Spent fuel storage and transport

Why the concentration exists

Dry cask storage systems provide the physical infrastructure for storing spent nuclear fuel when reactor cooling pools approach their capacity limits. These systems use multi-purpose canisters made of stainless steel that are loaded with spent fuel assemblies, then sealed and placed inside shielded overpacks of concrete and steel. The canisters are designed for storage, transport, and eventual geological disposal, which eliminates the need to transfer fuel between containers as it moves through the waste management chain. This multi-purpose design reduces handling risks and costs over the decades that fuel remains in storage.[1][2][4][5]

Safety regulations have intensified since the September 11 attacks, when the NRC instituted rules requiring all fuel pools to withstand natural disasters and terrorist attacks. Used fuel pools must be encased in steel liners and thick concrete, with inspections for resilience to earthquakes, tornadoes, hurricanes, and seiches. The IAEA regulations for safe transport of radioactive material have been periodically revised since first publication in 1961, with the current edition published in 2018. Spent nuclear fuel has been safely transported for over 60 years, covering millions of kilometers without significant incidents. These regulatory requirements create high barriers to entry for new cask manufacturers.[14][20]

What the evidence shows

Who supplies it

Holtec International has built a substantial intellectual property portfolio with over 100 patents related to used fuel storage and transport. The company has provided solutions since 1986 and maintains an active market presence at over 115 reactor units worldwide for dry cask loading services. Holtec's Site Services division provides dry cask loading services and has performed spent fuel storage rack removal and installation services since 1986. The company has expanded wet spent fuel storage capacity at over 110 reactor units throughout the world through these rack services.[17][18][19]

International orders continue to flow to established vendors. Holtec was awarded a contract by Spain's Enresa for 10 HI-STAR 150 casks and is in advanced stages of production for two HI-STAR 180D casks destined for the Doel nuclear power plant in Belgium. In April 2024, Holtec signed an agreement with Energoatom in Ukraine to create manufacturing capabilities for storage and transportation systems for used nuclear fuel. This agreement also covered components for small modular reactors.[21][22]

Industry collaboration extends beyond the dominant vendors. Orano sponsored a December 2023 workshop on extended storage and transportation of spent fuel hosted by the NEA, Holtec, and EPRI in Camden, New Jersey. The Nuclear Energy Agency's Radioactive Waste Management Committee created the Ad-hoc Group on Extended Storage and Transportation in 2021 to address long-term storage challenges. Natural Resources Canada organized an international workshop on management of spent fuel from SMRs in November 2022 in Ottawa.[26]

What it depends on, and what depends on it

The United States generates approximately 2,000 metric tons of spent fuel each year from its commercial nuclear reactors. Since the 1950s, US reactors have generated about 90,000 metric tons of spent fuel, which is stored at more than 70 nuclear power plant sites across the country. As of the end of 2019, 3,203 casks had been loaded at 72 interim spent fuel storage installations. At least one-third of the total US used fuel is now in dry storage casks. The US inventory of spent nuclear fuel from commercial nuclear power plants is estimated to reach approximately 135,000 metric tons by mid-century.[5][6][7][10]

Spent fuel typically remains in reactor cooling pools for five to ten years before it may be moved into dry storage casks. The fuel must be stored on-site for at least five months before it can be transported, though it often remains in storage long-term. From 1968 through December 2017, a total of 276,879 fuel assemblies had been discharged and stored at the sites of 119 closed and operating commercial reactors. A 1,000 megawatt nuclear unit generates about 20 metric tons of used fuel each year. Used fuel pellets consist of about 96 percent uranium, 3 percent fission products, and 1 percent plutonium and other heavy metals.[11][23][24][27]

The absence of a permanent repository forces indefinite on-site storage. The United States has no permanent underground repository for high-level nuclear waste, and licensing of the Yucca Mountain repository stopped in 2010. The US government has paid reactor owners about $9 billion for storage of spent nuclear fuel. The Department of Energy has determined that a federal consolidated interim storage facility is needed to manage the nation's commercial spent nuclear fuel. Such a facility would initially be built to store around 15,000 metric tons of spent nuclear fuel.[6][8][11]

Where it sits in the stack

What would break it

Advanced reactor designs could alter the volume and characteristics of spent fuel requiring storage. TRISO-based reactors discharge approximately 10 to 16 times more spent fuel volume per unit of energy produced than traditional light water reactors. Savannah River National Laboratory is developing a vapor-based digestion process that can reduce the volume of tri-structural isotropic spent nuclear fuel by a factor of 20. The process removes the graphite binder without damaging the fuel particles. This technology could significantly reduce storage requirements for advanced reactor fuels.[9]

Reprocessing technologies could redirect spent fuel away from long-term storage. Several startups including Curio, Shine Technologies, and Oklo are exploring processes involving reprocessing spent fuel to extract uranium and other elements. These extracted materials would be used to create new fuel for small modular reactors. Japan's sole planned reprocessing plant is nearly 30 years behind schedule. One Japanese power company plans to send spent fuel to France for reprocessing.[3][15][16]

Intra-utility transhipment of spent fuel could reduce overall storage needs by approximately 10 percent, according to Department of Energy projections. The DOE evaluated 16 nuclear power plant sites for removing spent nuclear fuel and assessed shutdown sites including Maine Yankee, Yankee Rowe, Connecticut Yankee, Humboldt Bay, Big Rock Point, Rancho Seco, and Trojan. Over 55 years, more than 2,500 cask shipments of spent fuel have been transported across the United States without radiological releases. The DOE/EPRI High Burnup Spent Fuel Confirmatory Data Project loaded a TN-32 dry cask with 32 high-burnup spent fuel assemblies for at least ten years of testing.[7][10][12][25]

What to watch

Finland is scheduled to begin disposing of spent nuclear fuel underground in 2025, which would make it the first country to operate a permanent geological repository. This milestone could influence policy discussions in other countries about long-term waste management solutions. The Finnish approach demonstrates that permanent disposal is technically achievable. Other nations watching this development may accelerate their own repository programs.[24]

Savannah River National Laboratory's projects with partners including Westinghouse and the University of South Carolina Columbia are expected to complete in early 2027. The goal is a full process demonstration at engineering scale for reducing TRISO fuel volume. The INTEC Building 603 at Idaho National Laboratory must be reconfigured by 2030 to continue receiving spent fuel from the Advanced Test Reactor. As of May 2025, the building's inventory included 3,432 spent ATR fuel elements.[9][13]

Related nodes

Sources

1. en.wikipedia.org · 2026-05-27T03:08:57
2. nrc.gov
3. cnbc.com · 2025-11-10T16:02:55
4. www-pub.iaea.org
5. world-nuclear.org · end of 2019
6. energy.gov · May 15, 2024
7. energy.gov · October 3, 2022
8. gao.gov · 2010
9. srnl.gov · March 3, 2025
10. energy.sandia.gov
11. eia.gov · 2017-12-31
12. energy.gov · April 8, 2021
13. files.gao.gov · May 2025
14. nucleus.iaea.org · 2018
15. world-nuclear.org · end of 2012
16. asia.nikkei.com
17. holtecinternational.com · 2005
18. holtecinternational.com
19. holtecinternational.com
20. en.wikipedia.org
21. ans.org · July 13, 2021
22. world-nuclear-news.org · 17 April 2024
23. nuclear.duke-energy.com · December 01, 2011
24. thirdway.org · 2025
25. everycrsreport.com · 1995
26. oecd-nea.org · 2021
27. konecranes.com