The modern energy needs of mankind are growing at a tremendous pace. Its consumption for lighting cities, for industrial and other needs of the national economy is increasing. Accordingly, more and more soot from burned coal and fuel oil is emitted into the atmosphere, and the greenhouse effect is intensifying. In addition, there has been increasing talk in recent years about the commissioning of electric vehicles, which will also contribute to increased electricity consumption.
Unfortunately, environmentally friendly hydroelectric power plants are not able to cover such gigantic needs, and a further increase in the number of thermal power plants and thermal power plants is simply not practical. What to do in this case? And there’s especially nothing to choose from: nuclear power plants, when properly operated, are an excellent way out of the energy deadlock.
Despite what happened in Chernobyl, even mindful of the recent misfortunes of the Japanese, scientists around the world acknowledge that a peaceful atom is the only solution to the impending energy crisis today. Widely advertised alternative energy sources do not even give a hundredth of the amount of electricity that the world needs every day.
In addition, even the explosion of the Chernobyl nuclear power plant did not cause the environment and a hundredth part of the damage that is observed even with one disaster on the oil platform. The incident with BP is a vivid confirmation of this.
The principle of operation of a nuclear reactor
The heat source is fuel elements - fuel elements. In fact, these are tubes made of zirconium alloy, which is slightly susceptible to degeneration even in the zone of active fission of atoms. Uranium dioxide tablets or grains of an alloy of uranium and molybdenum are placed inside. Inside the reactor, this tube is assembled into assemblies, each of which contains 18 fuel elements.
In total, assemblies can be almost two thousand, and they are placed in channels inside graphite masonry. The generated heat is collected through the coolant, and in modern nuclear power plants there are two circulation circuits. In the second of them, water does not interact with the reactor core in any way, which significantly increases the safety of the structure as a whole. The reactor itself is located in the mine, and for graphite masonry a special capsule is created from the same zirconium alloy (30 mm thick).
The whole structure rests on an extremely massive base of high-strength concrete, under which the pool is located. It serves to cool nuclear fuel in the event of an accident.
The principle of operation is simple: the fuel elements are heated, the heat from them is transferred to the primary coolant (liquid sodium, deuterium), after which the energy is transferred to the secondary circuit, inside which water circulates under tremendous pressure. It immediately boils, and the steam spins the turbines of the generators. After this, the steam enters the condensing device, again goes into a liquid state, and then again goes to the secondary circuit.
History of creation
In the second half of the 40s, all efforts were made in the USSR to create projects involving the peaceful use of atomic energy. The famous academician Kurchatov, speaking at a regular meeting of the CPSU Central Committee, put forward a proposal on the use of atomic energy in the production of electricity, which the country being restored after the terrible war was in dire need of.
In 1950, construction began on a nuclear power plant (the first in the world, by the way), which was laid in the village of Obninskoye, in the Kaluga Region. Four years later, this station, with a capacity of 5 MW, was successfully launched. The uniqueness of the event also lies in the fact that our country became the first state in the world that was able to effectively use the atom exclusively for peaceful purposes.
Continuation of work
Already in 1958, work began on the design of the Siberian NPP. Design capacity immediately increased by 20 times, amounting to 100 MW. But the uniqueness of the situation is not even that. When the station was commissioned, its return was 600 MW. In just a couple of years, scientists have only been able to improve the project, and more recently, such effectiveness seemed completely impossible.
However, nuclear plants in the vast expanses of the Union then grew no worse than mushrooms. So, a couple of years after the Siberian, the Beloyarsk NPP was launched. Soon a station was built in Voronezh. In 1976, the Kursk Nuclear Power Plant was commissioned, the reactors of which were seriously modernized in 2004.
In general, nuclear power plants were built in a planned manner throughout the post-war period. Only the Chernobyl disaster was able to slow down this process.
How things were abroad
It should not be considered that such developments were carried out exclusively in our country. The British were well aware of how important nuclear plants could be, and therefore actively worked in this direction. So, already in 1952 they launched their own project for the development and creation of nuclear power plants. Four years later, the town of Calder Hall became the first English nuclear city with its own 46 MW power plant. In 1955, a nuclear power plant was solemnly commissioned in the US city of Shippingport. Its capacity was 60 MW. Since then, nuclear power plants began their triumphal march around the world.
Threats of a peaceful atom
The first euphoria from the taming of the atom soon gave way to anxiety and fear. Of course, the Chernobyl was the most serious disaster, but there was the Mayak plant, accidents with nuclear reactors in the nuclear submarines, and other incidents, many of which we will probably never know. The consequences of these accidents made people think about improving the level of culture of the use of atomic energy. In addition, mankind once again realized that it was not able to withstand the elemental forces of nature.
Many luminaries of world science have long discussed how to make nuclear power plants safer. The World Assembly was convened in Moscow in 1989, following the results of the meeting of which conclusions were drawn about the need to radically tighten control over nuclear energy.
Today, international communities are closely monitoring how all these agreements are respected. However, no observation and control can save from natural disasters or banal stupidity. This was once again confirmed by the accident at Fukushima-1, which resulted in hundreds of millions of tons of radioactive water spilling into the Pacific Ocean. In general, Japan, in which the nuclear power plant is the only means of providing the gigantic needs of industry and the population with electricity, has not refused the program for building nuclear power plants.
Classification
All nuclear power plants can be classified by the type of energy generated, as well as by the model of their reactor. The degree of safety, type of construction, as well as other important parameters, are also taken into account.
This is how they are divided by the type of energy generated:
- Nuclear power plants. The only energy that is generated on them is electricity.
- Nuclear power plants. In addition to electricity, these facilities also generate heat, which makes them especially valuable for placement in northern cities. There, the operation of nuclear power plants dramatically reduces the dependence of the region on fuel supplies from other regions.
Fuel used and other characteristics
The most common are nuclear reactors, for which enriched uranium is used as fuel. The coolant is light water. Such reactors are called light-water, and they are distinguished by two varieties. In the first case, the steam that serves to rotate the turbines is formed in the reactor core.
For the formation of steam in the second case, a heat sink system is used, due to which water does not enter the core. By the way, they began to develop this system already in the 50s of the last century, and the American military developments served as the basis for it. Around the same time, the first type of reactor was developed in the USSR, but with a retardation system, in the role of which graphite rods were used.
This is how a gas-cooled reactor appeared, which is used by many nuclear plants in Russia. The rapid acceleration of the construction of stations of this particular model was due to the fact that reactors produced weapons-grade plutonium as a by-product . In addition, even ordinary natural uranium, the deposits of which are very large in our country, is suitable as fuel for such a variety.
Another type of reactor, which is quite widespread in the world, is a model on heavy water and with natural uranium as a fuel. At first, such models were created by almost all countries that had access to nuclear reactors, but today Canada alone is among their exploiters, in the depths of which there are rich deposits of natural uranium.
How did reactors improve?
At first, ordinary steel was used to make the claddings of fuel elements and circulating channels. At that time, zirconium alloys, which are much better suited for such purposes, were not yet known. The reactor was cooled with water supplied under a pressure of 10 atmospheres.
The steam released in this case had a temperature of 280 degrees. All the channels in which the fuel elements were placed were made removable, since they needed to be replaced relatively often. The fact is that in the zone of activity of nuclear fuel, materials quickly undergo deformation and destruction. In fact, the structural elements in the core are designed for 30 years, but optimism is unacceptable in such matters.
TVELs
In this case, the scientists decided to use the option with one-sided tubular cooling. Such a design dramatically reduces the chances of fission products entering the heat exchange circuit even if the fuel element is damaged. Nuclear fuel itself is an alloy of uranium and molybdenum. This solution allowed us to create a relatively inexpensive and reliable equipment that can function stably even under conditions of significantly elevated temperatures.
Chernobyl
Oddly enough, but the infamous Chernobyl, whose nuclear power plant became a symbol of technological disasters of the last century, was a real triumph of science. At that time, the most advanced technologies were used in its construction and design. The power of the reactor alone reached 3200 MW. Fuel was also new: enriched natural uranium dioxide was first used at the Chernobyl nuclear power plant. One ton of such fuel contains only 20 kilograms of uranium-235. In total, 180 tons of uranium dioxide were charged into the reactor. It is still not known exactly who and for what purpose decided to conduct an experiment at the station, which contradicted all conceivable safety rules.
Nuclear plants in Russia
If it weren’t for the Chernobyl disaster, in our country (most likely) the program for the widest and most widespread construction of nuclear plants would still continue. In any case, such an approach was planned in the USSR.
In general, immediately after Chernobyl, many programs began to be massively curtailed, which immediately led to an increase in prices for many “environmentally friendly” varieties of coolants. In many areas, they were forced to return to the construction of thermal power plants, which (including) operate even on coal, while continuing to monstrously pollute the atmosphere of large cities.
In the mid-2000s, the government nevertheless realized the need to develop a nuclear program, since without this it is simply impossible to provide many regions of our country with the necessary amount of energy.
How many nuclear power plants do we have in our country today? Only ten. Yes, these are all nuclear power plants in Russia. But even this amount of them produces more than 16% of the energy that is consumed by our citizens. The capacity of all 33 power units that operate as part of these nuclear power plants is 25.2 GW. Almost 37% of the electricity needs of our northern regions are covered by nuclear power plants.
One of the most famous is the Leningrad Nuclear Power Plant , built back in 1973. Currently, intensive construction of the second stage is ongoing, which will increase the output power (4 thousand MW) at least twice.
Ukrainian nuclear power plants
The Soviet Union has done a lot, including for the development of energy in the Union republics. Thus, Lithuania at one time received not only excellent infrastructure and a host of industrial enterprises, but also the Ignalina NPP, which until 2005 was a real “Chicken Ryaba”, which provided almost all of the Baltic States with cheap (and their own!) Energy.
But the main gift was given to Ukraine, which received four power plants at once. Zaporizhzhya NPP is generally the most powerful in Europe, producing immediately 6 GW of energy. In general, Ukrainian nuclear power plants give her the opportunity to independently provide themselves with electricity, which they can no longer boast in in Lithuania.
Now all the same four stations are operating: Zaporizhzhya, Rivne, South Ukraine and Khmelnitsky. Contrary to popular belief, the third Chernobyl NPP unit continued to operate until 2000, regularly supplying the region with electricity. At the moment, 46% of all Ukrainian electricity is produced by nuclear power plants in Ukraine.
Strange political ambitions of the authorities in the country led to the decision in 2011 to replace Russian TVELs with American ones. The experiment completely failed, and nearly 200 million dollars worth of damage was caused to Ukrainian industry.
Prospects
Today, all over the world they again recall the advantages of a
peaceful atom. An entire city can be supplied with energy from a small and primitive nuclear power plant, which spends about 2 tons of fuel per year. How much gas or coal will have to be burned over the same period? So the prospects for the technology are enormous: energy sources of traditional types are constantly growing in price, and their number is decreasing.