The site in Washington state where plutonium for U. S. nuclear weapons was processed is in the midst of a decades-long cleanup.
RICHLAND, Wash. — Hundreds of workers at Hanford Nuclear Reservation were evacuated Tuesday after part of a tunnel, which stores rail cars filled with radioactive waste, collapsed.
Officials detected no radiation release, and no workers were in the tunnel when it caved in, said Randy Bradbury, a spokesman for the Washington state Department of Ecology. Around 11 a.m. PT, a robot was being used to sample contamination in the air and on the ground and had not found evidence of a release of contamination two hours later.
Hanford contractors working nearby were removed from the area while those farther away on the 586-square-mile site were told to remain indoors, according to the U. S. Department of Energy.
At around noon, workers in a few areas farthest from the collapse were allowed to go home using the safest route. The complex, about half the size of Rhode Island and located along the Columbia River, has more than 9,000 employees.
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Early in the morning, a manager sent a message to all personnel telling them to « secure ventilation in your building » and « refrain from eating or drinking. » Those restrictions were lifted around noon but most workers were told to continue to shelter in place.
The tunnel, which is hundreds of feet long and covered with about 8 feet of soil, contains highly contaminated materials such as trains that transported nuclear fuel rods. It connects to the Plutonium Uranium Extraction Facility, known at the site as PUREX.
The 20-foot-by-20-foot collapse occurred at one of two rail tunnels under the PUREX site, Bradbury said. In the past, rail cars full of radioactive waste were driven into the tunnels and buried.
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This incident caused the soil above the tunnel to sink 2 to 4 feet, according the Energy Department.
The closed PUREX plant was part of the nation’s nuclear weapons production complex.
Hanford — about 20 miles northwest of Richland, 150 miles southeast of Seattle and less than 50 miles from the Oregon border — was built during World War II and processed the plutonium for most of the U. S. nuclear arsenal, including the atomic bomb dropped on Nagasaki, Japan. For decades afterward, workers made plutonium for nuclear weapons.
Hanford’s emergency operations center was activated at 8: 26 a.m., and long-time workers think it may be the first time it was opened for a possible radioactive release. Oregon’s Department of Energy also activated its own emergency operations center.
“Hanford is 35 miles away from Oregon, ” said Rachel Wray, Oregon Energy Department spokeswoman. “We are concerned about Oregonians’ health and that concerns the food we eat.”
Winds at the time of the collapse were light at about 3 mph and variable, primarily from the south and southeast, according to Weather Underground.
More than 50,000 people live to the southeast in Richland, and almost 30,000 Oregonians live farther south in nearby communities of Boardman, Hermiston, Irrigon and Umatilla. About 6,000 people live in Desert Aire and Mattawa, Wash., less than 25 miles northwest of Hanford and downwind at the time of the incident.
Today the Hanford site contains 56 million gallons of radioactive waste and is the largest depository of radioactive waste from the Defense Department. Contractors are in the midst of a decades-long process of cleanup.
Contributing: Tracy Loew, (Salem, Ore.) Statesman Journal. The Associated Press. Follow Susannah Frame on Twitter: @SFrameK5
