Calder Hall Cooling Towers
ROM ENGINEERING NEWS RECORD/MCGRAW-HILL CONSTRUCTION – OCTOBER 3, 2007 “Oldest Nuke’s Towers Felled In U.K.’s Sellafield Complex” – By: Peter Reina
Within a few minutes of each other on Sept. 29, two pairs of cooling towers at the world’s first nuclear power plant disappeared from Sellafield’s skyline on the English coast. Their controlled explosions had been two years in the making.
Demolishing the 91.1-meter-tall towers for Calder Hall generating station’s four gas-cooled reactors was the most visible part of a program to remove hundreds of buildings at the 4-sq-kilometer nuclear site, and clean up after 60 years’ military and civil nuclear activity.
Toppling the towers went as planned, says Andy Scargill, decommissioning and clean-up superintendent for operator British Nuclear Group. “We had to go through a lot of steps to make sure the regulator was happy,” says Scargill. Of more than 200 towers demolished in the U.K., none was sited within 40 m of a nuclear fuel-handling plant.
BNG’s tower team, headed by Dyan Foss, probed in detail a range of risks, such as debris spread, projectiles and vibrations. Despite a dearth of recorded information, BNG produced “a complete historical evaluation of cooling towers and historic demolition methods, hazards and controls,” says Foss.
The final demolition procedure went as first planned, with one significant modification. As well as blasting 60% of towers’ supports, Controlled Demolition Inc., Phoenix, Md., detonated a vertical slot in each shell to aid its fracture.
BNG is spending around $1 billion a year cleaning up and demolishing facilities as Sellafield’s life nears its end next decade. Demolition and clean-up account for a fifth of that budget. Handling 75 projects, Scargill manages some 800 Sellafield and subcontractor staff. Among the projects is demolition of a 125-m-tall chimney, contaminated by a reactor fire.
Phasing out Sellafield is uniquely complicated, says Scargill. U.S. facilities may be bigger, “but this is the only site in the world that has one of everything and sometimes two or three,” he says, including weapons manufacturing facilities, power plants, vitrification plants and waste storage. And working around operational plants adds complexity.
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