Workers with EM contractor Central Plateau Cleanup Company last month placed the first steel columns — each weighing up to 28 tons — for a protective enclosure, or cocoon, over the former K East Reactor building at the Hanford Site.
Workers with EM contractor Central Plateau Cleanup Company last month placed the first steel columns — each weighing up to 28 tons — for a protective enclosure, or cocoon, over the former K East Reactor building at the Hanford Site.

RICHLAND, Wash. – A massive steel structure is rising more than 120 feet above the semiarid landscape of southeastern Washington, with construction well underway on the protective enclosure — or cocoon — for the seventh of nine former plutonium production reactors on the Hanford Site.

EM achieved one of its key construction priorities for 2022 by beginning construction of the enclosure. The structure is designed to protect the K East Reactor building while the radioactivity in the deactivated reactor core decays over the next several decades, making it safer and easier to complete disposition of the reactor in the future.

See this time-lapse video on construction of the steel structure.

Installation of the steel frame highlights a year of tremendous progress on the project. EM Richland Operations Office (RL) contractor Central Plateau Cleanup Company (CPCCo) awarded a subcontract for the work last summer, 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.

“It has been impressive to watch this project take shape over the past several months,” said Mark French, RL division director for Hanford’s Central Plateau Cleanup Project and Facilities Division. “Placing another reactor in interim safe storage is a huge achievement for the Hanford Site, and certainly a key part to our cleanup mission.”

An artist’s rendition of the K East Reactor safe-storage enclosure. K East will be the seventh former reactor at the Hanford Site to be placed in interim safe storage.
An artist’s rendition of the K East Reactor safe-storage enclosure. K East will be the seventh former reactor at the Hanford Site to be placed in interim safe storage.

The design allows for routine inspections of the reactor every five years. Additional safety features will include new lighting between the structure and the reactor building, as well as upgraded lighting inside the building.

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.

“I’m really proud of the team’s pace and performance on the K East cocoon,” said Travis Creach, CPCCo construction manager. “In less than a year, we’ve gone from a work planning document to nearly completing the steel frame while maintaining a spotless safety record. It has been an incredible project to work on.”

The K East Reactor operated from 1955 to 1971 and will be the seventh of Hanford’s nine former 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.