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In 2012, the year after the Fukushima disaster crushed public support for nuclear power, Congress established the Department of Energy’s accident-tolerant fuel program. At the time, Plant Vogtle was preparing to start construction on the first Westinghouse AP1000, a new generation of reactor with safety features that made a meltdown like the one in Japan almost impossible. The fuel program promised to make uranium pellets themselves that much safer.
The pellets are “doped,” meaning the uranium blend in the nuggets of fuel is modified with materials such as chromium oxide and alumina to improve performance under high heat.
In other words: all the highly radioactive materials that form during the fission process are better contained in the new fuel.
But the next breakthrough in Southern’s novel fuel is newer. The actual cladding in the fuel assemblies—the part that you load the candy into in a PEZ dispenser—is now coated in a zirconium alloy that can withstand more intense heat.
“That helps the rod protect itself in a high-temperature environment,” Chavers said. “[Let’s] say a Fukushima-style event occurred at a nuclear reactor. The coating would protect the rod for an additional amount of time so we could get cooling into the core.”
With those features in place, the reactor can run hotter, allowing it to burn up more U-235. That means the new fuel can be enriched higher—up to 8%. It may not sound like a lot, but the effect is nuclear reactors that must be refueled every 18 months can instead run for 24 months or longer without taking costly breaks to swap out the rods of uranium pellets.
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