Daily Dose / Sep 4, 2026 / Nuclear Waste

One Hole
in the Ground

Humanity has been making spent nuclear fuel for seventy years and has never once finished a place to put it. Every gram ever produced is still above ground, in a pool or a cask, waiting. This year, in Finland, that finally changes — once.

448,000tonnes of heavy metal, discharged

Spent fuel taken out of the world's power reactors, cumulative. About 322,000 t of it is still in storage where it was made; the rest was reprocessed. IAEA Global Spent Nuclear Fuel Inventory, 2nd ed., reported June 2026.

01 — The inventory

Everything ever burned is still here

Spent fuel does not go away when a reactor is done with it. It goes into a pool of water beside the reactor for years, then into a steel-and-concrete cask on a pad outside. Both are storage. Neither is disposal.

Shares from the IAEA's 2025 reporting cycle; tonnages are the shares applied to the 448,000 tHM total.

+7,000

tonnes added to storage / year

The global inventory in storage grows by roughly this much annually. IAEA Nuclear Technology Review, 2025.

86,584

tonnes in the U.S. alone (2020)

Held at reactor sites in 33 states, growing about 2,200 t a year since 2012. NWTRB, 2022.

repository for it, worldwide

Onkalo, Finland — cleared by the regulator in August 2026 and aiming for operational readiness by year-end.

02 — The clock

A spectrum of half-lives

"Nuclear waste" is not one substance with one deadline. It is a mixture of isotopes whose half-lives span nine orders of magnitude — from a caesium that is mostly gone in a human lifetime to an iodine that outlives the question.

Half-lives as listed by the U.S. Nuclear Waste Technical Review Board, 2022.

10,000×

less radioactive at 10,000 years

Compared with one month after leaving the reactor. The danger falls fast — then trails for a very long time. NWTRB, 2022.

23 bn

curies in the U.S. inventory (2012)

The total activity of the 70,100 t held at the time. Carter et al., 2013, via NWTRB.

100 k – 1 M

years of safety case, Finland

Finland's regulator assessed Onkalo's long-term safety over at least 100,000 years, and as long as 1 million. STUK, 2026.

03 — The pile grows

A curve with no exit

The United States has the world's largest civilian stockpile and no site to send it to. The line below has never bent, because nothing has ever been removed from it.

Reported points: 1968 start of commercial discharges and ~80,000 t cumulative through 2017 (EIA, 2021); 70,100 t in 2012 and 86,584 t at end-2020 (NWTRB, 2022). The 2026 figure is a projection, not a measurement — 86,584 t carried forward at the NWTRB's stated growth rate of ~2,200 t/yr.

04 — The bill

What indecision costs

American utilities paid into a federal fund on the promise that the government would take their fuel starting in 1998. It never did. Courts have been settling the difference ever since — out of the Judgment Fund, which is to say, out of general taxes.

The dashed outline marks the top of the liability range. Ratepayers were charged one tenth of a cent per nuclear kilowatt-hour under the Nuclear Waste Policy Act of 1982; the fund still holds the money.

05 — The map

Where the holes are

Thirty-odd countries run power reactors. Four have chosen a site in bedrock and got a government or regulator to sign off on it. All four are in Europe, and all four sit on old, dry, stable rock.

United States — two holes, neither for this

WIPP, New Mexico. The only operating deep geological repository on Earth: 655 m down in a 250-million-year-old salt bed, taking defense transuranic waste since 1999. It is not licensed for commercial spent fuel.

Yucca Mountain, Nevada. About $15 billion and thirty years of work. The licence application was withdrawn and the program terminated in 2010. Nothing has replaced it.

Why these rocks

Onkalo is cut into gneiss that is 1.9 billion years old — rock that has already survived several ice ages and continents rearranging themselves. Sweden's Forsmark uses the same crystalline shield at about 500 m; France's Cigéo uses a clay layer; Switzerland picked Opalinus clay north of Zurich.

Sources: Posiva and STUK, 2026; Swedish government decision, January 2022; Andra licence application, January 2023; Nagra site announcement, September 2022; U.S. DOE (WIPP); GAO, 2011.

06 — The engineering

Four hundred metres down, in copper

Finland's method is deliberately dumb, in the best sense: no moving parts, no monitoring, no maintenance. Twelve fuel assemblies go into a cast-iron insert, the insert goes into a copper capsule, the capsule goes into a hole packed with bentonite clay, and the clay swells shut when it meets groundwater.

6,500

tonnes of uranium — Onkalo's capacity

Enough for all the spent fuel Finland's reactors are expected to make. The repository fills for roughly a century, then is backfilled and sealed. Posiva.

€1 bn + €4 bn

to build; to operate and close

Construction licence granted November 2015; test disposal runs began 2024; the regulator cleared it for an operating licence in August 2026.

1.9 bn

years — the age of the host rock

The engineered barriers are copper, iron and clay. The final barrier is simply time-tested Finnish bedrock, chosen because it has done nothing interesting in two billion years.

Why it matters

The waste is not the hard part. The decision is.

The physics is finished. Deep geology, copper, clay: the barrier concept has been studied for fifty years and cleared by an independent regulator over a 100,000-year horizon. What stalled everywhere else was consent, not chemistry.
Storage is not a plan, it is a postponement — and a costly one. The U.S. is paying roughly $9 billion already spent plus a projected $37.6–44.5 billion to keep fuel sitting exactly where it was made.
Ask what your grid's waste plan actually is. If your country runs reactors — or is about to build more — the honest question is not whether nuclear waste can be disposed of, but whether anyone has picked the hole, and who was asked.
Finland's real innovation was procedural. The host municipality, Eurajoki, had a veto and chose to say yes, after decades of local involvement. That is the part other countries have not managed to copy.