When people think of nuclear power, one word often comes to mind: waste. The image of barrels of radioactive material sitting in storage for tens of thousands of years is hard to shake. But what if that waste wasn’t waste at all? What if it could be reused turned into new fuel to power cities, reduce emissions, and even cut down on the long-term risks that have made nuclear power so controversial?
Across the world, scientists and engineers are doing just that. In countries like France, Japan, and even parts of the U.S., used nuclear fuel is being recycled into something useful again. Technologies like fast reactors and MOX (Mixed Oxide) fuel are taking what was once considered a dead-end and transforming it into part of the energy solution. Rather than digging up more uranium or building more waste storage, some believe the smarter path is to reuse what we already have.
So why are we still throwing it away?
Used nuclear fuel still contains about 95% of its energy potential mostly in the form of uranium and plutonium. Only a small fraction is highly radioactive waste that must be isolated long term. In Japan, a country with no domestic uranium and limited land, this is a crucial point. As of 2023, Japan had generated roughly 25,000 tons of high-level nuclear waste. But much of that still holds usable material.
MYTH: Spent nuclear fuel is useless.
FACT: It still contains about 95% of its energy potential.
So why throw it away? Mostly because traditional reactors can’t extract all that energy. That’s where recycling comes in.
Think of it like making coffee and using only half the grounds before tossing them. Recycling spent fuel means extracting the good stuff uranium and plutonium and turning it into new fuel. This is often done through reprocessing to create MOX (Mixed Oxide) fuel, which can be used again in specially designed reactors.
Japan has long pursued a “closed fuel cycle,” aiming to reuse its nuclear material multiple times. The core of this system is reprocessing. Facilities like the Tokai Reprocessing Plant and the much larger Rokkasho Reprocessing Plant are built to recover useful materials from spent fuel. Though still under development, Rokkasho has already cost over ¥2.9 trillion (about $20 billion USD), reflecting Japan’s commitment to this path.
France leads the world in nuclear fuel recycling. At the La Hague facility, about 1,700 tons of spent fuel are processed each year. The extracted materials are turned into MOX fuel and reused in nuclear power plants, supplying about 10% of France’s nuclear electricity.
Japan has partnered with France on reprocessing while working to complete its own Rokkasho facility, expected to handle 800 tons annually. MOX fuel has already been used in reactors like Takahama and Genkai, and more are expected to adopt it as reactor restarts continue.
Recycling spent fuel has major advantages. First, it reduces waste volume. Japan’s Atomic Energy Commission estimates that reprocessing can cut the amount of high-level waste by roughly 75%. It also reduces the toxicity period from around 100,000 years to about 8,000 years when paired with advanced reactors.
Second, it makes better use of materials. Japan, which imports all its uranium, can stretch its resources further. Reusing fuel also enhances energy security and reduces pressure to find new long-term storage sites a major issue in Japan, where no final geological repository has been approved despite decades of discussion.
Third, it can help contain costs in the long run. While the upfront investment is high, reusing uranium reduces reliance on volatile global markets. For context, Japan’s uranium imports have exceeded 9,000 tons annually in some years, and reprocessing could help offset this demand.
Finally, it helps change the public narrative. Nuclear doesn’t have to mean endless waste. With the right systems in place, it can become part of a circular economy. A smart, transparent recycling strategy could help rebuild public trust, especially if communities are engaged in the process and feel they are part of the solution.
Fuel recycling isn’t cheap. The Rokkasho project has faced more than 20 delays over three decades, becoming a symbol of both ambition and frustration. Critics point to high costs, proliferation concerns, and technical complexity. Public trust, already shaken by the Fukushima accident, remains fragile.
Still, Japan continues to invest. Newer technologies like fast reactors and molten salt reactors may one day make the process cheaper, safer, and more efficient. International partnerships, such as Japan’s involvement in the U.S. Advanced Reactor Demonstration Program (ARDP), offer hope for breakthroughs.
Meanwhile, in the United States, spent fuel is still mostly treated as waste, stored at reactor sites, and awaiting long-term disposal. But as advanced reactor designs gain traction especially those that can use recycled or high-assay low-enriched uranium (HALEU) there is renewed interest in reprocessing, even in countries that have long avoided it.
And globally, the comparison is shifting. The once-through fuel cycle leaves behind large volumes of waste and misses out on remaining energy. A closed cycle, while complex, recovers value and shrinks the long-term waste footprint.
For Japan and many other countries, recycling spent nuclear fuel is not just about reducing waste. It’s about building a smarter, more secure energy future. With global energy demand rising and pressure to decarbonize intensifying, the ability to extract more value from existing fuel could prove critical.
Japan’s 6th Strategic Energy Plan already identifies nuclear as a key low-carbon source, aiming for 20–22% of the electricity mix by 2030. Recycling will be essential if that vision is to be achieved sustainably.
Young researchers and startups in Japan such as Kyoto Fusioneering and Clean Planet are also reimagining how nuclear systems can be designed with sustainability, modularity, and public trust in mind. Their innovations could help drive the next era of clean, circular nuclear energy.
Maybe it’s time to stop calling it waste at all. Maybe, in the nuclear age, the smartest thing we can do is close the loop and turn yesterday’s fuel into tomorrow’s power.