Zinc-Mediated Electrochemical Reduction and Recovery of Uranium in Simulated Molten Salt Reactor Spent Fuel

The recovery of uranium and removal of lanthanide fission products from spent nuclear fuel are critical for advancing nuclear reactor systems. This study investigates the electrochemical behavior of U(IV) and Gd(III) in simulated molten salt reactor (MSR) fuel salts in the presence of Zn(II) ions. Results demonstrate that uranium preferentially deposits on liquid zinc electrode as a Zn17U2 intermetallic compound. The Zn-assisted selective electrodeposition of uranium is systematically examined using complementary electrochemical techniques and microstructural analyses. Building on these findings, an electrochemical recovery process for uranium is successfully implemented using a liquid Zn electrode. SEM-EDS characterization reveals distinct deposition morphologies: uniform Zn–U deposits form on the liquid Zn electrode, whereas particulate Zn–U co-deposits are observed on the solid Mo electrode. ICP-OES analysis of residual U(IV) and Gd(III) concentrations confirms exceptional uranium recovery efficiency (>95%) and achieves a high U/Gd separation factor of 304.0, demonstrating promising potential for spent fuel reprocessing applications.