Nuclear energy consists of a large number of enterprises for various purposes. The raw materials for this industry are mined from uranium mines. It is then delivered to fuel production plants.
The fuel is then transported to nuclear power plants, where it enters the reactor core. When nuclear fuel reaches the end of its useful life, it is subject to disposal. It is worth noting that hazardous waste appears not only after fuel reprocessing, but also at any stage - from uranium mining to work in the reactor.
Nuclear fuel
There are two types of fuel. The first is uranium mined in mines, which is of natural origin. It contains raw materials that are capable of forming plutonium. The second is fuel that is created artificially (secondary).
Nuclear fuel is also divided according to its chemical composition: metallic, oxide, carbide, nitride and mixed.
Uranium mining and fuel production
A large share of uranium production occurs in just a few countries: Russia, France, Australia, the USA, Canada and South Africa.
Uranium is the main element for fuel in nuclear power plants. To get into the reactor, it goes through several stages of processing. Most often, uranium deposits are located next to gold and copper, so its extraction is carried out with the extraction of precious metals.
In mining, human health is at great risk because uranium is a toxic material, and the gases that appear during its mining cause various forms of cancer. Although the ore itself contains a very small amount of uranium - from 0.1 to 1 percent. The population living near uranium mines is also at great risk.
Enriched uranium is the main fuel for nuclear power plants, but after its use a huge amount of radioactive waste remains. Despite all its dangers, uranium enrichment is an integral process of creating nuclear fuel.
In its natural form, uranium practically cannot be used anywhere. In order to be used, it must be enriched. Gas centrifuges are used for enrichment.
Enriched uranium is used not only in nuclear energy, but also in weapons production.
Transportation
At any stage of the fuel cycle there is transportation. It is carried out by everyone accessible ways: by land, sea, air. This is a big risk and a big danger not only for the environment, but also for humans.
During the transportation of nuclear fuel or its elements, many accidents occur, resulting in the release of radioactive elements. This is one of the many reasons why it is considered unsafe.
Decommissioning of reactors
None of the reactors have been dismantled. Even the infamous Chernobyl The whole point is that, according to experts, the cost of dismantling is equal to, or even exceeds, the cost of building a new reactor. But no one can say exactly how much money will be needed: the cost was calculated based on the experience of dismantling small stations for research. Experts offer two options:
- Place reactors and spent nuclear fuel in repositories.
- Build sarcophagi over decommissioned reactors.
In the next ten years, about 350 reactors around the world will reach their end of life and must be taken out of service. But since the most suitable method in terms of safety and price has not been invented, this issue is still being resolved.
There are currently 436 reactors operating around the world. Of course, this is a big contribution to the energy system, but it is very unsafe. Research shows that in 15-20 years, nuclear power plants will be able to be replaced by stations that run on wind energy and solar panels.
Nuclear waste
A huge amount of nuclear waste is generated as a result of the activities of nuclear power plants. Reprocessing nuclear fuel also leaves behind hazardous waste. However, none of the countries found a solution to the problem.
Today, nuclear waste is kept in temporary storage facilities, in pools of water, or buried shallowly underground.
Most safe way- this is storage in special storage facilities, but radiation leakage is also possible here, as with other methods.
In fact, nuclear waste has some value, but requires strict compliance with the rules for its storage. And this is the most pressing problem.
An important factor is the time during which the waste is hazardous. Each has its own decay period during which it is toxic.
Types of nuclear waste
During the operation of any nuclear power plant, its waste enters the environment. This is water for cooling turbines and gaseous waste.
Nuclear waste is divided into three categories:
- Low level - clothing of nuclear power plant employees, laboratory equipment. Such waste can also come from medical institutions, scientific laboratories. They do not pose a great danger, but require compliance with safety measures.
- Intermediate level - metal containers in which fuel is transported. Their radiation level is quite high, and those who are close to them must be protected.
- The high level is spent nuclear fuel and its reprocessing products. The level of radioactivity is rapidly decreasing. High level waste is very small, about 3 percent, but it contains 95 percent of all radioactivity.
Novosibirsk Chemical Concentrates Plant is one of the world's leading producers of nuclear fuel for nuclear power plants and research reactors in Russia and foreign countries. The only Russian manufacturer of metal lithium and its salts. It is part of the TVEL Fuel Company of the Rosatom State Corporation.
Attention, comments under the photo!
Despite the fact that in 2011 NCCP produced and sold 70% of the world's consumption of the lithium-7 isotope, the plant's main activity is the production of nuclear fuel for power and research reactors.
The current photo report is dedicated to this species.
Roof of the main production complex building
Workshop for the production of fuel rods and fuel assemblies for research reactors
Area for the production of uranium dioxide powder using high-temperature pyrohydrolysis
Loading containers with uranium hexafluoride
Operators room
From here comes the control of the process of producing uranium dioxide powder, from which fuel pellets are then made.
Uranium pellet production area
In the foreground, bicones are visible where uranium dioxide powder is stored.
They mix the powder and plasticizer, which allows the tablet to be better compressed.
Nuclear ceramic fuel pellets
Next they are sent to the oven for annealing.
Torch (hydrogen afterburning) on a tablet sintering furnace
The tablets are annealed in ovens at a temperature of at least 1750 degrees in a hydrogen reducing environment for more than 20 hours.
Production and technical control of nuclear ceramic fuel pellets
One tablet weighing 4.5 g is equivalent in energy release to 400 kg of coal, 360 cubic meters. m of gas or 350 kg of oil.
All work is carried out in boxes using special gloves.
Unloading containers with tablets
Workshop for the production of fuel rods and fuel assemblies for nuclear power plants
Automated fuel rod manufacturing line
Here the zirconium tubes are filled with uranium dioxide tablets.
The result is finished fuel rods about 4 m in length - fuel elements.
Fuel rods are already used to assemble fuel assemblies, in other words, nuclear fuel.
Moving finished fuel rods in transport containers
Shoe covers even have wheels.
FA assembly area
Installation for applying varnish coating to fuel rods
Securing fuel rods in the loading mechanism
Frame manufacturing - welding of channels and spacer grids
312 fuel rods will then be installed into this frame.
Technical control of the frame
Channels and spacer grids
Automated fuel rod bundle loading stands
Beam assembly
Technical control of fuel assemblies
Fuel rods with barcode markings, which can literally be used to trace the entire production path of the product.
Stands for inspection and packaging of finished fuel assemblies
Inspection of finished fuel assemblies
Check that the distance between the fuel rods is the same.
Finished fuel assembly
Double-pipe containers for fuel assemblies transportation
Fuel for nuclear power plants produced at NCCP is used at Russian nuclear power plants and is also supplied to Ukraine, Bulgaria, China, India and Iran.
Life cycle nuclear fuel based on uranium or plutonium begins at mining enterprises, chemical plants, in gas centrifuges, and does not end at the moment the fuel assembly is unloaded from the reactor, since each fuel assembly has to go through a long path of disposal and then reprocessing.
Extraction of raw materials for nuclear fuel
Uranium is the heaviest metal on earth. About 99.4% of the earth's uranium is uranium-238, and only 0.6% is uranium-235. The International Atomic Energy Agency's Red Book report shows that uranium production and demand are rising despite the Fukushima nuclear accident, which has left many wondering about the prospects for nuclear power. Over the past few years alone, proven uranium reserves have increased by 7%, which is associated with the discovery of new deposits. The largest producers remain Kazakhstan, Canada and Australia; they mine up to 63% of the world's uranium. In addition, metal reserves are available in Australia, Brazil, China, Malawi, Russia, Niger, USA, Ukraine, China and other countries. Previously, Pronedra wrote that in 2016, 7.9 thousand tons of uranium were mined in the Russian Federation.
Nowadays, uranium is mined in three in different ways. The open method does not lose its relevance. It is used in cases where deposits are close to the surface of the earth. With the open method, bulldozers create a quarry, then the ore with impurities is loaded into dump trucks for transportation to processing complexes.
Often the ore body lies at great depth, in which case the underground mining method is used. A mine is dug up to two kilometers deep, the rock is extracted by drilling in horizontal drifts, and transported upward in freight elevators.
The mixture that is transported upward in this way has many components. The rock must be crushed, diluted with water and the excess removed. Next, sulfuric acid is added to the mixture to carry out the leaching process. During this reaction, chemists obtain a precipitate of uranium salts yellow. Finally, uranium with impurities is purified in a refining facility. Only after this is uranium oxide produced, which is traded on the stock exchange.
There is a much safer, environmentally friendly and cost-effective method called borehole in situ leaching (ISL).
With this method of field development, the territory remains safe for personnel, and the radiation background corresponds to the background in major cities. To mine uranium using leaching, you need to drill 6 holes at the corners of the hexagon. Through these wells, sulfuric acid is pumped into uranium deposits and mixed with its salts. This solution is extracted, namely, pumped through a well in the center of the hexagon. To achieve the required concentration of uranium salts, the mixture is passed through sorption columns several times.
Nuclear fuel production
It is impossible to imagine the production of nuclear fuel without gas centrifuges, which are used to produce enriched uranium. After reaching the required concentration, the uranium dioxide is pressed into so-called tablets. They are created using lubricants that are removed during firing in kilns. The firing temperature reaches 1000 degrees. After this, the tablets are checked to ensure they meet the stated requirements. Surface quality, moisture content, and the ratio of oxygen and uranium are important.
At the same time, tubular shells for fuel elements are being prepared in another workshop. The above processes, including subsequent dosing and packaging of tablets in shell tubes, sealing, decontamination, are called fuel fabrication. In Russia, the creation of fuel assemblies (FA) is carried out by the enterprises “Machine-Building Plant” in the Moscow region, “Novosibirsk Chemical Concentrates Plant” in Novosibirsk, “Moscow Polymetal Plant” and others.
Each batch of fuel assemblies is created for a specific type of reactor. European fuel assemblies are made in the shape of a square, while Russian ones have a hexagonal cross-section. Reactors of the VVER-440 and VVER-1000 types are widely used in the Russian Federation. The first fuel elements for VVER-440 began to be developed in 1963, and for VVER-1000 - in 1978. Despite the fact that new reactors with post-Fukushima safety technologies are being actively introduced in Russia, there are many old-style nuclear installations operating throughout the country and abroad, so fuel assemblies remain equally relevant for different types reactors.
For example, to provide fuel assemblies for one core of the RBMK-1000 reactor, over 200 thousand components made of zirconium alloys, as well as 14 million sintered uranium dioxide pellets, are needed. Sometimes the cost of manufacturing a fuel assembly can exceed the cost of the fuel contained in the elements, which is why it is so important to ensure high energy efficiency per kilogram of uranium.
Costs for production processes V %
Separately, it is worth mentioning fuel assemblies for research reactors. They are designed in such a way as to make observation and study of the neutron generation process as comfortable as possible. Such fuel rods for experiments in the fields of nuclear physics, isotope production, and radiation medicine are produced in Russia by the Novosibirsk Chemical Concentrates Plant. FAs are created on the basis of seamless elements with uranium and aluminum.
The production of nuclear fuel in the Russian Federation is carried out by the fuel company TVEL (a division of Rosatom). The company works on enriching raw materials, assembling fuel elements, and also provides fuel licensing services. The Kovrov Mechanical Plant in the Vladimir Region and the Ural Gas Centrifuge Plant in the Sverdlovsk Region create equipment for Russian fuel assemblies.
Features of transportation of fuel rods
Natural uranium is characterized by a low level of radioactivity, however, before the production of fuel assemblies, the metal undergoes an enrichment procedure. The content of uranium-235 in natural ore does not exceed 0.7%, and the radioactivity is 25 becquerels per 1 milligram of uranium.
Uranium pellets, which are placed in fuel assemblies, contain uranium with a concentration of uranium-235 of 5%. Finished fuel assemblies with nuclear fuel are transported in special high-strength metal containers. For transportation, rail, road, sea and even air transport are used. Each container contains two assemblies. Transportation of non-irradiated (fresh) fuel does not pose a radiation hazard, since the radiation does not extend beyond the zirconium tubes into which the pressed uranium pellets are placed.
A special route is developed for the fuel shipment; the cargo is transported accompanied by security personnel from the manufacturer or the customer (more often), which is primarily due to the high cost of the equipment. In the entire history of nuclear fuel production, not a single transport accident involving fuel assemblies has been recorded that would have affected the radiation background of the environment or led to casualties.
Fuel in the reactor core
A unit of nuclear fuel - a TVEL - is capable of releasing enormous amounts of energy over a long period of time. Neither coal nor gas can compare with such volumes. The fuel life cycle at any nuclear power plant begins with the unloading, removal and storage of fresh fuel in the fuel assembly warehouse. When the previous batch of fuel in the reactor burns out, personnel complete the fuel assemblies for loading into the core ( work area reactor where the decomposition reaction occurs). As a rule, the fuel is partially reloaded.
Full fuel is added to the core only at the time of the first startup of the reactor. This is due to the fact that the fuel rods in the reactor burn out unevenly, since the neutron flux varies in intensity in different zones of the reactor. Thanks to metering devices, station personnel have the opportunity to monitor the degree of burnout of each unit of fuel in real time and make replacements. Sometimes, instead of loading new fuel assemblies, assemblies are moved among themselves. In the center of the active zone, burnout occurs most intensely.
FA after a nuclear power plant
Uranium that has been spent in a nuclear reactor is called irradiated or burnt. And such fuel assemblies are used as spent nuclear fuel. SNF is positioned separately from radioactive waste, since it has at least 2 useful components - unburned uranium (the burnup depth of the metal never reaches 100%) and transuranium radionuclides.
Recently, physicists have begun to use radioactive isotopes accumulated in spent nuclear fuel in industry and medicine. After the fuel has completed its campaign (the time the assembly is in the reactor core under operating conditions at rated power), it is sent to the cooling pool, then to storage directly in the reactor compartment, and after that for reprocessing or disposal. The cooling pool is designed to remove heat and protect against ionizing radiation, since the fuel assembly remains dangerous after removal from the reactor.
In the USA, Canada or Sweden, spent fuel is not sent for reprocessing. Other countries, including Russia, are working on a closed fuel cycle. It allows you to significantly reduce the cost of producing nuclear fuel, since part of the spent fuel is reused.
The fuel rods are dissolved in acid, after which researchers separate the plutonium and unused uranium from the waste. About 3% of raw materials cannot be reused; these are high-level wastes that undergo bituminization or vitrification procedures.
1% plutonium can be recovered from spent nuclear fuel. This metal does not need to be enriched; Russia uses it in the process of producing innovative MOX fuel. A closed fuel cycle makes it possible to make one fuel assembly approximately 3% cheaper, but this technology requires large investments in the construction of industrial units, so it has not yet become widespread in the world. However, the Rosatom fuel company does not stop research in this direction. Pronedra recently wrote that in Russian Federation are working on fuel capable of recycling isotopes of americium, curium and neptunium in the reactor core, which are included in the same 3% of highly radioactive waste.
Nuclear fuel producers: rating
- The French company Areva until recently provided 31% of the global market for fuel assemblies. The company produces nuclear fuel and assembles components for nuclear power plants. In 2017, Areva underwent a qualitative renovation, new investors came to the company, and the colossal loss of 2015 was reduced by 3 times.
- Westinghouse is the American division of the Japanese company Toshiba. Actively developing the market in Eastern Europe, supplies fuel assemblies to Ukrainian nuclear power plants. Together with Toshiba, it provides 26% of the global nuclear fuel production market.
- The fuel company TVEL of the state corporation Rosatom (Russia) is in third place. TVEL provides 17% of the global market, has a ten-year contract portfolio worth $30 billion and supplies fuel to more than 70 reactors. TVEL develops fuel assemblies for VVER reactors, and also enters the market of nuclear plants of Western design.
- Japan Nuclear Fuel Limited, according to the latest data, provides 16% of the world market, supplies fuel assemblies to most of the nuclear reactors in Japan itself.
- Mitsubishi Heavy Industries is a Japanese giant that produces turbines, tankers, air conditioners, and, more recently, nuclear fuel for Western-style reactors. Mitsubishi Heavy Industries (a division of the parent company) is engaged in the construction of APWR nuclear reactors and research activities together with Areva. This company was chosen by the Japanese government to develop new reactors.
10.7% of the world's electricity generation annually comes from nuclear power plants. Along with thermal power plants and hydroelectric power stations, they work to provide humanity with light and heat, allow them to use electrical appliances and make our lives more convenient and simpler. It just so happens that today the words “nuclear power plant” are associated with global disasters and explosions. Ordinary people do not have the slightest idea about the operation of a nuclear power plant and its structure, but even the most unenlightened have heard and are frightened by the incidents in Chernobyl and Fukushima.
What is a nuclear power plant? How do they work? How dangerous are nuclear power plants? Don't believe rumors and myths, let's find out!
What is a nuclear power plant?
On July 16, 1945, energy was extracted from a uranium nucleus for the first time at a military test site in the United States. Powerful explosion atomic bomb, which brought a huge number of human casualties, became the prototype of a modern and absolutely peaceful source of electricity.
Electricity was first produced using a nuclear reactor on December 20, 1951 in the state of Idaho in the USA. To check its functionality, the generator was connected to 4 incandescent lamps; unexpectedly for everyone, the lamps lit up. From that moment on, humanity began to use the energy of a nuclear reactor to produce electricity.
The world's first nuclear power plant was launched in Obninsk in the USSR in 1954. Its power was only 5 megawatts.
What is a nuclear power plant? A nuclear power plant is a nuclear installation that produces energy using a nuclear reactor. A nuclear reactor runs on nuclear fuel, most often uranium.
The operating principle of a nuclear installation is based on the fission reaction of uranium neutrons, which, colliding with each other, are divided into new neutrons, which, in turn, also collide and also fission. This reaction is called a chain reaction, and it underlies nuclear power. This whole process generates heat, which heats the water to a scorching hot state (320 degrees Celsius). Then the water turns into steam, the steam rotates the turbine, which drives an electric generator, which produces electricity.
The construction of nuclear power plants today is carried out at a rapid pace. The main reason for the increase in the number of nuclear power plants in the world is the limited reserves of organic fuel; simply put, gas and oil reserves are running out, they are needed for industrial and municipal needs, and uranium and plutonium, which act as fuel for nuclear power plants, are needed in small amounts; their reserves are still sufficient .
What is a nuclear power plant? It's not just electricity and heat. Along with generating electricity, nuclear power plants are also used for desalination of water. For example, there is such a nuclear power plant in Kazakhstan.
What fuel is used at nuclear power plants?
In practice, nuclear power plants can use several substances capable of generating nuclear electricity; modern nuclear power plant fuels are uranium, thorium and plutonium.
Thorium fuel is not currently used in nuclear power plants, because it is more difficult to convert it into fuel elements, or fuel rods in short.
Fuel rods are metal tubes that are placed inside a nuclear reactor. There are radioactive substances inside fuel rods. These tubes can be called nuclear fuel storage facilities. The second reason for the rare use of thorium is its complex and expensive processing after use at nuclear power plants.
Plutonium fuel is also not used in nuclear power engineering, because this substance has a very complex chemical composition, which we still haven’t learned how to use correctly.
Uranium fuel
The main substance that produces energy at nuclear power plants is uranium. Uranium today is mined in three ways: open pits, closed mines, and underground leaching, by drilling mines. The last method is especially interesting. To extract uranium by leaching, a solution of sulfuric acid is poured into underground wells, it is saturated with uranium and pumped back out.
The largest uranium reserves in the world are located in Australia, Kazakhstan, Russia and Canada. The richest deposits are in Canada, Zaire, France and the Czech Republic. In these countries, up to 22 kilograms of uranium raw material are obtained from a ton of ore. For comparison, in Russia a little more than one and a half kilograms of uranium is obtained from one ton of ore.
Uranium mining sites are non-radioactive. In its pure form, this substance is of little danger to humans; a much greater danger is the radioactive colorless gas radon, which is formed during the natural decay of uranium.
Uranium cannot be used in the form of ore in nuclear power plants; it cannot produce any reactions. First, uranium raw materials are processed into powder - uranium oxide, and only after that it becomes uranium fuel. Uranium powder is converted into metal “tablets” - it is pressed into small neat flasks, which are fired within 24 hours at monstrously high temperatures ah more than 1500 degrees Celsius. It is these uranium pellets that enter nuclear reactors, where they begin to interact with each other and, ultimately, provide people with electricity.
About 10 million uranium pellets are working simultaneously in one nuclear reactor.
Of course, uranium pellets are not simply thrown into the reactor. They are placed in metal tubes made of zirconium alloys - fuel rods; the tubes are connected to each other into bundles and form fuel assemblies - fuel assemblies. It is FA that can rightfully be called nuclear power plant fuel.
Nuclear power plant fuel reprocessing
After about a year of use, the uranium in nuclear reactors needs to be replaced. Fuel elements are cooled for several years and sent for chopping and dissolution. As a result of chemical extraction, uranium and plutonium are released, which are reused and used to make fresh nuclear fuel.
The decay products of uranium and plutonium are used to manufacture sources of ionizing radiation. They are used in medicine and industry.
Everything that remains after these manipulations is sent to a hot furnace and glass is made from the remains, which is then stored in special storage facilities. Why glass? It will be very difficult to get out of it the remains of radioactive elements that can harm environment.
NPP news - appeared not so long ago new way disposal of radioactive waste. So-called fast nuclear reactors or fast neutron reactors have been created, which operate on recycled nuclear fuel residues. According to scientists, the remains of nuclear fuel, which are currently stored in storage facilities, are capable of providing fuel for fast neutron reactors for 200 years.
In addition, new fast reactors can operate on uranium fuel, which is made from 238 uranium; this substance is not used in conventional nuclear power plants, because It is easier for today’s nuclear power plants to process 235 and 233 uranium, of which there is little left in nature. Thus, new reactors are an opportunity to use huge deposits of 238 uranium, which no one had used before.
How is a nuclear power plant built?
What is a nuclear power plant? What is this jumble of gray buildings that most of us have only seen on TV? How durable and safe are these structures? What is the structure of a nuclear power plant? At the heart of any nuclear power plant is the reactor building, next to it is the turbine room and the safety building.
The construction of nuclear power plants is carried out in accordance with regulations, regulations and safety requirements for facilities working with radioactive substances. A nuclear station is a full-fledged strategic object of the state. Therefore, the thickness of the walls and reinforced concrete reinforcement structures in the reactor building is several times greater than that of standard structures. Thus, the premises of nuclear power plants can withstand magnitude 8 earthquakes, tornadoes, tsunamis, tornadoes and plane crashes.
The reactor building is crowned with a dome, which is protected by internal and external concrete walls. The inner concrete wall is covered with a steel sheet, which in the event of an accident should create a closed air space and not release radioactive substances into the air.
Each nuclear power plant has its own cooling pool. Uranium tablets that have already served their useful life are placed there. After the uranium fuel is removed from the reactor, it remains extremely radioactive, so that reactions inside the fuel rods stop occurring, it must take from 3 to 10 years (depending on the design of the reactor in which the fuel was located). In the cooling pools, the uranium pellets cool down and reactions stop occurring inside them.
The technological diagram of a nuclear power plant, or simply put, the design diagram of nuclear power plants is of several types, as well as the characteristics of a nuclear power plant and the thermal diagram of a nuclear power plant, it depends on the type of nuclear reactor that is used in the process of generating electricity.
Floating nuclear power plant
We already know what a nuclear power plant is, but Russian scientists came up with the idea to take a nuclear power plant and make it mobile. To date, the project is almost completed. This design was called a floating nuclear power plant. According to the plan, the floating nuclear power plant will be able to provide electricity to a city with a population of up to two hundred thousand people. Its main advantage is the ability to move by sea. The construction of a nuclear power plant capable of movement is currently underway only in Russia.
Nuclear power plant news is the imminent launch of the world's first floating nuclear power plant, which is designed to provide energy to the port city of Pevek, located in the Chukotka Autonomous Okrug of Russia. The first floating nuclear power plant is called "Akademik Lomonosov", a mini-nuclear power plant is being built in St. Petersburg and is planned to be launched in 2016 - 2019. The presentation of the floating nuclear power plant took place in 2015, then the builders presented almost finished project PAES.
The floating nuclear power plant is designed to provide electricity to the most remote cities with access to the sea. The Akademik Lomonosov nuclear reactor is not as powerful as that of land-based nuclear power plants, but has a service life of 40 years, which means that the residents of small Pevek will not suffer from a lack of electricity for almost half a century.
A floating nuclear power plant can be used not only as a source of heat and electricity, but also for desalination of water. According to calculations, it can produce from 40 to 240 cubic meters of fresh water per day.
The cost of the first block of a floating nuclear power plant was 16 and a half billion rubles; as we see, the construction of nuclear power plants is not a cheap pleasure.
Nuclear power plant safety
After the Chernobyl disaster in 1986 and the Fukushima accident in 2011, the words nuclear power plant cause fear and panic in people. In fact, modern nuclear power plants are equipped with last word equipment, special safety rules have been developed, and in general, nuclear power plant protection consists of 3 levels:
At the first level, normal operation of the nuclear power plant must be ensured. The safety of a nuclear power plant largely depends on the correct location for the nuclear plant, a well-created design, and the fulfillment of all conditions during the construction of the building. Everything must comply with regulations, safety instructions and plans.
At the second level, it is important to prevent normal operation of the nuclear power plant from transitioning into an emergency situation. For this purpose, there are special devices that monitor the temperature and pressure in the reactors and report the slightest changes in the readings.
If the first and second levels of protection do not work, the third is used - a direct response to an emergency situation. Sensors detect the accident and react to it themselves - the reactors are shut down, radiation sources are localized, the core is cooled, and the accident is reported.
Of course, a nuclear power plant requires special attention to the security system, both at the construction stage and at the operation stage. Failure to comply with strict regulations can have very serious consequences, but today most Responsibility for the safety of nuclear power plants falls on computer systems, and the human factor is almost completely excluded. Taking into account the high accuracy of modern machines, you can be confident in the safety of nuclear power plants.
Experts assure that it is impossible to receive a large dose of radioactive radiation in stably operating modern nuclear power plants or while being near them. Even nuclear power plant workers, who, by the way, measure the level of radiation received every day, are exposed to no more radiation than ordinary residents of large cities.
Nuclear reactors
What is a nuclear power plant? This is primarily a working nuclear reactor. The process of energy generation takes place inside it. Fuel assemblies are placed in a nuclear reactor, where uranium neutrons react with each other, where they transfer heat to water, and so on.
Inside a specific reactor building there are the following structures: a water supply source, a pump, a generator, a steam turbine, a condenser, deaerators, a purifier, a valve, a heat exchanger, the reactor itself and a pressure regulator.
Reactors come in several types, depending on what substance acts as a moderator and coolant in the device. It is most likely that a modern nuclear power plant will have thermal neutron reactors:
- water-water (with ordinary water as both a neutron moderator and coolant);
- graphite-water (moderator - graphite, coolant - water);
- graphite-gas (moderator – graphite, coolant – gas);
- heavy water (moderator - heavy water, coolant - ordinary water).
NPP efficiency and NPP power
The overall efficiency of a nuclear power plant (efficiency factor) with a pressurized water reactor is about 33%, with a graphite water reactor - about 40%, and a heavy water reactor - about 29%. The economic viability of a nuclear power plant depends on the efficiency of the nuclear reactor, the energy intensity of the reactor core, the installed capacity utilization factor per year, etc.
NPP news – scientists promise to soon increase the efficiency of nuclear power plants by one and a half times, to 50%. This will happen if fuel assemblies, or fuel assemblies, which are directly placed into a nuclear reactor, are made not from zirconium alloys, but from a composite. The problems of nuclear power plants today are that zirconium is not heat-resistant enough, it cannot withstand very high temperatures and pressures, therefore the efficiency of nuclear power plants is low, while the composite can withstand temperatures above a thousand degrees Celsius.
Experiments on using the composite as a shell for uranium pellets are being conducted in the USA, France and Russia. Scientists are working to increase the strength of the material and its introduction into nuclear energy.
What is a nuclear power plant? Nuclear power plants are the world's electrical power. The total electrical capacity of nuclear power plants around the world is 392,082 MW. The characteristics of a nuclear power plant depend primarily on its power. The most powerful nuclear power plant in the world is located in France; the capacity of the Sivo NPP (each unit) is more than one and a half thousand MW (megawatt). The capacity of other nuclear power plants ranges from 12 MW in mini-nuclear power plants (Bilibino NPP, Russia) to 1382 MW (Flanmanville nuclear plant, France). At the construction stage are the Flamanville block with a capacity of 1650 MW, and the Shin-Kori nuclear power plants of South Korea with a nuclear power plant capacity of 1400 MW.
NPP cost
Nuclear power plant, what is it? This is a lot of money. Today people need any means of generating electricity. Water, thermal and nuclear power plants are being built everywhere in more or less developed countries. Construction of a nuclear power plant is not an easy process; it requires large costs and capital investments; most often, financial resources are drawn from state budgets.
The cost of a nuclear power plant includes capital costs - expenses for site preparation, construction, putting equipment into operation (the amounts of capital costs are prohibitive, for example, one steam generator at a nuclear power plant costs more than 9 million dollars). In addition, nuclear power plants also require operating costs, which include the purchase of fuel, costs for its disposal, etc.
For many reasons, the official cost of a nuclear power plant is only approximate; today a nuclear power station would cost approximately 21-25 billion euros. To build one nuclear unit from scratch will cost approximately $8 million. On average, the payback period for one station is 28 years, the service life is 40 years. As you can see, nuclear power plants are quite an expensive pleasure, but, as we found out, incredibly necessary and useful for you and me.
Nuclear power plants - nuclear power plants- These are thermal power plants. Nuclear power plants use the energy of controlled nuclear reactions as a source. The unit capacity of nuclear power plants reaches 1.5 GW.
Nuclear power plants – nuclear power plants – types of fuel
It is used as a common fuel for nuclear power plants. U– uranium. The fission reaction takes place in the main unit of a nuclear power plant - a nuclear reactor. During a chain reaction of nuclear fission, a significant amount of thermal energy is released, which is used to generate electricity.
Nuclear power plants - nuclear power plants - operating principle
When uranium nuclei fission, fast neutrons are produced. The fission rate is a chain reaction; at nuclear power plants it is regulated by moderators: heavy water or graphite. Neutrons contain large number thermal energy. Energy enters the steam generator through the coolant. High pressure steam is sent to turbogenerators. The resulting electricity goes to transformers and then to distribution devices. Part of the electricity is used to meet the own needs of the nuclear power plant (NPP). Coolant circulation in nuclear power plants is ensured by pumps: main and condensate. Excess heat from nuclear power plants is sent to cooling towers.
Russian nuclear power plants - nuclear power plants - types of nuclear reactors:
- RBMK - high power reactor, channel,
- VVER – pressurized water power reactor,
- BN – fast neutron reactor.
Nuclear power plants – nuclear power plants – ecology
Nuclear power plants - nuclear power plants do not emit flue gases into the atmosphere. There is no waste in the form of ash and slag at the nuclear power plant. Problems in nuclear power plants include excess heat and storage of radioactive waste. To protect people and the atmosphere from radioactive emissions at nuclear power plants, special measures are taken:
- improving the reliability of nuclear power plant equipment,
- duplication of vulnerable systems,
- high requirements for personnel qualifications,
- protection and protection from external influences.
Nuclear power plants are surrounded by a sanitary protection zone.
