Operation Upshot-Knothole
1953 - Nevada Test Site
Efforts to prepare the U.S. military for atomic combat continued with proof-tests of a number of new tactical weapons, including the first nuclear artillery shell. The tests provided additional experience and information for planning atomic combat operations. Important information was also obtained for civil defense efforts.
And critically important — Upshot-Knothole also tested the radiation implosion systems for the world's first deployable thermonuclear weapons which would be proof-tested in Operation Castle the following year.
An estimated 18,000 DOD personnel participated in observer programs, tactical maneuvers, scientific studies, and support activities. Members of all four armed services participated in Exercise Desert Rock V.
Source: nuclearweaponarchive.org