It may be:
It was a nuclear bomb. Everyone was afraid of a nuclear bomb. The nuclear power plant malfunctioned. The Cold War was about fear of nuclear attack.
fear
nuclear warfare
a nuclear war
Fear of Nuclear War Fight against Communism / Spread of Communism
An end result of nuclear war.
luck, fear, etc.
Because the USSR had nuclear bombs that they were threatening to use on the Americans.
War fear that the Nazis would do it first - then there would be no chance to stop them.
a fear that they both would be destroyed in nuclear war. That is called Mutually Assured Destruction (MAD)
now do you mean after the cold war or during. if during it was from all the fear of nuclear attack
A nuclear arms race combined with fear and suspicion could lead to a disastrous nuclear war.