Deployment
Beginning in March 1953, the United States deployed a number of Mark 18 bombs. A total of 90 were manufactured and placed in service.
The weapon had a short lifetime, and was replaced by thermonuclear weapons in the mid-1950s. The Mark 18 weapons were all modified into lower yield Mark 6 nuclear bomb variants in 1956.
Read more about this topic: Mark 18 Nuclear Bomb