Engineers are completing plans for what may be the largest movable structure ever built -- a 20,000-ton steel shell to enclose Chernobyl Reactor 4, site of an apocalyptic nuclear accident whose consequences are still being felt more than 16 years later.
By next summer an international consortium led by Bechtel International Systems Corp., of San Francisco, will finish the conceptual design for a hangar-shaped arch nearly 370 feet high -- the height of a 35-story building -- that would be slid into place along greased steel plates to cover the ruined remains in a snug, weather-tight shelter.
In April 1986, a nuclear reaction at the Chernobyl power plant went out of control, causing an explosion that blew the roof off, killing 30 workers immediately and releasing tons of radioactive material into the atmosphere.
(File Photo /anatoly Maltsev -- AFP)
Inside, robotic cranes and, where possible, live workers will then begin prying apart the wreckage, removing radioactive dust from twisted girders, storing pieces of radioactive core in shielded canisters and cutting old steel into manageable lengths.
The whole job -- design, construction and "stabilization" of the derelict reactor 80 miles north of Kiev -- is part of a fully funded 10-year plan set in motion by the Group of 7 industrialized nations in 1997. The $768 million project, including the shell, is scheduled for completion in 2007, according to officials involved with the project.
And then the world will wait.
The shelter is designed to keep water out and dust in for 100 years, or for as long as it takes the Ukrainian government to designate a permanent storage facility and dispose of more than 200 tons of uranium and nearly a ton of lethally radioactive plutonium that remain inside the ruins.
Most of the fuel-containing material lies as a solid "lava" formed by the fusion of molten fuel, concrete, 30 tons of fuel dust and 2,000 tons of combustibles.
In the basement, rainwater and fuel dust have mixed together in a dangerous radioactive "soup." Lethal chunks of the reactor core lie unseen in the rubble and in the earth alongside the building. More pieces of core were boxed and buried in a "cascade wall" built and bulldozed into place by Soviet workers in the immediate aftermath of the explosion.
"We will need a lot of shielding," said Vincent Novak, director of the Nuclear Safety Department for the European Bank for Reconstruction and Development, overseers of the project. "If it weren't for the radioactivity, I could almost call the job 'a piece of cake,' but the radiation makes it hugely complex and extremely difficult."
The Chernobyl explosion occurred April 26, 1986, when an out-of-control nuclear reaction blew off the roof of the steel building and spewed tons of radioactive material into the air, releasing 30 to 40 times as much radioactivity as the Hiroshima and Nagasaki atomic bombs combined in 1945.
It was the worst nuclear accident in history. Thirty workers died immediately at the facility, and 135,000 people were evacuated from the surrounding "Exclusion Zone." As recently as 2000, the Ukrainian government was spending 5 percent of its gross domestic product to mitigate consequences of the disaster.
In the six months immediately following the explosion, the Soviets erected an improvised shelter known as the "sarcophagus," but within 10 years scientists became alarmed because of leaks and the building's threatened collapse. The walls were weakening, Novak said, and there was tremendous uncertainty because "it was almost impossible to determine" the real dangers.
In 1997, the Group of 7, plus Russia, the European Union and Ukraine, set up the Chernobyl Shelter Fund with the European reconstruction bank in charge. The bank established a shelter implementation plan, estimated the project cost at $768 million, and funded it with donations from 28 nations, ranging from $170 million from the United States to Iceland's $10,000.
In the first phase, completed in 1999, the sarcophagus's roof and structural pillars were strengthened, and the reactor's rickety ventilation stack, jutting more than 150 feet above the sarcophagus, was stabilized. The stack was an added concern, because it was shared by the contiguous Reactor No. 3, which was still operating.