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Introduction
Past experience shows that at least 80 years pass before some main energy sources are replaced by others - wood is replaced by coal, coal by oil, oil by gas, chemical fuels are replaced by nuclear energy. The history of mastering atomic energy - from the first experimental experiments - goes back about 60 years, when in 1939. The fission reaction of uranium was discovered.
In the 30s of our century, the famous scientist I.V. Kurchatov substantiated the need to develop scientific and practical work in the field of nuclear technology in the interests of national economy countries.
In 1946, the first nuclear reactor on the European-Asian continent was built and launched in Russia. A uranium mining industry is being created. The production of nuclear fuel - uranium-235 and plutonium-239 - was organized, and the production of radioactive isotopes was established.
In 1954, the world's first nuclear power plant began operating in Obninsk, and 3 years later the world's first nuclear-powered ship, the icebreaker Lenin, entered the ocean.
Since 1970, large-scale nuclear energy development programs have been implemented in many countries around the world. There are currently hundreds of nuclear reactors operating around the world.
Nuclear energy is an actively developing industry. It is obvious that it is destined for a great future, since reserves of oil, gas, and coal are gradually drying up, and uranium is a fairly common element on Earth. But it should be remembered that nuclear energy is associated with increased danger for people, which, in particular, manifests itself in the extremely adverse consequences of accidents with the destruction of nuclear reactors.
How dangerous is nuclear power? This question began to be asked especially often in lately, especially after the accidents at the Three Mile Island nuclear power plants and Chernobyl nuclear power plant.
Features of nuclear energy
Energy is the foundation. All the benefits of civilization, all material spheres of human activity - from washing clothes to exploring the Moon and Mars - require energy consumption. And the further, the more.
Today, atomic energy is widely used in many sectors of the economy. Powerful submarines and surface ships with nuclear power plants are being built. The peaceful atom is used to search for minerals. Massive application in biology, agriculture, medicine, radioactive isotopes were found in space exploration.
There are 9 nuclear power plants (NPPs) in Russia, and almost all of them are located in the densely populated European part of the country. More than 4 million people live within the 30-kilometer zone of these nuclear power plants.
The positive significance of nuclear power plants in the energy balance is obvious. For its work, hydropower requires the creation of large reservoirs, under which large areas of fertile land along the banks of rivers are flooded. The water in them stagnates and loses its quality, which in turn aggravates the problems of water supply, fisheries and the leisure industry.
Thermal power plants contribute most to the destruction of the biosphere and natural environment Earth. They have already destroyed many tens of tons of organic fuel. To extract it, huge areas of land are taken from agriculture and other areas. In areas of open-pit coal mining, “lunar landscapes” are formed. And the increased ash content in fuel is the main reason for the release of tens of millions of tons into the air. All thermal power plants in the world emit up to 250 million tons of ash and about 60 million tons of sulfur dioxide into the atmosphere per year.
Nuclear power plants are the third “whale” in the modern world energy system. Nuclear power plant technology is undoubtedly a major achievement of scientific and technological progress. During trouble-free operation, nuclear power plants produce virtually no pollution environment, except thermal. True, as a result of the operation of nuclear power plants (and nuclear fuel cycle enterprises), radioactive waste is generated, which poses a potential danger. However, the volume of radioactive waste is very small, it is very compact, and it can be stored in conditions that guarantee that it will not leak out.
Nuclear power plants are more economical than conventional thermal stations, and, most importantly, when operated correctly, they are clean sources of energy.
At the same time, when developing nuclear energy in the interests of the economy, we must not forget about the safety and health of people, since mistakes can lead to catastrophic consequences.
In total, since the start of operation of nuclear power plants in 14 countries around the world, more than 150 incidents and accidents of varying degrees of complexity have occurred. The most typical of them: in 1957 - in Windscale (England), in 1959 - in Santa Suzanne (USA), in 1961 - in Idaho Falls (USA), in 1979 - at the Tri nuclear power plant -Mile Island (USA), in 1986 - at the Chernobyl nuclear power plant (USSR).
Today, approximately 17% of global electricity production comes from nuclear power plants (NPPs). In some countries its share is much higher. For example, in Sweden it makes up about half of all electricity, in France - about three quarters. Recently, according to a program adopted in China, the contribution of energy from nuclear power plants is planned to be increased five to six times. Nuclear power plants play a noticeable, although not yet decisive, role in the USA and Russia.
More than forty years ago, when the first nuclear power plant produced electricity in the little-known town of Obninsk at that time, it seemed to many that nuclear energy was completely safe and environmentally friendly. The accident at one of the American nuclear power plants, and then the disaster in Chernobyl, showed that in fact nuclear energy is fraught with great danger. People are scared. Public resistance today is such that the construction of new nuclear power plants in most countries has practically stopped. The only exceptions are the East Asian countries - Japan, Korea, China, where nuclear energy continues to develop.
Specialists who know the strengths and weaknesses reactors, look at the nuclear danger more calmly. The accumulated experience and new technologies make it possible to build reactors whose probability of going out of control, although not zero, is extremely small. At modern nuclear enterprises, the strictest control of radiation in the premises and in the reactor channels is ensured: replaceable overalls, special shoes, automatic radiation detectors that will never open the airlock doors if you have even small traces of radioactive “dirt” on you. For example, at a nuclear power plant in Sweden, where the cleanest plastic floors and continuous air purification in spacious rooms would seem to exclude even the thought of any noticeable radioactive contamination.
Nuclear energy was preceded by tests nuclear weapons. Nuclear and thermonuclear bombs were tested on the ground and in the atmosphere, the explosions of which horrified the world. At the same time, engineers were developing and nuclear reactors, intended to receive electrical energy. Priority was given to the military direction - the production of reactors for naval ships. The military departments saw the use of reactors on submarines as particularly promising: such vessels would have an almost unlimited range of action and could remain under water for years. The Americans concentrated their efforts on creating pressurized water reactors, in which ordinary (“light”) water served as a neutron moderator and coolant and which had great power per unit mass of the power plant. Full-scale ground-based prototypes of transport reactors were built, on which all design solutions were tested and control and safety systems were tested. In the mid-50s of the XX century. The first nuclear-powered submarine, the Nautilus, sailed under the ice of the Arctic Ocean.
Similar work was carried out in our country, only along with pressurized water reactors, a channel graphite reactor was developed (in which water also served as the coolant and graphite as the moderator). However, compared to a pressurized water reactor, the graphite reactor has a low power density. At the same time, such a reactor had an important advantage - there was already considerable experience in the construction and operation of industrial graphite reactors, which differed from transport plants mainly in the pressure and temperature of the cooling water. And having experience meant saving time and money on development work. When creating a ground-based prototype of a graphite reactor for transport installations, its futility became obvious. And then it was decided to use it for nuclear energy. The AM reactor, or rather its 5000 kW turbogenerator, was connected to the electrical network on June 27, 1954, and the whole world learned that the world's first nuclear power plant, a nuclear power plant, had been launched in the USSR.
Along with channel graphite reactors in our country, as well as in the USA, since the mid-50s of the 20th century. years, a direction based on the use of pressurized water power reactors (VVER) developed. Their characteristic feature- a huge building with a diameter of 4.5 m and a height of 11 m, designed for high blood pressure- up to 160 atm. The production and transportation of such casings to the nuclear power plant site is an extremely difficult task. American firms, having begun the development of nuclear energy based on PWR reactors, built factories on river banks for the production of reactor vessels, built barges for transporting them to the site of nuclear power plant construction and cranes with a lifting capacity of 1000 tons. This thoughtful approach allowed the United States not only to satisfy its own needs, but also to capture the foreign market for nuclear energy production in the 70s. The USSR could not develop the industrial base for nuclear power plants with VVER reactors so widely and quickly. At the beginning, only one Izhora plant could produce one reactor vessel per year. The launch of Attommash took place only in the late 70s.
The RBMK reactor (high-power reactor, channel), in which the water cooling the fuel elements is in a boiling state, appeared as the next stage in the sequential development of channel graphite reactors: an industrial graphite reactor, a reactor of the world's first nuclear power plant, reactors of the Beloyarsk NPP. The Leningrad NPP at RBMK showed its temper. Despite the presence of traditional automatic system regulation, the operator had to intervene in the control of the reactor more and more often as the fuel burned out (up to 200 times per shift). This was due to the emergence or intensification of positive feedback during operation of the reactor, leading to the development of instability with a period of 10 minutes. For the normal stable operation of any device with positive feedback, a reliable automatic control system is required. However, there is always a danger of an accident due to the failure of such a system. The problem of instability was also encountered in Canada, when in 1971 they launched a channel reactor with heavy water as neutron moderators and boiling light water as a coolant. Canadian specialists decided not to tempt fate and closed the installation. A new automatic control system adapted to the RBMK was developed relatively quickly. Its implementation ensured acceptable stability of the reactor. In the USSR, serial construction of nuclear power plants with RBMK reactors began (such plants were not used anywhere in the world).
Despite the introduction of a new regulatory system, a terrible threat remains. The RBMK reactor is characterized by two extreme states: in one of them, the reactor channels are filled with boiling water, and in the other, with steam. The neutron multiplication coefficient when filled with boiling water is greater than when filled with steam. Under this condition, a positive feedback, in which an increase in power causes the appearance of an additional amount of steam in the channels, which in turn leads to an increase in the neutron multiplication factor, and therefore to a further increase in power. This has been known for a long time, since the design of the RBMK. However, only after Chernobyl disaster As a result of a thorough analysis, it turned out that it was possible to accelerate a reactor using prompt neutrons. At 1 hour 23 minutes. On April 26, 1986, the reactor of the 4th block of the Chernobyl nuclear power plant exploded. Its consequences are terrible.
So is it necessary to develop nuclear energy? Energy generation at nuclear power plants and ACT (nuclear heat supply plants) is the most environmentally friendly way of producing energy. Energy from wind, sun, underground heat, etc. cannot immediately and quickly replace nuclear energy. According to the forecast in the USA at the beginning of the 21st century. All such methods of energy production will account for no more than 10% of the energy generated worldwide.
It is possible to save our planet from pollution by millions of tons of carbon dioxide, nitrogen oxide and sulfur, which are constantly emitted by thermal power plants operating on coal and fuel oil, and to stop burning huge quantities of oxygen only with the help of nuclear energy. But only if one condition is met: Chernobyl must not happen again. To do this, it is necessary to create an absolutely reliable energy reactor. But in nature there is nothing absolutely reliable; all processes that do not contradict the laws of nature occur with greater or lesser probability. And opponents of nuclear energy argue something like this: an accident is unlikely, but there are no guarantees that it will not happen today or tomorrow. When thinking about this, you need to consider the following. Firstly, the explosion of the RBMK reactor in the state in which it was operated before the accident is by no means an unlikely event. Secondly, with this approach, we all must live in constant fear that the Earth will collide with a large asteroid today or tomorrow; the probability of such an event is also not zero. It seems that a reactor for which the probability of a major accident is quite low can be considered absolutely safe.
The USSR has accumulated many years of experience in the construction and operation of nuclear power plants with VVER reactors (similar to American PWRs), on the basis of which a more safe power reactor can be created in a relatively short time. Such that in the event of an emergency, all radioactive fission fragments of uranium nuclei must remain within the containment envelope
Developed countries with large populations will not be able to in the foreseeable future due to the approaching environmental disaster do without nuclear power even with some reserves of conventional fuels. The energy saving mode can only postpone the problem for a while, but not solve it. In addition, many experts believe that in our conditions it will not be possible to achieve even a temporary effect: the efficiency of energy supply enterprises depends on the level of economic development. Even the USA took 20-25 years from the date of introduction of energy-intensive production into industry.
The forced pause that has arisen in the development of nuclear energy should be used to develop a fairly safe power reactor based on the VVER reactor, as well as to develop alternative power reactors, the safety of which should be at the same level, and the economic efficiency is much higher. It is advisable to build a demonstration nuclear power plant with an underground VVER reactor in the most convenient location to test its economic efficiency and safety.
Recently, various design solutions for nuclear power plants have been proposed. In particular, the compact nuclear power plant was developed by specialists from the St. Petersburg Marine Engineering Bureau "Malachite". The proposed station is intended for the Kaliningrad region, where the problem of energy resources is quite acute. The developers have provided for the use of liquid metal coolant (an alloy of lead and bismuth) in the nuclear power plant and exclude the possibility of radiation-hazardous accidents occurring there, including under any external influences. The station is environmentally friendly and economically efficient. All its main equipment is supposed to be placed deep underground - in a tunnel with a diameter of 20 m laid among rocks. This makes it possible to minimize the number of above-ground structures and the area of alienated land. The structure of the designed nuclear power plant is modular, which is also very important. The design capacity of the Kaliningrad NPP is 220 MW, but it can be reduced or increased several times as necessary by changing the number of modules.
NUCLEAR ENERGY
a field of technology based on the use of the fission reaction of atomic nuclei to generate heat and electricity. In 1990, nuclear power plants (NPPs) produced 16% of the world's electricity. Such power plants operated in 31 countries and were built in 6 more countries. The nuclear energy sector is most significant in France, Belgium, Finland, Sweden, Bulgaria and Switzerland, i.e. in those industrialized countries where there are insufficient natural energy resources. These countries produce between a quarter and half of their electricity from nuclear power plants. The United States produces only an eighth of its electricity from nuclear power plants, but this is about one-fifth of its global production. Nuclear energy remains the subject of heated debate. Supporters and opponents of nuclear energy sharply differ in assessments of its safety, reliability and economic efficiency. In addition, there is widespread speculation about the possible leakage of nuclear fuel from electricity production and its use for the production of nuclear weapons.
Nuclear fuel cycle. Nuclear energy is a complex industry that includes many industrial processes that together form the fuel cycle. There are different types of fuel cycles, depending on the type of reactor and how the final stage of the cycle occurs. Typically the fuel cycle consists of the following processes. Uranium ore is mined in the mines. The ore is crushed to separate uranium dioxide, and the radioactive waste goes into a dump. The resulting uranium oxide (yellow cake) is converted into uranium hexafluoride, a gaseous compound. To increase the concentration of uranium-235, uranium hexafluoride is enriched at isotope separation plants. The enriched uranium is then converted back into solid uranium dioxide, from which fuel pellets are made. Fuel elements (fuel elements) are collected from the pellets, which are combined into assemblies for insertion into the core of a nuclear reactor of a nuclear power plant. The spent fuel removed from the reactor has a high level of radiation and, after cooling on the territory of the power plant, is sent to a special storage facility. Provision is also made for the removal of low-level radiation waste accumulated during operation and maintenance of the plant. At the end of its service life, the reactor itself must be decommissioned (with decontamination and disposal of reactor components). Each stage of the fuel cycle is regulated to ensure the safety of people and the protection of the environment.
Nuclear reactors. Industrial nuclear reactors were initially developed only in countries with nuclear weapons. The USA, USSR, Great Britain and France were actively exploring different options for nuclear reactors. However, subsequently, three main types of reactors began to dominate in nuclear energy, differing mainly in the fuel, the coolant used to maintain the required temperature of the core, and the moderator used to reduce the speed of neutrons released during the decay process and necessary to maintain the chain reaction. Among them, the first (and most common) type is an enriched uranium reactor, in which both the coolant and the moderator are ordinary, or “light” water (light water reactor). There are two main types of light water reactor: a reactor in which the steam that rotates the turbines is generated directly in the core (boiling reactor), and a reactor in which steam is generated in an external, or second, circuit connected to the first circuit by heat exchangers and steam generators (water -water power reactor - VVER). The development of a light water reactor began under the programs of the US Armed Forces. Thus, in the 1950s, General Electric and Westinghouse developed light water reactors for submarines and aircraft carriers of the US Navy. These companies were also involved in the implementation of military programs for the development of technologies for regeneration and enrichment of nuclear fuel. In the same decade, the Soviet Union developed a boiling water reactor with a graphite moderator. The second type of reactor, which has found practical application, is a gas-cooled reactor (with a graphite moderator). Its creation was also closely related to early nuclear weapons programs. In the late 1940s - early 1950s, Great Britain and France, seeking to create their own atomic bombs, paid special attention to the development of gas-cooled reactors, which quite efficiently produce weapons-grade plutonium and, moreover, can operate on natural uranium. The third type of reactor that has had commercial success is a reactor in which both the coolant and moderator are heavy water, and the fuel is also natural uranium. At the beginning of the nuclear age, the potential benefits of the heavy water reactor were explored in a number of countries. However, production of such reactors then concentrated primarily in Canada, partly because of its vast uranium reserves.
Development of the nuclear industry. After the Second World War, tens of billions of dollars were invested in the electric power industry around the world. This building boom was fueled by rapidly growing demand for electricity, far outpacing population and national income growth. The main emphasis was on thermal power plants (TPPs) running on coal and, to a lesser extent, on oil and gas, as well as hydroelectric power plants. There were no industrial-type nuclear power plants before 1969. By 1973, almost all industrialized countries had exhausted the resources of large-scale hydropower. The rise in energy prices after 1973, the rapid increase in the demand for electricity, as well as the growing concern about the possibility of losing the independence of the national energy sector - all this contributed to the establishment of a view of nuclear energy as the only real alternative source of energy in the foreseeable future. The Arab oil embargo of 1973-1974 gave rise to an additional wave of orders and optimistic forecasts for the development of nuclear energy. But everyone next year made his own adjustments to these forecasts. On the one hand, nuclear energy had its supporters in governments, in the uranium industry, research laboratories and among influential energy companies. On the other hand, a strong opposition arose, which united groups defending the interests of the population, the cleanliness of the environment and consumer rights. The debate, which continues to this day, has focused mainly on the harmful effects of various stages of the fuel cycle on the environment, the likelihood of reactor accidents and their possible consequences, the organization of construction and operation of reactors, acceptable options for the disposal of nuclear waste, the potential for sabotage and terrorist attacks. at nuclear power plants, as well as issues of multiplying national and international efforts in the field of non-proliferation of nuclear weapons.
Security issues. The Chernobyl disaster and other nuclear reactor accidents in the 1970s and 1980s, among other things, made clear that such accidents are often unpredictable. For example, in Chernobyl, the reactor of the 4th power unit was seriously damaged as a result of a sharp power surge that occurred during its planned shutdown, for a reason that remained unknown. The reactor was in a concrete shell and was equipped with an emergency cooling system and other modern safety systems. But it never occurred to anyone that when the reactor was turned off, a sharp jump in power could occur and the hydrogen gas formed in the reactor after such a jump, mixed with air, would explode so that it would destroy the reactor building. As a result of the accident, more than 30 people died, more than 200,000 people in Kyiv and neighboring regions received large doses of radiation, and Kyiv's water supply was contaminated. To the north of the disaster site - directly in the path of the radiation cloud - are the vast Pripyat swamps, which are of vital importance for the ecology of Belarus, Ukraine and western Russia. In the United States, facilities building and operating nuclear reactors also faced numerous safety issues that slowed construction, forced numerous changes to design and operating standards, and increased costs and power costs. There appear to have been two main sources of these difficulties. One of them is the lack of knowledge and experience in this new energy sector. The other is the development of nuclear reactor technology, during which new problems arise. But old ones also remain, such as corrosion of steam generator pipes and cracking of boiling water reactor pipelines. Other safety problems, such as damage caused by sudden changes in coolant flow, have not been fully resolved.
Economics of Nuclear Energy. Investment in nuclear energy, like investment in other areas of electricity production, is economically justified if two conditions are met: the cost per kilowatt-hour is no more than the cheapest alternative production method, and the expected demand for electricity is high enough that the energy produced can be sold at a price exceeding its cost. In the early 1970s, global economic prospects looked very favorable for nuclear energy: both the demand for electricity and prices for the main fuels - coal and oil - were growing rapidly. As for the cost of constructing a nuclear power plant, almost all experts were convinced that it would be stable or even begin to decline. However, in the early 1980s, it became clear that these estimates were erroneous: the growth in demand for electricity stopped, prices for natural fuel not only no longer grew, but even began to decline, and the construction of nuclear power plants was much more expensive than expected in the most pessimistic forecast. As a result, nuclear energy everywhere entered a period of serious economic difficulties, and they turned out to be most serious in the country where it originated and developed most intensively - in the USA. If you carry out comparative analysis economics of nuclear energy in the USA, it becomes clear why this industry has lost its competitiveness. Since the early 1970s, nuclear power plant costs have risen sharply. The costs of a conventional thermal power plant consist of direct and indirect capital investments, fuel costs, operating costs and maintenance costs. Over the service life of a coal-fired thermal power plant, fuel costs average 50-60% of all costs. In the case of nuclear power plants, capital investments dominate, accounting for about 70% of all costs. Capital costs for new nuclear reactors, on average, significantly exceed the costs of fuel for coal-fired thermal power plants over their entire service life, which negates the advantage of fuel savings in the case of nuclear power plants.
Prospects for nuclear energy. Among those who insist on the need to continue the search for safe and economical ways to develop nuclear energy, two main directions can be distinguished. Proponents of the first believe that all efforts should be focused on eliminating public mistrust in the safety of nuclear technologies. To do this, it is necessary to develop new reactors that are safer than existing light water ones. Two types of reactors are of interest here: a “technologically extremely safe” reactor and a “modular” high-temperature gas-cooled reactor. A prototype of a modular gas-cooled reactor was developed in Germany, as well as in the USA and Japan. Unlike a light water reactor, the design of a modular gas-cooled reactor is such that the safety of its operation is ensured passively - without direct actions of operators or electrical or mechanical system protection. Technologically extremely safe reactors also use a passive protection system. Such a reactor, the idea of which was proposed in Sweden, apparently did not advance beyond the design stage. But it has received significant support in the United States among those who see its potential advantages over a modular gas-cooled reactor. But the future of both options is uncertain due to their uncertain costs, development difficulties, and the controversial future of nuclear power itself. Proponents of the other school of thought believe that there is little time left to develop new reactor technologies before developed countries need new power plants. In their opinion, the first priority is to stimulate investment in nuclear energy. But in addition to these two prospects for the development of nuclear energy, a completely different point of view has emerged. She places hopes on more complete utilization of supplied energy, renewable energy resources (solar batteries, etc.) and energy saving. According to supporters of this point of view, if advanced countries switch to developing more economical light sources, household electrical appliances, heating equipment and air conditioners, then the saved electricity will be enough to do without all existing nuclear power plants. The observed significant reduction in electricity consumption shows that efficiency can be an important factor in limiting electricity demand. Thus, nuclear energy has not yet passed the tests of efficiency, safety and public goodwill. Its future now depends on how effectively and reliably control over the construction and operation of nuclear power plants will be exercised, as well as how successfully a number of other problems, such as the problem of radioactive waste disposal, will be resolved. The future of nuclear energy also depends on the viability and expansion of its strong competitors - coal-fired thermal power plants, new energy-saving technologies and renewable energy resources.
See also
NUCLEUS FISSION;
INDUSTRIAL WASTE RECYCLING.
LITERATURE
Dementiev B.A. Nuclear power reactors. M., 1984 Thermal and nuclear power plants. Directory, book. 3. M., 1985 Sinev N.M. Economics of nuclear energy: Fundamentals of nuclear fuel economics technology. Economics of nuclear power plants. M., 1987 Samoilov O.B., Usynin G.B., Bakhmetyev A.M. Safety of nuclear power plants. M., 1989
Collier's Encyclopedia. - Open Society. 2000 .
See what "NUCLEAR ENERGY" is in other dictionaries:
nuclear energy- The energy sector that uses nuclear energy for the purposes of electrification and district heating. As a field of science and technology, it develops methods and means of converting nuclear energy into electrical and thermal energy. )