How does the nuclear reactor work?
Well, only if it's very simple: there is fuel(heavy elements). This fuel is placed in device, in which the controlled chain reaction, the division of these elements. In the process of division, a thermal energy. it is what we need. The rest is technical issues.
The simplest way to explain how a nuclear reactor of the VVER type (water-water power reactor) works,
To understand this, remember the principle of the work of the samovar.
Everything is absolutely the same.
Capacity in which poured water inside, which is the furnace.
The difference is that the water in the samovar is heated from burning wood chips, and in the reactor from the energy of fission of uranium nuclei.
How the reactor works - the principle of operation and the design of a nuclear reactor
A nuclear reactor is an apparatus designed to utilize the energy of nuclear fuel through a controlled fission chain reaction.
Utilization of nuclear fuel energy is due to the conversion of the kinetic energy of fission products to thermal energy. Where does nuclear energy come from, see here:
Nuclear reactors are divided into energy reactors, breeder reactors and research / experimental reactors. But irrespective of its purpose, a nuclear reactor generates heat during operation.
The structural diagram of the nuclear reactor is shown in the figure:
The nuclear reactor consists of the following main elements:
I. Core: 1 Fuel Element. 2 Retarder. 3 Thermal screen.
A fuel element is a certain amount of nuclear fuel enclosed in a metal sheath. Nuclear fuel mixture of fissile material with moderator. The heat shield is used to configure the flow of the coolant for the effective removal of heat from the heated fuel elements.
II. Controls and protection: 6, 7 Absorbers of operational regulation. 8 Absorbers of emergency protection. 9, 10 Drive controls. 11 Power and temperature measuring device.
Operational control absorbers control the neutron flux, maintaining a given power. Emergency protection absorbers urgently, automatically stop the chain reaction of division in case of emergency situations. Drive controls move them in the core. A device for measuring power and temperature; a set of sensors (ionization chambers and thermocouples) that produce corresponding signals on the state of the reactor.
III. Case: 4 Reactor body. 5,12 Reflectors of neutrons. 13 Biological protection.
The reactor vessel is a sturdy design with placed elements of the apparatus. Neutron reflectors prevent neutrons from escaping outside the core. Biological protection prevents the emission into the environment of radiation associated with the fission chain reaction of fissionable material.
Structurally, the main elements of different reactors are made in different ways. How they are arranged and interact is the topic of individual issues.
In the stopped (deactivated) reactor, all absorbers are lowered into the core and do not allow nuclear fission.
To start a nuclear reactor, the absorbers of the emergency protection are removed from the core and raised to the required height (corresponding to the specified power) absorbers of operational control. The chain reaction of division begins and the intensive heating of the heat-releasing elements, the heat from which is diverted continuously by the circulating coolant. To regulate the power of the reactor, it is necessary to raise or lower the absorbers of the operational control. When removing them from the core - the power increases, while lowering decreases.
That's actually all - that's how it works ...
The reactor is loaded, depending on its type, enriched (isotope 235) uranium or not enriched (fast neutron reactor). It is possible to use plutonium. When the nucleus captures a slow neutron, the nucleus divides into fragments with flight more than one neutron. This reaction is accompanied by the release of energy, which is millions of times greater than the energy of chemical reactions. Departing neutrons, falling into neighboring nuclei, cause their fission with the emission of additional neutrons, etc. If most neutrons get into the cores (and not fly out), and if the process is not controlled, then a nuclear bomb will turn out. And in the reactor the number of neutrons is tightly controlled, their multiplication factor is supported by a little more than one. And then the rate of heat release is such that it can be effectively removed and used to heat water, which turns into steam. Further - as in a conventional thermal power plant, running on gas, coal, etc.