More importantly, however, this time delay between the fission and the release of more neutrons allows some time for human beings to react and make adjustments, controlling the power of the chain reaction so it doesn't proceed too fast. (scientificamerican.com)
«The Los Alamos experiment was critical for the analysis we pursued: In the end, because it has this additional set of neutrons, it gets us to information which helps us to further clarify the physics of neutron stars — where there are many more neutrons relative to protons. (sciencedaily.com)
The thermal neutrons can then be absorbed by uranium - 235, which undergoes further reactions to produce even more neutrons in order to sustain a fission chain reaction. (nuclearstreet.com)