What is a common outcome of nuclear fission?

Nuclear fission is a process that occurs when a heavy atomic nucleus splits into two smaller nuclei along with a few neutrons and a significant amount of energy. This energy is released due to the conversion of mass into energy, as described by Einstein's equation (E=mc^2). The large amounts of energy produced by the fission process are what make it a viable source of power in nuclear reactors and weapons.

In contrast, the other outcomes listed do not accurately represent what typically occurs during nuclear fission. For instance, heavy water, which contains deuterium, is not a product of fission but rather a substance used as a neutron moderator in some nuclear reactors. While stable isotopes can form as a result of the decay of products from fission, the primary outcome of the fission process itself is not their direct creation. Similarly, while some fission products may be radioactive gases, the characteristic outcome of the fission reaction is the release of energy, making it a key factor in both energy generation and the management of nuclear reactions. Thus, the release of a large amount of energy is the defining feature of nuclear fission.