The researchers computationally simulated the interaction between electrons and molten zinc chloride salt and discovered three distinct states. The discovery is crucial for understanding the effects of radiation on future salt-fueled nuclear reactors. Insights from this study will drive further research into the reactivity of molten salts under radiation.
Scientists have revealed three unique electron states in molten salt, a discovery crucial for the radiation effects of future salt-fueled nuclear reactors.
A discovery by scientists that helps shed light on how molten salt in advanced nuclear reactors might behave shows how electrons interact with ions in molten salt to form three states with different properties. Understanding these states can help predict the effects of radiation on salt-fueled reactor performance.
Researchers from the U.S. Department of Energy's Oak Ridge National Laboratory and the University of Iowa computationally simulated introducing excess electrons into molten zinc chloride salt to see what would happen.
They found three possible scenarios. In one case, the electron becomes part of a molecular radical containing two zinc ions. In the other case, the electrons are localized on a single zinc ion. In the third case, the electrons are dispersed, or diffused, across multiple salt ions.
When exposed to radiation, electrons generated in molten zinc chloride (or ZnCl2) can be observed in three different single-occupied molecular orbital states, as well as a more diffuse, dispersed state. Source: Hung H. Nguyen/University of Iowa
Implications for future reactor design
Since molten salt reactors are one of the reactor designs being considered for future nuclear power plants, "the big question is what happens when molten salt is exposed to high radiation," said Vyacheslav Bryantsev, leader of ORNL's Chemical Separations Group, one of the scientists on the study and an author on the paper. "What happens to the salt used to carry the fuel in these advanced reactor concepts?
Claudio Margulis, professor of chemistry at the University of Iowa and one of the investigators and authors of the study, said: "It is very important to understand how electrons interact with salts. We see from the study that in very short time periods, electrons can promote the formation of zinc dimers, monomers, and can also delocalize. It is conceivable that on longer time scales, these species can further interact to form other more complex species."
In this study, scientists wanted to understand how electrons emerging from radiation produced by nuclear fuel or other energy sources would react with the ions that make up molten salt.
"This study doesn't answer all of these questions, but it's a start to a deeper look at how electrons interact with salts," Margulis said.
Potential long-term interactions and published findings
"Our first-principles molecular dynamics calculations show that these three species can form in the melt in a very short time, which begs the question: What other species can form in a longer time period. We don't have an answer to this yet. One option is that the electrons can return to the species from which they came," Magris said. ; For example, a chlorine radical can take back an electron to form chloride. Another possibility is that radical species may react in more complex ways, and of particular interest is that when enough radicals are produced by radiation, these radicals may be brought into close proximity, at which point they may react to form more complex species."
The researchers, along with Iowa State graduate student Hung Nguyen, published their findings in the American Chemical Society's Journal of Physical Chemistry B in a paper titled "Do high-temperature molten salts react with excess electrons?" "The Case of ZnCl2" was selected as an American Chemical Society Editor's Choice Paper, an honor awarded by the American Chemical Society to a paper of broad public interest selected from all its papers. The paper was also selected as the cover of the magazine.
The research is part of the Department of Energy's Molten Salts in Extreme Environments Energy Frontier Research Center (MSEEEFRC), led by Brookhaven National Laboratory. EFRC is a basic research program funded by the Department of Energy's Office of Basic Energy Sciences that brings together creative multidisciplinary and multi-institutional teams of researchers to solve the toughest major scientific challenges at the forefront of basic energy science research.
wider meaning
"This study is important because it shows how excess electrons produced by radiation in molten salt reactors can have many forms of reactivity. Other members of the MSEE team and I are trying to experimentally determine these other forms of reactivity," said Brooksea cultural scientist James Wishart, MSEEEFRC director.
"This study gives us some insight into how electrons interact with molten salt," Bryantsev said. "There are still many questions that remain unanswered. For example, is this interaction similar to what happens with other salts?"
"I will continue to work with Professor Margulis, Dr. Bryantsev and other members of the MSEE project to expand our research by studying other salt systems," said Nguyen, first author of the paper. "Hopefully we can answer more questions about the effects of radiation on molten salts."