LEMONT, Ill. Down a bright fluorescent hallway and through a secure door in one of the United States most storied federal research institutes is a room where only American citizens can go. Its small and dimly lit, a rather modest workshop. Entering means surrendering your phone and camera; exiting requires first scanning your body for radiation. Much of the space is taken up by a blue, windowed box thats about the size of three SUVs stacked on top of each other. Dozens of thick black gloves hang off the transparent walls.

Back in 2018, the year United Nations scientists warned that the window to avoid catastrophic global warming was quickly closing without dramatic cuts to fossil fuel use, Krista Hawthorne slid her hands into those gloves and, suddenly, everything made sense.

Wow, Hawthorne, 34, remembered thinking as she curled her fingers, Thanos -like, around a fist-sized chunk of ancient stardust metal. I really get to do this.

That single silvery sample of uranium contained roughly enough energy to power a single U.S. home for six centuries. But a traditional nuclear reactor could only tap into a fraction of that cosmic power before rendering the atomic fuel too contaminated with fission byproducts to be considered anything but dangerous waste.

Hawthorne, a young electrochemical engineer just starting her job at the Argonne National Laboratory here in the quiet Chicago suburbs, was determined to find a solution. If we just get to the 95% of energy left over in spent uranium fuel, it would be easier to stop burning so many planet-heating fossil fuels. And using more of that energy would shorten the period the final waste product needed to decay back to the radiation levels of uranium mined from the Earth.

Were looking at ways to recycle used nuclear fuel because it reduces the amount of waste that has to be disposed of, Hawthorne said in a conference room outside her lab one morning last October. It also decreases the amount of time the waste has to be isolated for, from about 300,000 years to about 300 years. And it provides

A stoic scientist who chooses her words carefully, she corrected herself mid-sentence: It would provide a sustainable source of fuel for advanced reactors.

She may not need the conditional verb tense for long. Over the past year, the U.S. Department of Energy and a California-based nuclear reactor startup called Oklo have been jointly funding her experiments in a technique known as pyroprocessing in hopes of bringing fuel recycling to market. Last month, Oklo unveiled the proposal it submitted to the U.S. Nuclear Regulatory Commission to build the United States first commercial fuel recycling plant.

Theres enough energy content in used fuel in the U.S. alone to power the country for 150 years, and that number is going to grow, said Oklo chief executive Jacob DeWitte. Each year, we produce enough waste to power the country for four years. Its effectively an inexhaustible fuel. Were taking a huge burden and liability and turning it into complete decarbonization that can power the country for centuries.

Completing such a facility would be a milestone feat for the U.S. nuclear industry, which has not finished building a single new reactor ordered since the 1979 Three Mile Island accident, much less spawned a new sector. Sticking to the regulatory process that prevented any new nuclear from being built in decades, the U.S. Nuclear Regulatory Commission has been slow to approve any new next-generation fission technology. And the last time a company tried to build a nuclear fuel recycling plant, the White House at the time pulled the plug, fearing the facility might accelerate an apocalyptic arms race. Investors lost a fortune.

Yet many, like DeWitte, see the winds turning.