A York County nuclear plant is now licensed to operate an additional 20 years past its 60-year license.

The Nuclear Regulatory Commission approved the extension request from Exelon Generation for Units 2 and 3 on Friday after a 20-month review process.

Peach Bottom Atomic Power Station, in Peach Bottom Township, is only the second plant in the country to be approved for operation past 60 years. Florida Power and Light's Turkey Point Nuclear Generating Station in Florida, was the first.

Exelon executives lauded the extension.

"The ability to operate Peach Bottom for another 20 years is good news for the environment, our employees and the community,” said Bryan Hanson, Exelon's chief nuclear officer, in a news release.

Dominion Energy has an application under review for a second renewal for two units at Surry Power Station and has submitted a letter of intent to do the same for North Anna Nuclear Generating Station. Both plants are in Virginia.

Duke Energy also submitted a letter of intent for three units at Oconee Nuclear Station in South Carolina.

Second renewals have been a point of controversy among anti-nuclear activists, who say not enough is known about the effects of aging on nuclear equipment.

More:Activists challenge license extension for Peach Bottom nuclear plant

Anti-nuclear watchdog group Beyond Nuclear opposed the extension at Peach Bottom and argued against it before the U.S. Atomic Safety and Licensing Board at NRC headquarters in Rockville, Maryland, last March.

The group said Exelon did not meet NRC standards for renewal because it did not provide enough evidence of studying aging equipment.

Exelon should be harvesting materials from other plants such its decommissioned Oyster Creek plant, which has the same boiling-water reactor as Peach Bottom, the group argued.

The board denied a subsequent hearing regarding the license renewal in June on the basis that arguments against the extension were "too vague" and speculative.

More:Ruling: Arguments against Peach Bottom nuke license 'too vague'

After reviewing potential safety issues, the NRC concluded that Peach Bottom met the requirements of the law, and there were no severe accident mitigation alternatives that would reduce plant risk by 50% or more.

The NRC's Advisory Committee on Reactor Safeguards determined it could continue operating "without undue risk to the health and safety of the public."

Peach Bottom's Unit 2 license will now expire Aug. 8, 2053, and its Unit 3 license will expire July 2, 2054.

Last year, Exelon unsuccessfully lobbied state lawmakers for a bailout that would have boosted profits at its financially failing Three Mile Island Nuclear Generating Station in Dauphin County. But the bills died in the Legislature, leading the company to announce the closure of the plant in September.

“Nuclear plants must remain financially viable to continue to operate," Hanson said. "It’s critical that we continue to pursue policy reforms that value the environmental, economic and reliability benefits that zero-carbon nuclear energy provides.”

State lawmakers in several states — including Illinois, New York and New Jersey — have approved bills that bolstered Exelon's bottom line.