2018

International Journal of Electrochemical Science

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The behavior of Nd(III)/Nd(0) redox reaction at a solid tungsten (W) and liquid cadmium (Cd) electrodes in the LiCl-KCl-NdCl 3 system at 773 K was analyzed by using a cyclic voltammetry. The Nd(III)/Nd(0) reaction in the solid W electrode was found to occur in two steps through the process of Nd(II) ion generation. As the analytic results of the maximum current value according to scan rates in the region of 0.05 V/s to 0.3 V/s, the Nd(III)/Nd(II) reaction showed reversible reaction characteristics over the whole range, while the Nd (II)/Nd(0) reaction showed the reversible reaction in the region of 0.05 V/s to 0.2 V/s, as well as the quasi-reversible in the range of 0.2 V/s or higher. Furthermore, the diffusion coefficients of Nd(III) ion and Nd(II) ion were calculated by using the maximum current value, which were considerably consistent with the previous results of other researchers. The reduction potential of the Nd (III)/Nd(0) reaction in the liquid Cd electrode was measured as approximately 0.54 V higher than that of the solid W electrode because the reduced Nd formed an Nd-Cd intermetallic compound with a liquid Cd electrode, lowering the activity of Nd. To confirm this mechanism, experiments using Cd-coated W electrodes were conducted by using cyclic voltammetry and chronopotentiometry. The experimental results showed that 6 Nd-Cd intermetallic compounds were present. When the ratio of Cd is the highest, NdCd 11 is formed, and the potential in this case was very similar to the potential at the liquid Cd electrode. Furthermore, the Gibbs free energy and activity coefficient of Nd-Cd intermetallic compounds were calculated by analyzing the results of chronopotentiometry. The results could thermodynamically explain the potential difference of the Nd(III)/Nd(0) reactions occurring between the solid W electrode and the liquid Cd electrode.

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Section: Analysis Of Peak I Cmentioning

confidence: 99%

Electrode Reactions of Nd3+/Nd Couple in LiCl-KCl-NdCl3 Solutions at Solid W and Liquid Cd Electrodes

Sim

Kim²,

Paek

et al. 2018

International Journal of Electrochemical Science

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“…2,3 It has been proposed that U could be selectively recovered at the solid cathode due to the difference in the formation energies of chlorides, and Pu and MAs at the liquid metal cathode due to their small activity coefficients in the liquid metals such as Cd or Bi. 4,5 During the dissolution of spent fuel, metals or nitrides of alkali, alkaline earths and rare earths are also dissolved into the salt phase at the same time, while metal fission products such as Ru, Tc and Mo are not dissolved. In order to recover actinides effectively from the salt phase, electrolysis using a liquid metal cathode or extraction separation between the salt and the liquid metal has been proposed.…”

mentioning

confidence: 99%

mentioning

confidence: 99%

“…2,3 Therefore, several studies were conducted on the distribution behaviors of actinides, alkali, alkaline earths and rare earths between LiCl-KCl eutectic melt and liquid metal, and the activities and separation factors of these elements in liquid metal phase were estimated. [4][5][6][7][8] From the standpoint of separation of actinides and rare earths, Bi is more convenient than Cd as the liquid metal. 4 However, there is little information on the electrode reaction of Pu and MAs at the liquid Bi electrode, and the mechanism has not been completely elucidated.…”

mentioning

confidence: 99%

“…[4][5][6][7][8] From the standpoint of separation of actinides and rare earths, Bi is more convenient than Cd as the liquid metal. 4 However, there is little information on the electrode reaction of Pu and MAs at the liquid Bi electrode, and the mechanism has not been completely elucidated. For the liquid Cd electrode, the deviation of the redox potential of metal deposition was interpreted in terms of a lowering of activity of the deposited metal in the Cd phase, and the relation between the activity and the formation energy of intermetallic compounds such as PuCd6 was evaluated in the previous work.…”

mentioning

confidence: 99%

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Electrode Reaction of Pu3+/Pu Couple in LiCl-KCl Eutectic Melts: Comparison of the Electrode Reaction at the Surface of Liquid Bi with That at a Solid Mo Electrode

et al. 2001

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Pyrochemical reprocessing of nuclear fuels using molten salt as a solvent shows promise for advanced nuclear engineering because of its compactness, economy, radiation resistance and nonproliferation. 1 In the electrorefining process, which is a key step in pyrochemical reprocessing, spent fuels are anodically dissolved in LiCl-KCl eutectic melt, and U, Pu and minor actinides (MAs; Np, Am, Cm, etc.) are recovered together at the cathode. 2,3 It has been proposed that U could be selectively recovered at the solid cathode due to the difference in the formation energies of chlorides, and Pu and MAs at the liquid metal cathode due to their small activity coefficients in the liquid metals such as Cd or Bi. 4,5 During the dissolution of spent fuel, metals or nitrides of alkali, alkaline earths and rare earths are also dissolved into the salt phase at the same time, while metal fission products such as Ru, Tc and Mo are not dissolved. In order to recover actinides effectively from the salt phase, electrolysis using a liquid metal cathode or extraction separation between the salt and the liquid metal has been proposed.2,3 Therefore, several studies were conducted on the distribution behaviors of actinides, alkali, alkaline earths and rare earths between LiCl-KCl eutectic melt and liquid metal, and the activities and separation factors of these elements in liquid metal phase were estimated. [4][5][6][7][8] From the standpoint of separation of actinides and rare earths, Bi is more convenient than Cd as the liquid metal. 4 However, there is little information on the electrode reaction of Pu and MAs at the liquid Bi electrode, and the mechanism has not been completely elucidated. For the liquid Cd electrode, the deviation of the redox potential of metal deposition was interpreted in terms of a lowering of activity of the deposited metal in the Cd phase, and the relation between the activity and the formation energy of intermetallic compounds such as PuCd6 was evaluated in the previous work. 9 The change of the redox potential on metal deposition at Hg electrode or amalgam electrode in aqueous solution has been interpreted in terms of a lowering of activity of the deposited metal in the Hg or amalgam phase. 10,11 The relation between the activity and the formation energy of intermetallic compounds between Hg and deposited metal, however, has not been analyzed in detail.In the present paper, the electrode reaction of Pu 3+ /Pu couple at the interface between LiCl-KCl eutectic melt and liquid Bi was investigated in comparison with a solid electrode. The difference between the redox potentials of Pu 3+ /Pu at the solid electrode and at liquid Bi electrode was thermodynamically interpreted based on the formation energy of PuBi2. The Gibbs free energies of formation of the intermetallic compound, PuBi2, were evaluated by the analysis of cyclic voltammograms in the temperature range from 723 to 823 K. ExperimentalThe electrochemical cell used for the voltammetric studies is shown in Fig. 1. A liquid Bi electrode, which was used a...

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Actinide Separation Science and Technology

Nash¹,

Madic²,

Mathur³

et al. 2010

The Chemistry of the Actinide and Transactinide Elements

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Thermodynamic quantities of actinides and rare earth elements in liquid bismuth and cadmium

Cited by 83 publications

References 6 publications

Electrode Reactions of Nd3+/Nd Couple in LiCl-KCl-NdCl3 Solutions at Solid W and Liquid Cd Electrodes

Electrode Reactions of Nd3+/Nd Couple in LiCl-KCl-NdCl3 Solutions at Solid W and Liquid Cd Electrodes

Electrode Reaction of Pu3+/Pu Couple in LiCl-KCl Eutectic Melts: Comparison of the Electrode Reaction at the Surface of Liquid Bi with That at a Solid Mo Electrode

Actinide Separation Science and Technology

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