Shutting off the power at a nuclear plant takes only a few minutes. But decommissioning one — safely removing and storing dangerous radioactive material and closing down the plant for good — can take decades.
In announcing Tuesday that it planned to close the Pilgrim Nuclear Power Station, owner Entergy Corp. revealed few details about how it plans to decommission its aging plant in Plymouth, rated among the least safe in the country. But recent history at nuclear plants in New England and beyond suggests that the process could be long, contentious and cost hundreds of millions of dollars.
Entergy has 60 years to close the plant, according to Nuclear Regulatory Commission guidelines, and that clock may not even start running until 2019, the year by which the company plans to cease operations at Pilgrim. That means it could be 2079 before radioactivity is reduced to safe levels — the ultimate goal of decommissioning.
Company officials say Pilgrim shouldn’t take that long.
“We don’t intend to wait until 60 years,” said Bill Mohl, president of Entergy Wholesale Commodities, which oversees most of its nuclear plants.
Still, decommissioning any nuclear power plant takes time. Giant industrial edifices such as the reactor, where the fuel generates heat that is converted to steam, would be difficult to dismantle even if they were not brittle and dangerously radioactive. Radioactive nuclear fuel must remain in storage pools for years after the plant has ceased to generate power.
And even after the fuel is stowed in giant canisters called dry casks, deciding where to store the nuclear waste is still tied up by debate in Washington, and remains years away.
“It’s going to take years in any event,” said Geoffrey Fettus, a senior attorney at the Natural Resources Defense Council. “It’s very complicated, very expensive industrial cleanup.”
Under federal guidelines, operators have options for decommissioning a plant: They can decontaminate and remove all radioactive material as soon as possible; leave the plant largely intact as the remaining radiation dissipates; or do some combination of the strategies.
Entergy did not announce Tuesday which path it would take at Pilgrim. But work can’t begin until there’s enough money in Pilgrim’s federally mandated trust fund to ensure it can shutter the plant. Mohl said the company is trying to determine how much decommissioning Pilgrim will cost.
The decommissioning trust fund had a balance of approximately $870 million as of Sept. 30, Mohl said — $240 million more than the company is legally required to have at this time, but $380 million less than the estimated $1.25 billion cost to decommission Entergy’s Vermont Yankee plant.
At Vermont Yankee, which ceased operations last December, the company’s decommission plan largely calls for leaving the plant intact and keeping radioactive material onsite, a strategy known as SAFSTOR.
Under that plan, the company will spend about five years removing the radioactive waste from the plant’s spent-fuel pools — water-filled chambers 40 or more feet deep that contain the intense heat and high levels of radiation generated by the fuel rods. Once cool enough to be moved, the fuel will be placed in dry casks — massive, reinforced canisters weighing more than 300,000 pounds that are designed to vent amounts of radiation so small they are not considered harmful. They will be left on storage pads somewhere on the plant’s property.
And there the spent fuel will remain, until the federal government finds a suitable location to store it. That could take decades: The Obama administration ended funding for Nevada’s planned Yucca Mountain Nuclear Waste Repository in 2011, and no long-term storage site for the waste from nuclear reactors currently exists.
Vermont Yankee’s plan is likely a pretty good predictor of how Entergy might approach decommissioning at Pilgrim, said Michael Mariotte, president of an environmental advocacy group, the Nuclear Information and Resource Service.
Mariotte said he expects Entergy will try to maneuver its way out of regulatory obligations in Massachusetts, as he said it did in Vermont. There, Entergy obtained federal permission to reduce the emergency planning area — the 10-mile evacuation zone around the plant in which the company must pay for training and preparedness in case of disaster. The state is fighting that move.
Though the chances of a dangerous release of radiation lessen once the plant goes offline, he said, “the problem from a public safety perspective is that the radiation is still there.”
Also of concern, Mariotte said, is the security of the casks. While Vermont Yankee is inland and far from large population centers, Pilgrim is potentially in the path of hurricanes and a target for terrorists.
“We believe that storage should be hardened with berms and protected from the elements,” Mariotte said. “You also want to keep them so some guy with a shoulder-fired missile can’t reach them.”
Neil Sheehan, a public affairs officer for the Nuclear Regulatory Commission, described Entergy’s decommission process in Vermont as “pretty straightforward.” He also said reducing the emergency-planning requirements once the plant shut down made sense.
“The risk of an event that could have offsite consequences is greatly reduced,” he said.
Fettus, who testified about decommissioning before a congressional committee last year, said communities, companies and the country are all still inexperienced when it comes to safely shuttering plants.
The ideal way to ensure the safety of workers and residents during the process has yet to emerge, he said.
“It really does leave a complicated situation with some head-scratchers,” Fettus said. “But it’s starting to happen, and it’s happening fast.”