The U.S. Department of Energy (DOE) is investigating a chemical explosion at the Oak Ridge (TN) Y-12 nuclear weapons plant that injured 10 workers on Wednesday. The workers were cleaning a welding area that had been shut down since 1993 when the explosion occurred.
The workers were removing an old crucible used in casting nuclear weapons parts. The explosion occurred after a volatile sodium-potassium mixture used as a cooling agent in the casting of nuclear warheads spilled into the bottom of a furnace. A spokesman for DOE said the mixture might have reacted with moisture, but the exact cause of the explosion has not been determined.
Three workers were hospitalized for burns or smoke inhalation, with one man suffering second-degree burns over his face and chest. The others were treated and released.
Plant officials said the workers were exposed to limited amounts of radioactive contamination because of depleted uranium in the crucible. Bob Van Hook, president of Lockheed Martin Energy Systems, which operates the facility for the Department of Energy, said nothing was released from the site that would have affected the public or employees.
Approximately 50 people were evacuated from the million-square-foot building where the explosion took place and it has been sealed off for investigators. David Stadler, the DOE's acting deputy assistant secretary for oversight, will lead the investigation.
The Y-12 building where the explosion occurred houses a portion of the plant's enriched uranium operation. The enriched uranium operation was shut down for five days last month because of unrelated safety problems.
The Y-12 facility, created as part of the top-secret Manhattan Project in World War II to build components for the first atomic bomb, now makes warhead components for the MX missile system and is the primary uranium storage site for the nation's nuclear arsenal.
The entire 5,300-employee plant was shut down in 1994 for safety reasons. DOE and Lockheed Martin have been slowly restarting the plant, section by section.