The K East Reactor at Hanford has been torn down to little more than its radioactive core and more than 50 openings have been sealed up.
The reactor will remain that way, in what the Department of Energy calls temporary surveillance mode, possibly for several years.
"Visually, the reactor is almost unrecognizable from when we started, and you can see that cleanup is taking place," said Carroll Phillips, project director for DOE contractor CH2M Hill Plateau Remediation Co., in a statement.
The K East Reactor is one of three of Hanford's nine plutonium-production reactors lining the Columbia River yet to be cocooned, or placed in storage for up to 75 years to let radiation decay to lower levels.
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B Reactor is planned to be saved as a museum. The remaining two, the K East Reactor and the nearby K West Reactor, would be cocooned at the same time to save money, under a proposed change to the legal deadlines of the Tri-Party Agreement. DOE and its regulators, the state Department of Ecology and the U.S. Environmental Protection Agency, support the change.
In the past, Hanford reactors have been cocooned by sealing up their core area and reroofing them. But a new method is proposed for the K East and West reactors. A steel shell would be built around each, topped with an angled roof to direct rainwater runoff away from adjacent soil waste sites.
However, the K West Reactor cannot be cocooned until radioactive sludge is removed from containers in its cooling basin and the basin is demolished.
The proposed new deadline for cocooning both reactors is December 2019.
At the K East Reactor, crews have used concrete to close openings and penetrations in the exterior of the reactor building, including doorways, tunnels and stairwells. Crews also have cleaned out hazardous and flammable materials from the building.
Outside the reactor, some of the contaminated soil has been dug up and subcontractor Wildlands Inc. has sprayed seed on an area immediately surrounding the reactor to grow native plants on disturbed land.
Since October 2008, CH2M Hill has dug up 36 waste sites near the two reactors, removing about 613,440 tons of soil, and has torn down 61 buildings that once supported work at the two reactors.
Some soil is believed to be contaminated beneath the K East Reactor after water leaked from the basin used to cool its irradiated fuel. Work to characterize the soil will be done in the near term, including boring holes into the ground under and adjacent to the reactor, said DOE spokesman Geoff Tyree.
That information will be used to make a decision on how to clean up the soil.
There also are waste sites yet to be dug up in the 535-acre area around the reactors.
Work to cocoon the K East Reactor is about 60 percent complete. Until the remaining work to cocoon it is done, periodic surveys will be done.
-- Annette Cary: 582-1533; firstname.lastname@example.org; Twitter: @HanfordNews