WISCASSET – Old atomic power plants die hard.

Seven years after Maine Yankee stopped producing electricity, the dome that once covered the state’s only nuclear reactor is coming down.

The 20 million pound structure will be exploded Friday morning, part of a demolition job costing $500 million – twice what it cost to build the plant 30 years ago.

The reactor itself is long gone, shipped to a waste facility in Barnwell, S.C., but 1,434 spent fuel rods – nuclear power’s deadly leftovers – remain on site, stored in 60 airtight canisters contained in concrete.

Friday’s explosion will mark the first time a containment building of that size has been exploded or even just taken down, said Maine Yankee spokesman Eric Howes.

There are 19 nuclear power plants in the United States that have been permanently shut down and are at some stage of decommissioning, according to the Nuclear Regulatory Commission. Maine Yankee is further along in dismantling than any other plant, Howes said.

The plant used to churn out some 5 billion kilowatt-hours of electricity, enough to meet the needs of about 25 percent of Maine’s power customers.

It also kicked in $12 million to $15 million a year in property taxes for Wiscasset, Maine’s self-proclaimed “prettiest village.”

“It kept taxes low for everybody else,” said Town Manager Andrew Gilmore. “That’s no longer the story.”

So in 1995 – two years before Yankee stopped producing power – Karl Tarbox’s mother paid $285 a year in taxes. “Her sewer bill now is more than her tax bill was eight years ago,” her son, a town selectman, said Friday. Now, her house taxes are roughly $2,200.

The resulting rise in property taxes since Maine Yankee’s heyday is “about a factor of eight for most people,” Tarbox said.

A revaluation had not been done for 40 years, Tarbox said, so one was ordered in 1998, the year after Maine Yankee closed.

The plant, which was run by a consortium of utilities, was plagued by operating problems, and the sour U.S. enthusiasm for nuclear power after the 1979 Three Mile Island and 1986 Chernobyl accidents. Opponents forced a referendum on the plant.

Today, 103 reactors in 31 states still produce electricity.

“Maine Yankee is in the business of going out of business,” Howes said as he walked around the Bailey Point site Friday, pointing to where various buildings once stood. Even the parking lot pavement has been ripped up and removed. The project has already generated 249 million pounds of non-nuclear waste.

By spring, about all that will remain on site is an independent spent-nuclear-fuel facility. Exactly when the 1,434 “assemblies” of high-level waste are carted away by rail is up to the federal government.

Maine Yankee and other nuclear facilities are suing the federal government for not meeting its own deadline to provide a permanent repository for the spent fuel by 1998. A site at Yucca Mountain, Nev., is targeted to open in 2010. “It’s uncertain if they’ll meet that one,” Howes said, referring to the deadline.

Until a disposal facility is opened, the spent radioactive fuel will remain on the roughly 150-acre parcel being retained by Maine Yankee.

Maine Yankee has sold 430 acres of its 800-acre property to the town, which in turn, sold it to a development firm. Point East of Greenwich, Conn., will eventually create a mixed-use technology village on the Ferry Road North property.

Another 200 acres of Maine Yankee’s land, known as Eaton Farm, will be donated to the Chewonki Foundation for environmental education, conservation and public access as part of a Federal Energy Regulatory Commission settlement agreement, Howes said.

“The decommissioning of Maine Yankee is significant to us on many levels,” said Gilmore, the town manager.

For years, Wiscasset was economically “a one-horse town,” he acknowledged.

From the plant’s closing in 1997, Maine Yankee has seen its assessed value plummet from $500 million-plus to $35 million in 2002, Howes said.

Gilmore said Wiscasset adjusted to the loss with the help of “a healthy fund balance.” He cited a $12.6 million reserve account that exists today. Between some reserve money and the revaluation, “people’s taxes went up, but it didn’t push them off the cliff overnight,” he said.

A full-blown assessment had never been done on Maine Yankee, town officials said, so a consulting team was hired in March 2003 to conduct a review. Since 2002, the value of the property has risen to $218.8 million, Gilmore said, which Maine Yankee is disputing.

Meanwhile, crews were busy Friday making preparations for the 150-foot-tall dome’s removal.

It was built to withstand natural disasters and sits on top of 75-foot walls. The dome is 144 feet in diameter and 21/2 feet thick. The cylinder walls are 41/2 feet thick. The entire structure is made of concrete reinforced with 2-inch diameter rebar and backed with steel plating.

Nine large rectangular sections have been cut out from the concrete containment building walls, creating an eerie-looking structure that resembles a backdrop for a science fiction movie.

After seeing it, Howes’ children described the partially dismantled building as “a giant jellyfish.”

The columns are being wrapped with chain-link fencing and cloth to minimize dust and debris when the horns sound and the explosive charges are detonated. When the dome lands on the ground, there will be a massive pile of low-level radioactive rubble to remove.

“In simplest terms, they’re going to blow the legs out from under it,” Howes said.

The demolition materials will then be transported by rail to Envirocare of Clive, Utah, where they will be buried in the desert, Howes said.

When the U.S. government finally takes the high-level waste away, the Nuclear Regulatory Commission will release the license on the property, Howes said. What happens to the 150 acres then is undetermined, he said.

Meanwhile, Wiscasset continues to blaze trails in uncharted waters, Gilmore said.

First, it was the only town in Maine to play host to a nuclear power plant, he said. Now it is the only Maine town to host a nuclear storage facility.

“Maine Yankee’s going to be here for a long time,” Gilmore said.