"Nearly two years before peace activists broke into a U.S. nuclear weapons facility in late July, government investigators warned in classified reports of lax security at the complex where the nation's largest concentration of weapons-grade uranium is stored."
"The previously undisclosed 2010 criticism of the Y-12 National Security Complex near Oak Ridge, Tenn., found that security cameras were inoperable, equipment maintenance was sloppy and guards were poorly trained.
On July 28, an 82-year-old nun, an elderly gardener and a house painter slipped past security costing millions of dollars a year — sensors, cameras, barbed wire, heavy weaponry, roving patrols and dozens of guards — to reach the walls of a new uranium storage facility at Y-12. They splattered blood on the building and held up protest signs before being arrested."
Dana Priest reports for the Washington Post September 11, 2012.