Answer:
Uranium-235 absorbing a neutron and breaking into Barium-141, Krypton-92 and three neutrons
Explanation:
A fission reaction is said to have occurred when an unstable nucleus is bombarded with a neutron such that it disintegrates into daughter nuclei and produces more neutrons in the process. Hence, Uranium-235 absorbing a neutron and breaking into Barium-141, Krypton-92 and three neutrons is a fission reaction.
This fission reaction is often a self sustaining reaction. The neutrons produced in the reaction bombards more of the parent nucleus and the process continues indefinitely(chain reaction).
Control rods and moderators are used to keep the chain reaction in check.
