Designations Of U.S. Nuclear Weapons

Copyright © 2001-2023 Andreas Parsch

1 Designation System

2 List of Weapons

3 Sources

1 Designation System

All U.S. nuclear weapons (missile warheads, free-fall bombs, artillery shells, etc.) are numbered in a single, consecutive series. The numbers are assigned by the organization controlling the design and manufacture of nuclear weapons. From 1946 to 1974, this was the Atomic Energy Commission (AEC). In 1974, the AEC was abolished and its tasks being taken over by the newly formed Energy Research and Development Administration (ERDA). In 1977, the Department of Energy (DOE) was founded and took over, among many other things, the responsibility for nuclear weapons.

When designating nuclear weapons, a variety of prefixes and suffixes are used with the numbers. However, I don't have any official, first-hand source describing or regulating their use. The following prefixes were used at least once:

• XW - Warhead in the development and test phase
• W - Warhead (production)
• Mark (MK, Mk) - Bomb (until 1968)
• B - Bomb (after 1968)
• TX - "Test Experimental" (prototype bomb or warhead)
• EC - "Emergency Capability" (bomb prototype design stockpiled in very limited numbers)
• S - Artillery shell (rarely used)
• BA - "Basic Assembly" (used only for bombs specially adapted to the B-58's pod)

The first four designs used roman numerals, but this was soon changed to arabic numerals with the MK-IV/MK-4. A dash is usually written between the prefix and the number. In newer references, however, the dash is frequently omitted. Especially the reference to bombs as Bn instead of B-n is quite common, presumably to avoid confusion with US Air Force bomber designations. The warhead (i.e. the nuclear package) of a free-fall bomb always retained its W designation, using the same number as the bomb itself. E.g. the nuclear components of the MK-28 bomb were known as W-28 (in the strictest sense, the MK nomenclature applied only to the non-nuclear bomb components).

Suffixes are used to designate variants of a weapon. The basic suffix is a "Mod" designator. This is used in the same way as in the US Navy's MARK/MOD Nomenclature System, i.e. the first version is designated "Mod 0", followed by "Mod 1", etc. The Mod suffix is often abbreviated to a dash and a number, e.g. B61-11 or W80-1. Different yield options for a weapon can be indicated by a Yn (n = 1, 2, ...) designator immediately behind the number. Of course, Y and Mod suffixes can be combined, as in W-39Y1 Mod 2. Modifications of bomb and warhead prototypes were often indicated by a -Xn (n = 1, 2, ...) suffix, as in TX-7-X1. If an -Xn design was put into production, the -Xn usually became a Mod number (e.g. TX-7-X1 became MK-7 Mod 1).

2 List of Weapons

The list includes every nuclear weapon which was ever assigned a number in the AEC/DOE series. Warheads are always listed as W-n, but bombs are generally shown with the most "common" prefix. All warheads had XW or TX designations when the number was first assigned. Similarly, most bombs started as TX designs before being designated as MK, B or EC.

For each weapon, the developing laboratory (LANL = Los Alamos National Laboratory, LLNL = Lawrence Livermore National Laboratory), the approximate yield(s) and the delivery platforms (carrier aircraft for bombs, missiles for warheads) are listed. Brackets indicate cancelled bombs, warheads and platform/warhead combinations.

Most rockets and missile designations are linked to the corresponding page in the Directory of U.S. Military Rockets and Missiles, which includes detailed information about the weapon.

3 Sources

In no particular order:

[1] Chuck Hansen: "Swords of Armageddon", 1995
[2] James N. Gibson: "Nuclear Weapons of the United States", Schiffer Publishing Ltd, 1996
[3] Stephen I. Schwartz (ed.): "Atomic Audit: The Costs and Consequences of U.S. Nuclear Weapons Since 1940", Brookings Institution Press, 1998

Back to U.S. Military Aviation Designation Systems

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Last Updated: 12 December 2023