How Long Does A Nuclear Power Plant Last?
Nuclear power plants are facilities that use nuclear fission reactions to generate electricity. They rely on controlled nuclear chain reactions within nuclear reactors to produce heat, which is then used to power steam turbines connected to electrical generators.
The lifespan of a nuclear power plant refers to the operating lifetime from when it first begins generating electricity to when it is retired and decommissioned. This lifespan is determined by several factors, including the initial designed operating life, safety regulations, economic viability, maintenance programs, and license renewals.
Most nuclear plants are initially licensed to operate for 40 years, but they can apply for license renewals to extend their operating lives by another 20 years. With proper maintenance and upgrades, most plants can continue operating safely well beyond their initial 40 year lifespan. However, economic factors, changing regulations, and political pressures can lead utilities to decide to retire plants earlier.
Overall, the typical lifespan of a nuclear power plant ranges from 40-60 years. However, some plants have operated for over 50 years and others have closed after just 25 years of service. Regular maintenance, equipment upgrades, license renewals and evolving safety standards all play roles in determining nuclear power plant lifespans.
History
The world’s first nuclear power plant opened in Obninsk, Russia in 1954 with a design life of 30 years (1). The first commercial nuclear power plant opened in Sellafield, England in 1956. In the United States, the Shippingport Atomic Power Station opened in 1957 as the first full-scale nuclear power plant. Early nuclear plants in the U.S. were initially licensed to operate for 40 years, though regulations allowed extensions (2).
The passage of the Atomic Energy Act of 1954 opened the door for commercial nuclear power in the U.S. The Eisenhower administration saw nuclear power as a clean energy source that could meet anticipated growth in electricity demand. Dozens of nuclear plants were built through the 1960s and 1970s. However, growth slowed after the Three Mile Island accident in 1979.
(1) https://www.nuclear-power.com/nuclear-power-plant/history-nuclear-power-plants/
(2) https://visualizingenergy.org/watch-the-history-of-nuclear-power-in-the-u-s/
Design Life
When commercial nuclear power was first developed in the 1950s and 1960s, reactors were initially given a licensed lifetime of 30-40 years based on economic and anti-trust reasons, not for technical limitations (Dumitra, 2020).[1] This established timeframe of 30-40 years set the precedent for the expected design life of most reactors built afterwards.
However, thanks to extensive maintenance, upgrades and safety improvements, reactors today are operating well beyond their original licensed periods. The IAEA reports reactors have proven able to operate up to 60 years and beyond.[2] New reactors are now being designed for 60+ years of operation from the start.
License Renewals
The original operating licenses for U.S. nuclear power plants are issued for 40 years. The Nuclear Regulatory Commission (NRC) has the authority to grant license renewals, allowing plants to operate for up to 60 years total.
The process for renewing an operating license begins 5 years prior to expiration. The licensee must submit an application that includes technical information demonstrating how aging effects will be managed. The NRC thoroughly reviews the application, which can take 22-30 months. Reviews assess the environmental impacts, safety evaluation, opportunities for public participation, and legal considerations. If approved, the operating license is extended for 20 additional years.
As of January 2023, the NRC has granted subsequent renewed licenses to 94 of the current 93 operating U.S. nuclear reactors, extending their licenses from 40 to 60 years. Only a few plants, like Palo Verde in Arizona, have initial 40-year licenses that have not yet expired or been renewed as of 2023. According to the NRC, “All plants that have received renewed licenses are subsequently granted a 20-year extension beyond their initial 40-year license term.”
Sources:
https://www.nrc.gov/docs/ML2301/ML23010A074.pdf
Limiting Factors
There are several key factors that limit the lifespan of nuclear power plants:
Economic Viability – Nuclear plants have high operating and maintenance costs. Over decades of operation, maintenance costs tend to rise as components age and require replacement or upgrades. At some point, the costs may make the plant uneconomical to continue operating.
Maintenance Costs – Regular maintenance and equipment replacements are needed to keep nuclear plants running safely and efficiently. Major components like steam generators need to be replaced periodically. Refurbishment and upgrade costs can be substantial after decades of operation.
Technological Obsolescence – Nuclear plant equipment and design can become outdated compared to newer technologies. Upgrading to meet current standards and replace obsolete parts increases costs. At some point it may not be feasible or cost-effective to continue upgrading aged technology.
According to the IAEA, economic factors, maintenance costs, and obsolescence typically limit conventional nuclear plants to around 40-60 years of operation.
Safety Upgrades
Nuclear power plants have undergone significant safety upgrades and enhancements over the decades since the early commercial plants first came online. According to the IAEA, there have been continuous improvements in nuclear safety over the three decades leading up to the late 1980s, with more rigorous standards and requirements put in place for new plants and backfitting implemented at existing plants.
Some of the key safety upgrades made over the years include:
- Installation of additional backup systems for power, water, and core cooling.
- Enhanced instrumentation and control systems.
- Improved operator training and procedures.
- New emergency response requirements and drills.
- Stronger containment structures.
- More robust protection against natural disasters like earthquakes and floods.
These and other changes have led to significantly lower risk of accidents at nuclear plants over time. However, these upgrades do come at a cost. Backfitting existing plants with new safety systems and features is expensive. A World Nuclear Association report notes that the substantial safety enhancements made after the Three Mile Island accident in 1979 cost over $100 million per reactor.
The cost of meeting ever more stringent safety requirements is one factor in the economic challenges facing some existing nuclear plants today. But overall, the industry’s commitment to continuous safety improvement has paid off in improved performance and risk reduction.
Case Studies
The Oyster Creek Nuclear Generating Station in New Jersey was one of the oldest operating nuclear power plants in the United States until it permanently ceased operation on September 17, 2018. The plant had been in operation for 49 years before its closure (https://en.wikipedia.org/wiki/Oyster_Creek_Nuclear_Generating_Station).
One of the oldest still-operating nuclear power plants in the U.S. is the R.E. Ginna Nuclear Power Plant located outside Rochester, NY. The plant started operating in 1969 and is currently licensed to operate until 2029 (http://large.stanford.edu/courses/2017/ph241/conaton2/).
The future of the Ginna plant has been uncertain at times. In 2015, the plant owners proposed a deal to keep it operating and prevent its closure, as its closure could have major impacts on jobs and electricity supply in the region (https://www.democratandchronicle.com/story/news/2015/03/27/regulators-now-considering-plan-prop-ginna/70546950/).
Newer Designs
The newer generation III and IV nuclear reactor designs are expected to have significantly longer lifespans compared to earlier generations. Many of these new designs have a targeted operational life of 60 years or more.
For example, the generation III+ VVER reactor developed by Russia has a designed lifespan of 60 years. The advanced passive pressurized water reactors (AP1000) developed by Westinghouse also have a 60 year operating license period.
These newer reactors also utilize passive safety features that do not require active controls or human intervention. For example, the AP1000 relies on gravity, natural circulation, and compressed gas to control emergency cooling systems. Such features improve safety and reduce maintenance requirements over the lifespan of the plant.
Other generation IV designs like the high-temperature gas-cooled reactors (HTGR) or sodium-cooled fast reactors (SFR) are also engineered for at least 60 year lifespans and include inherent safety features that require less active maintenance over time.
Decommissioning
When a nuclear plant reaches the end of its operating life, it must undergo a process of decommissioning to safely shut down and dismantle the facility. Decommissioning involves removing and disposing of radioactive components and materials associated with the reactor. The Nuclear Regulatory Commission outlines a three-stage decommissioning process:
The first stage, DECON, starts shortly after the nuclear plant ceases operation. Equipment, structures, and portions of the facility containing radioactive contaminants are removed or decontaminated to a level that permits termination of the NRC license. This process can take 5-10 years.
The second stage, SAFSTOR, involves placing the facility in a safe storage configuration and reducing radioactivity through decay over an extended period, up to 50 years or more. The plant is then fully dismantled in the same manner as DECON.
The third stage, ENTomb, entails encasing radioactive structures, systems, and components in a structurally long-lived substance such as concrete. The entombed structure is appropriately maintained, and continued surveillance is carried out until the radioactivity decays to a level permitting termination of the license.
According to the World Nuclear Association, most reactors require 2-10 years for decommissioning with a deferred dismantling (SAFSTOR) strategy, and 4-7 years with an immediate dismantling (DECON) strategy. Significant time and resources are needed to safely decommission and remove all radioactive waste from a nuclear site.
Conclusion
Typical real-world lifespans for nuclear power plants today are around 40-60 years. The average age of retired nuclear reactors in the US between 2000-2015 was around 46 years old [1]. However, many plants receive 20 year operating license extensions, allowing them to operate for 60 years or more. With proper maintenance and component replacement, there are no hard technical limits to a plant’s lifespan [2].
Newer generation III/III+ reactor designs aim to increase lifespans to 80 years or more. Features like passive safety systems, modular construction, and simplified maintenance are expected to improve longevity. Decommissioning is also built into the design to be faster and more efficient. These reactors could operate until near the end of the 21st century if constructed soon.
