Was there a plan for if the atom bomb failed to detonate over Hiroshima/Nagasaki to prevent it from falling into Japanese hands?

by notapersonaltrainer
tactics14

Follow up question, let's say the bomb didn't detonate and just fell and broke on the street. Who would have gone to investigate it, would they have known what they were dealing with? Would it just end up in a trash heap somewhere or would it be noted as a different kind of bomb and sent up the ranks to some knowledgeable scientists?