Successive neutrons captures
Successive captures of neutrons are responsible for the formation of isotopes of plutonium and actinides in reactors. This map of nuclei shows how a succession of neutron captures and beta decays can reach the isotopes of plutonium. In the case of plutonium-239 and plutonium-241. In most cases the capture of slow neutrons triggers fission. Fast neutrons are able to split the other isotopes of plutonium.