Fission and the r-process: Competition between neutron-induced and beta-delayed fission

We show that for the discussed scenario of a neutron-star merger in highly neutronized ejecta (Y _e ?0.1), neutron-induced fission plays a major role in the r-process cycling and is the main obstacle to the formation of superheavy elements. At the final stage of the r-process, when the free-neutron density is already too low to maintain rapid nucleosynthesis and only beta-decay and beta-delayed fission take place, the leading role in forming the final abundances of chemical elements passes to delayed fission. The latter ultimately changes the abundances of individual isotopes in the region before the second peak and heavier than lead, which, in particular, affects the determination of the age of the Galaxy.