Rashmi Singh
If artificial intelligence (AI) and data centers are the engines driving the revival of nuclear energy, nuclear fuel is its centerpiece. The United States requires—but does not have—an adequate and stable supply of nuclear fuel, both to support its existing fleet of reactors—which provide nearly 20 percent of the country’s electricity—and to power the advanced reactors expected to quadruple US nuclear capacity by mid-century, meeting the demand of data centers. Today, nuclear energy offers dense, clean, baseload power, relying on low-enriched uranium in current-generation reactors.
The Evolution and Potential of Nuclear Fuel
Uranium, a relatively abundant element, contains about 0.7 percent of uranium-235, the fissile isotope required for nuclear reactions. When enriched to levels between three percent and five percent, this uranium serves as low-enriched uranium fuel (LEU) used in most existing reactors. Further enrichment, up to 10 percent, powers certain advanced reactors and small modular reactors (SMRs). High-assayed low-enriched uranium (HALEU), enriched up to the maximum civilian use limit of 19.75 percent, can fuel certain small modular reactors and micro-reactors that are not yet commercial.
Higher enrichment levels have several advantages. They allow for longer fuel cycles, i.e., reactors can run longer than the current 18-24-month cycle, and they improve fuel utilization when paired with fast neutron reactors, resulting in reduced waste volume. Advanced forms of nuclear fuel, such as Tri-Structural Isotropic Particle Fuel (TRISO), have also undergone significant refinement since their initial conceptualization in the 1980s in national labs in the United States and the United Kingdom (UK). These small uranium kernels, encased in layers of carbon and ceramic with extremely high melting points, are considered “accident resistant.” Such innovative fuel designs are compatible with high-temperature gas reactors and molten salt reactors, which makes them a perfect substitute for coal power plants catering to heat-intensive industries such as steel and cement. Despite a higher level of enrichment, the fuel particles are designed in a way to make unwanted proliferation difficult, if not impossible. Expensive and still under refinement, they are provided by the Department of Energy and are far from being available on a commercial scale.
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