Key Takeaways:
- Secure Financial and Regulatory Support Early
- Recommissioning projects (like Palisades and TMI Unit 1) demonstrate the importance of securing strong financial backing (government loans, state support) and long-term PPAs
- Early engagement with USNRC is crucial given the complex regulatory process
- Leverage Experienced Contractors and Learn from Precedents
- Engage experienced regulatory counsel and third-party contractors to identify potential risks early
- Study recommissioning cases (like Palisades and TMI Unit 1) as they establish regulatory precedents
Introduction
At its peak, the commercial nuclear power industry in the United States included 112 operating nuclear reactors. Many of those reactors entered operation in the 1970s and 1980s and were typically licensed to operate for 40 years. When some of these reactors reached the end of their operating life, they were decommissioned. Others were taken out of service for various reasons but not fully dismantled. Yet others received extensions of their operating licenses and continue to provide clean, reliable, baseload electricity. The Trump Administration’s recent Executive Order, “Unleashing American Energy,” counts nuclear energy among the resources for which regulatory burdens must be reviewed, and suggests uranium should be included in the US’ list of critical minerals. With the renewed interest in nuclear power, former and existing nuclear power plants will be critical among the opportunities to meet the growing demand for electricity to power a variety of energy intensive industries.
This article explores the challenges and opportunities associated with nuclear power plants at or near the end of their planned operating life.
…there is a growing interest in nuclear power as a non-greenhouse gas emitting source of baseload electricity.
Old Plants, New Licenses : Nuclear Power’s Extended Stay
The average age of currently operating commercial nuclear reactors in the US is more than 40 years.1 Under current regulations,2 the US Nuclear Regulatory Commission (USNRC) may grant a 20-year extension of the plant’s original operating license, and potentially a subsequent 20-year license extension for a total of 80 operating years. Given the economic and regulatory pressures that have driven the retirement of coal-fired baseload generating power plants in recent years, there is a growing interest in nuclear power as a non-greenhouse gas emitting source of baseload electricity. This interest is driving some utilities to consider whether it is appropriate to pursue operating license extensions for nuclear power plants that would otherwise be considered for decommissioning.
A recent example of the confluence of these factors is Pacific Gas & Electric’s two-reactor Diablo Canyon Power Plant – California’s largest power plant. In 2023, driven by concerns related to statewide electricity reliability and climate change, California Senate Bill No. 846 became law and directed PG&E to pursue an extension of Diablo Canyon’s operating license to 2030. Following the conclusion of litigation that sought to prevent the license extension, PG&E’s application is currently under review by USNRC while both reactors continue to operate. Since 2000, USNRC has issued operating license extensions for more than 90 nuclear reactors. 3
The Long Goodbye: Navigating Nuclear Plant Decommissioning
Despite opportunities for life extension, some nuclear plant owners choose decommissioning for financial or operational reasons. In such cases, plant owners must first notify the USNRC of their planned shutdown, then work with the USNRC to coordinate all post-shutdown decommissioning activities including developing and implementing a License Termination Plan. Once these steps are complete, the owner must finish the full decommissioning process within 60 years of terminating plant operations. The final goal is to have the reactor site approved by the USNRC for future use which may be subject to specific restrictions. 4 Navigating this highly regulated process can be challenging in the best of circumstances and, in some instances, may be the subject of litigation, including with respect to disposal of spent reactor fuel. There are currently 20 US commercial nuclear reactors in various stages of the regulated decommissioning process. 5
These risks tend to become more apparent as the DECON phase progresses and the true scope of the necessary decontamination becomes apparent.
Full scale decommissioning and dismantling to obtain release of the USNRC license is a multi-year and costly process fraught with risks. This process includes: 6
- Removing the spent nuclear fuel from the reactor.
- Storing the spent nuclear fuel, typically in dry storage containers, either on-site or at licensed off-site locations.
- Dismantling radioactive systems and equipment; and
- Cleaning up contaminated material (e.g., contaminated soil, groundwater, etc.) and packaging and transporting it to a disposal facility.
Nuclear plants can be decommissioned and dismantled in either one or two phases. The first is safe storage (SAFSTOR), where the facility is placed in protective storage for an extended period. During this time, radioactivity naturally decreases in key components like the reactor vessel, fuel pools, and turbines. Spent fuel is removed from the reactor vessel and placed in secure storage, and the plant remains under USNRC oversight throughout this period.
The second phase is decontamination (DECON) during which contaminated equipment and materials are removed from the site. Plant owners with sufficient decommissioning funds may choose to skip SAFSTOR and proceed directly to DECON. However, those needing to accumulate additional funds may opt for SAFSTOR, in part to allow their decommissioning fund to grow over time. As part of DECON, the nuclear plant owner decontaminates and removes contaminated equipment and material. The DECON process can take up to five years, if not longer. 7
Given the number of US commercial nuclear reactors that have been decommissioned or are in the process of decommissioning, a number of third-party contractors have gained vital experience that can help nuclear plant owners better understand the risks inherent in decommissioning. These risks tend to become more apparent as the DECON phase progresses and the true scope of the necessary decontamination becomes apparent. For example, while it is expected that components in close contact with radioactive material will need to be decontaminated, other debris from the dismantling effort may be more contaminated than initially expected, requiring special techniques for removal and disposal. The scope, duration, and expense of decommissioning will further expand, sometimes significantly, if surrounding soil and ground water is also contaminated and requires treatment and removal. These risks cannot be eliminated entirely, but an experienced contractor and knowledgeable regulatory counsel can help the nuclear plant owner identify the potential issues early and develop the most cost-effective and regulatorily efficient solution.
…USNRC has taken a number of regulatory actions to oversee what it describes as a “first of a kind effort to restart a shuttered plant.”
Recommissioning: Back from the Brink
As noted above, some nuclear power plants have been decommissioned but not fully dismantled. For many of the same reasons some plant owners are seeking operating license extensions for existing reactors, other plant owners are seeking to restart reactors that have begun the decommissioning process.
The Palisades Nuclear Plant (PNP) ceased operations in 2022, and Entergy transferred the plant’s operating license to Holtec Decommissioning International for purposes of decommissioning the facility. In 2023, however, citing the need for safe, reliable, carbon-free electricity, Holtec announced plans to seek USNRC approval to restart PNP. Holtec’s plans have received financial assistance from the State of Michigan, a $1.52 billion loan from the US Department of Energy, and the company has entered into a long-term power purchase agreement (PPA). In response to Holtec’s plans, USNRC has taken a number of regulatory actions to oversee what it describes as a “first of a kind effort to restart a shuttered plant.”8 In addition to restarting the plant’s 800 MW reactor by late-2025, Holtec has also announced its intent to explore siting small modular reactors (SMRs) at the facility to make the plant a major clean energy hub for the region.
Similarly, in 2023, Constellation Energy announced its plans to restart operations at Three Mile Island (TMI) Unit 1, the companion to TMI Unit 2 which experienced a partial core meltdown in 1979. TMI Unit 1 ceased operations in 2019 and, like PNP, its license status was changed to SAFSTOR (Safe Storage) to facilitate later decommissioning efforts. Constellation estimates the cost to bring TMI-1 back to operating status at $1.6 billion. The project is supported by a 20-year PPA with Microsoft to purchase all power from the plant to supply its regional data center operations with carbon-free electricity. Assuming all regulatory approvals are obtained, TMI Unit 1, which is to be renamed the Crane Clean Energy Center, is projected to resume operations in 2028.
The future of America’s nuclear power plants stands at a critical crossroads.
In July 2024, NextEra announced that it was considering a possible restart of the 45-year-old Duane Arnold nuclear plant in Palo, Iowa which ceased operations in August 2020. In a clear response to growing electricity demand, on January 23, 2025, NextEra filed with the USNRC a proposed regulatory path for the potential reauthorization of operations at the Duane Arnold power plant.
While there are likely a limited number of nuclear plants that could be considered for recommissioning, recent statements by the Trump Administration suggesting that nuclear energy will be viewed as a priority resource to meet future energy demand may bode well for the regulatory path forward for nuclear plant restarts.
Conclusion
The future of America’s nuclear power plants stands at a critical crossroads. The growing demand for reliable, baseload power, coupled with concerns about climate change and energy security, has sparked renewed interest in preserving and expanding nuclear capacity. As a result, while some nuclear plants may face decommissioning, others are finding new life through license extensions and recommissioning efforts.
Early indications are the Trump Administration intends to “unleash commercial nuclear power in the United States” through the development and deployment of next-generation nuclear technology.9 It is possible that the Administration’s support for nuclear power will extend to optimizing the use of the nation’s existing and former nuclear plants. Similarly, the Administration’s concurrent interest in streamlining regulatory processes may provide more regulatory certainty for existing and former nuclear plants being considered for operating license extensions or for recommissioning.
The story of America’s nuclear plants is thus not simply one of sunset versus second life, but rather one of evolution and adaptation to meet the changing energy needs of the 21st century.
1https://www.eia.gov/tools/faqs/faq.php?id=228&t=3
210 CFR § 54
3https://www.nrc.gov/reactors/operating/licensing/renewal/applications.html#completed
410 CFR § 20 and §§ 50.75, 50.82, 51.53, and 51.95
5https://www.nrc.gov/info-finder/decommissioning/power-reactor/index.html
6https://www.nei.org/advocacy/make-regulations-smarter/decommissioning
7https:// www.nei.org/resources/fact-sheets/decommissioning-nuclear-power-plants
8https://www.nrc.gov/info-finder/reactors/pali.html
9Secretary Wright Acts to “Unleash Golden Era of American Energy Dominance” | Department of Energy