RICHLAND, Wash. – Workers at EM’s Hanford Site recently entered the 100 K East Reactor to begin preliminary plans for interim stabilization of the reactor, or cocooning, which will involve building a safe storage enclosure.
As part of surveillance and maintenance activities, workers have performed general entries into the reactor every five years, but workers will now enter more often, as part of the work planning process. The photos accompanying this story illustrate a crew’s recent entry to the reactor.
“Although the actual construction to cocoon the reactor won’t happen for several years, entering the reactor more regularly will allow workers to gain familiarity with the aging facility and determine how best to design the future enclosure,” said Richland Operations Office Project Director Mark French.
The reactor is one of Hanford’s “sister” reactors. The K East and K West reactors were built side by side in the early 1950s and went into service in 1955. They are located less than 400 yards from the Columbia River and operated for more than 15 years before being shut down in the early 1970s.
The K East Reactor operated until 1971. A spent fuel basin attached to the reactor was reactivated and stored irradiated fuel from Cold War operations from another Hanford reactor through 2004. Removal of the irradiated fuel, associated radioactive sludge and debris, and then the basin itself, took place between 2004 and 2009 and was critical to cleanup along the Columbia River.
Workers have cocooned six other reactors at Hanford. When a reactor is cocooned, about 80 percent of the buildings and auxiliary structures needed to support the reactor operations are demolished and removed. The remaining 20 percent of the reactor complex, including the reactor core itself, is enclosed in a cement and steel, airtight and watertight structure called a cocoon. It prevents any remaining radiation or contamination from escaping to the environment.