The Shippingport Atomic Power Station in western Pennsylvania became the first commercial nuclear power plant in the United States when it came online in 1958. Since then, nuclear energy has become an integral part of the national power grid. Today, there are 55 commercial nuclear power plants nationwide, and for the last four decades, nuclear reactors have accounted for about 20% of U.S. energy production annually.

Of course, nuclear power plants have limited lifespans. The Shippingport Atomic Powers Station, for example, was shut down in 1982 amid safety concerns. Currently, the U.S. Nuclear Regulatory Commission, or NRC, licenses plants to operate a nuclear reactor for 40 years, after which, plants must apply to extend their license in 20 year increments.

Though the oldest commercial nuclear plant in the United States is long since closed, there are dozens of active plants that have been in operation for decades.

Using data from the NRC, 24/7 Wall St. identified the oldest nuclear power plant in the United States. Plants were examined based on the date their oldest active nuclear reactor went online.

It is important to note that nuclear power plants generate electricity often through multiple nuclear reactors that went online at different times. For the purposes of this story, only the oldest active reactor at each plant was considered.

Partially because of the hazardous nature of nuclear waste, fully decommissioning a nuclear reactor can be a decades-long process.

The oldest nuclear power plant in America is Nine Mile Point Nuclear Station. Here are the details:

> Start of commercial operations: 12/1/1969
> Electricity production capacity: 1,913 megawatts
> Location: Scriba, NY (6 mi. NE of Oswego, NY)
> Operator: Nine Mile Point Nuclear Station, LLC

Methodology: To identify the oldest nuclear power plant in the U.S., 24/7 Wall St. reviewed the start dates of commercial operation for nuclear reactors in the United States using data compiled by the Nuclear Regulatory Commission. Plants are ranked by the date their oldest active nuclear reactor went online.

To compare each power plant’s electricity production capacity, we summed each plant’s reactors’ megawatt electricity (MWe).

Plant names and data are as identified on the license as of August 202. The next printed update will be in September 2022.

Click here to read America’s Oldest Nuclear Power Plants

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