The Nuclear Notebook is researched and written by Hans M. Kristensen, director of the Nuclear Information Project with the Federation of American Scientists, and Matt Korda, a research associate with the project. The Nuclear Notebook column has been published in the Bulletin of the Atomic Scientists since 1987. This issue’s column examines the US nuclear arsenal, which remained roughly unchanged in the last year, with the Department of Defense maintaining an estimated stockpile of nearly 3,800 warheads. Most of these warheads are not deployed; approximately 2,050 warheads are held in reserve and approximately 2,385 retired warheads are awaiting dismantlement, giving a total inventory of approximately 6,185 nuclear warheads. Of the approximately 1,750 warheads that are deployed, roughly 1,300 are on ballistic missiles, 300 at strategic bomber bases in the United States, with another 150 tactical bombs deployed at European bases.
At the beginning of 2019, the US Department of Defense maintained an estimated stockpile of 3,800 nuclear warheads for delivery by more than 800 ballistic missiles and aircraft. Most of the warheads in the stockpile are not deployed, but rather stored for potential upload onto missiles and aircraft as necessary. Many are destined for retirement. We estimate that approximately 1,750 warheads are currently deployed, of which roughly 1,300 strategic warheads are deployed on ballistic missiles, 300 at strategic bomber bases in the United States, while another 150 tactical bombs are deployed at air bases in Europe. The remaining warheads – approximately 2,050 – are in storage as a so-called hedge against technical or geopolitical surprises. Several hundred of those warheads are scheduled to be retired before 2030.
Through 2018, the Trump administration followed the Obama administration’s practice of declassifying the size of the stockpile and number of dismantled warheads. In April 2019, however, the Defense Department – presumably under guidance from the White House – rejected declassifying the numbers. The decision reverses US nuclear transparency policy and will, if not reversed, create uncertainty and mistrust about the size of the US nuclear arsenal (Kristensen 2019 Kristensen, H. M. 2019. “Pentagon Slams Door On Nuclear Weapons Stockpile Transparency.” FAS Strategic Security Blog, April 17, 2019. https://fas.org/blogs/security/2019/04/stockpilenumbersecret/ [Google Scholar]). In addition to the warheads in the Department of Defense stockpile, approximately 2,385 retired – but still intact – warheads are stored under custody of the Department of Energy and are awaiting dismantlement, giving a total US inventory of an estimated 6,185 warheads.
The nuclear weapons are thought to be stored at an estimated 24 geographical locations in 11 US states and five European countries. The location with the most nuclear weapons is the large Kirtland Underground Munitions and Maintenance Storage Complex (KUMMSC) south of Albuquerque, NM. Most of the estimated 2,475 weapons in this location (and estimated 1,785) are retired weapons awaiting shipment for dismantlement at the Pantex Plant in Texas. The state with the second-largest inventory (1,620) is Washington, which is home to the Strategic Weapons Facility Pacific (SWFPAC) and the ballistic missile submarine at Naval Submarine Base Kitsap. (Washington is the state with most nuclear weapons (1,120) if counting only stockpiled weapons.) In addition to stockpiled weapons, the two ballistic missile submarine bases are thought to store retired Navy warheads awaiting dismantlement. With the completion of the W76-1 life-extension program production, these excess warheads are scheduled to be dismantled during the 2020s. Of the five nuclear weapons storage locations in Europe, Incirlik Air Base in Turkey stores the most – about 50 or one-third of the weapons in Europe, although there are unconfirmed rumors that the weapons may have been withdrawn.