A Nuclear Reactor



The term Nuclear Reactor means an interaction between two or more Nuclei, Nuclear Particles, or Radiation, possibly causing transformation of the nuclear type; includes, for example, fission, capture, elastic container. Reactor means the core and its immediate container. Nuclear Reactors are used to produce electricity . The numbers of Nuclear Reactor plants have grown sufficiently . Electricity is being generated in a number of ways, it can be generated by using Thermal Power. It can be employed by using two basic systems a Steam Supply System and an Electricity Generating System these two systems are related to each other. The Steam Supply System produces steam from boiling water by the burning of coals and the Electricity Generating System produces electricity by steam turning turbines. The Nuclear power plants of this century depend on a particular type of Nuclear Reaction, Fission (The splitting of a heavy nucleus like the uranium atom to form two lighter "fission !
fragments" as well as less massive particles as the Neutrons). In the Nuclear Reactors this splitting is induced by the interaction of a neutron with a fissionable nucleus. Under suitable conditions, a "chain" reaction of fission in which events may be sustained. The energy released from the fission reactions provide heat, part of which is ultimately converted into electricity. In the present day Nuclear power plants, this heat is removed from the Nuclear fuel by water that is pumped past rods containing fuel. The basic feature of the nuclear reactor is the release of a large amount of energy from each fission event that occurs in the nuclear reactors core. On the average, a fission event releases about 200 million electron volts of energy. a typical chemical reaction, on the other hand releases about one electron volt. The difference, roughly a factor of 100 million electron volts. The complete fission of one pound of uranium would release roughly the same amount of energy as!
the combination of 6000 barrels of oil or 1000 tons of high quality oil. The reactor cooling fluid serves a dual purpose. Its most urgent function is to remove from the core the heat that results when the energy released from the Nuclear reactions is transformed by the collisions into the random nuclear motion. An associated function is to transfer this heat into an outside core, typically for the production of electricity. The designer provides for a nuclear core in a container through which a cooling fluid is pumped. This fluid may be used directly to drive a turbine generator. alternately, it may be used to heat a secondary fluid which drives the turbine. In most all the commercial systems that fluid is vaporized water.
Fission is the term used to describe the splitting of a heavy nucleus into two or more smaller nuclei. Slow moving neutrons are more easily captured by the nucleus. A moderator is a medium which causes neutrons to travel more slowly.Graphite, heavy water, and beryllium are all excellent moderators, capable of slowing neutrons without absorbing them. The neutrons liberated by fission travel very quickly unless moderated. A very large amount of energy is released when an atom undergoes fission.
In a typical fission reaction, the energy released is distributed as follows: 170 MeV(megavolt) of kinetic energy of fission fragments, 5 MeV of kinetic energy of neutrons, 15 MeV of energy beta particles and gamma rays, and 10 MeV as energy of antineutrinos.
An example of a typical fission is: Mass is not conserved in a nuclear reaction. The products formed during nuclear fission have a slightly lower mass, due to the nuclear mass defect. This nuclear mass defect can be used to determine the nuclear binding energy which held the heavier nucleus together and was released when fission occurred. The energy released by a fission can be calculated by finding the difference between the mass of the parent atom and neutron, and the masses of the daughter atoms and emitted neutrons, and converting this mass "loss" into energy using . Neutrons released when an atom undergoes fission are capable of causing other nuclei to undergo fission, if the neutrons are slowed down by a moderator. A sustained fission reaction caused in this way is called a chain reaction. Natural uranium ore contains about 0.7% uranium-235. To increase the