KANSAS CITY NATIONAL SECURITY CAMPUS, Mo. \u2014 In an ultra-sterile room at a secure factory in Kansas City, U.S. government technicians refurbish the nation\u2019s nuclear warheads. The job is exacting: Each warhead has thousands of springs, gears and copper contacts that must work in conjunction to set off a nuclear explosion.<\/p>\n\n\n\n
Eight hundred miles (about 1,300 kilometers) away in New Mexico, workers in a steel-walled vault have an equally delicate task. Wearing radiation monitors<\/a>, safety goggles and seven layers of gloves, they practice shaping new warhead plutonium cores \u2014 by hand.<\/p>\n\n\n\n And at nuclear weapons bases across the country, troops as young as 17 keep 50-year-old warheads working until replacements are ready. A hairline scratch on a warhead\u2019s polished black cone could send the bomb off course.<\/p>\n\n\n\n The Associated Press was granted rare access to key parts of the highly classified nuclear supply chain<\/a> and got to watch technicians and engineers tackle the difficult job of maintaining an aging nuclear arsenal. Those workers are about to get a lot busier. The U.S. will spend more than $750 billion over the next 10 years replacing almost every component of its nuclear defenses, including new stealth bombers, submarines and ground-based intercontinental ballistic missiles in the country\u2019s most ambitious nuclear weapons effort since the Manhattan Project.<\/p>\n\n\n\n It\u2019s been almost eight decades since a nuclear weapon has been fired in war. But military leaders warn that such peace may not last. They say the U.S. has entered an uneasy era of global threats<\/a> that includes a nuclear weapons buildup by China<\/a> and Russia\u2019s repeat threats to use a nuclear bomb in Ukraine. They say that America\u2019s aged weapons need to be replaced to ensure they work.<\/p>\n\n\n\t