The word "nonproliferation" means to prevent the spread or increase of something. Specifically, it is commonly used in the context of preventing the spread of nuclear weapons or other dangerous weapons. Full definition
PULLMAN, Wash. — The role of university research in national security will be discussed by the deputy administrator for defense nuclear nonproliferation for the National Nuclear Security Administration (NNSA) at 3:30 p.m. Monday, Oct. 17, in the Goertzen Hall atrium at Washington State University. (news.wsu.edu)
Leonard Spector of the Center for Nonproliferation Studies in Washington DC told a US Congressional committee last week that in a recent military exercise, the US and 18 other nations, and «more than 12,000 participants» rehearsed ways to «prevent the transfer of chemical arms out of Syria». (newscientist.com)
That's why nonproliferation experts generally prefer that countries that use nuclear power buy fuel on the international market instead of doing their own enrichment and reprocessing. (businessinsider.com)