The particle that is responsible for the nuclear fission in a nuclear reactor is

Nuclear fission is a process in which the nucleus of an atom is split into two or more smaller nuclei, along with the release of a large amount of energy. This process is typically initiated by the absorption of a neutron by the nucleus of an atom. In a nuclear reactor, the fuel consists of heavy atoms, such as uranium-235 or plutonium-239, which are capable of undergoing nuclear fission when struck by a neutron. When a neutron is absorbed by the nucleus of an atom, the nucleus becomes unstable and splits into two smaller nuclei, along with the release of two or three neutrons and a large amount of energy. These released neutrons can then go on to collide with other atoms and cause further fission reactions, leading to a chain reaction that releases a large amount of energy. In a nuclear reactor, the chain reaction is carefully controlled to ensure that the energy is released at a steady rate and that the reactor does not overheat or become unstable. Therefore, the particle that is responsible for the nuclear fission in a nuclear reactor is a neutron.