WASHINGTON/LONDON - As U.S. policymakers revive ambitions for a significant expansion of nuclear power to meet surging electricity demand, they are confronting a persistent and unresolved issue: where to put the most hazardous radioactive waste for the very long term.
The Department of Energy (DOE) last week published a request for information (RFI) asking states to come forward if they are willing to host a permanent geological repository for spent reactor fuel. That repository would be one element of a broader campus concept that could include advanced reactors, waste reprocessing, uranium enrichment and data centers, according to officials in the DOE Office of Nuclear Energy.
The move represents a notable pivot in U.S. policy. Previously, nuclear deployment initiatives and long-term waste disposal were treated as largely separate policy streams. The new RFI links them directly, effectively offering large economic incentives as part of a package to communities willing to accept a permanent disposal site for high-level waste.
The proposed approach rests on a blunt political calculation: pair desirable investments and jobs with facilities that many communities would view as undesirable. "By combining this all together in a package, it’s a matter of big carrots being placed alongside a waste facility which is less desirable," said Lake Barrett, a former official at the U.S. Nuclear Regulatory Commission and the DOE. Barrett noted that a number of states, including Utah and Tennessee, have already signaled interest in nuclear-related investments.
The DOE’s nuclear office said the RFI has generated interest but declined to comment on which states might respond. State officials have 60 days to reply. Officials in Utah and Tennessee did not reply to requests for comment.
Policy context and the administration’s goals
The Trump administration aims to dramatically expand U.S. nuclear capacity, seeking to increase installed nuclear generation to 400 gigawatts by 2050 - about four times current levels - to meet what it sees as rising electricity demand driven by data centers powering artificial intelligence and wider electrification of transport.
As part of that drive, the DOE in 2025 selected 11 advanced nuclear reactor designs for fast-track licensing and said it aimed to have three pilot reactors built by July 4 this year. The accelerated timeline for advanced designs is intended to move new technologies from concept to deployment more quickly than past programs.
Waste remains the unresolved piece
Any credible plan to expand nuclear generation at scale requires a durable solution for spent fuel, according to U.S. and international studies cited by policymakers. The DOE’s Office of Nuclear Energy emphasized that a comprehensive nuclear strategy must include "safe, durable pathways for final disposition, and that remains a required element of the RFI."
Across the United States there is no permanent repository in operation. Instead, an estimated 100,000 tons of highly radioactive used fuel sits in interim storage at reactor sites and other locations. That stockpile grows by roughly 2,000 tons a year as reactors operating in the United States - the country with more operational reactors than any other - continue to generate electricity and add to existing inventories.
Absent a permanent site, much of the nation’s spent fuel remains on site first in pools and then in concrete and steel casks. The federal government has paid utilities to store spent fuel on their behalf; as of the end of 2024, U.S. taxpayers have paid about $11.1 billion in compensation to utilities for storing spent fuel, according to the DOE Office of Nuclear Energy.
Past efforts and political obstacles
The United States has a history of attempting to establish a permanent repository. The DOE’s search for a site began in 1983 and culminated in the selection of Yucca Mountain, Nevada, in 1987. However, funding for Yucca was halted in 2010 under the Obama administration amid strong opposition from Nevada lawmakers, leaving the project unfinished after nearly $15 billion had been spent.
That episode highlights the political complexity of siting such facilities. Local and state resistance has repeatedly thwarted past efforts to build a central repository, and the DOE’s new RFI intentionally places the decision in the hands of local communities by asking states to volunteer.
Small modular reactors and the waste equation
To accelerate new nuclear build, the United States and several other countries including Britain, Canada, China and Sweden are promoting so-called small modular reactors or SMRs. Advocates argue SMRs can be largely prefabricated in factories, enabling faster and potentially less costly onsite assembly compared with conventional large reactors.
But SMR designs do not inherently solve the question of long-term waste disposal. Designers are required to outline how waste will be managed, yet there is no systemic obligation to redesign reactors to reduce long-lived waste at the source. "This rush to create new designs without thinking about the full system bodes really poorly for effective regulatory oversight and having a well-run, safe, and reliable waste management program over the long term," said Seth Tuler, an associate professor at Worcester Polytechnic Institute who formerly served on the U.S. Nuclear Waste Technical Review Board.
Independent analysis has suggested many SMR designs will produce comparable or greater volumes of waste per unit of electricity than large reactors. A study published in the Proceedings of the National Academy of Sciences in 2022 concluded that most new SMRs are likely to generate similar waste quantities - or even higher amounts - on a per-megawatt-hour basis.
Because SMRs can be sited in locations that lack the infrastructure needed for larger plants, their deployment raises the prospect of many more sites storing interim waste, potentially increasing the number of interim storage locations across the country. The U.S. nuclear regulator has noted that "interim" storage can in practice last more than a century after a reactor closes.
Reuters contacted the nine companies behind the 11 SMR designs in the DOE’s fast-track program. Responses indicated a range of views. Some firms said responsibility for managing waste rests primarily with reactor operators and the federal government. Others expressed hope that technological advances over coming decades would improve prospects for recycling or reprocessing used fuel, while acknowledging that a permanent geological repository is still required.
Reprocessing: promises and scepticism
The prospect of expanding reprocessing of spent fuel - separating uranium and plutonium for potential reuse - has reemerged as interest in new nuclear builds grows. Proponents within the DOE’s nuclear office argued modern recycling and reprocessing technologies could greatly reduce the volume of material requiring disposal. "Modern technologies, particularly advanced recycling and reprocessing, can dramatically shrink the volume of nuclear material requiring disposal," said a spokesperson for the Office of Nuclear Energy. The spokesperson added that reprocessing would not remove the need for a permanent disposal path.
But not all experts share that optimism. Nuclear security specialists have warned that reprocessing attempts have historically encountered high costs, technical problems and security concerns linked to proliferation risks. Ross Matzkin-Bridger, a former DOE official, said past attempts have failed and created additional security and management complications. "Every time it’s been attempted, it’s failed, it creates security and proliferation risks, the costs are enormous, and it complicates waste management," he said. He noted that the countries that do reprocess now recycle only a very small share of their spent fuel compared with the large percentages sometimes promised.
International progress on permanent repositories
Globally, countries have also wrestled with the same issue. The consensus for decades among nuclear professionals has been that the most toxic wastes are safest if emplaced in deep, stable geological formations and sealed from the biosphere. But creating such repositories is a slow, technically demanding and politically sensitive process that requires community acceptance and extensive scientific study of groundwater movement and rock stability to depths of up to 1,000 metres.
Finland has advanced the farthest toward a permanent facility. Posiva, the Finnish company behind the Olkiluoto project, began placing test canisters at depths of more than 400 meters in 2024 and said it aimed to begin commercial operations this year pending final approval from the Finnish Radiation and Nuclear Safety Authority and subsequent technical checks. In Finland, spent fuel would be encased in copper and iron canisters, placed in underground tunnels and permanently sealed.
Other countries are at various stages. Sweden began construction of its repository in January 2025 and aims to open it in the late 2030s. Canada has agreed on a site in Ontario with a goal of operation by the late 2040s. Switzerland and France have selected sites and hope for openings around 2050. Britain has set a target in the late 2050s but has not finalized a location.
Britain’s Dounreay: a cautionary example
The experience at Britain’s Dounreay site illustrates the practical and public-relations challenges of dealing with legacy waste. The last reactor at Dounreay closed in 1994, and decommissioning and cleanup there have repeatedly extended both timelines and budgets as unexpected complications have arisen during waste handling.
Large vaults are accumulating low-level radioactive materials in metal containers as the once-leading facility is dismantled. Historic practices included flushing irradiated fuel into the sea, and small radioactive fragments have continued to appear. A "minor" fragment was found on a local beach in January, and the last "significant" particle was located in April. Fishing is banned within a 2 kilometer radius of Dounreay’s outlet pipe because of radioactive particles on the seabed. The projected completion date for cleanup at Dounreay was pushed out from 2033 into the 2070s.
Some stakeholders have promoted decommissioned sites such as Dounreay as potential locations for data centers, noting that they already connect to the power grid and would not require new transmission hookups. However, the extensive cleanup still required at these sites means conversion to other uses is likely to be prolonged and costly.
The tradeoffs ahead
The DOE’s RFI frames a choice for local communities: volunteer to host a permanent repository as part of an integrated nuclear campus and potentially attract significant investment, or continue to store growing amounts of spent fuel on site at reactors and other facilities. The federal government’s previous efforts to site a repository demonstrate how difficult it can be to secure community and state buy-in.
Proponents of the administration’s approach argue that packaging waste disposal together with new investment can make siting politically feasible. Opponents point to technical, environmental and security uncertainties, as well as the long time horizons involved in both repository construction and cleanup at legacy sites.
For now, the United States and many other nations remain in a holding pattern: new reactor designs are being promoted and partially fast-tracked, interim storage continues to grow, and a permanent disposal path remains the missing piece of an otherwise expanding nuclear strategy.
As policymakers and potential host communities weigh the RFI, the enduring lesson from past efforts is clear: securing a permanent repository requires not only geological suitability and engineering diligence, but also deep and sustained public and political consent.