For the first time, scientists at Lawrence Livermore National Laboratory have watched hydrogen and uranium react from the very first moment of contact—capturing a process that has been invisible to science until now. The breakthrough matters because this corrosion cycle happens inside fusion reactors, hydrogen storage systems, and nuclear fuel repositories, where understanding degradation can mean the difference between safe, long-lasting technology and catastrophic failure.
The hydrogen-uranium interaction works like an underground geyser, according to Jibril Shittu, the LLNL scientist who led the study published in npj Materials Degradation. Hydrogen gas seeps into uranium metal, dissolving and diffusing silently through the material until the metal can hold no more. When saturation hits, the two elements combine to form uranium hydride—a compound that takes up significantly more volume than the original uranium. That pressure builds until it creates a tiny blister on the surface. The blister grows and grows until the strain becomes unbearable, and it bursts open, releasing uranium hydride powder and exposing fresh metal underneath. "Once that protective surface is breached, fresh metal is exposed, and the reaction accelerates," Shittu said. "Adsorb, dissociate, diffuse, accumulate, blister, rupture, spall. That's the cycle, and once it starts, it's hard to stop."
The problem: the two conventional techniques scientists use to study hydrogen-uranium reactions are "essentially blind to the very first events," Shittu explained. By the time existing tools could see anything, the reaction was already well underway—like trying to understand a car crash by only watching the wreckage. To fill that gap, the LLNL team deployed white-light interferometry, a technique that creates a tiny topographic map by measuring how light reflects off the uranium surface compared to a reference beam. The method is sensitive enough to detect hydride blisters—which are wide and shallow—without physically touching or destroying them. "We can scan the same uranium surface repeatedly through the entire reaction, building a frame-by-frame record," Shittu said. "It's the difference between hearing about an event after the fact and having a security camera rolling the whole time."
What they found surprised them. The hydride blister appeared in unexpected locations and spread sideways across the uranium surface rather than burrowing deep into it, contradicting earlier predictions. These discoveries will help scientists build better predictive models for how uranium components actually degrade—critical knowledge for designing fusion reactors with longer lifespans, hydrogen storage systems that work reliably, and nuclear fuels that can safely remain in storage for decades.
The next phase of research will extend these observations across a wider range of temperatures, hydrogen pressures, and material conditions. "That's how we get from 'we can see it now' to 'we can predict it under any condition you give us,'" Shittu said. The technique also holds promise beyond uranium: white-light interferometry could illuminate how hydrogen reacts with other metals, potentially advancing fields like hydride superconductors and solving other corrosion and degradation puzzles. Shittu credited the study's success to Lawrence Livermore's unusual culture of institutional memory, where decades of senior scientist expertise gets passed down across generations of researchers. "Sitting down with the old-timers, asking dumb questions and listening hard to the answers is what kept us from re-learning things the field already knew," he said.