Cocooning of Hanford’s K East Reactor begins

June 29, 2022, 7:00AMRadwaste Solutions
The first steel columns, each weighing up to 28 tons, were placed for a cocoon over the former K East Reactor building at the Hanford Site. (Photo: DOE-EM)

The Department of Energy’s Office of Environmental Management (EM) said that construction is well underway on a protective enclosure, or cocoon, for the K East Reactor building at the Hanford Site near Richland, Wash.

EM reports that is has achieved one of its key construction priorities for 2022 by beginning construction of the enclosure, which is designed to protect the reactor building while the radioactivity in the deactivated reactor core decays over the next several decades, making it safer and easier to decommission.

A time-lapse video showing the construction of the cocoon’s massive 120-foot steel frame can be seen here.

The work: Last summer, EM contractor Central Plateau Cleanup Company was awarded a subcontract for the installation of the steel frame, and crews broke ground on the site last fall.

Earlier this year, workers finished backfilling and compacting the area around the former reactor with approximately 34,000 cubic yards of sand and gravel to level the site before pouring a 6-foot-thick concrete foundation to support construction of the cocoon. The first steel columns for the enclosure were placed in mid-May.

Construction activities will continue through the summer, with workers expected to finish the structural steel skeleton and install metal siding on the walls and roof to fully enclose the building by this fall. The completed structure will be more than 150 feet wide and 120 feet tall. The design allows for routine inspections of the reactor every five years. Additional safety features include new lighting between the structure and the reactor building, as well as upgraded lighting inside the building.

The reactor: The K East Reactor operated from 1955 to 1971 and will be the seventh of Hanford’s nine former plutonium production reactors to be placed in interim safe storage. The K West Reactor will be the eighth.

The ninth, the B Reactor, has been preserved as the world’s first full-scale plutonium production reactor and is part of the National Park Service’s Manhattan Project National Historical Park. Hanford’s other six reactors were cocooned between 1998 and 2012.


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