In the early years of nuclear energy, uranium was thought to be scarce, and the industry was afraid it would run out. (This was very wrong, but no more so than similar predictions about oil or gas or coal.)
The reactor designers knew that after months in a reactor, the fuel would need replacing because the reactor had fissioned most of the easy-to-split atoms, but it still had a lot of useable uranium in it—plus plutonium, an element created when one type of uranium captured a stray neutron let loose by an atom that split. If the plutonium and other usable materials could be harvested, they could yield a lot more energy.
And so, engineers came up with a plan. The idea, briefly put into practice, was to let the used fuel cool for a while and then take it to a factory where it would be mechanically chopped up and dissolved in acid. The reusable elements could be chemically separated from the waste—fragments from uranium that had been split and various other ingredients—and fashioned into new fuel. The waste would still have to be buried somewhere, but the volume would be smaller, and some of the transuranics, whose radioactivity lasted the longest, would go into new fuel.
But this “reprocessing” ran into two problems. One was economics; as often happens in mining and drilling, plenty of raw material was soon found. Using virgin uranium turned out to be much cheaper than scavenging unused uranium and plutonium from spent fuel.
The other was fear; if the United States was able to reprocess spent fuel, it might set a bad example for countries around the world that wanted nuclear weapons and thought they could pull off something similar. From a technical standpoint, many nuclear experts doubted the likelihood of such plans, because many of the plutonium atoms in spent fuel pick up more than one neutron and become a mix of plutonium types that is not good bomb fuel. (It is generally referred to as “civil grade” plutonium, not “weapons grade.”) And at any rate, the invention and continuous improvement of centrifuges for uranium enrichment in the years since have created a path to a uranium bomb that is simpler and cheaper than using spent reactor fuel.
Nonetheless, President Gerald Ford and then President Jimmy Carter banned the technology in the United States. This had the effect of increasing the quantity and longevity of used fuel that would require burial.
But where to bury spent nuclear fuel?
In the 1960s, the Atomic Energy Commission set about looking for a burial site, and its successor agency, the Department of Energy, continued the search.
Then, in 1982, Congress passed the Nuclear Waste Policy Act, which instructed the DOE to study five particular sites, recommend three to the president by 1985, and build a repository and open it by January 1998, at which point the Energy Department would have to start picking up spent fuel for burial. A state could block the selection, but Congress could override that block, according to the legislation. To pay for the facility, Congress told the DOE to collect a fee from the nuclear utilities, which was later set at a tenth of a cent per kilowatt-hour produced at reactors. Some members of Congress, notably from Texas and Washington State, sought to make political points by taking their states or districts off the target list. And so, in 1987, Congress amended the law, to tell the DOE to concentrate on Yucca Mountain, a volcanic structure about 100 miles from Las Vegas. That change drew support from all the other candidate sites, and Nevada, politically isolated, wasn’t able to stop the process.
In February 2002, U.S. Secretary of Energy Spencer Abraham recommended Nevada to President George Bush, Nevada objected, and Congress overruled.
Burial at Yucca remains the law of the land, and the Nuclear Waste Trust Fund, including interest earned, has a balance of over $43 billion from the nuclear utilities. But there has been no progress on building the repository because, over the years, Nevada gained political muscle. In turn, the utilities and an organization representing state public service commissions sued the Federal government, and a judge ruled in 2013 that they no longer had to pay the tenth-of-a-cent fee.
The utilities also sued the government because it did not, in fact, start picking up the fuel for burial in 1998. It still hasn’t.
The courts ruled that the government violated the contracts it signed and would have to pay for the cost to build dry casks, where much of the spent fuel is now stored, and other expenses. The government has so far paid out more than $8.6 billion, but not from the waste trust fund that was created with the money it got by collecting rents from the nuclear utilities. Instead, the money comes from a standing account at the Treasury called the Judgment Fund, the same fund used to pay simpler damages, like re-imbursing a driver whose car was rear-ended by a government vehicle.
What went so wrong with Yucca?
As part of its work in the 1980s and 1990s, the Energy Department conducted substantial research on Yucca Mountain, and, following the law, applied in 2008 to the Nuclear Regulatory Commission for a license to build and operate it. Like a lot of DOE projects, this one was way behind schedule, but the scientific and engineering evaluations of Yucca indicated that the combination of the containers and the geology of the site could contain the wastes until they were no longer radioactive enough to cause a problem.
Two developments torpedoed the Yucca project.
One was that then-Senator Barack Obama, fighting hard for Nevada’s electoral votes, promised to stop the project. He cut funding soon after he came into office. Second, Harry Reid, a Senator from Nevada, became the Democratic leader in 2005 and the majority leader in 2007, and he bottled up funding for the project and managed to install an opponent of Yucca, and an opponent of nuclear power generally, as chairman of the Nuclear Regulatory Commission.
At one point, President Donald Trump then promised to restart Yucca, but he apparently changed his mind. President Biden has not revived the project.
Before Congress stopped funding the licensing process, the Nuclear Regulatory Commission, began its evaluation of the suitability of Yucca, and the commission staff found that the site appeared to be suitable. But the loss of funding blocked the NRC’s next step, an adjudicatory hearing where the staff, the applicant (the DOE), opponents, and other interest parties get to make arguments about its technical merits.
So the spent fuel sits in deep pools of water, safe from earthquakes and other natural hazards, with redundant cooling systems, inside the security perimeter of the nuclear plants where it was used. In most plants, much of the fuel has been moved out of the pools, and sealed up in steel canisters, filled with inert gas to prevent rust, and fitted into small concrete silos. These “dry casks” dissipate heat passively; they do not need pumps, fans, or other mechanical equipment. But in some cases, the dry casks are orphaned because the reactor at the site was decommissioned years ago.
At the sites, maintenance workers check that no animals have built nests in the vent holes at the bottom of the concrete silos, because this might reduce the airflow around the steel canisters. But there is hardly any other maintenance requirement. The casks are inspected regularly. Over the years, they have already survived floods and earthquakes.
Radiation outside the silos is very low; workers approach in street clothes. The concrete is warm to the touch. The fact that snow won’t stick to them is a clue to what’s inside. They are quite boring.
But centralized storage, and eventual burial, would be more economical.
The problem with burial is that opponents of nuclear energy have so thoroughly seized on the waste issue that it will be hard for any administration to make progress. It isn’t even clear that spent fuel is the concern of opponents. Rather, it is just a convenient way to build public resistance to nuclear energy. Opponents have argued that the dry casks can’t be safely shipped, for example, although there is a long history, in the United States and abroad, of safe transport of spent fuel.
It is also not clear that spent fuel is even waste. The Nuclear Energy Policy Act requires that the material be retrievable, so that if the economics change, it is available for re-use. In fact, the coming commercialization of “fast reactors” makes it somewhat more likely that there will be economic value to materials in the spent fuel. Fast reactors might also make it practical to put the longest-lived materials right back into a reactor and destroy them. They would be broken up and thus converted into elements that were more radioactive, but that would make disposal easier because they would burn out sooner; essentially, they would be converted from a log to a pile of crumpled newspaper.
Who has incentives to solve the nuclear waste problem?
Aside from wanting to end payments to the utilities for breach of contract, the federal government has another incentive to find a solution: It sits on a substantial volume of military nuclear waste. This includes liquids that have been “vitrified,” or mixed into a very strong form of glass. The lack of a permanent repository continues to be a talking point against the development of advanced reactors, on which the government has promised to spend billions of dollars.
With Yucca’s future uncertain, attention has turned to another concept, championed by a federal commission organized to study the issue: “consent-based siting.” That essentially means finding a place where residents will volunteer to host the project, perhaps in exchange for payments for local infrastructure or other emoluments. In September 2022, the Energy Department said it would offer $16 million to communities interested in learning about consent-based siting.
The idea is not simple, however, because there is a dispute about who would have to consent. In the Yucca case, some communities in Nevada favor the project, but the state government does not. The same split developed in Texas and New Mexico when interim storage of dry casks was proposed. Local people see economic benefits, but state-level elected officials with broader constituencies have found it good politics to oppose the projects.
Some impetus for opening a repository may come from developments in Sweden and Finland, though. Both countries are proceeding expeditiously to dig storage tunnels in granite formations. But both have a governmental structure unlike the one in the United States; they have strong national governments, and local governments. There is no equivalent of America’s sovereign states.
A growing public acceptance of nuclear energy as essential to preventing radical climate change may translate into less national opposition to nuclear energy, but it seems unlikely to change local reactions to a radioactive waste repository. But local feelings could change.
Success in Scandinavia will go a long way to refute one argument, that building a repository is impossible. And it will buttress the argument for consent-based siting. In Sweden, several towns competed to host the project. In Finland, the utility negotiated with the municipality, offering benefits to win local approval.
In the meantime, the national inventory is growing, But in the early years, most of the radiation comes from varieties of cesium and strontium that have half-lives in the range of 30 years; that is, every 30 years, their radiation output drops by half. That means that the oldest fuel is now substantially less radioactive, and somewhat simpler to transport and bury.