While a nuclear plant is operational, safety is Job #1. Workers at nuclear plants take immense pride in the fact their facility is preventing millions of tonnes of CO2 emissions annually, while accomplishing that feat safely and responsibly.

That can change quickly after shutdown, however. Oyster Creek Nuclear Generating Station, near Waretown, New Jersey, was shut down ten years early - even though the Nuclear Regulatory Commission had unconditionally certified its safety for at least another decade:

"This has been the most extensive license renewal review to date...the staff’s licensing and inspection scrutiny...should give the people of New Jersey added confidence that Oyster Creek will remain safe during its continued operation."

and found that employees at the plant averaged less radiation exposure than workers at any other nuclear power plant of similar design in the U.S.
Virulent anti-nuclear shadow groups "Friends of the Earth", "Nuclear Information & Resource Service", "Beyond Nuclear", "NukeFree.org", "Greenpeace", and "Physicians for Social Responsibility", disagreed. Together with attorney Harvey Wasserman, an attorney who for decades has successfully employed fearmongering to market anti-nuclear legal services and paraphernalia, forced Exelon to defend its decision to re-license the plant in a federal court of appeals. When the groups alleged its once-through cooling (OTC) system killed billions of aquatic creatures (by considering microscopic plankton "aquatic creatures"), and legislation was passed forcing Exelon to spend $billions to replace its OTC system with cooling towers, the company threw in the towel.

After it was shut down, Oyster Creek was sold to Holtec International, a company that specializes in decommissioning services. In May, Holtec bragged that

"The last spent fuel was moved 32 months after the nuclear power plant ceased operations in September 2018, setting a world record and putting the former nuclear power plant on track to becoming the fastest decommissioned plant...it took contractors 21 weeks to load a total of 33 high-capacity HI-STORM 100 FW systems, setting a new world record."

apparently elevating speed above security in a list of decommissioning priorities:

"During a discretionary inspection at the Oyster Creek Nuclear Generating Station, the Nuclear Regulatory Commission identified apparent violations related to physical protection programs designed and implemented to safeguard against design basis threats of radiological sabotage. Some of the possible violations could be escalated for enforcement purposes, including a civil penalty.
“Once the issues were identified, we notified the NRC and took corrective actions,” said Suzanne D’Ambrosio, communications and supplier diversity manager at Oyster Creek. “We will continue to work with the NRC to provide additional information for further discussions.”
Since the issues in question are security-sensitive matters, details cannot be publicly released under the NRC’s regulations, according to D’Ambrosio."

The premature shutdown is estimated to cost New Jersey ratepayers $822 million.