Safety issues probed at Texas nuclear plant - Los Angeles Times The high level of activity at the Pantex plant apparently reflects the increasing amount of work to maintain aging U.S. nuclear weapons that must be overhauled, as well as to decommission weapons under the 2002 Moscow Treaty. The U.S. and Russia have agreed to reduce deployed strategic warheads to about 2,000 each by 2012, a two-thirds reduction for the U.S.