Scientists have observed, for the first time, the initial stages of a potent chemical reaction between hydrogen gas and uranium metal. This breakthrough could enhance the safety of nuclear fuels, hydrogen storage solutions, and upcoming fusion energy systems. The research was conducted by scientists at Lawrence Livermore National Laboratory and published in npj Materials Degradation.
When hydrogen interacts with uranium metal, the two can react to produce uranium hydride, a chemically unstable powder. This reaction can rapidly escalate, causing damage to critical components of advanced energy systems. Previously, scientists struggled to observe how this reaction begins.
Researcher Jibril Shittu compared the process to a geyser’s pressure buildup. First, hydrogen gas quietly infiltrates the uranium and disperses throughout, with no noticeable surface change. Over time, the uranium absorbs more hydrogen than it can contain, leading to the formation of uranium hydride, which takes up much more space than the original metal.
As the hydride expands, pressure accumulates beneath the surface, creating a tiny blister that gradually enlarges. Eventually, the surface cracks open, releasing uranium hydride powder and revealing fresh uranium beneath. Once the protective surface layer breaks down, the reaction accelerates quickly and becomes harder to control.
Understanding these initial moments is vital because interactions between uranium and hydrogen can influence the longevity and safety of technologies such as fusion reactors and nuclear fuel storage systems. Conventional scientific tools were only effective once the reaction was already well underway, making it difficult to observe the beginning stages.
To address this, the Lawrence Livermore team employed a technique called white-light interferometry. This method analyzes light reflection from the metal surface in comparison to a reference beam, enabling the creation of highly detailed surface maps. Unlike older methods, this approach allowed scientists to repeatedly scan the same uranium surface during the entire reaction without disturbance.
Shittu likened it to the difference between hearing about an event afterward and having a security camera record it live. Using this technique, researchers made unexpected discoveries — the hydride blister formed in an unusual location and spread horizontally across the surface, rather than deep into the metal.
These insights could help improve computer models that predict how uranium components degrade under various conditions. So far, experiments were conducted under a specific set of temperature and hydrogen conditions. The next phase involves testing across multiple environments to better forecast uranium behavior in real-world applications.
The researchers also believe this imaging approach could be useful in studying hydrogen reactions in other metals, with potential impacts on corrosion resistance and advanced superconducting materials. The study emphasizes the value of the extensive scientific knowledge accumulated over many decades at national laboratories, where generations of scientists’ expertise guided the discovery of previously unseen phenomena.
Source: KSR.