The spread of nuclear weapons, nuclear technology, or nuclear materials

a thought process used to generate creative ideas by exploring many possible solutions

The prevention of the spread of nuclear weapons and technology; nuclear nonproliferation

Process by which gases mix or spread due to the motion of their particles; specifically used in the context of isotope separation

The Treaty on the Non-Proliferation of Nuclear Weapons; an international treaty whose objective is to prevent the spread of nuclear weapons and weapons technology

measures taken to prevent the spread of weapons or technology; anti-proliferation

to let everyone know; to spread the word widely