No, that is a dramatization from The Simpsons.
It is related to the specific nuclear reactor design including the nuclear fuel amount and the reactor control system and the energy extracting medium (coolant) capacity.
They are what could be called medium weight elements. There are two peaks in yield, one around 100 and one around 130 in atomic weights. See the link from Wikipedia below
Heavy water (deuterium) functions as a moderator. It slows down fast neutrons released by fission reactions in order to allow the reaction to be sustained. Fast neutrons pass through the reactor before initiating another fission reaction.
The chain reaction in a nuclear power plant occurs in the reactor core, where nuclear fission reactions take place. Heat generated from these reactions is used to produce steam, which then drives turbines to generate electricity.
The nuclear reactor is the device where it occurs a controlled nuclear fission chain reaction. The nuclear fission reaction results in loss of mass (or mass defect) that transforms into energy according to formula E = mc2 (c is light velocity). The resulting energy manifests itself as heat energy that produces steam. The steam spins the turbines that spins electric generators and hence producing electricity.
This is used in the nuclear reactor that is known as Boiling Water Reactor (BWR) in which heat produced by the nuclear fission in the nuclear fuel allows the light water reactor coolant to boil. Then, the nuclear reactor moisture separator is used to increase the dryness of the produced steam before it goes to the reactor steam turbines.
Nuclear fission typically produces more radioactive by-products compared to nuclear fusion. This is because fission involves the splitting of large atoms into smaller, unstable fragments which can emit radiation. Fusion, on the other hand, involves the combining of light atoms to form a heavier nucleus with less unstable by-products.
Control rods are used as moderators in nuclear reactors to regulate the rate of fission reactions by absorbing neutrons. By adjusting the position of the control rods, the reactor can be managed to sustain a controlled chain reaction.
The moderator used in the nuclear reactor at Madras Atomic Power Station in Kalpakkam is usually heavy water (deuterium oxide) or light water (ordinary water). These moderators are important for slowing down neutrons produced during nuclear fission reactions to sustain the chain reaction in the reactor.
Heat is produced in a nuclear reactor through a process called nuclear fission. When a uranium atom is split, it releases energy in the form of heat. This heat is transferred to water, which is then used to produce steam to drive turbines and generate electricity.
It is a reactor, where atomic nuclei are either combined (fusion) or split (fission), with the consequent release of energy . That great big bright yellow UFO ( unidentified flying object) in the sky , the SUN is a giant nuclear reactor, whereby hydrogen nuclei are fused together to form helium nuclei. , with the consequent release of energy ; electromagnetic waves( heat, radio waves, UV waves , light etc.,) If we could see inside a nuclear reactor on Earth it would just look the same, however, nuclear reactors on Earth are just used to collect heat, for electric generation.
light water moderated Soviet designed reactor