Communication—Electrochemical Behavior of UO₂²⁺ and Its Electrodeposition from UO₂F₂-FLiBe Melt

Abstract

To support the proposal for separating uranium from used fuel salt of Molten Salt Reactor (MSR), the electrochemical behavior of UO 2 2+ in the carrier salt of MSR (LiF-BeF 2 , FLiBe) was investigated in this work. Cyclic voltammetry and square wave voltammetry measurements showed that the reduction of UO 2 2+ in UO 2 F 2 -FLiBe melt with addition of KF exhibited one step with two exchanged electrons: UO 2 2+ +2e − →UO 2 , with reduction peak of 1.93 V (vs. Be 2+ /Be). By potentiostatic electrolysis, the product of octahedral UO 2 single crystals with micron size was obtained.

Chemical Species Transformation during the Dissolution Process of U3O8 and UO3 in the LiCl–KCl–AlCl3 Molten Salt

“…The cyclic voltammetry (CV) technique was employed to study the electrochemical behaviors of U on the W electrode during the U 3 O 8 and UO 3 dissolution process, as displayed in Figure . It is found that the oxidation signal A at 2.36 V is related to the oxidation of UO 2 to UO 2 Cl 4 2– and the redox couple B/B′ is attributed to UO 2 Cl 4 2– /UO 2 Cl 4 3– . , Peaks C and C′ are attributed to the soluble–soluble redox process of UCl 6 2– /UCl 6 3– . − , The cathodic peak D′, at 0.19 V, might be due to the reduction of UCl 6 3– to the U metal, and its corresponding anodic peak D is related to the dissolution of the U metal. , In addition, the peaks E and E′ correspond to the formation/reduction between the U metal and UO 2 …”

“…It is found that the oxidation signal A at 2.36 V is related to the oxidation of UO 2 to UO 2 Cl 4 2− and the redox couple B/B′ is attributed to UO 2 Cl 4 2− /UO 2 Cl 4 3− . 43,44 Peaks C and C′ are attributed to the soluble−soluble redox process of UCl 6…”