V. A. Volkovich

Reaction of Curium(III) Ions with Oxo-Species in Alkali Chloride Melts

Pyrochemical reprocessing of spent nuclear fuels employing alkali metal chloride based melts is considered as a possible alternative to the existing extraction technology. Curium is one of the minor actinides present in the spent fuel and understanding its behavior in molten salts is important for designing a feasible process. Curium in chloride melts is present in the form of Cm(III) chloro-species, CmCl6, and similar to lanthanides is capable of reacting with the oxide ions to produce oxychloride and oxide:

Electrode potentials of uranium in the LiCl–KCl–CsCl eutectic melt

The electrode potentials of uranium in the melt of the eutectic mixture of lithium, potassium, and cesium chlorides are measured in the temperature range 573–1073 K. Formal standard potentials EU*(III)/U and the main thermodynamic characteristics of uranium trichloride in the LiCl–KCl–CsCl melt are calculated, and the electronic absorption spectra of UCl63– ions are measured.

Uranium and neodymium partitioning in alkali chloride melts using low-melting gallium-based alloys

Abstract Partitioning of uranium and neodymium was studied in a ‘molten chloride salt - liquid Ga-X (X = In or Sn) alloy’ system. Chloride melts were based on the low-melting ternary LiCl-KCl-CsCl eutectic. Nd/U separation factors were calculated from the thermodynamic data as well as determined experimentally. Separation of uranium and neodymium was studied using reductive extraction with neodymium acting as a reducing agent. Efficient partitioning of lanthanides (Nd) and actinides (U), simulating fission products and fissile materials in irradiated nuclear fuels, was achieved in a single stage process. The experimentally observed Nd/U separation factor valued up to 106, depending on the conditions.

Corrosion behavior of austenitic steels and their components in niobium-containing chloride melts

The mechanism of corrosion of austenitic steels 12Kh18N10T, 10Kh17N13M2T, and 03Kh17N14M3 and metals Cr, Fe, Ni, and Mo in a NaCl-KCl-NbCln (n = 3.5, Nb content is 5 ± 0.1 wt %) melt at 750°C is studied. The metal and steel corrosion rates under these conditions are determined. The character of material fracture and the mechanisms of material corrosion are found.

Thermodynamic properties of metallic Ga-In alloys saturated with lanthanum

The activity of lanthanum is determined in a Ga-In eutectic alloy and alloys with indium in the temperature range 573–1073 K using the electromotive force (emf) method.

Thermodynamic properties of alloys of praseodymium with the gallium-indium eutectic melt

Equilibrium potentials of Pr-In alloys containing 8.7–12.1 mol % Pr and alloys of Pr with In-Ga eutectic saturated by praseodymium up to 6.71 mol % Pr are measured by the emf method between 573–1073 K in the (Li-K-Cs)Cleut based salt melt. Metallic praseodymium is used as the reference electrode when studying the Pr-In system, and the two-phase praseodymium-indium alloy L + PrIn3 with the known thermodynamic properties having no phase transitions in the studied temperature range is used as the reference electrode when studying the Pr-In-Ga system. Partial thermodynamic properties and activity of praseodymium in alloys with indium and the Ga-In eutectic mixture are calculated.

Study of uranium solubility in gallium-indium eutectic alloy by emf method

Activity, activity coefficients and solubility of uranium in Ga-In eutectic alloy as well as activity of uranium in U-Ga and U-In alloys were determined between 573 and 1073 K using electromotive force (emf) method.

Redox potentials of uranium in molten eutectic mixture of lithium, potassium, and cesium chlorides

The behavior of uranium(III) and (IV) ions in the melts based on the eutectic mixture of lithium, potassium, and cesium chlorides has been studied using cyclic voltammetry in the range of 573–1073 K. The red-ox potentials of uranium have been determined and formal standard EU(III)/U(IV)* red-ox potentials have been calculated.

Diffusion coefficients of the uranium(III) and (IV) ions in the LiCl–KCl–CsCl eutectic melt

Diffusion coefficients of the uranium(III) and (IV) ions in the eutectic melt of the lithium, potassium, and cesium chlorides in the temperature range of 573–1073 K have been determined using two independent methods: cyclic voltammetry and chronopotentiometry.

Electrochemical properties of molybdenum in individual molten alkali metal chlorides and their mixtures

The behavior of molybdenum in chloride melts is studied, and the standard potentials of Mo are determined in the melts based on eutectic mixtures LiCl-KCl-CsCl (at 633–1173 K) and NaCl-CsCl (at 793–1023 K), an equimolar NaCl-KCl mixture at 973–1123 K, and individual LiCl, NaCl, KCl, RbCl, and CsCl at 1123 K. The change in the conventional standard Gibbs energy of molybdenum trichloride formation in the NaCl-KCl, NaCl-CsCl, and LiCl-KCl-CsCl melts is calculated. The effect of the cation composition of the salt solvent on the conventional standard electrode potential of molybdenum in the chloride melts is considered. The diffusion coefficients of Mo(III) ions in the LiCl-KCl-CsCl melt are determined.