Abstract
Next-generation nuclear power plants may include exciting novel designs in which molten salts are the coolant or a combination of the coolant and fuel. Whereas it is straightforward to see why having a low volatility coolant can be advantageous for safety, much is not understood about the production of volatile halogen gases as a result of radiation and even less is known about the distribution of these species at and away from interfaces. Using first principles molecular dynamics simulations, we investigate the product of the disproportionation reaction between chlorine anion radicals (nominally Cl2˙−) in the bulk and slab configurations. We find that the product depends on the chlorobasicity of the medium. For example, in ZnCl2, Cl2 forms, but in a eutectic mixture of LiCl and KCl, Cl3− is formed as a product. We also find that Cl3− prefers to form at the vapor interface and this may have implications for corrosion and reactivity. Furthermore, the mechanisms of the mobility of Cl2 and Cl3− are radically different, the first one being vehicular and the second Grotthus-like. Chlorobasicity is linked to the electronic structure of the host melt; ZnCl2 forms extended networks along which metal ions and anionic counterions have significant electronic orbital overlap forming long, linear, molecular-like constructs; the opposite is true for the alkali metal eutectic salt.
| Original language | English |
|---|---|
| Pages (from-to) | 4290-4297 |
| Number of pages | 8 |
| Journal | Physical Chemistry Chemical Physics |
| Volume | 27 |
| Issue number | 8 |
| DOIs | |
| State | Published - Jan 22 2025 |
Funding
This work was supported as part of the Molten Salts in Extreme Environments (MSEE) Energy Frontier Research Center, funded by the U.S. Department of Energy Office of Science, Office of Basic Energy Sciences. MSEE work at the University of Iowa was supported under a subcontract from Brookhaven National Laboratory, which is operated under DOE contract DE-SC0012704. Work at ORNL was supported under DOE contract DE-AC05-00OR22725. This research mainly used resources of the Oak Ridge Leadership Computing Facility, which is a DOE Office of Science User Facility, and, in part, the Compute and Data Environment for Science (CADES) at the Oak Ridge National Laboratory, both supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC05-00OR22725. We also acknowledge the University of Iowa High Performance Computing Facility. This manuscript has been authored by UT-Battelle, LLC, under contract DE-AC05-00OR22725 with the US Department of Energy (DOE). The US government retains and the publisher, by accepting the article for publication, acknowledges that the US government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for US government purposes. DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (https://www.energy.gov/doe-public-access-plan).