4 hours ago
The prospect of making trash useful is always fascinating to me. Whether it’s used batteries, solar panels, or spent nuclear fuel, getting use out of something destined for disposal sounds like a win all around.
In nuclear energy, figuring out what to do with waste has always been a challenge, since the material needs to be dealt with carefully. In a new story, I dug into the question of what advanced nuclear reactors will mean for spent fuel waste. New coolants, fuels, and logistics popping up in companies’ designs could require some adjustments.
My reporting also helped answer another question that was lingering in my brain: Why doesn’t the world recycle more nuclear waste?
There’s still a lot of usable uranium in spent nuclear fuel when it’s pulled out of reactors. Getting more use out of the spent fuel could cut down on both waste and the need to mine new material, but the process is costly, complicated, and not 100% effective.
France has the largest and most established reprocessing program in the world today. The La Hague plant in northern France has the capacity to reprocess about 1,700 tons of spent fuel each year.
The plant uses a process called PUREX—spent fuel is dissolved in acid and goes through chemical processing to pull out the uranium and plutonium, which are then separated. The plutonium is used to make mixed oxide (or MOX) fuel, which can be used in a mixture to fuel conventional nuclear reactors or alone as fuel in some specialized designs. And the uranium can go on to be re-enriched and used in standard low-enriched uranium fuel.
Reprocessing can cut down on the total volume of high-level nuclear waste that needs special handling, says Allison Macfarlane, director of the school of public policy and global affairs at the University of British Columbia and a former chair of the NRC.
But there’s a bit of a catch. Today, the gold standard for permanent nuclear waste storage is a geological repository, a deep underground storage facility. Heat, not volume, is often the key limiting factor for how much material can be socked away in those facilities, depending on the specific repository. And spent MOX fuel gives off much more heat than conventional spent fuel, Macfarlane says. So even if there’s a smaller volume, the material might take up as much, or even more, space in a repository.
It’s also tricky to make this a true loop: The uranium that’s produced from reprocessing is contaminated with isotopes that can be difficult to separate, Macfarlane says. Today, France essentially saves the uranium for possible future enrichment as a sort of strategic stockpile. (Historically, it’s also exported some to Russia for enrichment.) And while MOX fuel can be used in some reactors, once it is spent, it is technically challenging to reprocess. So today, the best case is that fuel could be used twice, not infinitely.
“Every responsible analyst understands that no matter what, no matter how good your recycling process is, you’re still going to need a geological repository in the end,” says Edwin Lyman, director of nuclear power safety at the Union of Concerned Scientists.
Reprocessing also has its downsides, Lyman adds. One risk comes from the plutonium made in the process, which can be used in nuclear weapons. France handles that risk with high security, and by quickly turning that plutonium into the MOX fuel product.
Reprocessing is also quite expensive, and uranium supply isn’t meaningfully limited. “There’s no economic benefit to reprocessing at this time,” says Paul Dickman, a former Department of Energy and NRC official.
France bears the higher cost that comes with reprocessing largely for political reasons, he says. The country doesn’t have uranium resources, importing its supply today. Reprocessing helps ensure its energy independence: “They’re willing to pay a national security premium.”
Japan is currently constructing a spent-fuel reprocessing facility, though delays have plagued the project, which started construction in 1993 and was originally supposed to start up by 1997. Now the facility is expected to open by 2027.
It’s possible that new technologies could make reprocessing more appealing, and agencies like the Department of Energy should do longer-term research on advanced separation technologies, Dickman says. Some companies working on advanced reactors say they plan to use alternative reprocessing methods in their fuel cycle.
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