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So What Do We Do With Nuclear Waste?

The world has made almost half a million tons of nuclear waste. There are only two paths, store it or recycle it, and both end in the same place.

Published · Watch on YouTube · 29 sources

The rabbit hole

The extra context that didn't fit in the Short. Little numbers link to the sources below.

Storage: the waiting rooms

Right now, most of the world’s nuclear waste is just waiting. About 41% of everything ever made sits in cooling pools, and another 31% sits in steel-and-concrete dry casks 1. The United States holds about a fifth of the world’s total, and recycles none of it 1.

Pools and casks are built for decades. A permanent home has a much harder job. The US rule for its planned site set strict limits for 10,000 years and looser ones out to a million 4. Those are limits on radiation dose, not a promise of “zero leakage,” so we say “lock it away.”

The one permanent home

Finland’s Onkalo is the first. On Oct 22, 2026, it became the first repository in the world to get an operating licence 6. It still has to be commissioned before the first waste goes in, and there’s no date for that yet 6.

How it works, in chips:

  • Deep: tunnels about 430 to 450 meters down 8.
  • Old rock: bedrock about 1.9 billion years old 8. Finland’s nuclear safety authority names earthquakes during future ice ages as the main long-term risk 5.
  • Layers: copper canisters, packed in clay, with a safety case covering 100,000 to 1,000,000 years 9.
  • Small: it’s sized for Finland’s own waste, about 6,500 tonnes, roughly 1.5% of the world’s pile 10.

France is building one too, called Cigéo, 500 meters down in clay, expected around 2040 to 2050 16.

The train test, in numbers

The 1984 crash wasn’t a stunt. A 140-ton locomotive hit a 50-ton shipping flask at 100 mph. Afterward, the flask had lost 0.29 psi of its 100 psi of internal pressure 11. That’s less than a third of one percent.

Recycling: what the “4%” really is

Recycling at France’s La Hague plant pulls out the uranium and plutonium so they can be made into new fuel 13. What’s left is the ash: mostly atoms that have already split, plus a tiny sliver (about 0.1%) of heavier elements that also go into the glass 14. Recycling shrinks the waste that needs a deep hole by 80% or more 15, but it doesn’t make it zero. That’s why even France, the recycling leader, is digging a hole.

Even the waiting rooms fill up: La Hague’s storage pools were projected to be nearly full around 2030 17.

Why 96% isn’t as good as it sounds

Most of the recovered 96% is a kind of uranium that today’s reactors barely burn. Recycling the plutonium stretches the original fuel only about 12%; recycling the uranium too gets you to about 22% 18. And in normal reactors, plutonium can only go around about once before the heavier versions of it build up, so used recycled fuel goes back into storage 18. Meanwhile, fresh uranium is cheaper 19.

Plutonium: both sides

Plutonium is fuel: over a third of a normal reactor’s power already comes from plutonium that forms inside the fuel as it runs 22. It’s also bomb material, and the IAEA treats almost all of it as weapons-usable, even though plutonium from old reactor fuel makes a poor bomb 23.

On China, here’s what the record shows, and only that:

  • China says its program is for fuel 25.
  • Experts point to its new fast reactors, which can produce weapon-grade plutonium as a byproduct 26.
  • China calls those reactors civilian; the Pentagon reported that China described one as a “national defense investment project” 26.

We don’t claim to know China’s intent.

Sources

Every claim in the Short and in this write-up, numbered, with where it comes from. Spot a mistake? Email hello@rigorousrabbitholes.com and we'll fix it in public.

Source being added marks a claim we're still attaching a source to.

  1. The world has made almost half a million tons of spent nuclear fuel (about 448,000 tonnes); about 72% is in storage and 28% has been recycled.ANS Nuclear Newswire: IAEA releases interactive tool on global spent nuclear fuel (June 2026)447,758 tonnes, so "almost half a million" rather than "half a million". Of the stored share, about 41% of the world's total is in pools and 31% in dry casks. The US holds 21% of the world total and recycles none of it.
  2. The same IAEA figures, second write-up.Interesting Engineering: IAEA tool reveals global nuclear waste
  3. Fresh out of the reactor, spent fuel cools in a pool of water; after a few years it moves into steel and concrete casks. Source being addedStandard industry practice, not yet tied to a specific source in our fact-check sheet.
  4. A permanent repository has to lock the waste away for at least 10,000 years. Source being addedThe US EPA rule for the planned Yucca Mountain site (strict limits for 10,000 years, looser ones out to 1,000,000 years)These are radiation dose limits, not a promise of literally zero leakage. That's why the Short says "lock it away". The specific EPA document still needs to be linked.
  5. It has to survive even earthquakes during the next ice age.ScienceAlert, quoting an expert at STUK (Finland's nuclear safety authority); World Nuclear News (2016) on Finnish and Swedish safety cases (link to come)STUK names earthquakes during future ice ages as the main long-term risk. The Finnish and Swedish safety assessments assume future ice sheets over Scandinavia.
  6. So far the world has exactly one permanent repository; Finland got the green light to operate it in October 2026.World Nuclear News; Al Jazeera (both Oct 23, 2026) (link to come)The Finnish government granted Onkalo's operating licence on Oct 22, 2026, the world's first. The safety assessment had passed in August. First disposal still waits on commissioning, with no date set.
  7. Onkalo passed its safety assessment in August 2026.ANS Nuclear Newswire: Onkalo SNF repository passes safety assessment
  8. Its tunnels are more than 400 meters down, in rock almost two billion years old.WTOP / Associated Press: Finland's plan to bury spent nuclear waste (April 2026)Bedrock about 1.9 billion years old. Depth about 430 to 450 meters (World Nuclear News).
  9. The waste goes into copper canisters packed in clay, and once sealed it needs nobody to watch it. Source being addedOur research log, from the Onkalo coverage above; the exact document still needs to be attached.The safety case covers 100,000 to 1,000,000 years.
  10. It's built for Finland's waste alone, about one and a half percent of what the world has made.Our math: capacity 6,500 tonnes (World Nuclear News; Al Jazeera) ÷ 448,000 tonnes (source 1) ≈ 1.5%. (link to come)
  11. In 1984, Britain rammed a train into a nuclear fuel container at 100 mph; the train was wrecked, the container held.ANS Nuclear Newswire: A look back at the 1984 UK spent fuel flask testA 140-ton locomotive hit a 50-ton shipping flask. The flask lost 0.29 psi of its 100 psi internal pressure. It was a shipping flask, not a storage site, which is why the Short says "even getting it there".
  12. The US has no permanent home for its waste, so the government pays power companies for breaking its promise to take it, more than $11 billion so far. Source being addedOur research log; the specific government document still needs to be attached.$11.1 billion paid through fiscal year 2024, with about $37.6 billion more expected. The US holds about 95,000 tonnes at more than 70 sites.
  13. The world's biggest recycling plant is in France; it chops up old fuel, dissolves it in acid and pulls out about 96% of it, the uranium and plutonium. Source being addedWikipedia: La Hague siteLa Hague: about 1,700 tonnes a year of capacity, 40,000+ tonnes processed. The plutonium is made into new "MOX" fuel. Still to confirm: that this page carries the 96% / 4% split and the "biggest" claim.
  14. The other 4% is the ash, atoms that already split; it's melted into glass and still has to go underground. Source being addedOur research log; the specific document still needs to be attached.The 4% is mostly fission products, plus a sliver (about 0.1%) of heavier elements called minor actinides, which also go into the glass.
  15. Recycling shrinks the high-level waste that needs disposal by 80% or more.OECD (Nuclear Energy Agency), as noted in our research log (link to come)
  16. France is building its own deep repository, Cigéo, 500 meters down in clay.ANS Nuclear Newswire: France's Cigéo repository receives satisfactory safety review (Dec 2025)Expected to start around 2040 to 2050.
  17. France's storage pools at La Hague were projected to be nearly full around 2030.AFP via Connaissance des Énergies (2021)
  18. Most of the recovered 96% is uranium today's reactors barely burn, so one round of recycling stretches the fuel only about a fifth further, at most.World Nuclear Association (link to come)About 12% from recycling the plutonium alone, about 22% if the uranium is recycled too. In normal reactors, plutonium can only be recycled about once.
  19. Fresh uranium is cheaper than recycled fuel.Cameco (link to come)Cameco describes recycled fuel's cost as "markedly higher".
  20. Japan started building its recycling plant in 1993; it was due in 1997, has been delayed 27 times and still isn't finished.CNIC News Watch: Rokkasho 28th postponement (Aug 2026)A 28th delay was expected but not yet official when the Short was made.
  21. Its glass melter kept failing, and after Fukushima, tougher safety rules (Dec 2013) brought a long review.Adnkronos: Japan faces tough road ahead over nuclear fuel reprocessing plant (May 2026)There were also leaks and worker exposures during 2006 testing. GlobalSecurity puts the lifetime cost estimate at about $125 billion.
  22. About a third of a normal reactor's power already comes from plutonium formed inside the fuel.World Nuclear Association, as noted in our research log (link to come)"Over a third" in most reactors.
  23. Plutonium is also bomb material; the world's nuclear watchdog treats almost all of it as usable in weapons, even though plutonium from old reactor fuel is a poor bomb ingredient.IAEA policy, as described by the World Nuclear Association (link to come)
  24. China quietly switched on its first recycling plant; a second is ready and a third is being built.IPFM (International Panel on Fissile Materials): China has started operating its demonstration reprocessing plant (May 2026)The first plant, in Gansu, handles about 200 tonnes a year and began running around 2025 without an official announcement.
  25. China says its program is for fuel. Source being addedChinese government statements, as reported in our research log; the specific source still needs to be attached.Civilian fuel for fast reactors and carbon goals.
  26. China is also building fast reactors that experts say could make weapon-grade plutonium.Institute for Science and International Security (October 2025) (link to come)The concern is the CFR-600 fast reactors, whose uranium "blankets" can produce weapon-grade plutonium as a byproduct. China calls them civilian; the Pentagon reported China described one as a "national defense investment project".
  27. China's warhead count is still growing.SIPRI (January 2026 data) (link to come)About 620 warheads, up 20 in a year.
  28. China hasn't publicly reported its plutonium since 2018.Hiroshima Report 2024 (link to come)China last reported its civilian plutonium to the IAEA in 2018.
  29. A 2025 executive order made recycling official US policy.Executive Order 14302, signed May 23, 2025 (link to come)Also see: POWER magazine, "Nuclear recycling has reached a prime moment" (April 2026), https://www.powermag.com/nuclear-recycling-has-reached-a-prime-moment-and-the-u-s-may-be-running-out-of-time/