How Dangerous Nuclear Waste Is Stored in the U.S.
The decades-long struggle to find a permanent place to dispose of nuclear waste in the U.S. will continue, probably for many years to come
Storage site for high level radioactive waste at the Hanford Reservation. The site once produced plutonium for nuclear weapons.
Karen Kasmauski/Getty Images
The following essay is reprinted with permission from 
The Conversation, an online publication covering the latest research.
Around the U.S., about 90,000 tons of nuclear waste is stored at over 100 sites in 39 states, in a range of different structures and containers.
For decades, the nation has been trying to send it all to one secure location.
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A 1987 federal law named Yucca Mountain, in Nevada, as a permanent disposal site for nuclear waste – but political and legal challenges led to construction delays. Work on the site had barely started before Congress ended the project’s funding altogether in 2011.
The 94 nuclear reactors currently operating at 54 power plants continue to generate more radioactive waste. Public and commercial interest in nuclear power is rising because of concerns regarding emissions from fossil fuel power plants and the possibility of new applications for smaller-scale nuclear plants to power data centers and manufacturing. This renewed interest gives new urgency to the effort to find a place to put the waste.
In March 2025, the U.S. Supreme Court heard arguments related to the effort to find a temporary storage location for the nation’s nuclear waste – a ruling is expected by late June. No matter the outcome, the decades-long struggle to find a permanent place to dispose of nuclear waste will probably continue for many years to come.
I am a scholar who specializes in corrosion; one focus of my work has been containing nuclear waste during temporary storage and permanent disposal. There are generally two forms of significantly radioactive waste in the U.S.: waste from making nuclear weapons during the Cold War, and waste from generating electricity at nuclear power plants. There are also small amounts of other radioactive waste, such as that associated with medical treatments.
Waste from weapons manufacturing
Remnants of the chemical processing of radioactive material needed to manufacture nuclear weapons, often called “defense waste,” will eventually be melted along with glass, with the resulting material poured into stainless steel containers. These canisters are 10 feet tall and 2 feet in diameter, weighing approximately 5,000 pounds when filled.
For now, though, most of it is stored in underground steel tanks, primarily at Hanford, Washington, and Savannah River, South Carolina, key sites in U.S. nuclear weapons development. At Savannah River, some of the waste has already been processed with glass, but much of it remains untreated.
At both of those locations, some of the radioactive waste has already leaked into the soilbeneath the tanks, though officials have said there is no danger to human health. Most of the current efforts to contain the waste focus on protecting the tanks from corrosion and cracking to prevent further leakage.
Waste from electricity generation
The vast majority of nuclear waste in the U.S. is spent nuclear fuel from commercial nuclear power plants.
Before it is used, nuclear fuel exists as uranium oxide pellets that are sealed within zirconium tubes, which are themselves bundled together. These bundles of fuel rods are about 12 to 16 feet long and about 5 to 8 inches in diameter. In a nuclear reactor, the fission reactions fueled by the uranium in those rods emit heat that is used to create hot water or steam to drive turbines and generate electricity.
After about three to five years, the fission reactions in a given bundle of fuel slow down significantly, even though the material remains highly radioactive. The spent fuel bundles are removed from the reactor and moved elsewhere on the power plant’s property, where they are placed into a massive pool of water to cool them down.
After about five years, the fuel bundles are removed, dried and sealed in welded stainless steel canisters. These canisters are still radioactive and thermally hot, so they are stored outdoors in concrete vaults that sit on concrete pads, also on the power plant’s property. These vaults have vents to ensure air flows past the canisters to continue cooling them.
As of December 2024, there were over 315,000 bundles of spent nuclear fuel rods in the U.S., and over 3,800 dry storage casks in concrete vaults above ground, located at current and former power plants across the country.
Even reactors that have been decommissioned and demolished still have concrete vaults storing radioactive waste, which must be secured and maintained by the power company that owned the nuclear plant.
Salt spray from the ocean can corrode waste containers at nearby nuclear waste storage sites, like this one at the San Onofre Nuclear Generating Station in California.
Allen J. Schaben/Los Angeles Times via Getty Images
The threat of water
One threat to these storage methods is corrosion.
Because they need water to both transfer nuclear energy into electricity and to cool the reactor, nuclear power plants are always located alongside sources of water.
In the U.S., nine are within two miles of the ocean, which poses a particular threat to the waste containers. As waves break on the coastline, saltwater is sprayed into the air as particles. When those salt and water particles settle on metal surfaces, they can cause corrosion, which is why it’s common to see heavily corroded structures near the ocean.
At nuclear waste storage locations near the ocean, that salt spray can settle on the steel canisters. Generally, stainless steel is resistant to corrosion, which you can see in the shiny pots and pans in many Americans’ kitchens. But in certain circumstances, localized pits and cracks can form on stainless steel surfaces.
In recent years, the U.S. Department of Energy has funded research, including my own, into the potential dangers of this type of corrosion. The general findings are that stainless steel canisters could pit or crack when stored near a seashore. But a radioactive leak would require not only corrosion of the container but also of the zirconium rods and of the fuel inside them. So it is unlikely that this type of corrosion would result in the release of radioactivity.
A long way off
A more permanent solution is likely years, or decades, away.
Not only must a long-term site be geologically suitable to store nuclear waste for thousands of years, but it must also be politically palatable to the American people. In addition, there will be many challenges associated with transporting the waste, in its containers, by road or rail, from reactors across the country to wherever that permanent site ultimately is.
Perhaps there will be a temporary site whose location passes muster with the Supreme Court. But in the meantime, the waste will stay where it is.
This article was originally published on The Conversation. Read the original article.
