The Army’s Nuclear Power Program (ANPP) had 7 nuclear prototypes. One of those was the Power Barge Sturgis. It was the highest nuclear power providing reactor in the fleet. The MH-1A nomenclature stood for Mobile High Power (over 10mW) – the first one (1) built and (A) field installation. It was in service from 1968 to 1976. It was first testing in Ft. Belvoir, Virginia. It was then moored in Gatun Lake, Panama.

Photo courtesy NS SAVANNAH ASSOCIATION, INC. via https://www.ans.org/news/article-1685/nuclear-power-barge-sturgis-begins-last-voyage/

Today, the only publicized dedicated floating nuclear power plant is the Russian Akademik Lomonosov.

Akademik Lomonosov courtesy of Rosatom Global Twitter