Paul Scherrer Institute researchers use X-rays to study nuclear fuel rod corrosion

Researchers at the Paul Scherrer Institute (PSI) have developed a high-resolution 3D X-ray imaging technique to examine the corrosion layers on nuclear fuel rod cladding. Using the Swiss Light Source, the team was able to detect features and pores as small as 80 nanometers within the zirconium oxide layers that form on the protective metal tubes.

To manage radiation risks, the researchers used a focused ion beam to shape tiny cylindrical specimens, only 20 micrometers in diameter, from used cladding. This miniature size allowed the samples to be measured outside of heavily shielded cells. The study compared these real-world samples from operating power plants with laboratory-tested materials to determine if conventional corrosion tests accurately reflect the conditions inside a nuclear reactor.

The findings indicate that the protective oxide layers on the cladding remained effective and leak-tight after service, providing critical data to help scientists assess material safety and improve the evaluation of components used to contain radioactive fuel.