Researchers from the Argonne National Laboratory in Illinois, along with collaborators, have discovered how a compound molecule could improve the safety and effectiveness of nuclear reactors.
Interesting Engineering reported that the scientists tested liquid plutonium oxide, or PuO2, in temperatures as hot as 3,000 Kelvin (4,940 degrees Fahrenheit) to see how it would react in extreme environments.
They analyzed this behavior by suspending PuO2 molecules that were 2 millimeters in diameter via a gas stream and melting them with a carbon dioxide laser beam "without risking sample contamination from container interactions." The team also adjusted the temperature and changed the gas stream to observe how the PuO2's structure and volatility would respond under various conditions.
"We solved the structure of liquid plutonium oxide and found that some covalent bonding was indeed present," senior physicist Chris Benmore said in a news release. "We also discovered that the liquid structure was similar to cerium oxide, which can be used as a non-radioactive substitute."
Though using levitators to melt substances isn't a new technique, per the release, using the method to study a complex nuclear fuel made the experiment challenging.
"... To move this technique into studying nuclear fuel materials where there are other concerns required a much higher level of sophistication and safety review," lead author Stephen Wilke, of the collaborating company Materials Development Inc., said in the release. "I think it paid off in a large way."
"Argonne is probably the only place in the world capable of performing this very difficult type of experiment," Benmore added.
The U.S. Department of Energy-funded facility used a similar method in 2014 to measure the structure of molten uranium dioxide, a crucial component of the fuel used in modern-day nuclear reactors.
Now, the results from the new research -- as well as the supercomputer the team utilized to predict how electrons would react with "quantum mechanical accuracy," per the release -- provide a path to test mixed oxide fuels generally for potential use in next-generation reactors.
Unlike dirty energy sources that produce planet-warming gases, standard nuclear reactors produce carbon-free electricity.
That advantage has led the Biden administration to approve a $1.5 billion loan to reopen a nuclear power plant in Michigan. The U.S. Nuclear Regulatory Commission also recently approved the construction of a nuclear reactor that uses molten fluoride salt to power the generator.
While the dangers of nuclear power are debated, and put in perspective by statistics from Our World in Data, critics believe that money and resources are better spent on other forms of clean energy. However, the hope is that progress in this field, like the one demonstrated by Argonne National Laboratory, makes it a safer, cleaner, and cheaper option.
"The data from the combined set of experiments not only provides information of technological importance, it also provides insights into the fundamental behavior of actinide oxides at extreme temperatures," Mark Williamson, division director of Argonne's Chemical and Fuel Cycle Technologies, said.
"This has been a fantastic collaboration of experts, and it's an excellent example of how we work together to continually improve nuclear energy systems."