The discovery of the neutron was a harbinger of the atomic era of mankind, since in the hands of physicists there was a particle capable, due to the absence of a charge, to penetrate into any, even heavy, nuclei. In the course of experiments on the bombardment of uranium nuclei by neutrons, carried out by the Italian physicist E. Fermi, radioactive isotopes and transuranic elements, neptunium and plutonium, were obtained. Thus, it became possible to create a nuclear reactor - an installation that surpasses in its energy power everything that was previously created by mankind.
A nuclear reactor is an apparatus where a controlled nuclear fission reaction takes place, based on the chain principle. This principle is as follows. The uranium nuclei bombarded by neutrons decay and form several new neutrons, which, in turn, cause the fission of the following nuclei. In this process, the number of neutrons increases rapidly. The ratio of the number of neutrons in one fission phase to the number of neutronsthe previous phase of nuclear decay is called the multiplication factor.
In order for a nuclear reaction to be controlled, a nuclear reactor is needed, which is used in nuclear power plants, submarines, nuclear icebreakers, in experimental nuclear facilities, etc. An uncontrolled nuclear reaction inevitably leads to an explosion of colossal destructive power. This type of chain reaction is used exclusively in nuclear bombs, the explosion of which is the goal of nuclear decay.
Atomic reactor, in which the released neutrons move at great speed, in order to control the reaction, it is equipped with special materials that absorb part of the energy of elementary particles. Such materials, which have the ability to reduce the speed and inertia of neutrons, are called nuclear reaction moderators.
The principle of operation of a nuclear reactor is as follows. The internal cavities of the reactor are filled with distilled water circulating inside special tubes. The nuclear reactor automatically turns on when graphite rods are removed from the active zone, which absorb part of the neutron energy. With the start of a chain reaction, a huge amount of thermal energy is released, which, circulating in the reactor core, reaches the fuel elements. At the same time, the water is heated to a temperature of 320 oC.
Then, the water of the primary circuit, moving inside through the tubes of the steam generator, gives off the thermal energy received from the corereactor, secondary water, while not in contact with it, which excludes the ingress of radioactive particles outside the reactor hall.
The further process is no different from what is happening at any thermal power plant - the water of the secondary circuit, which has turned into steam, gives rotation to the turbines. And the turbines activate giant electric generators, which generate electricity.
The nuclear reactor is not a purely human invention. Since the same laws of physics apply throughout the universe, the energy of nuclear decay is necessary to maintain the orderly structure of the cosmos and life on Earth. Natural natural nuclear reactor are stars. And one of them is the Sun, which, with its energy of thermonuclear fusion, created all the conditions for the emergence of life on our planet.
