(Reuters) - The U.S. Department of Energy's Savannah River Site in South Carolina is on lockdown and experiencing a "potential security event," according to a statement from the nuclear facility and an internal memo sent to workers.
"Site barricades are currently closed to incoming traffic," according to a Facebook post, also issued by the DoE. "There is no indication of a consequence beyond the Savannah River Site boundaries."
The Savannah River Site has placed its H Area on a "phase II" security alert, according to an internal memo seen by Reuters. The H Area is where highly enriched uranium is blended down to produce low enriched uranium for use in commercial reactors.
The exact nature of the threat was unclear.
"All personnel should remain in their offices or labs and standby for further instructions via the Site public address system or instruction via email," the memo said.
The government-run site was constructed in the 1950s to produce basic materials for nuclear weapons, according to a DoE website, and produced one third of U.S. weapons grade plutonium from 1953 to 1988.
Two of the Savannah River Site's 5 reactors have been deactivated. It now blends down enriched uranium for use in commercial reactors. It also is used to store spent fuel. About 36 million gallons of radioactive liquid are stored there in 49 underground tanks.
(Reporting by Emily Stephenson, Robert Gibbons and Timothy Gardner; Editing by Sandra Maler and Bill Rigby)