After years of effort, the Idaho National Laboratory (INL) scientists have created fuel for the world’s first fast-spectrum molten salt reactor. The Molten Chloride Reactor Experiment (MCRE) will test this advanced reactor, which uses molten chloride salt mixed with uranium as both fuel and coolant.
Due to its liquid fuel, this reactor design is highly efficient, generates less waste, and offers safety benefits. To create the special salt fuel, uranium metal is converted into a form that dissolves in molten salt. This breakthrough could provide cleaner electricity and heat for industries and communities.
Bill Phillips, the technical lead for the Molten Chloride Reactor Experiment (MCRE), likened the challenge to “baking a cake.” The team needed to convert over 90% of uranium metal feedstock into usable fuel salt, a feat never attempted on this scale. Starting in 2020, they had to design the entire process and equipment from scratch.
Nick Smith, MCRE project director, revealed that early efforts wasted too much uranium, making it impossible to produce enough fuel salt for the reactor. However, years of persistence and revisions finally led to a successful process, achieving the desired efficiency and yield.
Low-temp, low-cost molten salt battery for grid-scale energy storage
Smith emphasized the dedication required, stating, “It takes a special kind of perseverance to solve a problem without any guarantee of success.” Through relentless innovation, the team overcame significant hurdles to reach this milestone.
The team faced major technical challenges, such as building a custom furnace and specialized safety equipment. To explain their methods, they used playful terms like “angel cake” and “French press.”
To avoid wasting expensive enriched uranium, they experimented with depleted uranium. Initially, they could only make 2–3 ounces of fuel at a time. They can now produce over a dozen pounds in a single batch thanks to their improvements.
The project has reached a critical phase, with the team ready to move into full-scale production of enriched fuel salt for the Molten Chloride Reactor Experiment (MCRE). “We’re almost at the moment where we can bake the cake,” said Bill Phillips, indicating they now have all the necessary components and methods.
The next objective is to produce five batches of this fuel salt by October 2025. The MCRE is expected to become operational by 2028, alongside the LOTUS test bed, where it will be the first reactor experiment.
Jacob Yingling highlighted the team’s drive, saying they are motivated by the unique capabilities of molten chloride reactors, which can outperform other energy technologies. The team remains committed to deploying this transformative technology.
