The long search for the location of a rare element within nuclear fuel particles has ended. Researchers have finally pinpointed where silver congregates inside irradiated particles of a new type of nuclear fuel.
The finding will help scientists better understand how select fission products such as silver can escape from tristructural isotropic (TRISO) fuel. This specialized fuel could run high-temperature gas-cooled reactors (HTGRs) that have numerous enhanced safety features.
“This is a major achievement for our research in TRISO particle fuel,” says David Petti, Idaho National Laboratory’s director of the Very High Temperature Reactor Technology Development Office. “Understanding the behavior of fission products in our fuel is critical because of the TRISO coating’s containment function in the overall safety strategy for HTGRs.”
Next-generation HTGR designs incorporate safety systems that rely on the naturallaws of physics more than mechanical systems or human intervention. These safety systems extend all the way down to the design of the fuel itself.
For nearly 10 years, INL researchers have been studying TRISO fuel, a spherical particle with uranium dioxide or uranium oxycarbide at its core. The core is coated with layers of carbon and silicon carbide—the TRISO coating—which acts as “the primary containment” for fission products. The coated particles are about the size of a poppy seed.
Researchers had known silver fission products were amassing somewhere inside the coated particles. Silver is one of the few fission products that can migrate outside the particles, and scientists want to better understand such movement. But they had not been able to adequately “see” inside the particles until now. The research team reached the new milestone by spotting a tiny sliver of silver using an extremely powerful microscope at the Center for Advanced Energy Studies (CAES).
Read more at: Phys.org