Voronezh Nuclear Power Plant. Nuclear combined heat and power plants and nuclear heat supply stations

Nuclear power plant.

Russia is one of the few countries where options for building nuclear power plants are being seriously considered. This is explained by the fact that in Russia there is a centralized system of water heating of buildings, in the presence of which it is advisable to use nuclear power plants to obtain not only electrical, but also thermal energy. The first projects of such stations were developed back in the 70s of the XX century, however, due to the economic upheavals that occurred in the late 80s and severe public opposition, none of them was fully implemented. The exception is the Bilibino NPP of small capacity, which supplies heat and electricity to the village of Bilibino in the Arctic (10 thousand inhabitants) and local mining enterprises, as well as defense reactors (the main task of which is the production of plutonium):

• Siberian NPP, which supplied heat to Seversk and Tomsk.
• The ADE-2 reactor at the Krasnoyarsk Mining and Chemical Combine, from 1964 until its shutdown in 2010, supplied heat and electricity to the city of Zheleznogorsk.

The construction of the following NPPs based on reactors similar in principle to VVER-1000 was also started:

• Voronezh AST (not to be confused with Novovoronezh NPP)
• Gorky AST
• Ivanovskaya AST (only planned)

The construction of all three ASTs was stopped in the second half of the 1980s or early 1990s.
At present (2006), the Rosenergoatom concern is planning to build a floating NPP for Arkhangelsk, Pevek and other polar cities based on the KLT-40 reactor plant used at nuclear icebreakers. There is a variant of a small unattended nuclear heating plant based on the Elena reactor, and a mobile one ( by rail) of the Angstrem reactor plant.
In Ukraine, a number of cities are heated from nuclear power plants, including Energodar, which is heated by the largest nuclear power plant in Europe.

The production of hot water and steam (low-temperature heat) for the needs of cities and industry consumes one and a half times more fuel than for generating electricity, while a significant part of the heat is produced by small, inefficient installations that burn the most valuable fuels - oil and gas.
It is assumed that in the near future the annual consumption of low-temperature heat (it is also called low-potential) will reach a very impressive figure - 6 billion Gcal. To generate such an amount of heat, for example, it would be necessary to burn about 600 million tons of oil, that is, practically our entire annual production in 1981, and this is only on condition that its heat content is used 100%, which, of course, is not the case in reality.
About 30-40% of all types of fuel are consumed precisely for the production of hot water and process steam.
The parameters and modes of their operation are designed so that the stations fit into existing networks as an additional source of heat. The creation of such new powerful centralized sources will make it possible to dismantle obsolete installations operating on organic fuel, and to use technically advanced enough, but small ones, in the peak load mode, which most often occurs in the cold season. ACT themselves will take over base part loads.
In terms of controllability, ACT is a very flexible unit that does not impose any specific requirements on the management of heating networks in terms of regulating heat distribution, which is very important. In principle, ACT can also cover the peak load, but for a nuclear power plant, as for any capital-intensive equipment (capital investments are large, and the fuel component is small), the most economical mode is the maximum possible constant power, that is, the basic one.
It is clear that the use of atomic energy to produce low-temperature heat should have an enormous effect.
The use of atomic energy to produce high-temperature heat also has high hopes for many industries.

However, there is also a significant drawback. The fact is that if electrical energy can be transmitted without significant losses over tens and even hundreds of kilometers, which is impossible for thermal energy (hot water). And this means that the station should be located practically within the city.
Indeed, in environmental terms, nuclear power plants are the cleanest, of course, if there is no serious accident.
in the Soviet Union, a series of similar stations was planned, and work has already begun on the first stage. But, as they say: "If you want to make God laugh, tell him about your plans."

The specifics of ACT work is close proximity to the city- makes you take into account even these extremely rare damage. For this you need to create technical means, who are able to provide the required sanitary conditions for ACT operation not only in case of a pipeline rupture, but also in case of damage to the reactor pressure vessel.
Features of the ACT reactor (the use of natural circulation and integral layout, as well as low pressure inside the vessel) allow this problem to be successfully solved at an acceptable cost. And this boils down to the creation of a rather simple design: a second, safety body, which would not exclude the possibility of inspecting the main, supporting body, would not weaken our requirements for its reliability as the main element of the installation, but would allow, in the event of the most extreme, unforeseen violations, to completely keep in its volume, the entire filling of the reactor and the entire coolant containing radioactive substances.
Here is a model for such an extreme event. If the main body breaks, the internal volume now occupied by the coolant will increase slightly, the pressure will accordingly drop by about 30%, although the water level will drop, but it will still cover the entire core and provide its cooling. Due to this correspondence between the characteristics of the operating and protective equipment, reliable cooling of the core is ensured.

At one time, the President of the Academy of Sciences of the Soviet Union, Aleksandrov, said that the RBMK reactor (high-capacity channel reactor) could even be installed on Red Square in Moscow. But they put it in Chernobyl. In this sense, Moscow was simply lucky, because the nuclear scientists were completely sincerely convinced of the safety of this type of reactor.

Voronezh seems to be less fortunate. Thirty kilometers from the city, the first nuclear power plant in Russia was built, the reactors of which have already practically exhausted their resource and should be stopped within two years.

Back in 1979, another project appeared - to build in Voronezh, eight kilometers from the historical center of the city, the world's first nuclear heat supply station. Then the residents of Voronezh made a sharp protest, held a referendum and achieved a cessation of construction. However, this autumn, simultaneously with the start in Voronezh heating season, representatives of the city authorities again started talking about the resuscitation of the project for the construction of a nuclear power plant.

Our Voronezh correspondent Mikhail Zherebyatiev tells about the history of construction.

Mikhail Zherebyatiev:

In 1979, by decision of the allied Council of Ministers, the construction of a nuclear boiler house began on the outskirts of Voronezh. At that time, the AST-500 project, developed by the Nuclear Industry Research Institute in Gorky, was going to be replicated throughout the USSR. Ten years later, on the wave of glasnost, the democratic community of Voronezh demanded that the local authorities refuse to complete the construction of the facility, which caused alarm among the townspeople, and the authorities sanctioned a plebiscite. On May 15, 1990, a referendum was held in Voronezh on the fate of the nuclear stoker. 96 percent voted for the construction and reconstruction of thermal power plants and boiler plants without building a nuclear power plant. But even after the referendum, until the end of 1992, construction work continued at the station.

The Russian energy crisis of the 2000 model led to the activation of Rosenergoatom's activities in the Voronezh direction. The concern again offered its services to the city. Two billion rubles for the completion of the nuclear boiler. Another billion - for the development of heating network infrastructure - the city and the region should get themselves.

At the same time, the fundamental issues of both economic and environmental order are still not clarified. For example, who will own the facility, under what conditions will the city begin to consume the heat produced by the station? After all, if the NPP is a nuclear facility, then, according to current regulations, it should be located at a distance of thirty kilometers from large settlements.

The most active supporters of the project in Voronezh intend to cancel the judicial order the results of a ten-year-old referendum under the pretext that the population did not vote against AST, but for the development of a network of boiler houses.

Marina Katys:

In order to at least slightly clarify the position of representatives of local authorities, I called Vyacheslav Bachurin, deputy chairman of the municipal council of Voronezh. Vyacheslav Ivanovich agreed that at present there is no shortage of heat supply in Voronezh. This is due to the economic downturn and the fact that most of the city's large enterprises are not working. However, in the future, when the economic recovery begins in the region, there will be a shortage of heat.

Are you not embarrassed by the fact that this is the world's first thermal nuclear power plant and there were no trial models, and is being built right away in the city center?

Vyacheslav Bachurin:

This is far-fetched: that she is the first in the world. In Tomsk-27, or whatever, 67, there is such an experimental station that is working. But what is the most important thing in a nuclear power plant? This is a reactor. And this reactor is on the same Kursk nuclear boat underwater. But he didn't explode. In an extreme situation, he did not explode, right? But only this is a reactor, the power of which is reduced tenfold. That is, its reliability increases tenfold.

Marina Katys:

Most of the experts to whom I addressed do not see a direct relationship between a decrease in the power of a reactor and an increase in its reliability. But it is quite possible that Vyacheslav Ivanovich has other sources of information.

Center President environmental policy Russia, Corresponding Member of the Russian Academy of Sciences Alexei Yablokov believes that the Voronezh nuclear power plant has no analogues.

Alexey Yablokov:

There are no nuclear power plants anywhere in the world. The closest analogue is the use of industrial plutonium production reactors in Tomsk-7 for heating residential areas. A specially made nuclear power plant does not exist anywhere, nowhere. This is the first project.

Marina Katys:

This is also confirmed by Professor Stanislav Kadmensky.

Stanislav Kadmensky: Initially, it was planned to build about four nuclear power plants of this type. In a memorandum on this matter, it was written that it would be useful to take the Moscow region as the location of these stations, because Moscow has a shortage of heat, ordinary boiler houses connected with gas or coal cannot cope with this. And even in the political sense it was useful to build one of the first stations in the suburbs. But, of course, this project was not implemented, and the first two stations began to build one in Gorky, in Nizhny Novgorod, and another - in Voronezh.

In Gorky, after Nemtsov's victory in the elections, construction was stopped, and the station was completely redesigned. In Voronezh, this station was under construction, and although there was a referendum in Voronezh, nevertheless, the construction of the station was not stopped.

Marina Katys:

And one of the reasons for this is the hostile attitude of the Voronezh authorities towards environmentalists. Vyacheslav Bachurin simply considers them illiterate people and hopes that in this case the Voronezh region will follow the example of France.

Vyacheslav Bachurin:

In France, they took it - and legally these environmentalists were removed. And the future must be judged by the end result. Final result ecologists - to return to the primitive order. They need to read more Vernadsky. Everything is bad for them. Isn't food bad if you overeat it? Yes? And unless you overdrink - is it not harmful? Isn't smoking harmful?

What is optimization? Maximum pleasure at minimum cost, right?

Marina Katys:

It is difficult to object to such a principle of optimizing all processes, however, Mr. Bachurin surprisingly reminds me of one of the characters of the Strugatsky brothers, namely, a professor who worked as a scientific consultant at the Institute of Witchcraft and Wizardry.

As for the cost of building a nuclear power plant in Voronezh, at present this issue has not yet been finally resolved. According to Vyacheslav Bachurin, the project will require...

Vyacheslav Bachurin:

Probably, with all the recalculations - about 3 billion.

Marina Katys:

It's money from federal budget, or is the local budget also involved?

Vyacheslav Bachurin:

Well, that's how we deal. If, as you say, this is an experiment that is needed for the whole country, and the whole country should take care of it. If this is our problem, Voronezh, well, we need to get together with Voronezh ... But then we from this nuclear power plant should spend all the energy only on Voronezh. And we don't have to pay any taxes for this station... Do you understand? So that they don’t make requisitions from the nuclear power plant later.

Marina Katys:

That is - you want to say that the issue of funding has not yet been finally resolved?

Vyacheslav Bachurin:

Well, he made up his mind. Decided how? You can finance: Voronezh, for example, Minatom and the country's budget. Like this. Divide all these expenses into three.

Because, well, you understand: Voronezh alone will never pull such a construction. What is there to talk about? It must be stretched again for ten years. And it must be completed in two and a half years.

Marina Katys:

That is - 2003.

Vyacheslav Bachurin:

Yes, so that the next elections will be warm. Because the nuclear power plant gives a hundred million dollars in savings. One billion cubic meters of gas. Can you imagine what it is? One billion cubic meters of gas.

Marina Katys:

Saving natural gas is, of course, a good thing, although for a start it would be quite possible to confine ourselves to repairing urban heating networks, in which heat losses currently exceed 50 percent.

Here is what academician Alexei Yablokov says about this.

Alexey Yablokov:

The Novovoronezh nuclear power plant is the oldest nuclear power plant in Russia, well, if you don't talk about Obninsk, which was experimental there. There are two nuclear reactors on it, put out of action almost 12 years ago. Now the Ministry of Atomic Energy has made such a decision in the government - to extend the life of existing reactors.

There were several commissions, expert groups with the IAEA (this International Agency on atomic energy, which differs in that it never gave any conclusions about the closure of nuclear plants). IAEA experts said: "It is impossible to bring their security up to the level of acceptable Western security by any alterations."

Marina Katys:

This whole idea with a nuclear heating plant, is it caused by the lack of energy in this region? Why, in fact, did they suddenly start talking about the need to build a nuclear heating plant? What, Voronezh cannot be heated in other ways?

Alexey Yablokov:

Analysis of heating networks showed a terrible state of heating systems. Just yesterday I spoke with my colleagues from Voronezh. In heating networks, up to half of the heat that is sent to these heating networks disappears.

A normal economic decision is to repair the heating systems. This will save half the heat that is now being wasted. And no heating station is needed. It will probably cost ten times less than the construction of a nuclear power plant.

Marina Katys:

By the way, in assessing the cost of construction, Academician Alexei Yablokov differs significantly from Vyacheslav Bachurin, Deputy Chairman of the Municipal Council of Voronezh.

Alexei Yablokov continues.

Alexey Yablokov:

It will be even more expensive than a conventional nuclear power plant. So, then it turns out that the construction of a conventional nuclear power plant is, just like that, two or three billion dollars. Dollars, not rubles!

Marina Katys:

Those are huge costs. Can leadership Voronezh region to participate in such an expensive project?

Alexey Yablokov:

Of course not. We know that Adamov came to Voronezh several times. We know that the governor of the Voronezh region, Shabanov, is the most "pro-nuclear" governor in all of Russia. They want to convince us that there is money to start construction. And when construction begins, they will have an argument: well, construction has begun. Give us some more money to continue this construction. This is a typical, Soviet type approach.

Marina Katys:

They would like to complete the construction of the nuclear heating plant and put it into operation by 2003. Is it real at all?

Alexey Yablokov:

This is absolutely unrealistic, 2003. In this regard, I have only one ... in 2003, the service life of these very old nuclear reactors that they have ends. Here it is 2002-2003. This is what I know.

Marina Katys:

But we must not forget that the real cost of this project should include waste disposal. According to experts, the apparent cheapness of nuclear energy in Russia is explained precisely by the fact that Minatom does not take into account the cost of disposing of spent nuclear fuel in its calculations. However, the municipal authorities of Voronezh are not embarrassed by this.

Here is what Vyacheslav Bachurin, deputy chairman of the municipal council, says about this.

Vyacheslav Bachurin:

Not only Voronezh, but the whole world is working on these problems. And all the submarines... And how many of them do we have? 150. After all, they are being disposed of, and even more so, now they are declining submarine fleet. Are disposed of.

Well, one more boat will be more. So what? This is problem? This is just artificially inflating the problem and focusing on it.

Marina Katys:

Professor of Voronezh University, nuclear physicist Stanislav Kadmensky disagrees with this.

Stanislav Kadmensky:

This station replaces conventional fuel (gas, fuel oil) with nuclear fuel. When it started to cost, atomic fuel was quite cheap, and it seemed that it was economical. Now nuclear fuel has a rather high price. The very economic profitability of such boiler houses is under a very strong question.

The whole world is not heated by nuclear energy. The whole world is heated by ordinary fuel. In America, according to Danish projects, coal-fired thermal stations have been built, which are quite environmentally friendly in the sense that they have fuel preparation for combustion, filters ... The entire Western world is heated - with ordinary fuel.

Marina Katys:

Don't confuse local authorities and the results of a ten-year-old referendum.

Professor Kadmensky continues.

Stanislav Kadmensky:

More than 90 percent of those participating in the referendum voted against the nuclear power plant. For a while, its construction was stopped, although not completely. It was the first referendum, perhaps of this nature in Russia, but it was completely within the law.

Now they explain to us that when the referendum was held, there was no law on referendums...

Marina Katys:

Tried your public organizations apply to Supreme Court to stop construction?

Stanislav Kadmensky:

No. The fact is that in our country it is, of course, all very inefficient. Such appeals, they are good in order to portray a certain pose or position or to attract attention. Seriously, this doesn't work.

Marina Katys:

Although, as Academician Yablokov is convinced, only another referendum can cancel the results of the past referendum.

Alexey Yablokov:

Recently, Putin, speaking about the construction of the Rostov nuclear power plant, said: "Well, of course, you can't build a plant if there is no full consent of the population." Something like that he said.

The results of a referendum can only be canceled by a referendum, and nothing else. Of course, in 1990 there was no law on referendums. The law on referendums appeared in 1995, but still, since the referendum was held, we have a powerful reason to say: the people are against it, the people will not let this station be built.

Marina Katys:

Moreover, the repeatedly interrupted process of building the station led to inevitable in this case errors in the technology of this construction, and the communication equipment over the past decade has become obsolete. In addition, during the construction, significant changes were made to the project, which, from the point of view of Professor Stanislav Kadmensky, is simply unacceptable in the construction of nuclear facilities.

Stanislav Kadmensky:

From the point of view of the reasonable development of nuclear energy, there should be the following sequence: first, such a type of plant is built in some city, a nuclear city like our Novo-Voronezh, for example, where this option is being worked out, experience is obtained, and then this plant begins to be replicated inside large settlements.

The point is that by objective reasons a nuclear heat supply station must be close enough to the object it supplies heat, otherwise there will be large heat losses along the routes, and so on. Here, our nuclear power plant should be, well, about eight kilometers from the city center.

But, on the other hand, these stations had no analogues in their structure. They say that the analogues of these stations were nuclear reactors. submarines. They gave us as an analogue the VK-50 reactor, which worked or is working in Dimitrovgrad, but the VK-50 mode of operation is boiling, but the reactor that is being built in Voronezh is not boiling. There is a difference in pressures, and therefore there is a difference in thermal conditions, and so on. The station, as an experimental one, the first station in the world was built without testing in the full version ...

We found out a lot of details related to the violation of environmental standards and technological provisions. And most importantly, during the construction process, a change in the project began, which, of course, made an amazing impression on us. This is not a canning factory where you can replace one tank with another. And changing the regime during the construction process is just a tragic situation, I think, for the construction of the world's first object of this class.

Marina Katys:

In addition, the construction of a nuclear power plant in a residential area of ​​the city, and even less than a kilometer from the reservoir, is a direct violation of Russian law.

Word to Academician Alexei Yablokov.

Alexey Yablokov:

The heat supply station is located eight kilometers from the center of Voronezh. Well, it's ridiculous to say that it is possible to build a nuclear reactor eight kilometers from the center of a city with a population of one million. This is prohibited by all existing regulations. Forbidden.

We have a law on atomic energy, a law on radiation safety. There is a law on the protection of the natural environment, which stipulates... There are norms and rules on how to build nuclear power plants. It stands on the banks of the Tsymlyansk reservoir (a federal body of water). It is impossible to build nuclear power plants on the banks of federal reservoirs.

Marina Katys:

However, nuclear power plants are still somewhat different from conventional nuclear power plants.

Professor Stanislav Kadmensky talks about the fundamental differences between these objects.

Stanislav Kadmensky:

The first difference is that these stations are located inside big cities. The second difference is that the water reactors of the base station, which is the Novovoronezh station, these reactors were quite consistently and intensively tested in these cities. And then gradually replicated in other cities and in other objects.

We have not seen anything like this in a heat supply station, a nuclear power plant. She immediately began to build in the city of Voronezh.

Generally speaking, it is safer in its design than an electric station. It is less powerful, it contains more circuits, well, and so on. Well, and, of course, there are differences in the processes themselves that occur in nuclear reactors, and in all thermal systems, and not just in the thermal systems of reactors. They are different. Safety is enhanced by the fact that it is a three-circuit system. (In nuclear power plants - a two-circuit system.)

However, the world's first operating station cannot be built in the city. During the construction process, the project was intensively refined and changed, which, generally speaking, does not climb into any gates.

This is a dangerous item.

Marina Katys:

But in Russian Federation There is Gosatomnadzor, whose duties include monitoring compliance with all standards that guarantee the safety of nuclear facilities operation.

Why does this body not pay attention to construction in Voronezh? I am talking about this with Academician Yablokov, President of the Center for Environmental Policy of Russia.

Now, in principle, Gosatomnadzor oversees all processes related to the construction of the Ministry of Atomic Energy. Why does he not express any opinion on the construction of a nuclear power plant in the city of Voronezh?

Alexey Yablokov:

Gosatomnadzor is now in a very difficult position. There is a massive attack on him. The destruction of the State Ecology Committee and the Forest Service is only the beginning. Now Gosatomnadzor, according to the draft law, which has already passed the government discussion and is in the Duma, is trying to take away licensing and control. Now licensing of nuclear facilities is the prerogative of Gosatomnadzor. Control over nuclear facilities - too. Well, of course, for this he was created.

The amendment to the law on atomic energy, which is now in the State Duma, transfers these functions to Minatom. Just as it was done in 1995, the control functions of Gosatomnadzor over military reactors were transferred to the Ministry of Defense.

They want to bleed it, this Gosatomnadzor, and then turn it into a department of Minatom.

Marina Katys:

Do you want to say that the situation is repeating when the Ministry of Natural Resources was entrusted with the functions of control over its own activities? Will the same be with the Ministry of Atomic Energy, which will control its activities?

Alexey Yablokov:

Well, of course, it's the same scheme.

Marina Katys:

Does the Russian leadership really not understand that the closure of Gosatomnadzor, an independent agency that controls all nuclear facilities in the country, will lead to a rather negative reaction in the West?

Alexey Yablokov:

Of course, the West will not remain silent. I even think that the IAEA will oppose it.

By the way, when this issue was just started to be discussed, do you know who strongly advocated the preservation of Gosatomnadzor? Our Ministry of Foreign Affairs.

Marina Katys:

In conclusion, I will quote a few lines from Alexei Yablokov's book "The Myth of the Safety of Nuclear Power Plants".

“On average, on the planet, every year, one person in a million is at risk of dying from a lightning strike. This risk is 10 to the -6th degree and is considered acceptable for man-made accidents. According to IAEA Deputy Director General Mr. Murogov, if there are 1,000 operating reactors in the world, then every ten years at nuclear power plants with a fairly high probability there will be serious accidents. There are now 440 nuclear reactors operating in the world. "

Page 1

Nuclear heat supply stations (ACT) are designed to supply heat for heating, ventilation and hot water supply and are performed according to a three-loop scheme. In the first (reactor) circuit and in the heating system, a pressure of 15–2 MPa is maintained, and in the intermediate circuit it is 1–2 MPa. This eliminates the leakage of both radioactive water into the heating system and mineralized network water into the reactor circuit. The water regime of the intermediate circuit is maintained by purging it in combination with cleaning the purging water.

The developed domestic nuclear power plants (ACT) consist of two units with a total thermal power of 1000 MW with AST-500 reactors. In order to eliminate the possibility of radioactive substances getting into the hot water flow directed to the heat consumer, the ACT scheme is made three-loop. In the primary (reactor) circuit, heat exchange occurs with natural water circulation, the pressure here is maintained at 1 6 - 2 MPa. In the second and third circuits, the circulation, of course, is forced.

The construction of the first nuclear heat supply stations (NPP) with a thermal capacity of 3600 GJ / h (860 Gcal / h) in Gorky and Voronezh is underway.

Nuclear stations for industrial heat supply are currently being developed to supply enterprises with process steam at a pressure of 2 MPa and hot water.

In order to cover industrial and mixed industrial-heating loads, it is necessary to create special nuclear industrial heat supply stations (ASPT), which can produce heat in the form of process steam and hot water.

Energy program The USSR provides for the creation of nuclear heat and power plants, nuclear heat supply stations and nuclear industrial heat supply stations (ASPTs), which will provide significant savings in expensive organic fuel, which is currently used by most thermal power plants.

As sources of heat in the coming years, apparently, nuclear heat supply stations (ACT), which are essentially atomic steam generators, will begin to be widely introduced. At present, two main ACTs are already being built - near Gorky and Voronezh, each with two reactors (for redundancy reasons) of 500 MW each. Construction sites are located at a distance of 1 5 - 2 km from the city. These ACTs will provide heat to urban areas with approximately 300,000 to 400,000 inhabitants. By 1990, the construction of such stations will be economically justified for hundreds of settlements in the USSR. ACT will save a large number of oil, equal to a third of its current production in the country. It is assumed that atomic heat will be twice as cheap as that provided by fossil fuel boilers.

The designs of nuclear power plants (NPP), nuclear combined heat and power plants (ATES) and nuclear heat supply plants (ACT) with vessel, channel and other types of nuclear reactors are described. The fundamental issues of work technology, equipment and the basics of operation are considered. The main attention is paid to the choice of sites for construction, the design of buildings and structures of the NPP complex, radiation protection, and the organization of construction work.

In 1978 - 1980. initial technical and economic studies were carried out in the direction of creating nuclear industrial heat supply plants (ASTS) designed to supply consumers with both hot water and steam of various parameters for technological purposes, which could further expand the possibility of replacing fossil fuel with nuclear. In the eleventh five-year plan, the corresponding developments will be continued even with favorable technical and economic results the question of the construction of the first ASPT will be decided.

The design features of reactor vessels, specific operating conditions and increased requirements for the reliability and safety of nuclear power plants for industrial heat supply require a complex of research and development work to create strength calculation standards, develop rules for design and safe operation, general provisions for welding and rules for controlling welded joints in multilayer vessels nuclear reactors.

Further centralization of heat supply is envisaged through the construction of predominantly powerful thermal power plants running on organic and nuclear fuel, nuclear heat supply stations and large boiler houses.

Science and Life No. 1 1981

More than a quarter of a century has passed since that significant day when the world's first nuclear power plant (NPP) gave industrial current in the Soviet Union. During this time, the nuclear power industry, which has become the general direction in the use of nuclear energy, has achieved considerable success. In the eleventh five-year plan, a further increase in the capacities of nuclear power plants and an increase in their share in the total generation of electricity is planned. This will make it possible to build the country's fuel and energy balance more rationally and save such resources as oil and gas. But nuclear power is the only way to use the energy of nuclear fission. In recent years, a new direction has been developing: nuclear heat supply, the widespread introduction of which should give an even more significant effect in saving scarce fuel resources than nuclear power plants.
Our correspondent S. Kipnis asked one of the leading scientists in this field, professor, doctor of technical sciences, laureate to answer a number of questions about nuclear heat supply State Prize USSR Victor Alekseevich SIDORENKO, director of the department of the I. V. Kurchatov Institute of Atomic Energy.

OBJECTIVE OF SPECIAL IMPORTANCE
  Correspondent. In one of the recently published articles, the President of the USSR Academy of Sciences, Academician A.P. Alexandrov wrote: “The development and all-round expansion of the types technological processes, which can be converted to nuclear energy, are one of the most important practical tasks facing our generation.
With the advent of the possibility of using the energy of nuclear fission, the first direction of its application was determined - the electric power industry. But even if all power plants were transferred to nuclear fuel, the effect would not be very significant: the consumption of natural fuel would decrease by only 20 percent, and the consumption of oil and gas would be even less - by only 10 percent (since about half of the power plants run on coal) .
Therefore, the time has come to think about other areas of application of atomic energy. The production of industrial and heating heat, the inclusion of nuclear power in metallurgy and the chemical industry is a task on a much larger scale than the electric power industry. In the coming years, humanity will certainly witness the penetration of nuclear energy into these areas.”
For the vast majority of people, it is customary to believe that the main profession of the atom is the production of electricity, work at nuclear power plants. And therefore it is very difficult to perceive the statement that atomic energy has things to do on a larger scale.
  V. Sidorenko. And yet it is so. Thermal power plants are by no means the largest consumer of fuel. Suffice it to say that, for example, the production of hot water and steam (low-temperature heat) for the needs of cities and industry consumes one and a half times more fuel, while a significant part of the heat is generated by small, inefficient installations that burn the most valuable types of fuel - oil and gas.
It is clear that the use of atomic energy to produce low-temperature heat should have an enormous effect.
We will not talk about the supply of industry, primarily metallurgy and chemistry, with high-temperature heat (800-1000 ° C and above). This is a separate, independent big topic. I will only note that the use of atomic energy to produce high-temperature heat also has high hopes for many branches of industry.

COUNTRY SCALE
  Correspondent. What are the needs of the housing and communal sector and industry in low-temperature heat?
  V. Sidorenko. First of all, I will clarify that the main heat carrier for the purposes of heating and hot water supply of cities is water at a maximum temperature of 150 ° C (depending primarily, of course, on the time of year), and as for industrial heat supply, hot water is also used here (about 30 %) and saturated steam (approximately 70%) with a pressure of 3 to 40 atm (0.3-4 megapascal - MPa). The range of consumers of low-temperature heat in industry is very wide: after all, the vast majority of technological processes cannot go without hot water or steam, which are needed to heat working media.
Now about the scale of low-temperature heat consumption in our country.
The demand for low-temperature heat is indeed enormous. For example, a city with a population of 300-400 thousand people for domestic purposes requires an average of 800-1000 Gcal of heat per hour (gigacalorie (Gcal) - a billion calories). To get so much heat (taking into account the inevitable losses), one would have to burn 300-400 tons of fuel oil every hour.
It is assumed that in the near future (in 15-20 years) in the USSR, the annual consumption of low-temperature heat (it is also called low-potential) will reach a very impressive figure - 6 billion Gcal. To generate such an amount of heat, for example, it would be necessary to burn about 600 million tons of oil, that is, almost our entire annual production, and, keep in mind, this is only if its heat content is used 100%, which, of course, is not the case.
Let me emphasize once again that about 30-40% of all types of fuel are consumed specifically for the production of hot water and process steam.

  Correspondent. What is the difference between the use of nuclear energy for heat supply and the traditional scheme of energy production at nuclear power plants?
  V, Sidorenko. Let's start not with the differences between these two processes, but with their similarities. In both cases, the nuclear reactor serves as the heat producer. Let me remind you that in its core there is a controlled chain reaction of nuclear fission, for example, uranium-235. The resulting fission fragments fly apart at high speeds; when they are braked, all their kinetic energy is converted into heat, which is taken away by the coolant circulating through the core to cool it. The schemes for the further use of this heat can be different: either heat the water circulating in the secondary circuit in a heat exchanger and turn it into steam, or directly superheat the water in the reactor itself and obtain steam of the required parameters.
To understand the specifics of the process of producing low-temperature heat in a nuclear reactor, let us dwell on some features of a nuclear energy source.
First, we note that such a source of energy is economically profitable, as all the practice of developing nuclear energy shows, only at rather large unit capacities. Therefore, I note here that when it comes to domestic heat supply to cities, the term “nuclear boiler house” sometimes used in this case should be considered in a certain sense as very conditional. Indeed, with the word “boiler house” we can also associate rather small energy sources, while associations with quarterly or house boiler houses involuntarily arise. A nuclear source of heat, in terms of its scale, cannot be, based on the requirements of the economy, so small.
This should be a fairly large plant - with nuclear reactors with a total capacity of 1000 MW (for reasons of redundancy, it is composed of two blocks of 500 MW each). Such a station will be able to provide heat to a city with a population of 300-400 thousand people.
To avoid the ambiguity that arises when using the term "boiler room", we have put into use a different name: nuclear power plant -- ACT. So we will continue to call it.
The second essential feature nuclear reactor- sensitivity to the level of temperatures that develop in it. This is what largely determines the choice of the most appropriate technical solutions for the use of nuclear fuel for heat supply.
Recall that a characteristic feature of the development of the Soviet thermal power industry was district heating. This has led to the fact that branched heating networks have become widespread in our country. And for many years now, all new cities, new residential areas have been developing precisely on the basis of centralized heat supply. And if so, then it became possible to reasonably, on the basis of scientific and technical optimization, approach the choice of a method of supplying heat.
From considerations of optimizing the heat and power cycle, it follows that the most cost-effective is the simultaneous generation of heat and electricity. That is why combined heat and power plants have become the main strategic direction in the development of heat supply sources.
It would be quite natural, and, moving to a new type of fuel - nuclear, turn to a similar solution, that is, the creation of nuclear combined heat and power plants (LATES). However, the history of technology shows that the specifics of a new energy source always entails some other optimal solutions.
  Correspondent. Probably, the history of the development of nuclear energy already confirms this position?
  V. Sidorenko. Yes, sure. I will give an example that concerns the choice of steam parameters for nuclear power plants.
By the time they began to develop, the main direction for improving the energy cycle of traditional thermal power plants was clearly defined: superheating of steam. This, in turn, led to the creation of aggregates for supercritical parameters. And when it was time to choose the best option for the NPP in terms of the steam cycle, we settled on saturated steam, and not on superheated steam, although this was, I emphasize, very unusual for classical thermal power engineering, which spent a lot of effort to implement a cycle with superheated steam, and seeks to further increase its parameters.
Why did the designers of nuclear power plants make such a decision? On the one hand, during the transition from a saturated state of steam to an overheated state, which naturally requires high temperatures, the steam increases its heat content, although this increase is relatively small compared to what has already been accumulated by steam as a result of water evaporation. On the other hand, design features power plant, the reliability of its operation, the efficiency of the use of nuclear fuel strongly depend on the temperature level that we want to obtain in a nuclear reactor. The use of higher temperatures forces the use of more heat-resistant materials, and this, as a rule, leads to a less economical consumption of neutrons produced in the fission process (their absorption increases). And all this leads to a chain of deterioration in the economic indicators of the use of nuclear fuel and an increase in the cost of the power plant itself.
If we compare all these costs with the benefits that will give superheating of steam in a nuclear power plant, then the comparison is not in favor of superheating. In essence, in this case, the specifics of the new thermal unit - the nuclear reactor - are just affecting. For nuclear power plants, the optimal technology for today (of course, taking into account mainly the available materials) turned out to be obsolete for traditional energy technology with saturated steam of medium parameters; at the same time, the efficiency of the NPP thermal cycle remains at a fairly decent level - 30-34%.

THREE WAYS
  Correspondent. The example you gave, which reveals the logic of choosing steam parameters for a nuclear power plant, could obviously serve as an answer to the question why a nuclear reactor has not yet found application for producing high-temperature heat. When the materials needed for effective work A high-temperature reactor will probably disappear and all the problems that not only prevent the use of such reactors in metallurgy and the chemical industry, but also for heat supply.
  V. Sidorenko. Quite right. And here we come to the central question: how to most rationally use a nuclear reactor for heat supply, taking into account all those of its features that were discussed?
One can imagine three ways of district heating from a nuclear power source.
Firstly, the repetition of the traditional method for our energy sector of the simultaneous generation of electricity and heat using a combined heat and power plant (CHP), i.e. in our case, it will be a nuclear power plant - APEC. Here, the working heat - steam, before giving off heat to the heat supply network, pre-activates its potential in the turbine to generate electricity. Actually, this determines the thermodynamic efficiency of such combined method, i.e. high thermal cycle efficiency.
Another way that you can think of is this: the heat going to the consumer is obtained not from the steam of the steam turbine cycle, but directly by taking heat from the primary coolant of a nuclear reactor. Thus, there are two independent heat flows at the reactor boundary: one only for generating electricity, and the other only for heat supply (this is clearly explained by the diagrams on page 52).
If we divide the heat source itself, then we get the third way: two independently and independently operating reactors - one for the production of electricity (nuclear power plant), and the other - specifically for heat supply.
This is a single-purpose nuclear heating plant that produces only heat.
It turns out that for the purposes of heat supply in some conditions (we will talk about them later), it is more expedient to build not dual-purpose stations - ATES, but single-purpose - ACT. What explains this? In the case of nuclear thermal power plants, we are forced to remain at the same level of steam parameters that we use for nuclear power plants. The use of significantly lower temperatures than in thermal power engineering (which, as already mentioned, is due to the specifics of a nuclear reactor) undermines the basis for the economy of the dual-purpose use of heat. After all, a traditional combined heat and power plant is based on a superheated steam cycle. Some of the steam taken from the turbine to heat water in the boiler for heat supply has already used a significant part of its potential to generate electricity. But the saturated steam of average parameters used at the CHPP has a smaller initial energy reserve, therefore the amount of electricity generated with its participation is also less.
  General position about the fundamental profitability of the combined generation of electricity and heat in one unit, of course, remains valid, but when comparing the CHPP with a combined heat and power plant running on organic fuel, the advantage today is on the side of the latter.

MAIN CRITERION - EFFICIENCY
  Correspondent. But if we adopt the scheme of separate production of electricity at nuclear power plants, and heat at ACT, don’t we end up losing, because the efficiency of a nuclear power plant is always less than that of a CHP plant due to the fact that more heat is lost in the turbine condensers?
  V. Sidorenko To assess the overall efficiency of a particular method, to compare them according to some economic indicators, it is not enough to rely solely on the efficiency value: after all, it characterizes only the thermodynamic efficiency of the cycle. It is necessary to take a more general economic indicator, which takes into account not only unit costs fuel for the production of the final type of energy, as well as other components.
What are these components? First of all, the capital costs for the construction of the energy source itself. They may turn out to be significantly or, in any case, noticeably different for these variants. In particular, due to the fact that the ACHPP has the same reactor parameters as a nuclear power plant, but must be somewhat more complicated in order to provide heat in addition to electricity, it will be somewhat more expensive than a nuclear power plant in terms of specific indicators. On the other hand, ACT due to its specificity (operation at lower temperatures) will be cheaper than ATES in terms of specific indicators of capital costs. There is already a clear opportunity to compare different options for organizing heat supply: a cheaper ACT and an average cost of a nuclear power plant or a higher cost of a CHPP, but providing a better cycle efficiency, that is, the maximum use of fuel.
One more thing to take into account technical feature ATEC, which makes a significant contribution to the comparison of options. We are talking about the costs of building networks to deliver heat from the energy source to the consumer.
In our practice, in accordance with sanitary standards, nuclear power plants are located at a distance of at least 20 km from large settlements. And the need to build additional tens of kilometers of routes increases, of course, the cost of heat supply from the NPP.
At modern level knowledge, the development of technology, we are able to fulfill the necessary sanitary requirements with the use of any nuclear energy source, with any heat and energy intensity of the core, with any parameters. The whole thing comes down, of course, to the amount of costs. At the same time, an energy source with a lower temperature level, with a lower core tension requires cheaper technical solutions for this. Therefore, in the case of ACT, we can apply reasonable, economically justified technical means that allow us to reliably insure against the most unlikely of both external and internal damage. Consequently, it becomes possible to bring the nuclear source of heat supply directly to the settlement. As a result, thermal paths are reduced, and thus it is possible to influence another component of economic costs.
Until now, we have taken into account only the cost of funds for heating mains, but they "devour" not only money, but also land. Therefore, difficulties in allocating land for laying pipelines may be no less important factor than simply the cost of these heating mains.
In a particular situation, such a factor as the proportions in the provision of a given area with electricity and heat may turn out to be important. According to the specifics of energy supply that has developed in previous years, the region may experience, for example, an acute shortage of thermal energy, being sufficiently well supplied with electricity. The construction of a dual-purpose plant under these conditions, in particular the ACHPP, will lead to the fact that the excess amount of electricity will have to be transferred to the side, and this also increases the cost of this method of heat supply.
  Correspondent. What do the calculations of the effectiveness of various options, their comparison say?
  V. Sidorenko. All technical and economic studies, taking into account the specifics of energy consumption in various parts of our country, their availability of energy resources and many other factors, convincingly indicate that there are areas and regions where both ACT and ACHPP can be used in the next decade, and such nuclear heat supply should be developed to the maximum, especially in the European part of the USSR.

RELIABILITY...
  V. Sidorenko . I emphasize once again that the main condition determining all further decisions is the maximum reliability of the reactor and the fulfillment of the most stringent sanitary requirements. Simplicity of design is the key to solving these problems. On the one hand, the simplicity of the design in itself largely determines the reliability of the reactor as an energy source, and on the other hand, it opens the way for economically solving many other important issues.
The possibility of simplifying the design of the reactor lies in the very idea of ​​its use: only for the production of low-potential heat. Let me remind you that in comparison with a power reactor, the operation of a single-purpose reactor proceeds at significantly lower temperatures. In addition, the value of the heat stress of its active zone is chosen to be much smaller. Such facilitated operating conditions make it possible to abandon the forced movement of the coolant in the primary circuit, that is, through the reactor core. And if so, then circulation pumps, their power supply systems and other auxiliary equipment are not needed, the purpose of which is to ensure the reliable operation of all these mechanisms, devices, and devices.
  Correspondent. And what forces will make water circulate through the reactor core if there are no pumps?
  V. Sidorenko. The density of hot water leaving the upper part of the core is less than the density of water cooled in the heat exchanger (where it transfers part of its heat to the water of another circuit) and entering the core from below. Due to this difference in density, the natural movement of water from the bottom up, without outside help, occurs.
The transition to natural circulation, firstly, allows, as I said, to do without mechanisms, the absence of which in itself increases the reliability of the installation, simplifies its maintenance, and, secondly, the independence of natural circulation from external sources power supply eliminates any kind of damage that could happen to the power supply system.
Here, the features of a nuclear energy source, designed only to produce heat, are clearly manifested. They all seem to be pulled together into one knot. Going to a lower energy intensity of the reactor, we thereby got the opportunity to simplify the design: to abandon all very cumbersome and complex system forced circulation.
This decision paved the way for the next important step.

RELIABILITY AGAIN...
The main source of any kind of damage to equipment at nuclear power plants is usually associated with an extensive circulation circuit and with an extensive system of auxiliary pipelines that ensure the operation of the reactor plant. Therefore, wanting to reduce its potential accident rate and thereby increase reliability, they seek to "destroy" the secondary web of pipelines. So, by abandoning forced circulation, we thereby facilitated the solution of this problem. The external circulation circuit can be removed and natural circulation through the heat exchanger can be organized by placing it within the reactor vessel.
Thus, thanks to the adopted design solutions, it is possible to implement the integral layout of the reactor. With such a scheme, only the pipelines of the second, intermediate circuit, from which the heat will be further transferred to heating network, and control mechanisms of the regulation and protection system.
  Correspondent. But what about the size of such a reactor? After all, the vessel of a pressurized water reactor is already quite large, for example, with a power of 440 MW, its diameter reaches 4 m, and its height is about 20 m?
  V, Sidorenko. Of course, the integrated layout leads to some increase in the dimensions of the case. But the manufacture of such cases does not become too difficult a technological task. This is again due to the fact that the use of a reactor to generate low-temperature heat made it possible to reduce the pressure inside the vessel by a factor of ten - from 150-160 atm (15-16 MPa) to 15, maximum 20 atm (1.5-2 MPa) . This means that the thickness of the shell wall may not be 150-200 mm, as in high-power power reactors, but 30-40 mm. This greatly simplifies the manufacturing technology. The diameter of the reactor vessel with a capacity of 500 MW - namely, two such blocks are used to compose an ACT for 1000 MW - does not exceed 6 m. And although this is beyond the permissible railway dimensions (about 4.5 m), nevertheless, there are no special difficulties with transportation arises. Due to the smaller wall thickness, the mass of the reactor is not very large and it can be transported by road and by water.
Let us return to the design features of the ACT reactor.
The natural circulation within its body and the integral layout make it easy enough to take the ACT reliability one step further.

AND AGAIN RELIABILITY
  Correspondent. You quite often - and this is quite natural - turn to the problem of reliability. What criteria are used to evaluate it?
  V. Sidorenko. As a maximum damage from internal technical reasons for nuclear power plants, a rupture of the largest diameter pipeline of the primary or secondary circuits is usually considered. Based on this, the station is provided with all the necessary technical means that are able to neutralize damage, localize all possible consequences such damage.
Ruptures of the reactor vessel or other equipment are usually not considered for nuclear power plants, since these are considered to be extremely unlikely events.
  The specifics of ACT work is close proximity to the city- forces to take into account even these extremely rare damage. To do this, it is necessary to create technical means that are able to provide the required sanitary conditions for the operation of the ACT not only in the event of a pipeline rupture, but also in case of damage to the reactor pressure vessel.
Features of the ACT reactor (the use of natural circulation and integral layout, as well as low pressure inside the vessel) allow this problem to be successfully solved at an acceptable cost. And this boils down to the creation of a rather simple design: a second, safety body, which would not exclude the possibility of inspecting the main, supporting body, would not weaken our requirements for its reliability as the main element of the installation, but would allow, in the event of the most extreme, unforeseen violations, to completely keep in its volume, the entire filling of the reactor and the entire coolant containing radioactive substances.
Here is a model for such an extreme event. If the main body breaks, the internal volume now occupied by the coolant will increase slightly, the pressure will accordingly drop by about 30%, although the water level will drop, but it will still cover the entire core and provide its cooling. Due to this correspondence between the characteristics of the operating and protective equipment, reliable cooling of the core is ensured.

SIGNIFICANT CONTRIBUTION
  Correspondent. When and where will ACT with such reactors be built? What are the immediate prospects for the development of nuclear heat supply?
  V. Sidorenko. The construction of two head ACTs has already begun: near Gorky and Voronezh. Each of them is two-block - with two reactors of 500 MW each, that is, a total capacity of 1000 MW. Construction sites are located outside the city, at a distance of 1.5-2 km. ACT will provide heat to the districts of Gorky and Voronezh, with approximately 300-400 thousand inhabitants each. It is assumed that these stations will be put into operation in a few years.
Speaking about the prospects for nuclear heat supply, I would like to draw attention to one more significant feature of ACT. The parameters and modes of their operation are designed so that the stations fit into existing networks as an additional source of heat. The creation of such new powerful centralized sources will make it possible to dismantle obsolete installations operating on organic fuel, and to use technically advanced enough, but small ones, in the peak load mode, which most often occurs in the cold season. Themselves ACT will take on the basic part of the load.
In terms of controllability, ACT is a very flexible unit that does not impose any specific requirements on the management of heating networks in terms of regulating heat distribution, which is very important. In principle, ACT can also cover the peak load, but for a nuclear power plant, as for any capital-intensive equipment (capital investments are large, and the fuel component is small), the most economical mode is the maximum possible constant power, that is, the basic one. *** In conclusion, I will quote Vice President of the Academy of Sciences of the USSR Academician A.P. Aleksandrov on the prospects for the development of nuclear heat supply. Assessing the role of ACT in this matter, he writes that in the new five-year plan “we can expect their wide distribution. By 1990, the construction of such stations will make sense in several hundred settlements of the USSR, since ACT will save a large amount of oil, equal to a third of its current production. in the country. This will be a significant contribution to National economy, and most importantly, atomic heat will be two times cheaper than that provided by fossil fuel boilers” BR> ***
  about the author.
(b. 1929) - Russian scientist, corresponding member of the Russian Academy of Sciences (1991; corresponding member of the USSR Academy of Sciences since 1981).
Deputy Minister of the Russian Federation for Atomic Energy (1993-1996)
Member of the editorial board of the journals "Atomic Energy", "Nature";
member of the International Advisory Group on Nuclear Safety at CEO IAEA.
Twice winner of the State Prize of the USSR.
The main works on the creation of reactors for nuclear power plants.
***
Modern information about nuclear power plants.
  Voronezh AST(not to be confused with the Novovoronezh NPP) - a nuclear heating plant (VAST), consisting of two power units with a capacity of 500 MW each, is designed for year-round operation in the base mode in the district heating system of Voronezh in order to cover the existing heat shortage in the city (VAST was supposed to provide 23% of the city's annual demand for heat and hot water). The construction of the station was carried out from 1983 to 1990 and is currently frozen.
Wikipedia

  Nuclear power plant.
  25.07.2010
Russia is the only country where options for building nuclear power plants are being seriously considered. This is explained by the fact that in Russia there is a centralized system of water heating of buildings, in the presence of which it is advisable to use nuclear power plants to obtain not only electrical, but also thermal energy.

The first projects of such stations were developed back in the 70s of the XX century, however, due to the economic upheavals that occurred in the late 80s and severe public opposition, none of them was fully implemented. The exception is the Bilibino NPP of small capacity, which supplies heat and electricity to the village of Bilibino in the Arctic (10 thousand inhabitants) and local mining enterprises, as well as defense reactors (the main task of which is the production of plutonium):

Siberian NPP, which supplied heat to Seversk and Tomsk.
Reactor ADE-2 at the Krasnoyarsk Mining and Chemical Combine, since 1964 supplying heat and electricity to the city of Zheleznogorsk.
The construction of the following NPPs based on reactors similar in principle to VVER-1000 was also started:

Voronezh AST (not to be confused with Novovoronezh NPP)
Gorky AST
Ivanovskaya AST (only planned)
The construction of all three ASTs was stopped in the second half of the 1980s or early 1990s.

At present (2006) Rosenergoatom is planning to build a floating nuclear heating plant for Arkhangelsk, Pevek and other polar cities based on the KLT-40 reactor plant used on nuclear icebreakers. There is a variant of a small unattended AST based on the Elena reactor, and a mobile (by rail) Angstrem reactor plant.

The Nuclear Heat Supply Plant (NPP) consists of several autonomous units with a unit capacity of 500 MW each and is capable of generating 860 Gcal/h of heat in the form of water at a temperature of 150°C and a pressure of 20 atm for heating and hot water supply of a residential area with a population of 350,000 people . The nuclear power plant uses a pressurized water reactor, in which the neutron moderator and coolant is ordinary water.

The use of the reactor as a source of low-grade heat makes it possible to significantly reduce its parameters

• three-loop scheme of heat transfer from the reactor to the consumer;
• the first circuit is completely sealed and is located inside the reactor vessel, the circulation along the circuit is natural;
• the second circuit is hermetic, the circulation along the circuit is forced during normal operation and natural - in emergency modes. Includes steam volume compensator with safety device;
• circulation in the third (network) circuit is forced. A bypass with a control valve is provided on the network circuit to change the parameters of the network water;
• the pressure in the network circuit is higher than in the second circuit compared to the parameters of the VVER reactor: operating pressure of the primary circuit was reduced by 8 times (20 atm), the water temperature was lowered from 300 to 200°C, the energy intensity of the core was reduced by 4 times - from 110 to 27 MW/m 3 .

A feature of the design of the AST reactor is the placement of heat exchangers of the primary and secondary circuits in the gap between the strong hermetic reactor vessel and the in-vessel shaft separating the hot water flows from the core and the cooled water flows after heat exchange (Fig. 3.43). The water heated in the core, as lighter, rises inside the shaft to the upper part of the reactor, goes to the heat exchangers and, cooled by the transfer of heat to the water of the secondary circuit, descends in the gap between the shaft and the vessel down to the entrance to the core.

All fuel cassettes of the core are equipped with draft pipes, which are their continuation. This ensures that the water flow through the core is distributed among the fuel cassettes in accordance with their power. The uninterrupted and independent of external energy sources natural circulation of water in the reactor pressure vessel ensures reliable heat removal from the core under normal operation conditions, its cooling in emergency modes and makes it possible to abandon the use of main circulation pumps in the primary coolant circuit.

The reactor plant of the nuclear heat supply station transfers heat to the consumer according to the three-loop heat exchange scheme. The first coolant circulation circuit inside the reactor pressure vessel is designed to transfer heat from the core to the secondary circuit water. The second (intermediate) circuit is designed to transfer heat to the third (network) circuit and is equipped with forced circulation of the coolant. The third (network) circuit supplies heat to the consumer, the network water is circulated using pumps (Fig. 3.44).

The integrated layout of the reactor internal structures with heat exchangers of the first and second coolant circulation circuits made it possible to implement a technical solution that is fundamentally new for pressurized water reactors - to place the reactor in the second rugged case(Fig. 3.45). This makes it possible to keep the reactor core below the water level and prevent its overheating in the event of a depressurization of the main reactor vessel or its systems, and to localize the radioactive primary coolant. Thanks to the multi-level security system for the operation of AST, they can be placed at a distance of ~ 5 km from large cities.

At present, nuclear energy is used practically for the production of electricity, although there are stations that supply heat to consumers (for example, the Bilibino Thermal Power Plant in Chukotka) or desalinate water (Shevchenko, Kazakhstan). The most widespread and mastered in industrial production power nuclear reactors that received wide application at nuclear power plants, are reactors with water under pressure without its boiling VVER (foreign PWR - Pressured Water Reactor).

The Bilibino nuclear power plant (48 MW) is the first nuclear power plant in the Arctic, a unique facility in the center of Chukotka. The ATEC operates in the isolated Chaun-Bilibino energy center and is connected to this system by a 1,000 km power transmission line. In addition to BiATEC, the power unit includes the Northern Lights floating diesel power plant (24 MW) and Chaunskaya CHPP (30.5 MW). The total installed capacity of the system is 80 MW.