The W91 was an American
What was to become the W91 design entered into a Phase 2 design competition between the various nuclear weapons laboratories in November 1988. Further development details are somewhat unclear, but a Los Alamos National Laboratory design won the competition.
The design that emerged had a weight of 310 pounds (140 kg), with a two selectable yields of 10 or 100 kilotonnes of TNT (42 or 418 TJ).
The design was cancelled in September 1991 along with the SRAM T missile, prior to production of any units, though some test devices may have been manufactured.
Notably, the W91 was the last new US nuclear weapon design to reach the point of receiving a model number designation (entering Phase 3 development status).
- Sublette, Carey. "Complete List of All U.S. Nuclear Weapons". The Nuclear Weapon Archive. Retrieved 15 November 2015.
- University of California 1989 nuclear weapons labs status report
- Allbombs.html at the Nuclear Weapon Archive at nuclearweaponarchive.org