WISCASSET – With a fiery flash and a shattering boom, the most prominent symbol of Maine’s 30-year dance with nuclear power dropped to the ground Friday.

Using 1,100 pounds of explosives, crews took a split second to destroy the 20-million-pound concrete dome that once housed the 900-megawatt power plant’s nuclear reactor.

Earlier this month, rectangular openings were cut out of the walls of the building, creating what looked like concrete legs supporting the massive 150-foot tall dome. The legs were wrapped with chain-link fencing and fabric to minimize flying debris.

Before the 10 a.m. blast, a series of horns sounded. Then the final countdown was aired over loudspeakers.

Hundreds of spectators toted camp chairs and children to the viewing site from parking lots located well away from the demolition area.

Security was tight. At the initial checkpoint, a security officer clutched an assault rifle.

At the end of the countdown, flashes of fire spewed from the legs and smoke billowed from the building as it exploded. The huge boom brought a thunder of applause and cheers from spectators as the dome fell. Soon, fine cement dust was settling on cameras and clothing 1,000 feet from the blast site.

The nuclear energy complex – most of which is gone now – is situated on Bailey’s Point along the Back River in the self-described “prettiest town in Maine.”

Starting in 1968, it took four years to build Maine Yankee. Owned by a consortium of utilities, the plant was Maine’s only commercial nuclear energy producer. Plagued by problems in the 1990s, its owners shut the plant down. It has taken seven years to take it apart.

Soon the administration building will be gone.

By spring, all that will remain is an independent spent-nuclear-fuel facility and a security building.

The reactor was shipped to a waste facility in Barnwell, S.C., but 1,434 spent fuel rods will remain sealed in 60 airtight canisters contained in concrete until the federal government figures out where to bury high-level waste.

Maine Yankee’s demolition was a field trip for 8-year-old Jubal Gilbert of West Bath, who thought the containment building was weird looking, but liked the loud blast.

After the 10 a.m. detonation, only one person called the Lincoln County Communications Center to report a loud explosion, a dispatcher said Friday. “We expected to get flooded [with calls],” he said.

“I’ve never been to an implosion and here I am,” Norma Overhiser said. She traveled from Trumbull, Conn., to witness the event. Her son works for Manafort Brothers, which is a contractor for the demolition.

“It’s probably just an end of an era for a lot of people,” she said.

Maine Yankee milestones

1966: Maine Yankee Atomic Power Co. created.

1972: Commercial operation begins.

1980: Referendum to close plant fails.

1982: Referendum to close Maine Yankee fails.

1987: Referendum to close Maine Yankee fails.

1989: Best production year (6.9 billion kilowatt hours).

1994: Cracks discovered in steam generator tubes.

1995: Plant shut down most of the year during repairs.

1996: Plant shut down again for what proves to be the last time.

1997: Board decides to close plant permanently.

1999: Sirens intended to warn residents of meltdown removed.

2000: Workers begin gutting some buildings.

2003: Reactor vessel removed and shipped by barge to South Carolina.

2004: Containment building brought down by explosives.

2005: Maine Yankee to complete decommissioning.