Years from now, the iconic stack of the Oyster Creek nuclear power plant in Lacey will be a distant memory. The buildings will be gone, the vast majority of workers will be gone, and the 625-megawatt power plant will have long since stopped producing energy.

Yet one remnant will likely remain for decades – if not generations – into the future: radioactive waste.

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Accumulated over 50 years of energy generation, radioactive waste will remain on the property, entombed in concrete casks behind fencing. There it will stay, at least until U.S. officials answer a longstanding political and environmental riddle: what to do with the spent fuel when the nation's nuclear power plants close up shop.

"There’s no place to put it," said Jeff Brown, a Brick resident and member of the anti-nuclear group GRAMMES, or Grandmothers, Mothers, and More for Energy Safety.

"They have to isolate this waste up to 250,000 years," he said. "It’s almost forever."

The plant will produce its last energy by December 2019, when its parent company, Exelon Corp., plans to shutter it forever. Then, the company has 60 years to fully take apart and decontaminate the buildings and equipment.

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"Decommissioning is a very slow and methodical process," said plant spokeswoman Suzanne D'Ambrosio. Public health and safety is the top priority for the company, she said. "When we decommission, that will still hold true."

More than $888 million has been put into a trust fund to pay for the powering down of the plant, which occupies a 700-acre property. Exelon estimates decommissioning will cost more than $1 billion.

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While nuclear regulators and local politicians wait for Oyster Creek officials to release their decommissioning plan, radioactive material continues to accumulate on the site — where it will remain for the foreseeable future.

Aged plants like Oyster Creek Generating Station are closing one by one. They will leave behind their radioactive fuel rods, entombed in concrete and steel.

Over time, nuclear fuel loses its ability to maintain a chain reaction. Periodically, nuclear plants remove this "spent fuel" and and store it in pools, where the still-hot radioactive material is cooled.

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As such pools fill with spent fuel rods, plants such as Oyster Creek move the cooled rods to sealed metal cylinders, which are encased in metal or concrete outer shells to provide radiation shielding.

At Oyster Creek, 27 of these so-called "dry casks" hold decades worth of the plant's spent fuel, according to the Nuclear Regulatory Commission, which oversees safety at the plant.

This spent fuel remains dangerously radioactive for thousands of years. Yet the casks are licensed or certified for only 20 years, or up to 40 years if their licenses are extended.

Though the NRC says the casks are safe and environmentally sound, environmentalists worry about the security of the radioactive waste in the long term.

Jeff Tittel, director of the New Jersey Sierra Club, said sea level rise could pose a risk in the future.

"Ten thousand years from now, when that waste is benign, the coast of New Jersey could be 20 miles inland," he said.

Such a sea level rise would leave the casks underwater and at risk of degradation.

"We don't even know in 50 or 100 years from now what it's going to look like along the coast," Tittel said.

He added: "When that plant was built in 1969, people didn’t think about sea level rise or storm surge, though we did have massive hurricanes. But I don’t know if they really thought about how they would become more frequent or worse over time."

But moving the waste is generally considered a greater risk, exposing people who live along highways and rail lines to danger of a nuclear accident.

Currently there are no completed major repositories for nuclear waste. The NRC on Wednesday sought comment about disposing radioactive waste at Yucca Mountain in Nevada.

Such a project was originally planned for under the Nuclear Waste Policy Act but later stripped of funding by the Obama Administration — under pressure from former Nevada Sen. Harry Reid, the longtime Democratic leader, who opposed the Yucca Mountain plan. He retired in 2017.

Lacking Yucca Mountain's availability and risks of transporting nuclear material, Oyster Creek's radioactive waste will stay on plant property for the foreseeable future.

Janet Tauro, a member of Clean Ocean Action and GRAMMES, said the more serious risk exists while the hot fuel remains in the plant's cooling pool.

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The pool at Oyster Creek is about 38 feet deep and surrounded by concrete, which the NRC said is safe. The pools are designed to withstand both natural and man-made disasters.

But Tauro said Oyster Creek's pool – suspended some 75 feet high in the reactor building according to commission documents – poses a serious risk to public health.

"I don’t think Lacey Township should be a mini Yucca Mountain for 60 years," she said. "They gotta get that waste out of the fuel pool. ... It’s only covered by a thin metal roof. It’s very, very dangerous. You shouldn’t be storing that stuff in an overhead fuel pool."

The NRC will continue its oversight of Oyster Creek throughout the decommissioning, notes plant spokeswoman D'Ambrosio. She said said the company will continue to follow federal regulations "to the letter." (D’Ambrosio is married to Asbury Park Press News Director Paul D’Ambrosio. He had no editorial oversight of this story and did not read it prior to publication.)

While environmentalists and plant officials debate where to store the spent fuel, Lacey officials may have a strong incentive to keep it within the township's borders. The fuel could be a source ongoing revenue.

Lacey officials may look to the western shore of Lake Michigan for lessons about how to make storing spent fuel pay.

The rural Wisconsin town of Carlton is still reeling from the closure of Kewaunee Power Station in 2013. That year, the town's financial lifeline went off the grid. About $325,000 of income was cut from the town's half-million dollar budget, or about 60 percent, said Carlton Chairman David Hardtke. The town now receives $250,000 in support from the plant's parent company, Dominion Energy of Richmond, Virginia, and $50,000 for hosting the nuclear waste, Hardtke said.

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Lacey Committeeman Gary Quinn sees a financial opportunity within Oyster Creek's dry casks — though any gain would be a pittance compared with the $80 million the plant pumps into the economy each year. It employs about 550 workers directly.

But no federal rule entitles towns such as Lacey and Carlton to collect subsidies for hosting the waste. Quinn said the township is joining others like it in order to pressure the federal government to guarantee compensation for storage.

As more nuclear power plants shut down, triggered by competition from cheap natural gas, storing leftover waste will be a concern for a growing number of towns.

In May, Exelon Corp., which owns and operates Oyster Creek, announced that it would close another nuclear power plant in Pennsylvania: Three Mile Island. Other nuclear plants are planning to close as well: Diablo Canyon Nuclear Power Plant near Los Osos, California, and Indian Point nuclear power plant in Buchanan, New York.

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When Oyster Creek goes offline in December 2019, it will be another 10 years before its fuel is moved from the cooling pool into dry cask storage. Eventually, the plant's buildings will be tested for radiation and taken apart, but it is a process that could take decades.

Environmentalists do not want to wait.

"You have to understand that that plant will still be a threat, not only to the environment, but a safety threat, until all the rods cool down to a certain level," said Tittel. "And so it will still be vulnerable to storms and sea level rise and other things until then."

"This is a 1969 Chevy Nova in the age of Teslas," he said.

Amanda Oglesby: 732-557-5701; aoglesby@GannettNJ.com