EXPERT: LATEST STOCKPILE ESTIMATE SET AT 4,688 WARHEADS

How many total weapons are currently in the United States’ nuclear arsenal? If you do the math on statements made by National Nuclear Security Administration weapons program chief Don Cook at last week’s Nuclear Deterrence Summit—and nuclear weapons expert Hans Kristensen did—about 4,688 warheads. At the conference, Cook said that the U.S. stockpile had decreased 87 percent from a high of 31,255 warheads in 1967, then corrected that number to 85 percent in comments to Kristensen, according a blog post by the director of the Federation of American Scientists’ Nuclear Information Project. The U.S. last declared in 2010 that it had 5,113 warheads in 2009, but hasn’t released stockpile totals since. Kristensen and fellow nuclear weapons expert Robert Norris compile the most accurate outside estimates of the U.S. stockpile size for the Bulletin of Atomic Scientists, and had estimated the stockpile size to be 4,650 weapons. Kristensen said the bulk of the reductions likely include retired W80-0 warheads previously mounted on the Tomahawk land-attack cruise missile that the 2010 Nuclear Posture Review suggested wasn’t needed for the stockpile as well as excess W76-0 warheads that aren’t being refurbished and some B83 weapons.