The hydrogen bomb was a 20th century weapon. It was capable of great destruction. Protesters from the Campaign for Nuclear Disarmament annually marched in protest of the weapon. (PROSE: Come Friendly Bombs...)
When Caven attempted to create a blast "the equivalent of about eighty old-fashioned hydrogen bombs" by hooking up twenty demolition charges to the atomic fuel store, the Second Doctor dismantled the detonator and avoided the explosion. (TV: The Space Pirates)