Department of Innovation Management
in the discipline: “Concepts of modern natural science”
Presentation on the topic: Nuclear
energy: its essence and
use in technology and
technologies
Presentation plan
IntroductionNuclear power.
History of the discovery of nuclear energy
Nuclear reactor: history of creation, structure,
basic principles, classification of reactors
Areas of nuclear energy use
Conclusion
Sources used
Introduction
Energy is the most important sector of the national economy,covering energy resources, generation, transformation,
transmission and use of various types of energy. This is the basis
state economy.
The world is undergoing a process of industrialization, which requires
additional consumption of materials, which increases energy costs.
With population growth, energy consumption for soil cultivation increases,
harvesting, fertilizer production, etc.
Currently, many natural resources are readily available
planets are running out. It takes a long time to extract raw materials
deep or on sea shelves. Limited Worldwide Supplies
oil and gas, it would seem, pose humanity with the prospect of
energy crisis.
However, the use of nuclear energy gives humanity
the opportunity to avoid this, since the results of fundamental
research into the physics of the atomic nucleus makes it possible to avert the threat
energy crisis by using the energy released
in some reactions of atomic nuclei
Nuclear power
Nuclear energy (atomic energy) is energycontained in atomic nuclei and released
during nuclear reactions. Nuclear power plants,
those generating this energy produce 13–14%
world production of electrical energy. .
History of the discovery of nuclear energy
1895 V.K. Roentgen discovers ionizing radiation (X-rays)1896 A. Becquerel discovers the phenomena of radioactivity.
1898 M. Sklodowska and P. Curie discover radioactive elements
Po (Polonium) and Ra (Radium).
1913 N. Bohr develops the theory of the structure of atoms and molecules.
1932 J. Chadwick discovers neutrons.
1939 O. Hahn and F. Strassmann study the fission of U nuclei under the influence of
slow neutrons.
December 1942 - First self-sustaining
controlled chain reaction of nuclear fission at the SR-1 reactor (Group
physicists of the University of Chicago, headed by E. Fermi).
December 25, 1946 - The first Soviet reactor F-1 was put into operation
critical state (a group of physicists and engineers led by
I.V. Kurchatova)
1949 - The first Pu production reactor was put into operation
June 27, 1954 - The world's first nuclear power plant went into operation
power plant with an electrical capacity of 5 MW in Obninsk.
By the beginning of the 90s, more than 430 nuclear power plants operated in 27 countries around the world.
power reactors with a total capacity of approx. 340 GW.
History of the creation of a nuclear reactor
Enrico Fermi (1901-1954)Kurchatov I.V. (1903-1960)
1942 in the USA, under the leadership of E. Fermi, the first
nuclear reactor.
1946 The first Soviet reactor was launched under the leadership
Academician I.V. Kurchatov.
NPP reactor design (simplified)
Essential elements:Active zone with nuclear fuel and
retarder;
Neutron reflector surrounding
active zone;
Coolant;
Chain reaction control system,
including emergency protection
Radiation protection
Remote control system
The main characteristics of the reactor are
its power output.
Power of 1 MW - 3 1016 divisions
in 1 sec.
Schematic structure of a nuclear power plant
Cross-section of a heterogeneous reactor
Structure of a nuclear reactor
Neutron multiplication factor
Characterizes the rapid growth of the numberneutrons and is equal to the ratio of the number
neutrons in one generation
chain reaction to the number that gave birth to them
neutrons of the previous generation.
k=Si/Si-1
k<1 – Реакция затухает
k=1 – The reaction proceeds stationary
k=1.006 – Controllability limit
reactions
k>1.01 – Explosion (for a reactor at
thermal neutrons energy release
will grow 20,000 times per second).
Typical chain reaction for uranium;
10. The reactor is controlled using rods containing cadmium or boron.
The following types of rods are distinguished (according to the purpose of application):Compensating rods – compensate for the initial excess
reactivity, extend as fuel burns out; up to 100
things
Control rods - to maintain critical
states at any time, for stopping, starting
reactor; some
Note: The following types of rods are distinguished (according to purpose
applications):
Control and compensating rods are optional
represent different structural elements
registration
Emergency rods - reset by gravity
to the central part of the active zone; some. Maybe
Additionally, some of the control rods are also reset.
11. Classification of nuclear reactors by neutron spectrum
Thermal neutron reactor (“thermal reactor”)A fast neutron moderator (water, graphite, beryllium) is required to reach thermal
energies (fractions of eV).
Small neutron losses in the moderator and structural materials =>
natural and slightly enriched uranium can be used as fuel.
Powerful power reactors can use uranium with high
enrichment - up to 10%.
A large reactivity reserve is required.
Fast neutron reactor ("fast reactor")
Uranium carbide UC, PuO2, etc. is used as a moderator and moderation
There are much fewer neutrons (0.1-0.4 MeV).
Only highly enriched uranium can be used as fuel. But
at the same time, the fuel efficiency is 1.5 times greater.
A neutron reflector (238U, 232Th) is required. They return to the active zone
fast neutrons with energies above 0.1 MeV. Neutrons captured by nuclei 238U, 232Th,
are spent on obtaining fissile nuclei 239Pu and 233U.
The choice of construction materials is not limited by the absorption cross section, Reserve
much less reactivity.
Intermediate Neutron Reactor
Fast neutrons are slowed down to an energy of 1-1000 eV before absorption.
High load of nuclear fuel compared to thermal reactors
neutrons
It is impossible to carry out expanded reproduction of nuclear fuel, as in
fast neutron reactor.
12. By fuel placement
Homogeneous reactors - fuel and moderator represent a homogeneousmixture
Nuclear fuel is located in the reactor core in the form
homogeneous mixture: solutions of uranium salts; suspension of uranium oxides in
light and heavy water; solid moderator impregnated with uranium;
molten salts. Options for homogeneous reactors with
gaseous fuel (gaseous uranium compounds) or suspension
uranium dust in gas.
The heat generated in the core is removed by the coolant (water,
gas, etc.) moving through pipes through the core; or a mixture
fuel with a moderator itself serves as a coolant,
circulating through heat exchangers.
Not widely used (High corrosion of structural
materials in liquid fuel, the complexity of reactor design
solid mixtures, more loading of weakly enriched uranium
fuel, etc.)
Heterogeneous reactors - fuel is placed in the core discretely in
in the form of blocks between which there is a moderator
The main feature is the presence of fuel elements
(TVELs). Fuel rods can have different shapes (rods, plates
etc.), but there is always a clear boundary between fuel,
moderator, coolant, etc.
The vast majority of reactors in use today are
heterogeneous, which is due to their design advantages in terms of
compared to homogeneous reactors.
13. By nature of use
NamePurpose
Power
Experimental
reactors
Study of various physical quantities,
whose values are necessary for
design and operation of nuclear
reactors.
~103W
Research
reactors
Fluxes of neutrons and γ-quanta created in
active zone, used for
research in the field of nuclear physics,
solid state physics, radiation chemistry,
biology, for testing materials,
designed to work in intensive conditions
neutron fluxes (including nuclear parts
reactors) for the production of isotopes.
<107Вт
Standouts
I'm energy like
usually not
used
Isotope reactors
To produce isotopes used in
nuclear weapons, for example, 239Pu, and in
industry.
~103W
Energy
reactors
To obtain electrical and thermal
energy used in the energy sector, with
water desalination, for power drive
ship installations, etc.
Up to 3-5 109W
14. Assembling a heterogeneous reactor
In a heterogeneous reactor, nuclear fuel is distributed in the activezone discretely in the form of blocks, between which there is
neutron moderator
15. Heavy water nuclear reactor
AdvantagesSmaller absorption cross section
Neutrons => Improved
neutron balance =>
Use as
natural uranium fuel
Possibility of creating
industrial heavy water
reactors for production
tritium and plutonium, as well as
wide range of isotopic
products, including
medical purposes.
Flaws
High cost of deuterium
16. Natural nuclear reactor
In nature, under conditions likeartificial reactor, can
create natural areas
nuclear reactor.
The only known natural
nuclear reactor existed 2 billion
years ago in the Oklo region (Gabon).
Origin: a very rich vein of uranium ores receives water from
surface, which plays the role of a neutron moderator. Random
decay starts a chain reaction. When it is active, the water boils away,
the reaction weakens - self-regulation.
The reaction lasted ~100,000 years. Now this is not possible due to
uranium reserves depleted by natural decay.
Field surveys are being carried out to study migration
isotopes – important for the development of underground disposal techniques
radioactive waste.
17. Areas of use of nuclear energy
Nuclear power plantScheme of operation of a nuclear power plant on a double-circuit
pressurized water power reactor (VVER)
18.
In addition to nuclear power plants, nuclear reactors are used:on nuclear icebreakers
on nuclear submarines;
during the operation of nuclear missiles
engines (in particular on AMS).
19. Nuclear energy in space
space probeCassini, created by
project of NASA and ESA,
launched 10/15/1997 for
series of studies
objects of Solar
systems.
Electricity generation
carried out by three
radioisotope
thermoelectric
generators: Cassini
carries 30 kg 238Pu on board,
which, disintegrating,
releases heat
convertible to
electricity
20. Spaceship "Prometheus 1"
NASA is developing a nuclear reactorable to work in conditions
weightlessness.
The goal is to supply power to space
ship "Prometheus 1" according to the project
search for life on the moons of Jupiter.
21. Bomb. The principle of uncontrolled nuclear reaction.
The only physical need is to obtain criticalmasses for k>1.01. No control system development required –
cheaper than nuclear power plants.
The "gun" method
Two uranium ingots of subcritical masses when combined exceed
critical. The degree of enrichment 235U is not less than 80%.
This type of “baby” bomb was dropped on Hiroshima 06/08/45 8:15
(78-240 thousand killed, 140 thousand died within 6 months)
22. Explosive crimping method
A bomb based on plutonium, which, using complexsystems for simultaneous detonation of conventional explosives is compressed to
supercritical size.
A bomb of this type "Fat Man" was dropped on Nagasaki
09/08/45 11:02
(75 thousand killed and wounded).
23. Conclusion
The energy problem is one of the most important problems thatToday humanity has to decide. Such things have already become commonplace
achievements of science and technology as a means of instant communication, fast
transport, space exploration. But all this requires
huge expenditure of energy.
The sharp increase in energy production and consumption has brought forward a new
acute problem of environmental pollution, which represents
serious danger to humanity.
World energy needs in the coming decades
will increase rapidly. No one source of energy
will be able to provide them, so it is necessary to develop all sources
energy and efficient use of energy resources.
At the nearest stage of energy development (the first decades of the 21st century)
Coal energy and nuclear power will remain the most promising
energy with thermal and fast neutron reactors. However, you can
hope that humanity will not stop on the path of progress,
associated with energy consumption in ever-increasing quantities.
The energy contained in atomic nuclei and released during nuclear reactions and radioactive decay.
According to forecasts, organic fuels will be enough to meet humanity's energy needs for 4-5 decades. In the future, solar energy may become the main energy resource. The transition period requires a source of energy that is practically inexhaustible, cheap, renewable and does not pollute the environment. And although nuclear energy does not fully meet all of the above requirements, it is developing rapidly and our hope for solving the global energy crisis is connected with it.
The release of the internal energy of atomic nuclei is possible by the fission of heavy nuclei or the fusion of light nuclei.
Characteristics of the atom. An atom of any chemical element consists of a nucleus and electrons rotating around it. The nucleus of an atom consists of neutrons and protons. The term used as a common name for proton and neutron nucleon. Neutrons have no electrical charge, protons are positively charged, electrons - negative. The charge of a proton is equal in absolute value to the charge of an electron.
The number of protons of the Z nucleus coincides with its atomic number in the periodic table of Mendeleev. The number of neutrons in a nucleus, with few exceptions, is greater than or equal to the number of protons.
The mass of an atom is concentrated in the nucleus and is determined by the mass of nucleons. The mass of one proton is equal to the mass of one neutron. The mass of an electron is 1/1836 of the mass of a proton.
The dimension of atomic mass is used atomic mass unit(a.u.m), equal to 1.66·10 -27 kg. 1 amu approximately equal to the mass of one proton. The characteristic of an atom is the mass number A, equal to the total number of protons and neutrons.
The presence of neutrons allows two atoms to have different masses with the same electrical charges on the nucleus. The chemical properties of these two atoms will be the same; such atoms are called isotopes. In the literature, to the left of the element designation, the mass number is written at the top, and the number of protons at the bottom.
The nuclear fuel used in such reactors is isotope of uranium with atomic mass 235. Natural uranium is a mixture of three isotopes: uranium-234 (0.006%), uranium-235 (0.711%) and uranium-238 (99.283%). The uranium-235 isotope has unique properties - as a result of the absorption of a low-energy neutron, a uranium-236 nucleus is obtained, which is then split - divided into two approximately equal parts, called fission products (fragments). The nucleons of the original nucleus are distributed between the fission fragments, but not all of them - on average, 2-3 neutrons are released. As a result of fission, the mass of the original nucleus is not completely preserved; part of it is converted into energy, mainly into the kinetic energy of fission products and neutrons. The value of this energy for one atom of uranium 235 is about 200 MeV.
The core of a conventional 1000 MW reactor contains about 1 thousand tons of uranium, of which only 3 - 4% is uranium-235. Every day 3 kg of this isotope is consumed in the reactor. Thus, to supply the reactor with fuel, 430 kg of uranium concentrate must be processed daily, and this is an average of 2150 tons of uranium ore
As a result of the fission reaction, fast neutrons are produced in nuclear fuel. If they interact with neighboring nuclei of a fissile substance and, in turn, cause a fission reaction in them, an avalanche-like increase in the number of fission events occurs. This fission reaction is called a nuclear fission chain reaction.
Neutrons with energies less than 0.1 keV are most effective for the development of a fission chain reaction. They are called thermal because their energy is comparable to the average energy of thermal motion of molecules. For comparison, the energy possessed by neutrons produced during the decay of nuclei is 5 MeV. They are called fast neutrons. To use such neutrons in a chain reaction, their energy must be reduced (slowed down). These functions are performed by the moderator. In moderator substances, fast neutrons are scattered on nuclei, and their energy is converted into the energy of thermal motion of the atoms of the moderator substance. The most widely used moderators are graphite and liquid metals (primary circuit coolant).
The rapid development of a chain reaction is accompanied by the release of a large amount of heat and overheating of the reactor. To maintain a steady-state reactor mode, control rods made of materials that strongly absorb thermal neutrons, for example, boron or cadmium, are introduced into the reactor core.
The kinetic energy of decomposition products is converted into heat. Heat is absorbed by the coolant circulating in the nuclear reactor and transferred to the heat exchanger (1st closed circuit), where steam is produced (2nd circuit), which rotates the turbine of the turbogenerator. The coolant in the reactor is liquid sodium (1st circuit) and water (2nd circuit).
Uranium-235 is a non-renewable resource and if used entirely in nuclear reactors, it will disappear forever. Therefore, it is attractive to use the isotope uranium-238, which is found in much larger quantities, as the initial fuel. This isotope does not support a chain reaction under the influence of neutrons. But it can absorb fast neutrons, thereby forming uranium-239. In the nuclei of uranium-239, beta decay begins and neptunium-239 (not found in nature) is formed. This isotope also decays and becomes plutonium-239 (not found in nature). Plutonium-239 is even more susceptible to thermal neutron fission reactions. As a result of the fission reaction in the nuclear fuel plutonium-239, fast neutrons are formed, which, together with uranium, form new fuel and fission products that release heat in fuel elements (fuel elements). As a result, 20-30 times more energy can be obtained from a kilogram of natural uranium than in conventional nuclear reactors using uranium-235.
Modern designs use liquid sodium as a coolant. In this case, the reactor can operate at higher temperatures, thereby increasing the thermal efficiency of the power plant up to 40% .
However, the physical properties of plutonium: toxicity, low critical mass for spontaneous fission reactions, ignition in oxygen, brittleness and self-heating in the metallic state make it difficult to produce, process and handle. Therefore, breeder reactors are still less common than thermal neutron reactors.
For peaceful purposes, atomic energy is used in nuclear power plants. The share of nuclear power plants in global electricity production is about 14% .
As an example, consider the principle of generating electricity at the Voronezh Nuclear Power Plant. A liquid metal coolant with an inlet temperature of 571 K is sent through channels through channels under a pressure of 157 ATM (15.7 MPa), which is heated in the reactor to 595 K. The metal coolant is sent to a steam generator, which receives cold water, which turns into steam with a pressure of 65.3 ATM (6.53 MPa). Steam is supplied to the blades of a steam turbine, which rotates a turbogenerator.
In nuclear reactors, the temperature of the steam produced is significantly lower than in the steam generator of thermal power plants using organic fuel. As a result, the thermal efficiency of nuclear power plants operating with water as a coolant is only 30%. For comparison, for power plants running on coal, oil or gas it reaches 40%.
Nuclear power plants are used in electrical and heat supply systems for the population, and mini-nuclear power plants on sea vessels (nuclear-powered ships, nuclear submarines) for electric drive of propellers).
For military purposes, nuclear energy is used in atomic bombs. The atomic bomb is a special fast neutron reactor , in which a fast uncontrolled chain reaction occurs with a high neutron multiplication factor. The nuclear reactor of an atomic bomb does not contain moderators. As a result, the dimensions and weight of the device become small.
The nuclear charge of a uranium-235 bomb is divided into two parts, in each of which a chain reaction is impossible. To create an explosion, one half of the charge is fired into the other, and when they are connected, an explosive chain reaction occurs almost instantly. An explosive nuclear reaction results in the release of enormous energy. In this case, a temperature of about one hundred million degrees is reached. A colossal increase in pressure occurs and a powerful blast wave is formed.
The first nuclear reactor was launched at the University of Chicago (USA) on December 2, 1942. The first atomic bomb was detonated on July 16, 1945 in New Mexico (Alamogordo). It was a device created on the principle of plutonium fission. The bomb consisted of plutonium surrounded by two layers of chemical explosive with fuses.
The first nuclear power plant to produce current in 1951 was the EBR-1 nuclear power plant (USA). In the former USSR - Obninsk Nuclear Power Plant (Kaluga region, gave power on June 27, 1954). The first nuclear power plant in the USSR with a fast neutron reactor with a capacity of 12 MW was launched in 1969 in the city of Dimitrovgrad. In 1984, there were 317 nuclear power plants operating in the world with a total capacity of 191 thousand MW, which amounted to 12% (1012 kWh) of global electricity production at that time. The world's largest nuclear power plant as of 1981 was the Biblis NPP (Germany), the thermal power of its reactors was 7800 MW.
Thermonuclear reactions are called nuclear reactions of fusion of light nuclei into heavier ones. The element used in nuclear fusion is hydrogen. The main advantage of thermonuclear synetz is the practically unlimited resources of feedstock, which can be extracted from sea water. Hydrogen in one form or another makes up 90% of all matter. The fuel for thermonuclear fusion contained in the world's oceans will last for more than 1 billion years (solar radiation and humanity in the solar system will not last much longer). The raw materials for thermonuclear fusion contained in 33 km of ocean water are equivalent in energy content to all solid fuel resources (there is 40 million times more water on Earth). The energy of deuterium contained in a glass of water is equivalent to burning 300 liters of gasoline.
There are 3 isotopes of hydrogen : their atomic masses are -1.2 (deuterium), 3 (tritium). These isotopes can reproduce nuclear reactions in which the total mass of the final reaction products is less than the total mass of the substances that entered into the reaction. The difference in mass, as in the case of a fission reaction, accounts for the kinetic energy of the reaction products. On average, a decrease in the mass of the substance involved in the thermonuclear fusion reaction by 1 amu. corresponds to the release of 931 MeV of energy:
H 2 + H 2 = H 3 + neutron +3.2 MeV,
H 2 + H 2 = H 3 + proton +4.0 MeV,
H 2 + H 3 = He 4 + neutron +17.6 MeV.
There is practically no tritium in nature. It can be obtained by the interaction of neutrons with lithium isotopes:
Li 6 + neutron = He 4 + H 3 + 4.8 MeV.
The fusion of nuclei of light elements does not occur naturally (excluding processes in space). In order to force nuclei to enter into a fusion reaction, high temperatures are required (about 107 -109 K). In this case, the gas is an ionized plasma. The problem of confining this plasma represents the main obstacle to the use of this method of energy production. Temperatures of about 10 million degrees are typical for the central part of the Sun. It is thermonuclear reactions that are the source of energy that provides radiation from the Sun and stars.
Currently, theoretical and experimental work is underway to study methods of magnetic and inertial plasma confinement.
Method of using magnetic fields. A magnetic field is created that penetrates the channel of moving plasma. The charged particles that make up the plasma, while moving in a magnetic field, are exposed to forces directed perpendicular to the movement of the particles and the magnetic field lines. Due to the action of these forces, the particles will move in a spiral along the field lines. The stronger the magnetic field, the denser the plasma flow becomes, thereby isolating itself from the walls of the shell.
Inertial plasma confinement. The reactor carries out thermonuclear explosions with a frequency of 20 explosions per second. To implement this idea, a particle of thermonuclear fuel is heated using focused radiation from 10 lasers to the ignition temperature of the fusion reaction in the time before it has time to scatter over a noticeable distance due to the thermal motion of atoms (10-9 s).
Thermonuclear fusion is the basis of the hydrogen (thermonuclear) bomb. In such a bomb, a self-sustaining thermonuclear reaction of an explosive nature occurs. The explosive is a mixture of deuterium and tritium. The energy of a nuclear fission bomb is used as a source of activation energy (a source of high temperatures). The world's first thermonuclear bomb was created in the USSR in 1953.
At the end of the 50s, the USSR began working on the idea of thermonuclear fusion in reactors of the TOKAMAK type (toroidal chamber in the magnetic field of a coil). The principle of operation is as follows: the toroidal chamber is evacuated and filled with a gas mixture of deuterium and tritium. A current of several million amperes is passed through the mixture. In 1-2 seconds, the temperature of the mixture rises to hundreds of thousands of degrees. Plasma is formed in the chamber. Further heating is carried out by injection of neutral deuterium and tritium atoms with an energy of 100 - 200 keV. The plasma temperature rises to tens of millions of degrees and a self-sustaining fusion reaction begins. After 10-20 minutes, heavy elements from the partially evaporating material of the chamber walls will accumulate in the plasma. The plasma cools down and thermonuclear combustion stops. The chamber must be turned off again and cleaned of accumulated impurities. The torus dimensions for a reactor thermal power of 5000 MW are as follows: Outer radius -10m; internal radius - 2.5 m.
Research to find a way to control thermonuclear reactions, i.e. The use of thermonuclear energy for peaceful purposes is developing with great intensity.
In 1991, at a joint European facility in the UK, significant energy release was achieved for the first time during controlled thermonuclear fusion. The optimal mode was maintained for 2 seconds and was accompanied by the release of energy of about 1.7 MW. The maximum temperature was 400 million degrees.
Thermonuclear electric generator. When using deuterium as a fusion fuel, two-thirds of the energy must be released in the form of kinetic energy of charged particles. Using electromagnetic methods, this energy can be converted into electrical energy.
Electricity can be obtained in stationary and pulsed operating modes of the installation. In the first case, the ions and electrons resulting from a self-sustaining fusion reaction are inhibited by a magnetic field. The ion current is separated from the electron current using a transverse magnetic field. The efficiency of such a system during direct braking will be about 50%, and the rest of the energy will turn into heat.
Fusion engines (not implemented). Scope of application: spacecraft. The fully ionized deuterium plasma at a temperature of 1 billion degrees Celsius is held in the form of a cord by the linear magnetic field of coils of superconductors. The working fluid is fed into the chamber through the walls, cooling them, and heated by flowing around the plasma cord. The axial velocity of ion outflow at the exit from the magnetic nozzle is 10,000 km/s.
In 1972, at one meeting of the Club of Rome - an organization studying the causes and searching for solutions to problems on a planetary scale - a report was made by scientists E. von Weinzsäcker, A. H. Lovins and produced the effect of an exploding bomb. According to the data given in the report, the planet's energy sources - coal, gas, oil and uranium - will be sufficient until 2030. To mine coal, from which you can get $1 worth of energy, you will need to expend energy costing 99 cents.
Uranium-235, which serves as fuel for nuclear power plants, is not so abundant in nature: only 5% of the total amount of uranium in the world, 2% of which is in Russia. Therefore, nuclear power plants can only be used for auxiliary purposes. The research of scientists who tried to obtain energy from plasma on TOKAMAKs remains an expensive exercise to this day. In 2000, reports emerged that the European Atomic Community (CERN) and Japan were building the first segment of TOKAMAK.
The salvation may not be the “peaceful atom” of a nuclear power plant, but the “military” one – the energy of a thermonuclear bomb.
Russian scientists called their invention an explosive combustion boiler (ECC). The operating principle of the PIC is based on the explosion of an ultra-small thermonuclear bomb in a special sarcophagus - a boiler. Explosions occur regularly. It is interesting that in a VBC the pressure on the walls of the boiler during an explosion is less than in the cylinders of an ordinary car.
For safe operation of the boiler, the internal diameter of the boiler must be at least 100 meters. Double steel walls and a 30-meter thick reinforced concrete shell will dampen vibrations. Only high-quality steel will be used to construct it, like two modern military battleships. It is planned to build the KVS for 5 years. In 2000, in one of the closed cities of Russia, a project was prepared for the construction of an experimental installation for a “bomb” of 2-4 kilotons of nuclear equivalent. The cost of this FAC is $500 million. Scientists have calculated that it will pay for itself in a year, and for another 50 years it will provide practically free electricity and heat. According to the project manager, the cost of energy equivalent to burning a ton of oil will be less than $10.
40 KVGs are capable of meeting the needs of the entire national energy sector. One hundred - all countries of the Eurasian continent.
In 1932, a positron was experimentally discovered - a particle with the mass of an electron, but with a positive charge. Soon it was suggested that charge symmetry exists in nature: a) every particle must have an antiparticle; b) the laws of nature do not change when all particles are replaced by corresponding antiparticles and vice versa. The antiproton and antineutron were discovered in the mid-50s. In principle, there can be antimatter consisting of atoms, the nuclei of which include antiprotons and antineutrons, and their shell is formed by positrons.
Clots of antimatter of cosmological sizes would constitute antiworlds, but they are not found in nature. Antimatter is synthesized only on a laboratory scale. Thus, in 1969, at the Serpukhov accelerator, Soviet physicists detected antihelium nuclei consisting of two antiprotons and one antineutron.
With regard to the possibilities of energy conversion, antimatter is notable for the fact that when it comes into contact with matter, annihilation (destruction) occurs with the release of colossal energy (both types of matter disappear, turning into radiation). Thus, an electron and a positron, annihilating, generate two photons. One type of matter—charged massive particles—transforms into another type of matter—neutral massless particles. Using Einstein's relation about the equivalence of energy and mass (E=mc 2), it is not difficult to calculate that the annihilation of one gram of matter produces the same energy that can be obtained by burning 10,000 tons of coal, and one ton of antimatter would be enough to provide energy for the entire planet for a year.
Astrophysicists believe that it is annihilation that provides the gigantic energy of quasi-stellar objects - quasars.
In 1979, a group of American physicists managed to register the presence of natural antiprotons. They were brought by cosmic rays.
Einstein established the connection between energy and mass in his equation:
where c = 300,000,000 m/s is the speed of light;
Thus, the body of a person weighing 70 kg contains energy
the RBMK-1000 reactor plant will generate this amount of energy only in two thousand mass of the separated core. Of course, the complete conversion of mass into energy is still very far away, but already such a change in the mass of fuel in the reactor, which is not detected by ordinary scales, makes it possible to obtain a gigantic amount of energy. The change in fuel mass over a year of continuous operation in the RBMK-1000 reactor is approximately 0.3 g, but the energy released is the same as when burning 3,000,000 (three million) tons of coal.% years of operation. The main problem is learning how to convert mass into useful energy. Humanity took the first step to solve this problem by mastering the military and peaceful use of nuclear fission energy. To a very first approximation, the processes occurring in a nuclear reactor can be described as continuous fission of nuclei. In this case, the mass of the whole nucleus before fission is greater than the mass of the resulting fragments. The difference is approximately 0.1
Power.
In practice, when we talk about an energy source, we are usually interested in its power. You can lift a thousand bricks to the fifth floor of a house under construction with a crane, or with the help of two workers with a stretcher. In both cases, the work done and the energy expended are the same, only the power of the energy sources differs. Definition:Power source of energy (machine), this is the amount of energy received (work done) per unit of time.
power = energy (work) / time
dimension [J/sec = W]
Law of energy conservation
As mentioned above, in the world around us there is a continuous transformation of energy from one type to another. By tossing the ball, we caused a chain of transformations of mechanical energy from one type to another. A bouncing ball clearly illustrates the law of conservation of energy:
Energy cannot disappear into nowhere, or appear from nowhere, it can only pass from one type to another.
The ball, after making several bounces, will eventually remain motionless on the surface. Since the mechanical energy initially transferred to it is spent on:
a) overcoming the resistance of the air in which the ball moves (turns into thermal energy of the air)
b) heating of the ball and the impact surface. (a change in shape is always accompanied by heating, remember how aluminum wire heats up when repeatedly bent)
Energy conversion
The ability to transform and use energy is an indicator of the technical development of mankind. The first energy converter used by man can be considered a sail - the use of wind energy to move through water, further developed is the use of wind and water in wind and water mills. The invention and implementation of the steam engine made a real revolution in technology. Steam engines in factories and factories dramatically increased labor productivity. Steam locomotives and motor ships made transportation by land and sea faster and cheaper. At the initial stage, the steam engine served to convert thermal energy into mechanical energy of a rotating wheel, from which, using various types of transmissions (shafts, pulleys, belts, chains), the energy was transferred to machines and mechanisms.
The widespread introduction of electrical machines, engines that convert electrical energy into mechanical energy, and generators for producing electricity from mechanical energy marked a new leap in the development of technology. It became possible to transmit energy over long distances in the form of electricity, and an entire industry, the energy sector, was born.
Currently, a large number of devices have been created designed to convert electricity into any type of energy necessary for human life: electric motors, electric heaters, lighting lamps, and those that use electricity directly: televisions, receivers, etc.
NPP (with single-loop reactor)
History of the development of nuclear energy
The world's first pilot nuclear power plant with a capacity of 5 MW was launched in the USSR on June 27, 1954 in Obninsk. Before this, the energy of the atomic nucleus was used primarily for military purposes. The launch of the first nuclear power plant marked the opening of a new direction in energy, which received recognition at the 1st International Scientific and Technical Conference on the Peaceful Uses of Atomic Energy (August 1955, Geneva).
In 1958, the 1st stage of the Siberian Nuclear Power Plant with a capacity of 100 MW was put into operation (total design capacity 600 MW). In the same year, the construction of the Beloyarsk industrial nuclear power plant began, and on April 26, 1964, the generator of the 1st stage (100 MW unit) supplied current to the Sverdlovsk energy system, the 2nd unit with a capacity of 200 MW was put into operation in October 1967. A distinctive feature of the Beloyarsk NPP is overheating of steam (until the required parameters are obtained) directly in a nuclear reactor, which made it possible to use conventional modern turbines on it almost without any modifications.
In September 1964, the 1st unit of the Novovoronezh NPP with a capacity of 210 MW was launched. The cost of 1 kWh of electricity (the most important economic indicator of the operation of any power plant) at this nuclear power plant systematically decreased: it amounted to 1.24 kopecks. in 1965, 1.22 kopecks. in 1966, 1.18 kopecks. in 1967, 0.94 kopecks. in 1968. The first unit of the Novovoronezh NPP was built not only for industrial use, but also as a demonstration facility to demonstrate the capabilities and advantages of nuclear energy, the reliability and safety of nuclear power plants. In November 1965, in the city of Melekess, Ulyanovsk region, a nuclear power plant with a water-water reactor of the “boiling” type with a capacity of 50 MW came into operation; the reactor was assembled according to a single-circuit design, facilitating the layout of the station. In December 1969, the second unit of the Novovoronezh NPP (350 MW) was launched.
Abroad, the first industrial nuclear power plant with a capacity of 46 MW was put into operation in 1956 in Calder Hall (England). A year later, a nuclear power plant with a capacity of 60 MW came into operation in Shippingport (USA).
A schematic diagram of a nuclear power plant with a water-cooled nuclear reactor is shown in Fig. 2. The heat released in the reactor core 1 is taken away by the water (coolant) of the 1st circuit, which is pumped through the reactor by circulation pump 2. The heated water from the reactor enters the heat exchanger (steam generator) 3, where it transfers the heat generated in the reactor to the water 2nd circuit. The water of the 2nd circuit evaporates in the steam generator, and the resulting steam enters turbine 4.
Most often, 4 types of thermal neutron reactors are used at nuclear power plants: 1) water-water reactors with ordinary water as a moderator and coolant; 2) graphite-water with water coolant and graphite moderator; 3) heavy water with water coolant and heavy water as a moderator; 4) graphite-gas with gas coolant and graphite moderator.
The choice of the predominantly used type of reactor is determined mainly by the accumulated experience in reactor construction, as well as the availability of the necessary industrial equipment, raw material reserves, etc. In the USSR, mainly graphite-water and water-cooled reactors are built. At US nuclear power plants, pressurized water reactors are the most widely used. Graphite gas reactors are used in England. Canada's nuclear power industry is dominated by nuclear power plants with heavy water reactors.
Depending on the type and aggregate state of the coolant, one or another thermodynamic cycle of the nuclear power plant is created. The choice of the upper temperature limit of the thermodynamic cycle is determined by the maximum permissible temperature of the claddings of fuel elements (fuel elements) containing nuclear fuel, the permissible temperature of the nuclear fuel itself, as well as the properties of the coolant adopted for a given type of reactor. At nuclear power plants, the thermal reactor of which is cooled by water, low-temperature steam cycles are usually used. Gas-cooled reactors allow the use of relatively more economical steam cycles with increased initial pressure and temperature. The thermal circuit of the nuclear power plant in these two cases is 2-circuit: the coolant circulates in the 1st circuit, and the steam-water circuit circulates in the 2nd circuit. With reactors with boiling water or high-temperature gas coolant, a single-circuit thermal nuclear power plant is possible. In boiling water reactors, water boils in the core, the resulting steam-water mixture is separated, and the saturated steam is sent either directly to the turbine, or is first returned to the core for overheating (Fig. 3). In high-temperature graphite-gas reactors, it is possible to use a conventional gas turbine cycle. The reactor in this case acts as a combustion chamber.
During reactor operation, the concentration of fissile isotopes in nuclear fuel gradually decreases, i.e., fuel rods burn out. Therefore, over time they are replaced with fresh ones. Nuclear fuel is reloaded using remote-controlled mechanisms and devices. Spent fuel rods are transferred to a spent fuel pool and then sent for recycling.
The reactor and its servicing systems include: the reactor itself with biological protection, heat exchangers, pumps or gas-blowing units that circulate the coolant; pipelines and fittings of the circulation circuit; devices for reloading nuclear fuel; special systems ventilation, emergency cooling, etc.
Depending on the design, reactors have distinctive features: in vessel reactors, the fuel rods and moderator are located inside the housing, bearing the full coolant pressure; in channel reactors, fuel rods cooled by a coolant are installed in special pipe-channels that penetrate the moderator, enclosed in a thin-walled casing. Such reactors are used in the USSR (Siberian, Beloyarsk nuclear power plants, etc.).
To protect nuclear power plant personnel from radiation exposure, the reactor is surrounded by biological shielding, the main materials for which are concrete, water, and serpentine sand. The reactor circuit equipment must be completely sealed. A system is provided to monitor places of possible coolant leaks; measures are taken to ensure that the occurrence of leaks and breaks in the circuit does not lead to radioactive emissions and contamination of the nuclear power plant premises and the surrounding area. Reactor circuit equipment is usually installed in sealed boxes, which are separated from the rest of the NPP premises by biological protection and are not maintained during reactor operation. Radioactive air and a small amount of coolant vapor, due to the presence of leaks from the circuit, are removed from unattended rooms of the nuclear power plant by a special ventilation system, in which cleaning filters and holding gas tanks are provided to eliminate the possibility of air pollution. The compliance with radiation safety rules by NPP personnel is monitored by the dosimetry control service.
In case of accidents in the reactor cooling system, to prevent overheating and failure of the seals of the fuel rod shells, rapid (within a few seconds) suppression of the nuclear reaction is provided; The emergency cooling system has autonomous power sources.
The presence of biological protection, special ventilation and emergency cooling systems and a radiation monitoring service makes it possible to completely protect NPP operating personnel from the harmful effects of radioactive radiation.
The equipment of the turbine room of a nuclear power plant is similar to the equipment of the turbine room of a thermal power plant. A distinctive feature of most nuclear power plants is the use of steam of relatively low parameters, saturated or slightly superheated.
In this case, to prevent erosion damage to the blades of the last stages of the turbine by moisture particles contained in the steam, separating devices are installed in the turbine. Sometimes it is necessary to use remote separators and intermediate steam superheaters. Due to the fact that the coolant and the impurities it contains are activated when passing through the reactor core, the design solution of the turbine room equipment and the turbine condenser cooling system of single-circuit nuclear power plants must completely eliminate the possibility of coolant leakage. At double-circuit nuclear power plants with high steam parameters, such requirements are not imposed on the equipment of the turbine room.
Specific requirements for the layout of nuclear power plant equipment include: the minimum possible length of communications associated with radioactive media, increased rigidity of the foundations and load-bearing structures of the reactor, reliable organization of ventilation of the premises. In Fig. shows a section of the main building of the Beloyarsk NPP with a channel graphite-water reactor. The reactor hall houses a reactor with biological protection, spare fuel rods and control equipment. The nuclear power plant is configured according to the reactor-turbine block principle. Turbine generators and their servicing systems are located in the turbine room. Between the engine and reactor rooms, auxiliary equipment and plant control systems are located.
The efficiency of a nuclear power plant is determined by its main technical indicators: unit power of the reactor, efficiency, energy intensity of the core, burnup of nuclear fuel, utilization rate of the installed capacity of the nuclear power plant per year. As the capacity of a nuclear power plant increases, specific capital investments in it (the cost of an installed kW) decrease more sharply than is the case for thermal power plants. This is the main reason for the desire to build large nuclear power plants with large unit power units. It is typical for the economics of nuclear power plants that the share of the fuel component in the cost of generated electricity is 30-40% (at thermal power plants 60-70%). Therefore, large nuclear power plants are most common in industrialized areas with limited supplies of conventional fuel, and small-capacity nuclear power plants are most common in hard-to-reach or remote areas, for example, nuclear power plants in the village. Bilibino (Yakut Autonomous Soviet Socialist Republic) with an electric power of a typical unit of 12 MW. Part of the thermal power of the reactor of this nuclear power plant (29 MW) is spent on heat supply. In addition to generating electricity, nuclear power plants are also used to desalinate seawater. Thus, the Shevchenko Nuclear Power Plant (Kazakh SSR) with an electrical capacity of 150 MW is designed for desalination (by distillation) of up to 150,000 tons of water from the Caspian Sea per day.
In most industrialized countries (USSR, USA, England, France, Canada, Germany, Japan, East Germany, etc.), according to forecasts, the capacity of existing and under construction nuclear power plants will be increased to tens of gigawatts by 1980. According to the UN International Atomic Agency, published in 1967, the installed capacity of all nuclear power plants in the world will reach 300 GW by 1980.
The Soviet Union is implementing an extensive program of commissioning large power units (up to 1000 MW) with thermal neutron reactors. In 1948-49, work began on fast neutron reactors for industrial nuclear power plants. The physical features of such reactors make it possible to carry out expanded breeding of nuclear fuel (breeding factor from 1.3 to 1.7), which makes it possible to use not only 235U, but also raw materials 238U and 232Th. In addition, fast neutron reactors do not contain a moderator, are relatively small in size and have a large load. This explains the desire for intensive development of fast reactors in the USSR. For research on fast reactors, experimental and pilot reactors BR-1, BR-2, BR-Z, BR-5, and BFS were successively built. The experience gained led to the transition from research on model plants to the design and construction of industrial fast neutron nuclear power plants (BN-350) in Shevchenko and (BN-600) at the Beloyarsk NPP. Research is underway on reactors for powerful nuclear power plants, for example, a pilot reactor BOR-60 was built in Melekess.
Large nuclear power plants are also being built in a number of developing countries (India, Pakistan, etc.).
At the 3rd International Scientific and Technical Conference on the Peaceful Uses of Atomic Energy (1964, Geneva), it was noted that the widespread development of nuclear energy has become a key problem for most countries. The 7th World Energy Conference (WIREC-VII), held in Moscow in August 1968, confirmed the relevance of the problems of choosing the direction of development of nuclear energy at the next stage (conditionally 1980-2000), when nuclear power plants will become one of the main producers of electricity.
Atomic energy is the energy released during the transformation of atomic nuclei. The source of atomic energy is the internal energy of the atomic nucleus.
A more accurate name for atomic energy is nuclear energy. There are two types of nuclear energy production:
- implementation of a nuclear chain reaction of fission of heavy nuclei;
- implementation of a thermonuclear reaction of fusion of light nuclei.
Myths about nuclear energy
The world's uranium reserves are running out. Even a child knows about the depletion of natural resources nowadays. Indeed, reserves of many minerals are rapidly depleting. Uranium reserves are currently assessed as "relatively limited", but this is not that small. For comparison, there is as much uranium as tin and 600 times more than gold. According to preliminary estimates by scientists, the reserves of this radioactive metal should be enough for humanity for the next 500 years. In addition, modern reactors can use thorium as fuel, and its world reserves, in turn, exceed uranium reserves by 3 times.
Nuclear energy has an extremely negative impact on the environment. Representatives of various anti-nuclear campaigns often claim that nuclear energy contains "hidden emissions" of gases that have a negative impact on the environment. But according to all modern information and calculations, nuclear energy, even compared to solar or hydropower, which are considered practically environmentally friendly, contains a fairly low level of carbon.
Wind and wave energy are much less harmful from an environmental point of view. In reality, wind farms are being built or have already been built on key coastal sites, and the construction itself is already definitely polluting the environment. But the construction of wave stations is still experimental, and its impact on the environment is not precisely known, so it is difficult to call them much more environmentally sustainable compared to nuclear energy.
In areas where nuclear reactors are located, the incidence of leukemia is higher. The level of leukemia among children in the vicinity of nuclear power plants is no higher than, for example, in areas near so-called organic farms. The area of spread of this disease can cover both the area around the nuclear power plant and the national park; the degree of danger is absolutely the same.
Nuclear reactors produce too much waste. Nuclear energy actually produces minimal waste, contrary to environmentalists' claims. The earth is not at all filled with radioactive waste. Modern nuclear energy production technologies will make it possible to minimize the share of the total amount of radioactive waste over the next 20-40 years.
Nuclear energy contributes to the proliferation of weapons in the world. An increase in the number of nuclear power plants will lead precisely to a reduction in the proliferation of weapons. Nuclear warheads produce very good quality reactor fuel, and reactor warheads produce about 15% of the world's nuclear fuel. Increasing demand for reactor fuel is expected to "divert" such warheads from potential terrorists.
Terrorists choose nuclear reactors as targets. After the tragedy of September 11, 2001, a number of scientific studies were conducted to determine the likelihood of an attack on nuclear facilities. However, recent British studies have proven that nuclear power plants are quite capable of “withstanding” even a Boeing 767-400 raid. The new generation of nuclear reactors will be designed with increased levels of protection against potential attacks from all existing aircraft, and there are also plans to introduce special safety features that can be activated without human intervention or computer control.
Nuclear energy is very expensive. Controversial statement. According to the British Department of Trade and Industry, the cost of producing electricity from nuclear power plants exceeds only the price of gas, and is 10-20 times less than the energy produced by onshore wind farms. In addition, 10% of the total cost of nuclear energy comes from uranium, and nuclear energy is not as susceptible to constant price fluctuations for fuels such as gas or oil.
Decommissioning a nuclear power plant is very expensive. This statement applies only to nuclear power plants built earlier. Many of the current nuclear reactors were built without the expectation of their subsequent decommissioning. But during the construction of new nuclear power plants this point will already be taken into account. However, the cost of decommissioning a nuclear power plant will be included in the cost of electricity that consumers pay for. Modern reactors are designed to operate for 40 years, and the cost of decommissioning them will be paid over this long period, and therefore will have little impact on the price of electricity.
Nuclear power plant construction takes too long. This is perhaps the most unmotivated of all the statements of anti-nuclear campaigns. The construction of a nuclear power plant takes from 4 to 6 years, which is comparable to the construction time of “traditional” power plants. The modular structure of new nuclear power plants can somewhat speed up the process of constructing nuclear power plants.
An atom consists of a nucleus surrounded by clouds of particles called electrons(see picture). The nuclei of atoms - the smallest particles from which all substances are composed - contain a significant supply. It is this energy that is released in the form of radiation during the decay of radioactive elements. Radiation is dangerous to life, but nuclear reactions can be used to produce. Radiation is also used in medicine.
Radioactivity
Radioactivity is the property of the nuclei of unstable atoms to emit energy. Most heavy atoms are unstable, but lighter atoms have radioisotopes, i.e. radioactive isotopes. The reason for radioactivity is that atoms tend to become stable (see article " "). There are three types of radioactive radiation: alpha rays, beta rays And gamma rays. They are named after the first three letters of the Greek alphabet. Initially, the nucleus emits alpha or beta rays, and if it is still unstable, the nucleus emits gamma rays as well. 
In the picture you see three atomic nuclei. They are unstable, and each of them emits one of three types of rays. Beta particles are electrons with very high energy. They arise from the decay of a neutron. Alpha particles consist of two protons and two neutrons. The nucleus of a helium atom has exactly the same composition. Gamma rays are high-energy electromagnetic radiation that travels at the speed of light.
Alpha particles move slowly, and a layer of matter thicker than a sheet of paper traps them. They are no different from the nuclei of helium atoms. Scientists believe that helium on Earth is a product of natural radioactivity. An alpha particle flies less than 10 cm, and a sheet of thick paper will stop it. A beta particle flies about 1 meter in the air. A sheet of copper 1 millimeter thick can hold it back. The intensity of gamma rays drops by half when passing through a layer of lead of 13 millimeters or a layer of 120 meters.
Radioactive substances are transported in thick-walled lead containers to prevent radiation leakage. Exposure to radiation causes burns, cataracts, and cancer in humans. Radiation levels are measured using Geiger counter. This device makes a clicking noise when it detects radioactive radiation. Having emitted particles, the nucleus acquires a new atomic number and turns into the nucleus of another element. This process is called radioactive decay. If the new element is also unstable, the decay process continues until a stable nucleus is formed. For example, when a plutonium-2 atom (its mass is 242) emits an alpha particle whose relative atomic mass is 4 (2 protons and 2 neutrons), it turns into a uranium atom - 238 (atomic mass 238). Half life- this is the time during which half of all atoms in a sample of a given substance decay. Different ones have different half-lives. The half-life of radium-221 is 30 seconds, while that of uranium is 4.5 billion years.
Nuclear reactions
There are two types of nuclear reactions: nuclear fusion And fission (splitting) of the nucleus. "Synthesis" means "combination"; In nuclear fusion, two nuclei are combined and one is large. Nuclear fusion can only occur at very high temperatures. Fusion releases a huge amount of energy. In nuclear fusion, two nuclei are combined into one large one. In 1992, the COBE satellite discovered a special type of radiation in space, which confirms the theory that it was formed as a result of the so-called big bang. From the term fission it is clear that nuclei split apart, releasing nuclear energy. This is possible when nuclei are bombarded with neutrons and occurs in radioactive substances or in a special device called particle accelerator. The nucleus splits, emitting neutrons and releasing colossal energy.
Nuclear power
The energy released from nuclear reactions can be used to produce electricity and as a power source in nuclear submarines and aircraft carriers. The operation of a nuclear power plant is based on nuclear fission in nuclear reactors. A rod made of a radioactive substance such as uranium is bombarded with neutrons. Uranium nuclei split, emitting energy. This releases new neutrons. This process is called chain reaction. The power plant produces more energy per unit mass of fuel than any other power plant, but safety precautions and disposal of radioactive waste are extremely expensive.
Nuclear weapon
The action of nuclear weapons is based on the fact that the uncontrolled release of a huge amount of nuclear energy leads to a terrible explosion. At the end of World War II, the United States dropped atomic bombs on the Japanese cities of Hiroshima and Nagasaki. Hundreds of thousands of people died. Atomic bombs are based on fission reactions, hydrogen - on synthesis reactions. The picture shows the atomic bomb dropped on Hiroshima.
Radiocarbon method
The radiocarbon method determines the time that has passed since the death of an organism. Living things contain small amounts of carbon-14, a radioactive isotope of carbon. Its half-life is 5,700 years. When an organism dies, carbon-14 reserves in tissues are depleted, the isotope decays, and the remaining amount can be used to determine how long ago the organism died. Thanks to the radiocarbon dating method, you can find out how long ago the eruption occurred. To do this, they use insects and pollen frozen in lava.
How else is radioactivity used?
In industry, radiation is used to determine the thickness of a sheet of paper or plastic (see article ““). By the intensity of beta rays passing through the sheet, even slight heterogeneity in its thickness can be detected. Food products - fruits, meat - are irradiated with gamma rays to keep them fresh. Using radioactivity, doctors trace the path of a substance in the body. For example, to determine how sugar is distributed in a patient's body, a doctor might inject some carbon-14 into the sugar molecules and monitor the emission of the substance as it enters the body. Radiotherapy, that is, irradiating a patient with strictly dosed portions of radiation, kills cancer cells - overgrown cells of the body.