<human>:  How does nuclear fission work?
<bot>: Nuclear fission is a process in which a nucleus splits into two or more smaller nuclei. This process is triggered by the bombardment of a heavy, unstable nuclei with a neutron. The neutron splits off from the nucleus, releasing a huge amount of energy, and the nucleus breaks into two daughter nuclei. These nuclei may be either lighter nuclei or they could form other elements when they are hit further by other neutrons, or they could form isotopes. In some cases, two or three neutrons can also be released during the fission process, leading to a nuclear chain reaction. This reaction can produce an immense amount of energy, depending on the type of nucleus that undergoes fission.