Decommissioning Nuclear Power Plants

Background

When a power company decides to close a nuclear power plant permanently, the facility must be 

decommissioned by safely removing it from service and reducing residual radioactivity to a level that 

permits release of the property and termination of the operating license. The Nuclear Regulatory 

Commission has strict rules governing nuclear power plant decommissioning, involving cleanup of 

radioactively contaminated plant systems and structures, and removal of the radioactive fuel. These 

requirements protect workers and the public during the entire decommissioning process and the public 

after the license is terminated.

Discussion

Licensees may choose from two decommissioning strategies: DECON and SAFSTOR.

Under DECON (immediate dismantling), soon after the nuclear facility closes, equipment, 

structures, and portions of the facility containing radioactive contaminants are removed or 

decontaminated to a level that permits release of the property and termination of the NRC license.

Under SAFSTOR, often considered “deferred dismantling,” a nuclear facility is maintained and 

monitored in a condition that allows the radioactivity to decay; afterwards, the plant is dismantled and 

the property decontaminated. 

A licensee may also combine the two strategies

by dismantling and decontaminating some portions of 

the facility while leaving other parts in SAFSTOR. The 

decision may be based on factors besides radioactive 

decay, such as availability of waste disposal sites. There 

is no formal declaration of a strategy: A facility is said 

to be in DECON when active decommissioning work is 

underway.

Decommissioning must be completed within 60 

years of the plant ceasing operations. A time beyond 

that would be considered only when necessary to protect 

public health and safety in accordance with NRC 

regulations.

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Regulations

The requirements for decommissioning a nuclear power plant are set out in several NRC 

regulations.1 In August 1996, a revised rule went into effect that redefined the decommissioning process 

and required owners to provide the NRC with early notification of planned decommissioning activities. 

The rule allows no major decommissioning activities to be undertaken until after certain information has 

been provided to the NRC and the public.

Several nuclear power plants completed decommissioning in the 1990s without a viable option 

for disposing of their spent nuclear fuel because the federal government did not construct a geologic 

repository as planned. Accordingly, the NRC implemented regulations allowing licensees to sell off part 

of their land once it meets NRC release criteria, while maintaining a small parcel under license for 

storing the spent fuel. These stand-alone facilities, called “independent spent fuel storage installations,” 

remain under license and NRC regulation. Licensees are responsible for security and for maintaining 

insurance and funding for eventual decommissioning.

The NRC is currently developing new regulations that will implement lessons learned from 

transitioning several plants from operation to decommissioning since 2011. These regulations will 

enhance the efficiency and transparency of the transition and the early stages of decommissioning.

Decommissioning Funds

Before a nuclear power plant begins operations, the licensee must establish or obtain a financial 

mechanism – such as a trust fund or a guarantee from its parent company – to ensure there will be 

sufficient money to pay for the eventual decommissioning of the facility. 

Each nuclear power plant licensee must report to the NRC every two years the status of its 

decommissioning funding for each reactor or share of a reactor that it owns. The report must estimate 

the minimum amount needed for decommissioning by using the formulas found in 10 CFR 50.75(c). 

Licensees may alternatively determine a site-specific funding estimate, provided that amount is greater 

than the generic decommissioning estimate. Although there are many factors that affect reactor 

decommissioning costs, generally costs range from $300 million to $400 million. Approximately 

70 percent of licensees are authorized to accumulate decommissioning funds over the operating life of 

their plants. These owners – generally traditional, rate-regulated electric utilities or indirectly regulated 

generation companies – are not required today to have all the funds needed for decommissioning. The 

remaining licensees must provide financial assurance through other methods such as prepaid 

decommissioning funds and/or a surety method or guarantee. The staff performs an independent analysis 

of each of these reports to determine whether licensees are providing reasonable “decommissioning 

funding assurance” for radiological decommissioning of the reactor at the permanent termination of 

operation.

1 Title 10 of the Code of Federal Regulations, Part 20 Subpart E, and Parts 50.75, 50.82, 51.53, and 51.95
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Public Involvement

The public has several opportunities to participate 

in the decommissioning process. A public meeting is held 

in the vicinity of the facility after submittal of a postshutdown decommissioning activities report to the NRC. 

Another public meeting is held when NRC receives the 

license termination plan. An opportunity for a public 

hearing is provided prior to issuance of a license 

amendment approving the plan or any other license 

amendment request. In addition, when NRC holds a meeting with the licensee, members of the public 

may observe the meeting (except when the discussion involves proprietary, sensitive, safeguards, or 

classified information).

Phases of Decommissioning 

The requirements for power reactor 

decommissioning activities may be divided into 

three phases: (1) transition; (2) major 

decommissioning and storage; and (3) license 

termination activities. 

1) Transition from Operation to 

Decommissioning

When a nuclear power plant licensee shuts 

down the plant permanently, it must submit a 

written certification of permanent cessation of 

operations to the NRC within 30 days. When 

radioactive nuclear fuel is permanently removed 

from the reactor vessel, the owner must submit another written certification to the NRC, surrendering its 

authority to operate the reactor or load fuel into the reactor vessel. This eliminates the obligation to 

adhere to certain requirements needed only during reactor operation. Other requirements are currently 

eased through exemptions and license amendments; several of these transitional changes will be 

included in the new regulations under development.

Within two years after submitting the certification of permanent closure, the licensee must 

submit a post-shutdown decommissioning activities report to the NRC. This report provides a 

description of the planned decommissioning activities, a schedule for accomplishing them, and an 

estimate of the expected costs. The report must discuss the reasons for concluding that environmental 

impacts associated with the site-specific decommissioning activities have already been addressed in 

previous environmental analyses. Otherwise, the licensee must request a license amendment for 

approval of the activities and submit to the NRC details on the additional impacts of decommissioning 

on the environment.
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After receiving the report, the NRC publishes a notice of receipt in the Federal Register, makes 

the report available for public review and comment, and holds a public meeting in the vicinity of the 

plant to discuss the licensee’s intentions.

2) Major Decommissioning Activities

Ninety days after the NRC receives the planning 

report, the owner may begin major decommissioning 

activities without specific NRC approval. These include 

permanent removal of such major components as the 

reactor vessel, steam generators, large piping systems, 

pumps, and valves.

However, decommissioning activities conducted 

without specific prior NRC approval must not prevent 

release of the site for possible unrestricted use, result in 

there being no reasonable assurance that adequate funds 

will be available for decommissioning, or cause any 

significant environmental impact not previously 

reviewed. If any decommissioning activity does not meet these terms, the licensee is required to submit 

a license amendment request, which would provide an opportunity for a public hearing.

Initially, the owner can use up to 3 percent of its set-aside funds for decommissioning planning. 

The remainder becomes available 90 days after submittal of the planning report unless the NRC staff has 

raised objections.

3) License Termination Activities 

The owner is required to submit a license 

termination plan within two years of the expected 

license termination. The plan addresses each of the 

following: site characterization, remaining site 

dismantlement activities, plans for site remediation, 

detailed plans for final radiation surveys for release 

of the site, updated estimates of remaining 

decommissioning costs, and a supplement to the 

environmental report describing any new 

information or significant environmental changes 

associated with the final cleanup. Most plans 

envision releasing the site to the public for unrestricted use, meaning any residual radiation would be 

below NRC’s limits of 25 millirem annual exposure and there would be no further regulatory controls by 

the NRC. Any plan proposing release of a site for restricted use must describe the site’s end use, public 

consultation, institutional controls, and financial assurance needed to comply with the requirements for 

license termination for restricted release. 

The license termination report requires NRC approval of a license amendment. Before approval 

can be given, an opportunity for hearing is published and a public meeting is held near the plant site.
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The NRC uses a standard review plan (NUREG-1700, “Standard Review Plan for Evaluating 

Nuclear Power Reactor License Termination Plans”) to ensure high quality and uniformity of the license 

termination plan reviews. 

If the remaining dismantlement has been performed in accordance with the approved licence 

termination plan and the NRC’s final survey demonstrates that the facility and site are suitable for 

release, the NRC issues a letter terminating the operating license.

Current updates of all power reactor sites undergoing decommissioning are available on the NRC 

website.

October 2022