Primary is the technical term for the fission bomb component of a thermonuclear or fusion bomb, which is used to start the reactions going and implode and detonate the second, fusion stage.
It has been associated with the W48 nuclear warhead, but this is probably an error.
- Beware the old story by Chuck Hansen, Bulletin of the Atomic Scientists, March/April 2001 pp. 52-55 (vol. 57, no. 02)
- United States Nuclear Tests July 1945 to 31 December 1992, NRDC NWD 94-1, Robert Standish Norris and Thomas B. Cochran, accessed Dec 11, 2007
- Designations Of U.S. Nuclear Weapons, Andreas Parsch, 2005, accessed Dec 11, 2007