thThe Pentagon will have to spend billions of dollars over the next five years to make emergency fixes to its nuclear weaponsinfrastructure, Defense Secretary Chuck Hagel will announce on Friday, after two separate Pentagon studies concluded that there are “systemic problems across the nuclear enterprise,” according to senior defense officials. The reports are a searing indictment of how the Air Force’s and Navy’s aging nuclear weapons facilities, silos and submarine fleet have been allowed to decay since the end of the Cold War. A broad review was begun after academic cheating scandals and the dismissal of top officers for misbehavior, but it uncovered far more serious problems. More