Application of Low Melting Metals for Separation of Uranium and Zirconium in a “Fused Chloride—Liquid Alloy” System

Abstract

Closeness of electrochemical properties of uranium and zirconium makes separation of these metals in pyroelectrochemical reprocessing of spent nuclear fuels a challenging task. Varying electrode material can change metals’ deposition potentials. The study was aimed at assessing the effect of the cathode material on deposition potentials of zirconium and uranium from 3LiCl–2KCl based melts. Solid (tungsten) and liquid (gallium, zinc, Ga–Zn, Ga–Sn and Ga–In alloy) working electrodes were tested at 532–637 °C. Galvanostatic cathodic polarization was employed and the applied cathodic current varied from 0.0001 to 1 A. Gallium–zinc eutectic alloy demonstrated the largest difference of zirconium and uranium deposition potentials. Zirconium/uranium separation factors were experimentally determined in a “molten salt—liquid metal” system for gallium and Ga–Zn eutectic based alloys.

Electrical conductivity of ZrCl4 solutions in the molten LiCl-KCl eutectic

“…Currently much attention is paid to the analysis of the zirconium electrochemistry in molten LiCl-KCl, which is suggested as a possible electrolyte for the large scale pyrochemical processing of spent nuclear fuel (SNF) [12][13][14][15][16][17][18][19]. A new chlorination method of rare earth oxides (La 2 O 3 , CeO 2 , Nd 2 O 3 , Y 2 O 3 ) and actinide oxides (UO 2 and PuO 2 ), which implies gaseous ZrCl 4 in molten LiCl-KCl, is being developed and tested for the pyrometallurgical processing of SNF [20,21].…”

The Optimal Axis-Symmetrical Plasma Potential Distribution for Plasma Mass Separation

“…Currently used hydrometallurgical methods of reprocessing SNF involve the formation of concomitant liquid waste, the amount of which is difficult to reduce. In view of this problem, the “dry” methods of SNF processing such as fluoride volatility [ 21 ], pyroelectrochemical [ 22 , 23 , 24 ], and plasma methods [ 25 , 26 , 27 ] have received active development. The latter are modern developments of the aforementioned electromagnetic methods of mass separation, the principles of which were developed in the middle of the 20th century [ 9 , 28 , 29 ].…”

Recoveryof actinidesand fission products from spent nuclear fuel via electrolytic reduction: Thematic overview

“…As a result of the fission of U and Pu, several isotopes of zirconium are formed 8 . By its electrochemical properties, in particular, by the value of the standard apparent electrode potential, zirconium is the closest to uranium among all elements of FPs 9 . It was shown that a Ga‐Zn cathode gives a high efficiency of separation of uranium from zirconium at using chloride melts 9 .…”

“…By its electrochemical properties, in particular, by the value of the standard apparent electrode potential, zirconium is the closest to uranium among all elements of FPs 9 . It was shown that a Ga‐Zn cathode gives a high efficiency of separation of uranium from zirconium at using chloride melts 9 . Attempts are currently being made to separate alkali metals (AMs) and alkaline earth (AE) metals by the electrolytic reduction.…”

“…9 It was shown that a Ga-Zn cathode gives a high efficiency of separation of uranium from zirconium at using chloride melts. 9 Attempts are currently being made to separate alkali metals (AMs) and alkaline earth (AE) metals by the electrolytic reduction.…”