To dream of a nuclear bomb represents a event or life situation that devastates you or sacrifices everything you thought or believed in. Usually to negative thoughts or emotions.
A nuclear bomb suggests a dramatic change of events, views, or feelings. Often bringing feelings of a helplessness and loss of control over a situation. Something you thought was important may have ended.
To dream of a nuclear bomb that hasn't gone off symbolizes the potential, or expectation for dramatic change, or an emotionally devastating situation.
Examples could be a death of a family member, being fired from a job, a huge embarrassment, breaking up with someone, or big disappointment.
Example: A man dreamed of seeing a nuclear bomb go off. In waking life he was deeply in love with a woman and then found out she had a boyfriend whom she had been with for years. He was emotionally devastated at the discovery that he may never get to marry the woman.
*Please See Nuclear War