Nuclear energy accounts for about 15% of all energy produced on our planet. And in Ukraine, which became known to the world in 1986 thanks to Chornobyl - this share still reaches 50%. Why is nuclear energy so popular? There are several reasons for this: first, nuclear reactors do not consume scarce fossil fuels, and the fuel they consume for operation is needed only in moderation: to meet the annual fuel demand of a nuclear power plant with a capacity of 1 GW requires about 1.4 tons of natural uranium, for the extraction of which you need to process 2-3 hectares of land. A thermal power plant of similar capacity requires 2-3 million tons of coal and processing of 80 hectares of soil, i.e. 40 times more.
Nuclear power plants also do not require the creation of large reservoirs, which occupy large areas of fertile land, do not load rail transport with coal, do not consume atmospheric oxygen and do not pollute the environment with ash and combustion products - that's why they have a particular environmental friendliness.
However, nuclear power plants have a very negative reputation. Take, for example, the Chornobyl nuclear power plant, which is known worldwide for its tragedy. Here we want to tell more about its history and current state. After all, the station continues its work nowadays. Yes, we are not wrong. The Chornobyl nuclear power plant is still operating.
The strategic plan of the Soviet government in the 1960s was to build a nuclear power plant in Ukraine, which was to compensate for the deficit in the Central Region of the unified energy system of the USSR. About 20 locations were investigated to select a construction site. In 1967, a site was chosen near the city of Chornobyl on the banks of the Pripyat River, 18 kilometres from the town of Chornobyl, 16 kilometres from the Ukrainian-Belarusian border and 130 kilometres from Kyiv.
The project envisaged the construction of 6 power units with an electric capacity of 1000 MW with high-capacity uranium-graphite reactors (HPPs). On August 15, 1972, the first cubic meter of concrete was laid in the foundation of the main building of the nuclear power plant, and on August 1, 1977, the first assembly with nuclear fuel was loaded. Units 1 and 2 were built between 1970 and 1977, while Units 3 and 4 of the same design were completed in 1983. Two more RBMK reactors were under construction at the time of the accident.
For a more detailed understanding of the Chornobyl organization, the general principles of operation of a nuclear power plant should be considered. This is a rather complex industrial system that works based on a steam engine's relatively simple principle of operation known for hundreds of years. In a reactor, water is converted into steam by a heat source. Then the steam under pressure is fed to the turbine, which begins to rotate and, in turn, rotates the generator, which generates electricity. Electricity is supplied to the grid. At first glance, everything is simple.
A feature that distinguishes nuclear power plants from other power plants is the source of thermal energy. Here they use the most powerful process of obtaining energy, which humankind mastered - the decay of the atomic nucleus. During the decay, a large amount of thermal energy is released. Thus, one fuel element contains half a ton of uranium. During its operation, it provides as much energy as 60,000 tons of coal.
The downside of such energy efficiency: the need for radiation safety, radioactive waste disposal, complex management processes, high requirements for the level of personnel training and physical protection of the facility. Complexity and power create scale. The nuclear power plant is a real giant: it is an industrial complex with 1.5 by 0.5 km. On the territory of which there is even an artificial lake with about 22 square kilometres. It is located near the Pripyat River, a tributary of the Dnipro, and was used to cool the reactors.
The station required many workers, most of whom lived about 3 km from the reactor, in the new city of Pripyat, with a population of 49,000. Within a radius of 30 km from the power plant, the total population at the time of the accident ranged from 115,000 to 135,000 people.
Before the accident, the Chernobyl nuclear power plant generated 1/10 of Ukraine's electricity. However, after April 26, 1986, and one of the world's greatest catastrophes, electricity generation at the station was suspended.
The main task of the Chernobyl nuclear power plant after the accident was to create a protective shell over the destroyed fourth power unit - the Shelter, which was designed for three months and built in a record six months. The design and construction took place in parallel.
Also, at that time, work was carried out aimed at the post-commissioning of power units of the damaged station. And although this is rarely mentioned, it should be understood that the station continued to operate after the accident. Only in 1995 did the government decide to close the Chernobyl nuclear power plant. It is reflected in the Memorandum of Understanding between the governments of the G7 countries, the Commission of the European Communities and the Government of Ukraine on the station's closure by 2000. Following these commitments, in 1991 the first power unit was shut down, then the first in 1996, and the third at the end of 2000.
It has been 35 years since the tragedy, and although Chernobyl's life has come to a standstill. The main change that took place at the Chernobyl nuclear power plant was replacing the protective structure that protects the world from the wreckage of the 4th power unit.
After the accident at the Chernobyl nuclear power plant in 1986, the Shelter closed the ruins. Still, its building structures did not meet the requirements of safety regulations regarding structural integrity and reliability and had an indefinite service life. The results of research in recent years have shown that a significant reduction in the danger of "Shelter" is possible only as a result of the construction of a new protective structure - new safe confinement - a defensive form designed to transform this unit into an environmentally friendly system and ensure staff safety, population and environment.
Installation of the confinement began on February 13, 2012, when the first batches of basic metal structures were delivered to the Chernobyl site. For the construction, 45 donor countries joined forces with Ukraine, raising more than 1.5 billion euros. Ten thousand workers from 40 countries were involved in the project. Five thousand of them are Ukrainians.
On November 8, 2017, the Chornobyl NPP put the "enclosure circuit" of the NSC into operation. On July 24, 2020, a separate permit was obtained for the experimental and industrial process of the NSC PC-1.
The approach of the arch had a positive effect on the radiation situation nearby. According to the results of measurements of gamma radiation levels in the former area of the arch construction, radiation levels decreased by an average of 10 times. The arch also covered the Shelter from precipitation. For comparison, the number of radioactively contaminated waters pumped out of the Shelter in the first half of 2017 decreased by more than four times on average compared to similar periods of previous years. In addition, the emission of radioactive aerosols through the cracks in the Shelter facility has decreased. The arch made it impossible for the Shelter to be directly exposed to sunlight and wind, creating air currents inside the facility and carrying radioactive aerosols outside. Total emissions decreased by an average of 5 times.
Another essential process currently underway at the Chernobyl nuclear power plant is the preservation of radioactive waste. Nowadays, almost all Chernobyl fuel is in the Wet Spent Fuel Storage Facility № 1, but Ukraine has launched a process to move it to the Dry Type Storage Facility, where it will be stored for the next 100 years.
Transportation is carried out by a particular container car, which additionally performs the biological protection of personnel from radiation exposure. The storage of spent nuclear fuel will be carried out using dry modular storage technology. The general principle is that the fuel is stored in airtight metal baskets filled with inert gas. The baskets themselves are placed in concrete modules. The design of the module serves as radiation protection and also prevents damage to the metal basket.
Unlike radioactive waste, which is a by-product generated at all stages of the nuclear cycle of a nuclear power plant and has no value in terms of further use, spent nuclear fuel cannot be considered waste. More than 90% of the total volume of spent fuel is atomic material, which can be used as a recovered nuclear fuel in the future. In particular, spent energy contains a significant amount of unburned uranium and plutonium.
It takes about ten years to transport all the spent nuclear fuel stored in the SVYAP-1 wet storage facility.
In general, the Chernobyl decommissioning plan has been approved by 2065, and it is planned to carry out a whole range of works, culminating in the dismantling of the Chernobyl reactor equipment. However, today, the Chernobyl nuclear power plant exists and receives more than 2,000 loyal employees every day.