There was a pop, a low rumble and -- in just a few seconds -- Savannah River Site's K-reactor cooling tower was reduced to 52 million pounds of concrete rubble.
"It's down, and it went quick," said U.S. Energy Department spokesman Jim Giusti, one of the observers authorized to watch the 10 a.m. demolition of the 450-foot-tall structure.
"The bottom went out, and it just went straight down," he said in an interview Tuesday from the scene. "From where we're standing, it just disappeared from the horizon."
Reporters were not allowed to observe the demolition, but video and still images were made available.
The removal of the $90 million tower completed in 1992 was part of the site's $1.6 billion American Recovery and Reinvestment Act program, most of which was earmarked for cleanup and environmental-management projects.
As the second-largest cooling tower to be demolished worldwide, the 345-foot-wide tower posed a unique challenge to American DND and Controlled Demolition Inc. -- the contractors hired to complete the task.
Engineers who spent months surveying the tower placed 3,860 separate charges -- fueled by 1,300 pounds of nitroglycerin-based explosive -- along the lower 250 feet of the structure. The implosion occurred on time and was a complete success, observers said.
"The cooling tower demolition project is unlike any other closure initiative taking place at the site," said Dewitt Beeler, a Savannah River Nuclear Solutions director. "It isn't every day that we deal with the demolition of a structure the size of the K cooling tower, and it was clear early in the process that we needed expert help."
Now that the tower has been brought to the ground, the rubble will be transported to an on-site landfill for permanent disposal.
K-reactor, across the Savannah River from Plant Vogtle, first went critical in 1954 and was one of the site's five original heavy water reactors created to make material for the nuclear weapons program.
It was shut down in 1988, along with L- and P-reactors, but was later earmarked for restart with a mission to produce tritium -- an essential ingredient in hydrogen bombs.
The cooling tower was built to help the reactor comply with environmental standards for water released into the Savannah River.
In February 1992, the Energy Department announced that the reactor would be used only as a reserve facility, to be tested and then shut down unless needed. After a successful test in 1992, K-Reactor was placed on "cold standby" before being shut down completely in 1996.