Thermodynamics of Neptunium in LiCl-KCl Eutectic/Liquid Bismuth Systems

Sakamura, Yoshiharu; Shirai, Osamu; Iwai, Takashi; Suzuki, Yuzuru

doi:10.1149/1.1393246

Cited by 22 publications

(13 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The rest of rare earth and all of alkali and alkaline earth accumulate in the melt in the form of chlorides and are removed from the melt at the waste salt treatment step [4]. Due to the more positive dissolution potential of Zr compared to actinides [5][6][7][8][9][10], Zr remains in the anode basket together with the noble metal fission products as long as the anodic potential is kept below the Zr dissolution potential. On the other hand, when a higher dissolution rate of actinides is required, Zr is anodically dissolved and is recovered on the solid cathode as U-Zr alloy and/or is deposited on the wall of the electrorefiner [11].…”

Section: Introductionmentioning

confidence: 99%

Anodic dissolution of irradiated metallic fuels in LiCl–KCl melt

Murakami

Kato

Rodrigues³

et al. 2014

Journal of Nuclear Materials

View full text Add to dashboard Cite

Section: Introductionmentioning

confidence: 99%

Anodic dissolution of irradiated metallic fuels in LiCl–KCl melt

Murakami

Kato

Rodrigues³

et al. 2014

Journal of Nuclear Materials

View full text Add to dashboard Cite

“…The standard potential of Zr 4+ /Zr is reported to be more positive than those of actinides such as U 3+ /U, Pu 3+ /Pu, Np 3+ /Np and Am 2+ /Am in LiCl-KCl melts [3][4][5][6][7]. This means that zirconium theoretically remains in the anode basket with noble metal fission products and the cladding during electrolysis as far as anodic potential is kept more negative than the dissolution potential of zirconium.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical formation of uranium–zirconium alloy in LiCl–KCl melts

Murakami

Kato

Kurata

et al. 2009

Journal of Nuclear Materials

View full text Add to dashboard Cite

“…1 Assessment of feasibility of these processes requires a good knowledge of molten salt chemistry of these compounds, [2][3][4] and, therefore, basic data of these elements in molten chloride salts need to be obtained. It has been shown that the electrochemical techniques provide an efficient tool to investigate the reaction mechanisms in molten salts.…”

mentioning

confidence: 99%

Physicochemical Properties of Lanthanide and Yttrium Solutions in Fused Salts and Alloy Formation with Nickel

Lantelme

Cartailler

Berghoute

et al. 2001

J. Electrochem. Soc.

View full text Add to dashboard Cite

The thermodynamic and kinetic properties of solutions of lanthanide ͑lanthanum, cerium, praseodymium, gadolinium͒ and yttrium chlorides in fused alkali chlorides were obtained from transient electrochemical techniques. Digital simulation was used to obtain a precise analysis of transient responses including perturbing factors such as ohmic drop, electrocrystallization, and reduction of alkali ions. A fitting procedure, included in the numerical calculation, allows an accurate determination of reaction parameters, diffusion coefficients, standard potentials, and covering factor. The technique was extended to the formation of lanthanum and gadolinium alloys with nickel.An important issue concerning rare earth metals and molten salts is pyrochemical reprocessing of spent fuel since lanthanide elements, which are present in spent fuel from fast reactors, can be converted by anodic dissolution in fused salts. 1 Assessment of feasibility of these processes requires a good knowledge of molten salt chemistry of these compounds, 2-4 and, therefore, basic data of these elements in molten chloride salts need to be obtained. It has been shown that the electrochemical techniques provide an efficient tool to investigate the reaction mechanisms in molten salts. Indeed, the energetic level and the rate of reactions are easily measured from current and voltage. 5 These quantities can be followed all along the progress of the chemical transformation, which gives access to the kinetic parameters and opens the way to reaction study by relaxation or transient techniques. 6 These challenging techniques are particularly useful in the field of high temperature chemistry where the reactions are rapid and their use has expanded rapidly over the last two decades.The establishment of modern electrochemical analysis requires early evaluation of all the cell behavior with reliable procedures. It results in an increasing use of mathematical tools to evaluate the cell design. Increasingly, these are being used in conjunction with experimental studies of fundamental and laboratory scale operations. The analysis of electrode reactions composed of diffusion, electron transfer, kinetics, and additionally adsorption or crystallization is possible after suitable models have been formulated. 7 The preparation of rare earths and yttrium from fused salt electrochemistry illustrates this procedure. Indeed, in contrast to the well-known aluminum preparation, the metals are produced in the solid state. 8 The success of the experiments requires an accurate knowledge of the reaction scheme and of the physicochemical properties of the electrolyte solutions. The stability range of the various ionic species was obtained from emf measurements using reliable reference electrodes, such as a chlorine electrode or internal reference systems. The Gibbs energies of formation of various solutes were calculated. Special attention was devoted to the crystallization process generally controlled by the rate of nucleus formation and the diffusion of active species. The infl...

show abstract

Thermodynamics of Neptunium in LiCl-KCl Eutectic/Liquid Bismuth Systems

Abstract: Np (kcal/g atom) ϭ Ϫ32.5 (Ϯ0.7) ϩ 0.0072 (Ϯ0.0010) T. The values of the solubility and excess partial free energy for neptunium were closer to those for plutonium rather than uranium.

Cited by 22 publications

References 19 publications

Anodic dissolution of irradiated metallic fuels in LiCl–KCl melt

Anodic dissolution of irradiated metallic fuels in LiCl–KCl melt

Electrochemical formation of uranium–zirconium alloy in LiCl–KCl melts

Physicochemical Properties of Lanthanide and Yttrium Solutions in Fused Salts and Alloy Formation with Nickel

Contact Info

Product

Resources

About