Spent fuel and nuclear waste

Waste is the issue where nuclear supporters and opponents talk past each other most. Supporters say the volume is tiny and the storage record is clean. Opponents say some of it stays dangerous for longer than human civilization has existed and the country has no permanent place to put it. Both statements are accurate. The practical questions are usually who holds the waste, under what agreement, and for how long.

What spent fuel is

A fuel assembly spends about four to six years in a reactor. By then enough U-235 has been used up, and enough neutron-absorbing fission products have built up, that it no longer runs efficiently. It comes out as spent fuel: still mostly uranium, with about 1 percent plutonium and a few percent fission products. DOE notes more than 90 percent of its potential energy remains. It is intensely radioactive and hot.

The danger falls steeply with time. Most radioactivity is from short-lived fission products, which fade over decades. After a few hundred years, the remaining hazard comes mainly from plutonium and other heavy elements that last tens of thousands of years. That long tail is why disposal plans talk about isolation for 10,000 years or more.

How much there is

DOE says U.S. commercial reactors have generated about 90,000 metric tons of spent fuel since the 1950s, adding roughly 2,000 metric tons a year. Stacked together, it would fill a football field to a depth of less than 10 yards. It sits at more than 70 sites in 35 states, mostly at the plants that made it, including plants that have shut down and been torn down except for their cask pads.

Pools, then casks

Fresh spent fuel goes into a pool next to the reactor, under about 20 feet of water that cools it and blocks radiation. Pools are built with backup cooling and with neutron-absorbing racks so the fuel cannot restart a chain reaction. After several years, decay heat drops enough for air cooling.

Then the fuel can go into a dry cask: a welded or bolted steel canister filled with inert gas, inside a thick concrete or steel overpack. Air flows around it by natural convection. No pumps, no power. The NRC says 63 independent spent fuel storage installations (ISFSIs) are licensed and that dry casks have been used for more than 30 years "with an excellent safety record." Casks must withstand design-basis earthquakes, tornadoes and floods.

Yucca Mountain

The Nuclear Waste Policy Act of 1982 made the federal government responsible for permanently disposing of commercial spent fuel in a deep geologic repository, paid for by a fee on nuclear electricity. Utilities paid in. The government promised to start taking fuel by 1998.

Year	What happened
1982	Nuclear Waste Policy Act sets up a national repository program
1987	Amendments direct DOE to study only Yucca Mountain, Nevada
2002	Congress overrides Nevada's objection; President Bush signs approval of the site
2008	DOE submits its license application to the NRC
2010	DOE moves to withdraw the application
2011	Congress stops funding the project
2013	Federal appeals court orders the NRC to keep reviewing with available funds
2015 and 2016	NRC staff finish the safety evaluation report and an environmental supplement
Today	The NRC's licensing hearing remains suspended; no decision

The case for Yucca: decades of study and billions spent, a remote desert site, and an NRC staff safety evaluation that found DOE's application met key requirements. The case against: Nevada never consented and has fought it for 40 years, opponents cite earthquake faults and groundwater pathways, and transporting waste across many states raised its own opposition. Because the government missed its 1998 deadline, utilities sued and won. Taxpayers now pay damages from the federal Judgment Fund for storage the government was supposed to handle, a cost that keeps growing. Since about 2021, DOE has pursued a "consent-based" approach to finding storage sites, and in May 2025 Executive Order 14302 called for a new national spent fuel policy recommendation within 240 days that considers recycling and reprocessing.

Consolidated interim storage and NRC v. Texas

With no repository, the fallback idea is a private site that gathers casks from many plants and holds them for decades. The NRC licensed two: Interim Storage Partners in Andrews County, Texas, in 2021, and Holtec's HI-STORE in Lea County, New Mexico, in 2023. Both states objected and passed laws against storing the fuel without their consent. The Fifth Circuit vacated both licenses, ruling the NRC lacked authority to license that kind of away-from-reactor storage. In June 2025 the Supreme Court reversed in Nuclear Regulatory Commission v. Texas, 6 to 3. It held that Texas and an oil and gas landowner could not bring the challenge because they had not been parties to the licensing proceeding, and it did not decide whether the NRC has the authority. The licenses came back, but the politics did not change. Holtec cancelled the New Mexico project in October 2025, citing the state's opposition, and the Texas site had not been built as of October 2026. Supporters of interim storage say it would let the government start meeting its contracts and clear fuel from closed plants. Opponents, including both states' governments, say "interim" could become permanent and that it shifts the burden onto communities that never agreed to it.

Idaho's 1995 settlement agreement

Idaho's waste situation is different from any other state's. INL holds spent fuel from Navy ships, from DOE research reactors and from the damaged Three Mile Island Unit 2 core, plus liquid and buried waste from Cold War reprocessing. In the late 1980s and early 1990s Governor Cecil Andrus blocked waste shipments into the state. In 1995, under Governor Phil Batt, Idaho, DOE and the Navy signed a settlement agreement, later enforced by a federal court consent order. DOE describes Batt's principles: Idaho must not become a de facto repository, DOE must deal with the waste already there, and INL must stay a working national lab.

Key terms, from DOE and INL summaries:

• 2035: all spent nuclear fuel must be removed from Idaho.
• 2023: spent fuel to be moved from wet pools to dry storage.
• Caps on incoming fuel, including a 55 metric ton limit on spent fuel entering the site from 1995 to 2035 (INL's figure) and an annual shipment cap; commercial power plant fuel was largely barred, with later waivers for research quantities.
• Transuranic waste: a target of removing about 65,000 cubic meters by 2018, later litigated and modified by a 2008 agreement.
• Enforcement: if DOE misses a deadline, Idaho can suspend shipments into the state.

That last clause has teeth. DOE missed a 2012 deadline to treat 900,000 gallons of liquid sodium-bearing waste, and in 2014 Idaho refused DOE's request to bring in research quantities of commercial spent fuel. Shipments were blocked until a 2019 supplemental agreement, which allowed 25 research fuel rods once DOE treated at least one full canister of that waste and committed to other cleanup steps, including that Idaho receive at least 55 percent of shipments to the Waste Isolation Pilot Plant in New Mexico. INL says it received the 25 rods in 2023, and in 2025 Idaho signed a waiver allowing a high-burnup fuel cask and limited university reactor fuel. Idaho's position, as state officials have put it, is that research is welcome but the state will not become the default repository. Whether DOE can meet 2035 with no national repository is the open question.

Reprocessing

Reprocessing dissolves spent fuel and chemically separates uranium and plutonium so they can be made into new fuel. France does this at La Hague; the U.S. does not commercially. President Ford halted commercial reprocessing in 1976, and President Carter extended the halt in 1977 over proliferation fears. Reagan lifted the ban in 1981, but no company found it economic. Several advanced reactor companies, including Oklo, now propose recycling.

Arguments for reprocessing	Arguments against
Recovers energy from the 90%+ of potential energy still in spent fuel	The standard PUREX process separates pure plutonium, which could be diverted to weapons
Reduces volume and long-term heat of waste going to a repository	Has historically cost more than fresh uranium; France's program is state backed
Fast reactors could burn the long-lived heavy elements, shortening the hazard period	Creates liquid high-level waste and new waste streams; Idaho and Hanford's Cold War reprocessing waste is still being cleaned up
Newer methods like pyroprocessing (tested at INL on EBR-II fuel) keep plutonium mixed with other elements	Still needs a repository for what remains

Groups like the Union of Concerned Scientists have opposed reprocessing on proliferation and cost grounds. Industry groups and many advanced reactor developers support it as the way to close the fuel cycle. The 2025 executive orders lean toward recycling, but no commercial U.S. reprocessing plant was licensed as of October 2026.