Explain the nuclear chain reaction in a nuclear power plant.
Nuclear chain reaction in a nuclear power plant: If a slow moving neutron hits unstable heavy nucleus of nuclear fuel U235 or Pu239 , the neutron is absorbed, the nucleus splits into two more nuclei, two or three neutron are usually released with lot of heat energy and radiation of alpha, beta, gamma particles which are hazardous to human body. The heat energy is about 85% of energy released from this fission. Further these neutrons strike other nuclei causing them to split and release two or more neutrons and lot of heat energy.
This chain or cycle will continue and enormous amount of heat energy will be liberated, hence this process is called as chain reaction. The chain reaction is controlled by the moderator and control rods in nuclear power plant. The moderator slows down the neutrons and control rods absorb the neutrons, thus chain reaction can be controlled and desired heat energy can be obtained in nuclear power plant.