Reaction Kinetics of Zn2+ with Radiolysis Products in Molten LiCl-KCl Eutectic

Abstract

A thorough understanding of radiation effects on molten salt media is necessary to support the design, development, and deployment of molten salt reactor, using either fuel salt or solid fuel with salt as the coolant. Fundamental issues include the determination of the initial yields and reactivity of the primary radiolytic species, i.e., the solvated electron (esolv –), chlorine atom (Cl•), and dichloride radical anion (Cl2 •–) as their reactivity varies depending on the environment such as the salt cation and temperature. Here we report on the reaction kinetics for esolv – and Cl2 •– in molten LiCl-KCl eutectic doped with Zn2+ ions. Electron pulse radiolysis absorption spectroscopy was used to observe the transient behavior of esolv – and Cl2 •– on the nanosecond to microsecond time scale. Experiments were performed using the Brookhaven National Laboratory Laser-Electron Accelerator Facility (LEAF)1 and utilizing a recently developed high-temperature sample holder.2 Decay kinetics of of esolv – and Cl2 •– in 9.41 mM ZnCl2 in LiCl-KCl are shown in the figure. esolv – and Cl2 •– decays in different time scale due to different reaction kinetics and decay speed increase as temperature.This work was supported as part of the Molten Salts in Extreme Environments Energy Frontier Research Center, funded by the U.S. Department of Energy (US-DOE), Office of Science, Basic Energy Sciences, at BNL, INL and ORNL under contracts DE-SC0012704, DE-AC07-05ID14517 and DE-FC02-04ER15533, respectively. The Laser Electron Accelerator Facility of the BNL Accelerator Center for Energy Research is supported by the US-DOE Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences under contract DE-SC0012704. Wishart, J. F.; Cook, A. R.; Miller, J. R.; Rev. Sci. Instrum., 2004, 75 (11), 4359.Phillips, W. C.; Layne, B.; Gakhar, R.; Horne, G. P.; Ramos-Ballesteros, A.; Iwamatsu, K.; LaVerne, J. A.; Pimblott, S. M.; Wishart, J. F.; Rev. Sci. Instrum., 2019, in peer review. Figure 1