Washington State University researchers have developed a cutting-edge method to identify harmful salts during the vitrification of nuclear waste, potentially transforming clean-up practices at complex sites like Hanford.
A breakthrough technique developed by researchers at Washington State University (WSU) could pave the way for advanced nuclear waste clean-up technologies, particularly at challenging sites like the Hanford Site. This novel method allows for the detection of harmful salts during the vitrification process, thereby improving the safety and efficiency of nuclear waste processing.
In a study published in Measurement, WSU researchers used advanced detectors to identify thin layers of sulfate, chloride and fluoride salts while converting nuclear waste into glass — a process known as vitrification. The newly developed method provides a significant advantage by enabling real-time monitoring, which helps determine if the composition of the melt needs to be adjusted.
“We were able to demonstrate a technique to see when the salts are forming,” co-lead author John Bussey, a WSU undergraduate, said in a news release. “By doing that, the melters could be monitored to know if we should change what is being put in the melt.”
Hanford, one of the world’s largest and most complex nuclear waste clean-up sites, holds 55 million gallons of chemical and nuclear waste across 177 tanks. The presence of nearly all periodic table elements in the waste makes salt formation particularly problematic. These salts can corrode expensive vitrification equipment, and if salts dissolve in water, they could potentially lead to leaks and contamination, posing significant environmental risks.
The breakthrough method employs technology from Pacific Northwest National Laboratory and MIT, using optical and electrical components to analyze light emissions between infrared and microwave wavelengths during the melting process. By examining glass melts akin to those found at Hanford, the researchers leveraged two detectors to observe thermal emissions and track changes over time.
“The brightness is really interesting for identifying all of the melting, solidification and salt formation,” co-lead author Ian Wells, a graduate student in the WSU School of Mechanical and Materials Engineering, said in the news release. “What is really unique about this is you don’t have to add any additional lighting or additional systems — purely based on the heat that is coming off the melt, you are able to look at the brightness of one-pixel images, and you can tell what’s happening.”
Bussey highlighted the system’s potential for real-world application at the Hanford vitrification plant, an ongoing project by the U.S. Department of Energy.
“This work takes this monitoring technology a good step of the way closer to being able to be used inside the vitrification plant,” Bussey added. “This piece of equipment without too much modification could be put straight into the vitrification plant.”
The implications of this innovative method extend beyond nuclear waste management. The researchers believe it could also benefit molten salt nuclear reactors and various manufacturing processes, such as glass, epoxy or carbon fiber production, where understanding phase changes and compound formation is crucial.
Funded by the U.S. Department of Energy Office of Environmental Management, this research marks a significant step forward in making nuclear waste vitrification more reliable and eco-friendly.
Adding to its reliability, the sensors can detect salts remotely, avoiding the dangers of inserting equipment into radioactive molten glass. The next steps for the researchers involve scaling up from lab tests to larger melt tests, potentially leading to broader adoption and further advancements in waste processing technology.