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Backgrounder on Reactor License Renewal

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The Atomic Energy Act gives authority to the Nuclear Regulatory Commission to issue licenses for commercial power reactors to operate for up to 40 years. These licenses can be renewed for an additional 20 years at a time. This is known as the period of extended operation. Economic and antitrust considerations, not limitations of nuclear technology, determined the original 40-year term for reactor licenses. However, because of this selected time period, some systems, structures, and components may have been engineered on the basis of an expected 40-year service life.

The decision to seek license renewal rests entirely with nuclear power plant owners. This choice is typically based on the plant's economic situation and whether it can meet NRC requirements. Each power reactor is licensed based on a specific set of requirements, depending primarily on its design. This set of requirements is called the plant's "licensing basis." The license renewal review process provides continued assurance that the current licensing basis will maintain an acceptable level of safety for the period of extended operation.


In 1982, the NRC established a comprehensive program for nuclear plant aging research. These research results concluded that most nuclear plant aging issues are manageable and do not pose technical issues that would prevent them for operating additional years beyond their original license period of 40 years.

In 1991, the NRC published safety requirements for license renewal as 10 CFR Part 54. The NRC applied the new rule on several pilot plants to acquire experience and to establish implementation guidance. The rule limited its scope to age-related degradation unique to license renewal. However, during the pilot program, the NRC found that many aging effects are dealt with adequately during the initial 40-year license period. In addition, the NRC found that the rule did not give enough credit for existing programs to manage plant-aging issues, particularly those under NRC's maintenance rule.

As a result, in 1995, the NRC amended the license renewal rule. The amended Part 54 established a regulatory process that is more efficient, stable and predictable than the previous license renewal rule. In particular, Part 54 was clarified to focus on managing the adverse effects of aging. The rule changes were intended to ensure that important systems, structures and components would continue to perform their intended function during the 20-year period of extended operation.

In parallel with aging management efforts, the NRC pursued a separate rulemaking, 10 CFR Part 51, to focus the scope of its environmental reviews. Under the National Environmental Policy Act, the NRC must review the environmental impact of license renewal.

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License Renewal Process

Flow chart of the License Renewal Process

The license renewal process proceeds along two tracks -- one for review of safety issues (Part 54) and another for environmental issues (Part 51). An applicant must provide NRC an evaluation that addresses the technical aspects of plant aging and describes the ways those effects will be managed. It must also prepare an evaluation of the potential impact on the environment if the plant operates for another 20 years. The NRC reviews the application and verifies its evaluation through inspections.

The NRC will renew a license only if it determines that a currently operating plant will continue to maintain the required level of safety.

Over a plant's life, safety is ensured through maintenance of the plant and its unique licensing basis. A plant's licensing basis is a specific set of evolving requirements and commitments. Over time, as technology advances and operating experience provides new information, a plant's licensing basis may be changed—for example, when the NRC issues new requirements and the plant makes modifications.

  • Public Involvement

Public participation is an important part of the license renewal process. Information provided by the licensee is made available to the public in a variety of ways. Shortly after the NRC receives a renewal application, a public meeting is held near the plant. This meeting provides local stakeholders information about the license renewal process and opportunities for public involvement. This meeting is also used to solicit input on the scope of NRC's environmental review. Additional public meetings are held by the NRC during the review of the renewal application. NRC evaluations, findings and recommendations are published when completed.

All public meetings are posted on NRC's Public Meetings and Involvement page. Key meetings are announced in press releases and in the Federal Register. In addition, Concerns may be contested in a hearing if any party that would be adversely affected by the licensing action requests a hearing. In addition, members of the public may petition the Commission for consideration of issues other than aging during the license renewal process.

  • Schedule

A nuclear power plant licensee may apply to the NRC to renew its license as early as 20 years before expiration of its current license. There is no limit on how late a licensee may apply for license renewal. However, if the licensee submits a renewal application at least five years before expiration of its current license and the agency is still reviewing the application at the end of the five years, the plant can continue to operate until the NRC completes its review. If a sufficient application is not submitted at least five years before the current license expires the plant may have to stop operating if the license expires before a renewal decision is made.

Upon receipt of a license renewal application, the NRC staff reviews it according to the steps and time frames in the following table. License renewal schedules depend on a number of factors including available staff resources and the number of current and projected applications. In addition, the complexity of the review, applicant timeliness in responding to requests for additional information, and the coordination of the timing for on-site audits and inspections, all affect the review timeline.

Licensing Milestone Months Elapsed
Receive renewal application 0
Publish notice of opportunity for hearing 1.5
Conduct public meeting on license renewal process and scope of environmental impact statement 2.5
Opportunity for hearing closes 3.5
Pose environmental questions to applicant 5.5
Pose safety questions to applicant 6.0
Issue draft environmental impact statement for comment 11.0
Conduct public meeting on draft environmental impact statement 12.0
Issue safety evaluation report, identifying open items 13.0
Issue final environmental impact statement 18.0
Issue safety evaluation report 18.0
Complete Advisory Committee on Reactor Safety Review 20.0
Make decision on application (without hearing) 22.0
Complete hearing process (if needed) --­
Make decision on application (with hearing) 30.0
(contingent on the hearing process)

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Environmental Reviews

Environmental protection regulations were revised in 1996 to facilitate the environmental review for license renewal. Certain issues are evaluated generically for all plants, rather than separately in each plant's renewal application. The generic evaluation, NUREG-1437, "Generic Environmental Impact Statement for License Renewal of Nuclear Plants" (GEIS), assesses the scope and impact of environmental effects that would be associated with license renewal at any nuclear plant site such as endangered species, impacts of cooling water systems on fish and shellfish, and groundwater quality. A plant-specific supplement to the generic environmental impact statement is required for each application for license renewal.

The NRC performs plant-specific reviews of the environmental impacts of license renewal in accordance with the National Environmental Policy Act and the requirements of 10 CFR Part 51. A public meeting is held near the plant shortly after receipt of the application to identify environmental issues specific to the plant for the license renewal action. The result is an NRC recommendation on whether the environmental impacts are so great that they disqualify license renewal.

This recommendation is presented in a draft plant-specific supplement to the GEIS that is published for public comment and discussed at a separate public meeting. After consideration of comments on the draft, NRC prepares and publishes a final plant-specific supplement to the GEIS.

The NRC issued a standard review plan (NUREG-1555, Supplement No. 1) which provides guidance on how the agency reviews the environmental portions of renewal applications. The NRC also issued Supplement 1 to Regulatory Guide 4.2 that identifies the format and content of environmental reports that must accompany license renewal applications.

Safety Reviews

License renewal requirements for power reactors are based on two key principles:

  1. The current regulatory process is adequate to ensure that the licensing basis of all operating plants provides and maintains an acceptable level of safety; and
  2. Each plant's licensing basis is required to be maintained during the renewal term in the same manner and as during the original licensing term.

An applicant must identify all plant systems, structures and components whose failure could affect safety. These plant systems, structures and components, must demonstrate compliance with the NRC's regulations for fire protection, environmental qualification, pressurized thermal shock, anticipated transients without scrams and station blackout.

Some passive structures and components within the scope of the renewal evaluation do not require additional action. In these cases, the applicant must demonstrate that the existing programs provide adequate aging management throughout the period of extended operation. However, if additional aging management activities are needed for a structure or component, applicants have the flexibility to determine appropriate actions. These activities could include, for example, adding new monitoring programs or increasing inspections.

License renewal applicants must also identify and update "time-limited" aging analyses. During the design phase for a plant, certain assumptions about the length of time the plant will be operated are incorporated into design calculations. Under a renewed license, these calculations must be shown to be valid for the period of extended operation, or the affected systems, structures and components must be included in an appropriate aging management program.

The NRC developed guidance for implementation of the license renewal rule with input from interested stakeholders. Plant owners offered both generic process and technical suggestions. A Generic Aging Lessons Learned (GALL) report (NUREG-1801) was prepared. The report documents the basis for determining when existing programs are adequate and when existing programs should be augmented for license renewal. The GALL report is referenced in the standard review plan for license renewal (NUREG-1800) as the basis for identifying those programs that warrant particular attention during NRC's review of a license renewal application.

The NRC also issued Regulatory Guide 1.188, which provides the format and content of the safety aspects of a license renewal application. It endorses a guideline prepared by the Nuclear Energy Institute as an acceptable method of implementing the license renewal rule. The NRC will continue to include changes to the guide and the standard review plan as generic renewal issues are resolved. The agency also incorporated other changes resulting from lessons learned during the review of renewal applications.


The NRC established an inspection program for license renewal that verifies the information in the application and NRC's evaluation. The inspections sample the results used by the licensee to identify those structures and components within the scope of license renewal, aging management programs, and design analysis changes.

An additional inspection is performed upon approval of the application and issuance of a new operating license. This is typically done prior to entering the period of extended operation. This inspection verifies that the license conditions, license renewal commitments and aging management programs are implemented. Inspection results are documented in a publicly available report.

Status of License Renewal Applications

The status of pending planned applications as well as additional information on license renewal can be on the Reactor License Renewal page.


Map of the License Renewals Granted for Operating Nuclear Power Reactors

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Page Last Reviewed/Updated Friday, April 29, 2016