ABSTRACT
Nuclear energy, one of the two fundamental energy sources that drive the evolution of the universe, represents the stage of energy development nearest to the present time and perhaps the most complex one. Nuclear fission has become an energy source of practical importance as a consequence of the miraculous existence on earth of the natural fissile uranium 235 element. The understanding of how a nuclear reactor works, that is, how uranium is fissioned under controlled conditions, requires a knowledge of the neutron's basic properties as it moves and eventually is absorbed in the reactor core composed of uranium and inert materials. After being emitted through the fission process, the neutrons are slowed down by collisions with other nuclei, just as occurs in the game of bowls. Finally, a coolant transports the heat from the nuclear reactor core into a conventional thermal cycle where, eventually, it drives a vapor turbine and produces electricity.
