Study mapping U-10Zr porosity informs metallic fuel design

[Marlin]

Study mapping U-10Zr porosity informs metallic fuel design

https://www.ans.org/news/2026-08-17/article-8300/study-mapping-u10zr-porosity-informs-metallic-fuel-design/

[Core Content]

Researchers from Idaho National Laboratory and MIT utilized synchrotron X-ray tomography to map three-dimensional pore networks in irradiated U-10Zr fuel samples. By analyzing fuel pins from the decommissioned Fast Flux Test Facility, the team identified how zirconium distribution and pore morphology influence fission gas release and fuel-cladding chemical interactions during reactor operation.

This data challenges existing fuel performance models that previously represented pores as simple spheres. Understanding how these complex networks facilitate liquid sodium flow and fission product migration is necessary for the development of advanced metallic fuels. These findings provide a basis for more accurate simulations to predict fuel longevity and safety in next-generation sodium-cooled fast reactors.

Researchers at Idaho National Laboratory and the Massachusetts Institute of Technology have conducted a three-dimensional study of irradiated U-10Zr—uranium alloyed with 10 percent zirconium—across key radial regions, providing new insights into how the material swells, transfers heat, and interacts with the fuel cladding.

U-10Zr was extensively tested in historical sodium-cooled fast reactors and is now attracting attention for use in next-generation advanced reactors.

According to MIT, the researchers used samples extracted from fuel used in the Fast Flux Test Facility (FFTF) reactor, which operated from 1982 to 1992 at the Hanford Site in Washington state. In experiments conducted at Brookhaven National Laboratory, the team used high energy synchrotron X-ray computed tomography to analyze the pore networks and chemical changes that formed under irradiation.

Read the full article at ans.org:
https://www.ans.org/news/2026-08-17/article-8300/study-mapping-u10zr-porosity-informs-metallic-fuel-design/