The fuel rod was removed in 1979 from the Vermont Yankee reactor, which is currently shut down for refueling and maintenance. Remote-control cameras will be used to search a spent fuel pool on the property, officials said Wednesday.
"We do not think there is a threat to the public at this point. The great probability is this material is still somewhere in the pool," said Nuclear Regulatory Commission spokesman Neil Sheehan.
But Sheehan said it was possible the spent fuel was mixed in with a shipment of low-level nuclear waste and ended up at a repository in South Carolina, or a facility in Washington state. He said it was also possible it was taken to a nuclear testing facility run by General Electric, which designed the plant.
The material would be fatal to anyone who came in contact with it without being properly shielded, Sheehan said. Spent nuclear fuel also could be used by terrorists to construct so-called dirty bombs that would spread deadly radiation with conventional explosives.
The NRC is helping plant officials in the search. The rod was part of the fuel assembly used to power the reactor. One of the missing pieces is about the size of a pencil. The other piece is about the thickness of a pencil and 17 inches long.
"It would be very difficult to remove this material from the site without somebody knowing about it," Sheehan said. "It would set off radiation monitors."
Sheehan cited the heightened awareness of the need to control nuclear material that followed the Sept. 11 terror attacks. "We don't want this falling into the wrong hands," he said. "This is something we would never take lightly."
Gov. James Douglas, after speaking Wednesday afternoon with the head of the NRC, said he was "very concerned" about the missing fuel at the plant, run by Entergy Nuclear.
"This situation is intolerable," he said in a statement.
In 2002 a Connecticut nuclear plant was fined $288,000 after a similar loss. That fuel was never accounted for.
Vermont Yankee is located in the southeastern town of Vernon, on the border with Massachusetts and New Hampshire.
The state's Public Safety Department and Homeland Security Unit also were notified of the missing fuel.
By Wilson Ring