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Nuclear reactor, principle of operation, operation of a nuclear reactor. Great encyclopedia of oil and gas

Nuclear reactors.

A nuclear (atomic) reactor is a device designed to organize a controlled self-sustaining chain reaction fission of atoms, which is accompanied by the release of a large amount of energy.

Nuclear reactors are the main element of modern nuclear power plants.

The first nuclear reactors.

The first nuclear reactor was built and launched in December 1942 in the USA under the leadership of E. Fermi.

The first reactor built outside the United States was ZEEP, launched in Canada on September 5, 1945.

In Europe, the first nuclear reactor was the F-1 installation, which started operating on December 25, 1946 in Moscow under the leadership of I.V. Kurchatov.

By 1978, there were already about a hundred nuclear reactors of various types operating in the world.

History of the creation of nuclear reactors.

Scientific work in Germany.

The theoretical group “Uranium Project” of Nazi Germany, working in the Kaiser Wilhelm Society, was headed by Weizsäcker, but only formally. The actual leader was Heisenberg, who developed theoretical foundations chain reaction, Weizsäcker and a group of participants focused on creating a “uranium machine” - the first reactor.

In the late spring of 1940, one of the group's scientists, Harteck, conducted the first experiment attempting to create a chain reaction using uranium oxide and a solid graphite moderator. However, the available fissile material was not sufficient to achieve this goal.

In 1941, at the University of Leipzig, a member of Heisenberg's group, Doepel, built a stand with a heavy water moderator, in experiments on which, by May 1942, it was possible to achieve the production of neutrons in quantities exceeding their absorption.

German scientists managed to achieve a full-fledged chain reaction in February 1945 in an experiment conducted in a mine working near Haigerloch. However, a few weeks later, Germany's nuclear program ceased to exist.

Scientific work in the USA.

The nuclear fission chain reaction (chain reaction for short) was first carried out by American scientists in December 1942. A group of physicists at the University of Chicago, led by E. Fermi, created the world's first nuclear reactor, called the Chicago Pile-1 (CP-1). It consisted of graphite blocks, between which were located balls of natural uranium and its dioxide. Fast neutrons appearing after the fission of 235U nuclei were slowed down by graphite to thermal energies, and then caused new nuclear fissions. Reactors like SR-1, in which the majority of fissions occur under the influence of thermal neutrons, are called thermal neutron reactors. They contain a lot of moderator compared to nuclear fuel.

Scientific work in the USSR.

In the USSR, theoretical and experimental studies of the features of startup, operation and control of reactors were carried out by a group of physicists and engineers under the leadership of Academician I.V. Kurchatov.

The first Soviet reactor F-1 was built in Laboratory No. 2 of the USSR Academy of Sciences (Moscow). This reactor was brought into critical condition on December 25, 1946. The F-1 reactor was assembled from graphite blocks and had the shape of a ball with a diameter of approximately 7.5 m. In the central part of the ball with a diameter of 6 m, uranium rods were placed through holes in the graphite blocks. The F-1 reactor, like the CP-1 reactor, did not have a cooling system, so it operated at very low power levels (Average power did not exceed 20 W. For comparison, the first American CP-1 reactor rarely exceeded 1 W of power). The results of research at the F-1 reactor became the basis for projects of more complex industrial reactors. In 1948, the I-1 reactor (according to other sources it was called A-1) for the production of plutonium was put into operation.

June 27, 1954 started working world's first nuclear power plant with an electrical capacity of 5 MW in the city of Obninsk.

Physical principles of operation nuclear reactor.

Diagram of a thermal neutron nuclear reactor:

1 - Control rod.

2 - Radiation protection.

3 - Thermal insulation.

4 - Retarder.

5 - Nuclear fuel.

6 - Coolant.

The current state of a nuclear reactor can be characterized by the effective neutron multiplication factor k or reactivity ρ, which are related by the following relationship:

Thus, the following options for the development of a chain reaction of atomic fission are possible:

1. ρ<0, Кэф

2. ρ>0, Kef>1 - the reactor is supercritical, the reaction intensity and reactor power increase.

3. ρ=0, Kef=1 - the reactor is critical, the reaction intensity and reactor power are constant.

Classification of nuclear reactors.

According to their purpose and nature of use, nuclear reactors are divided into:

Energy reactors designed to produce electrical and thermal energy used in the energy sector, as well as for desalination of sea water (desalination reactors are also classified as industrial). Such reactors are mainly used in nuclear power plants. The thermal power of modern power reactors reaches 5 GW.

Transport reactors designed to supply energy to vehicle engines. The widest groups of applications are marine transport reactors used on submarines and various surface vessels, as well as reactors used in space technology.

Experimental reactors designed to study various physical quantities whose significance is necessary for the design and operation of nuclear reactors. The power of such reactors usually does not exceed several kW.

Research reactors, in which fluxes of neutrons and gamma quanta created in the core are used for research in the field of nuclear physics, solid state physics, radiation chemistry, biology, for testing materials intended to operate in intense neutron fluxes (including parts nuclear reactors) for the production of isotopes. The power of research reactors is usually no more than 100 MW. The released energy is usually not used.

Industrial (weapons, isotope) reactors used to produce isotopes used in various areas. Most widely used for the production of nuclear weapons materials, such as 239Pu. Industrial nuclear reactors also include reactors used for desalination of sea water.

Nuclear reactors are often used to solve two or more different problems, in which case they are called multi-purpose. For example, some power reactors, especially in the early nuclear energy, were intended mainly for experiments. Fast neutron reactors can simultaneously produce energy and produce isotopes. Industrial reactors, in addition to their main task, often generate electrical and thermal energy.

Nuclear reactor. Nuclear reactor.

A nuclear reactor is a device in which a controlled nuclear chain reaction occurs, accompanied by the release of energy.

Story

A self-sustaining controlled chain reaction of nuclear fission (chain reaction for short) was first carried out in December 1942. A group of physicists University of Chicago, led by E. Fermi, built the world's first nuclear reactor, called SR-1. It consisted of graphite blocks, between which were located balls of natural uranium and its dioxide. Fast neutrons appearing after nuclear fission 235U, were slowed down by graphite to thermal energies, and then caused new nuclear fissions. Reactors like SR-1, in which the majority of fissions occur under the influence of thermal neutrons, are called thermal neutron reactors. They contain a lot of moderator compared to uranium.

IN USSR theoretical and experimental studies of the features of start-up, operation and control of reactors were carried out by a group of physicists and engineers under the leadership of academician I. V. Kurchatova. The first Soviet reactor F1 placed in critical condition on December 25, 1946. The F-1 reactor is made of graphite blocks and has the shape of a ball with a diameter of approximately 7.5 m. In the central part of the ball with a diameter of 6 m, uranium rods are placed through holes in the graphite blocks. The results of research at the F-1 reactor became the basis for projects of more complex industrial reactors. In 1949, a plutonium production reactor was put into operation, and on June 27, 1954, the world's first nuclear power plant with an electrical capacity of 5 MW came into operation in Obninsk.

Design and principle of operation

Energy release mechanism

The transformation of the substance is accompanied by the release free energy only if the substance has a reserve of energy. The latter means that microparticles of a substance are in a state with a rest energy greater than in another possible state to which a transition exists. A spontaneous transition is always prevented by an energy barrier, to overcome which the microparticle must receive a certain amount of energy from the outside - excitation energy. The exoenergetic reaction consists in the fact that in the transformation following excitation, more energy is released than is required to excite the process. There are two ways to overcome the energy barrier: either due to the kinetic energy of colliding particles, or due to the binding energy of the joining particle.

If we keep in mind the macroscopic scale of energy release, then all or at first at least some fraction of particles of the substance must have the kinetic energy necessary to excite reactions. This is achievable only by increasing the temperature of the medium to a value at which the energy of thermal motion approaches the energy threshold limiting the course of the process. In the case of molecular transformations, i.e. chemical reactions, such an increase is usually hundreds of degrees Kelvin, but in the case of nuclear reactions it is at least 107°K due to the very high altitude Coulomb barriers of colliding nuclei. Thermal excitation of nuclear reactions is carried out in practice only during the synthesis of the lightest nuclei, in which the Coulomb barriers are minimal (thermonuclear fusion). Excitation by joining particles does not require large kinetic energy, and, therefore, does not depend on the temperature of the medium, since it occurs due to unused bonds inherent in the attractive forces of particles. But to excite reactions, the particles themselves are necessary. And if we again mean not a separate act of reaction, but the production of energy on a macroscopic scale, then this is possible only when a chain reaction occurs. The latter occurs when the particles that excite the reaction reappear as products of an exoenergetic reaction.

Schematic structure of a heterogeneous thermal neutron reactor1 - control rod; 2 - biological protection; 3 - thermal protection; 4 - moderator; 5 - nuclear fuel; 6 - coolant.

Schematic design of a heterogeneous thermal neutron reactor

control rod;

biological protection;

thermal protection;

moderator;

nuclear fuel;

coolant.

Design

Any nuclear reactor consists of the following parts:

Core with nuclear fuel and moderator;

Neutron reflector surrounding the core;

Coolant;

Chain reaction control system, including emergency protection

Radiation protection

Remote control system

The main characteristic of a reactor is its power output. A power of 1 MW corresponds to a chain reaction in which 3·1016 fissions occur in 1 second.

Physical principles of operation

The current state of a nuclear reactor can be characterized by the effective neutron multiplication factor k or reactivity ρ, which are related by the following relationship:

The following values are typical for these quantities:

k > 1 - the chain reaction increases over time, the reactor is in a supercritical state, its reactivity ρ > 0;

k< 1 — реакция затухает, реактор — подкритичен, ρ < 0;

k = 1, ρ = 0 - the number of nuclear fissions is constant, the reactor is in a stable critical state.

Criticality condition for a nuclear reactor:

ω is the fraction of the total number of neutrons produced in the reactor that are absorbed in the reactor core, or the probability of a neutron avoiding leakage from the final volume.

k 0 is the neutron multiplication factor in an infinitely large core.

Reversing the multiplication factor to unity is achieved by balancing the multiplication of neutrons with their losses. There are actually two reasons for the losses: capture without fission and leakage of neutrons outside the breeding medium.

It is obvious that k< k0, поскольку в конечном объёме вследствие утечки потери нейтронов обязательно больше, чем в бесконечном. Поэтому, если в веществе данного состава k0 < 1, то цепная самоподдерживающаяся реакция невозможна как в бесконечном, так и в любом конечном объёме. Таким образом, k0 определяет принципиальную способность среды размножать нейтроны

k0 for thermal reactors can be determined using the so-called “formula of 4 factors”:

μ—fast neutron multiplication factor;

φ is the probability of avoiding resonant capture;

θ—thermal neutron utilization factor;

η is the neutron yield per absorption.

The volumes of modern power reactors can reach hundreds of m3 and are determined mainly not by criticality conditions, but by heat removal capabilities.

The critical volume of a nuclear reactor is the volume of the reactor core in a critical state. Critical mass is the mass of fissile material in a reactor that is in a critical state.

Reactors that use fuel as fuel have the lowest critical mass. aqueous solutions salts of pure fissile isotopes with a water neutron reflector. For 235 U this mass is 0.8 kg, for 239 Pu - 0.5 kg. Theoretically, 251 Cf has the smallest critical mass, for which this value is only 10 g.

In order to reduce neutron leakage, the core is given a spherical or close to spherical shape, for example, a short cylinder or cube, since these figures have the smallest surface area to volume ratio.

Despite the fact that the value of (e - 1) is usually small, the role of fast neutron breeding is quite large, since for large nuclear reactors (K∞ - 1)<< 1. Без этого процесса было бы невозможным создание первых графитовых реакторов на естественном уране.

To start a chain reaction, neutrons produced during the spontaneous fission of uranium nuclei are usually sufficient. It is also possible to use an external source of neutrons to start the reactor, for example, a mixture of Ra and Be, 252 Cf or other substances.

Iodine pit

Iodine pit is a state of a nuclear reactor after it is turned off, characterized by the accumulation of a short-lived isotope of xenon (135 Xe). This process leads to the temporary appearance of significant negative reactivity, which, in turn, makes it impossible to bring the reactor to its design capacity within a certain period (about 1-2 days).

Classification

By nature of use

Based on the nature of their use, nuclear reactors are divided into:

Experimental reactors designed to study various physical quantities whose significance is necessary for the design and operation of nuclear reactors; the power of such reactors does not exceed several kW;

Research reactors, in which fluxes of neutrons and γ-quanta created in the core are used for research in the field of nuclear physics, solid state physics, radiation chemistry, biology, for testing materials intended to operate in intense neutron fluxes (including . parts of nuclear reactors), for the production of isotopes. The power of research reactors does not exceed 100 MW; The released energy is, as a rule, not used.

Isotope (weapons, industrial) reactors used to produce isotopes used in nuclear weapons, for example 239Pu.

Energy reactors designed to produce electrical and thermal energy used in the energy sector, for water desalination, to drive ship power plants, etc.; The thermal power of a modern energy reactor reaches 3-5 GW.

According to the neutron spectrum

Thermal neutron reactor (“thermal reactor”)

Fast neutron reactor ("fast reactor")

Intermediate Neutron Reactor

By fuel placement

Heterogeneous reactors, where fuel is placed discretely in the core in the form of blocks, between which there is a moderator;

Homogeneous reactors, where the fuel and moderator are a homogeneous mixture (homogeneous system).

Nuclear fuel blocks in a heterogeneous reactor are called fuel elements (fuel elements), which are placed in the core at the nodes of a regular lattice, forming cells.

By fuel type

By degree of enrichment:

Natural uranium

Lightly enriched uranium

Pure fissile isotope

By chemical composition:

metal U

UO 2 (uranium dioxide)

UC (uranium carbide), etc.

By type of coolant

H 2 O (water, see water-water reactor)

Gas, (see Graphite-gas reactor)

Organic cooled reactor

Liquid metal cooled reactor

Molten salt reactor

By type of moderator

C (graphite, see Graphite-gas reactor, Graphite-water reactor)

H 2 O (water, see Light water reactor, Water-water reactor, VVER)

D 2 O (heavy water, see Heavy water nuclear reactor, CANDU)

Metal hydrides

Without retarder

By design

Vessel reactors

Channel reactors

By steam generation method

Reactor with external steam generator

Boiling Reactor

At the beginning of the 21st century, the most common are heterogeneous nuclear reactors using thermal neutrons with moderators - H 2 O, C, D 2 O and coolants - H 2 O, gas, D 2 O, for example, water-water VVER, channel RBMK.

Fast reactors are also promising. The fuel in them is 238U, which makes it possible to improve the use of nuclear fuel tens of times compared to thermal reactors, this significantly increases the resources of nuclear energy.

Reactor materials

The materials from which reactors are built operate at high temperatures in the field of neutrons, γ-quanta and fission fragments. Therefore, not all materials used in other branches of technology are suitable for reactor construction. When choosing reactor materials, their radiation resistance, chemical inertness, absorption cross section and other properties are taken into account.

Fuel element shells, channels, moderators (reflectors) are made from materials with small absorption cross sections. The use of materials that weakly absorb neutrons reduces the wasteful consumption of neutrons, reduces the loading of nuclear fuel and increases the coefficient of reproduction of neutrons. For absorber rods, on the contrary, materials with a large absorption cross section are suitable. This significantly reduces the number of rods needed to control the reactor.

Fast neutrons, γ-quanta and fission fragments damage the structure of matter. Thus, in a solid matter, fast neutrons knock atoms out of the crystal lattice or move them out of place. As a result, the plastic properties and thermal conductivity of materials deteriorate. Complex molecules are broken down by radiation into simpler molecules or constituent atoms. For example, water decomposes into oxygen and hydrogen. This phenomenon is known as water radiolysis.

The radiation instability of materials has less effect at high temperatures. The mobility of atoms becomes so great that the probability of the return of atoms knocked out of the crystal lattice to their place or the recombination of hydrogen and oxygen into a water molecule increases markedly. Thus, the radiolysis of water is insignificant in energy non-boiling reactors (for example, VVER), while in powerful research reactors a significant amount of explosive mixture is released. Reactors have special systems for burning it.

Reactor materials are in contact with each other (fuel cladding with coolant and nuclear fuel, fuel cassettes with coolant and moderator, etc.). Naturally, the contacting materials must be chemically inert (compatible). An example of incompatibility is uranium and hot water entering into a chemical reaction.

For most materials, the strength properties deteriorate sharply with increasing temperature. In power reactors, structural materials operate at high temperatures. This limits the choice of construction materials, especially for those parts of the power reactor that must withstand high pressure.

Burnout and reproduction of nuclear fuel

During the operation of a nuclear reactor, due to the accumulation of fission fragments in the fuel, its isotopic and chemical composition changes, and transuranic elements, mainly Pu isotopes, are formed. The effect of fission fragments on the reactivity of a nuclear reactor is called poisoning (for radioactive fragments) and slagging (for stable isotopes).

The main cause of reactor poisoning is 135 Xe, which has the largest neutron absorption cross section (2.6 106 barn). Half-life of 135 Xe T½ = 9.2 hours; The fission yield is 6-7%. The main part of 135Xe is formed as a result of the decay of 135I (T½ = 6.8 h). In case of poisoning, Cef changes by 1-3%. The large absorption cross section of 135 Xe and the presence of the intermediate isotope 135 I lead to two important phenomena:

To an increase in the concentration of 135 Xe and, consequently, to a decrease in the reactivity of the reactor after it is stopped or the power is reduced (“iodine pit”), which makes short-term stops and fluctuations in output power impossible. This effect is overcome by introducing a reactivity reserve in regulatory bodies. The depth and duration of the iodine well depend on the neutron flux Ф: at Ф = 5·1018 neutron/(cm 2 ·sec) the duration of the iodine well is ˜ 30 hours, and the depth is 2 times greater than the stationary change in Kef caused by 135 Xe poisoning.

Due to poisoning, spatiotemporal fluctuations in the neutron flux F, and, consequently, in the reactor power, can occur. These oscillations occur at Ф > 1018 neutrons/(cm 2 sec) and large sizes reactor. Oscillation periods ˜ 10 hours.

When nuclear fission occurs large number stable fragments that differ in absorption cross sections compared to the absorption cross section of the fissile isotope. The concentration of fragments with a large absorption cross section reaches saturation within the first few days of reactor operation. This is mainly 149Sm, which changes Kef by 1%). The concentration of fragments with a small absorption cross section and the negative reactivity they introduce increase linearly with time.

The formation of transuranic elements in a nuclear reactor occurs according to the following schemes:

235 U + n → 236 U + n → 237 U →(7 days)→ 237 Np + n → 238 Np →(2.1 days)→ 238 Pu

238 U + n → 239 U →(23 min)→ 239 Np →(2.3 days)→ 239 Pu (+fragments) + n → 240 Pu + n → 241 Pu (+fragments) + n → 242 Pu + n → 243 Pu →(5 h)→ 243 Am + n → 244 Am →(26 min)→ 244 Cm

The time between the arrows denotes the half-life, "+n" denotes neutron absorption.

At the beginning of reactor operation, a linear accumulation of 239 Pu occurs, and the faster (with a fixed burnup of 235 U) the lower the uranium enrichment. Further, the concentration of 239 Pu tends to a constant value, which does not depend on the degree of enrichment, but is determined by the ratio of the neutron capture cross sections of 238 U and 239 Pu. The characteristic time for the establishment of the equilibrium concentration of 239 Pu ˜ 3/F years (F in units of 1013 neutrons/cm 2 ×sec). The isotopes 240 Pu and 241 Pu reach equilibrium concentrations only when fuel is re-combusted in a nuclear reactor after regeneration of nuclear fuel.

Nuclear fuel burnup is characterized by the total energy released in the reactor per 1 fuel. This value is:

˜ 10 GW day/t - heavy water reactors;

˜ 20-30 GW day/t - reactors using weakly enriched uranium (2-3% 235U);

up to 100 GW day/t - fast neutron reactors.

A burnup of 1 GW day/t corresponds to the combustion of 0.1% of nuclear fuel.

As the fuel burns out, the reactor reactivity decreases. Replacement of burnt fuel is carried out immediately from the entire core or gradually, leaving fuel rods of different “ages” in operation. This mode is called continuous refueling.

In the case of a complete fuel change, the reactor has excess reactivity that needs to be compensated, while in the second case compensation is required only when the reactor is first started. Continuous overloading makes it possible to increase the burnup depth, since the reactivity of the reactor is determined by the average concentrations of fissile isotopes.

The mass of loaded fuel exceeds the mass of unloaded fuel due to the “weight” of the released energy. After the reactor is shut down, first mainly due to fission by delayed neutrons, and then, after 1-2 minutes, due to β- and γ-radiation of fission fragments and transuranium elements, the release of energy in the fuel continues. If the reactor worked long enough before shutting down, then 2 minutes after shutdown the energy release is about 3%, after 1 hour - 1%, after 24 hours - 0.4%, after a year - 0.05%.

The ratio of the amount of fissile Pu isotopes formed in a nuclear reactor to the amount of burnt 235 U is called the conversion coefficient KK. The KK value increases with decreasing enrichment and burnup. For a heavy water reactor using natural uranium, at a burnup of 10 GW day/t, KK = 0.55, and at small burnups (in this case, KK is called the initial plutonium coefficient) KK = 0.8. If a nuclear reactor burns and produces the same isotopes (breeder reactor), then the ratio of the breeding rate to the burnup rate is called the breeding factor KB. In nuclear reactors using thermal neutrons KV< 1, а для реакторов на быстрых нейтронах КВ может достигать 1,4—1,5. Рост КВ для реакторов на быстрых нейтронах объясняется главным образом тем, что, особенно в случае 239 Pu, для быстрых нейтронов g растёт, а а падает.

Nuclear reactor control

A nuclear reactor can operate at a given power for a long time only if it has a reactivity reserve at the beginning of operation. The processes occurring in the reactor cause a deterioration in the multiplying properties of the medium, and without a mechanism for restoring reactivity, the reactor would not be able to operate even for a short time. The initial reactivity reserve is created by constructing a core with dimensions significantly exceeding the critical ones. To prevent the reactor from becoming supercritical, neutron absorbent substances are introduced into the core. Absorbers are part of the material of control rods that move along the corresponding channels in the core. Moreover, if only a few rods are enough for regulation, then to compensate for the initial excess reactivity the number of rods can reach hundreds. Compensating rods are gradually removed from the reactor core, ensuring a critical state during the entire time of its operation. Burnup compensation can also be achieved by using special absorbers, the effectiveness of which decreases when they capture neutrons (Cd, B, rare earth elements) or solutions of absorbing substances in the moderator.

Control of a nuclear reactor is simplified by the fact that during fission, some of the neutrons fly out of the fragments with a delay that can range from 0.2 to 55 seconds. Thanks to this, the neutron flux and, accordingly, the power change quite smoothly, giving time to make a decision and change the state of the reactor from the outside.

A control and protection system (CPS) is used to control a nuclear reactor. CPS bodies are divided into:

Emergency, reducing reactivity (introducing negative reactivity into the reactor) when emergency signals appear;

Automatic regulators that maintain a constant neutron flux F (i.e., output power);

Compensating, serving to compensate for poisoning, burnout, temperature effects.

In most cases, to control the reactor, rods inserted into the core and made of materials that strongly absorb neutrons (Cd, B, etc.) are used. The movement of the rods is controlled by special mechanisms that operate based on signals from devices sensitive to the magnitude of the neutron flux.

The operation of the control rods is noticeably simplified for reactors with a negative temperature coefficient of reactivity (r decreases with increasing temperature).

Based on information about the state of the reactor, a special computer complex generates recommendations for the operator to change the state of the reactor, or, within certain limits, the reactor is controlled without the participation of the operator.

In the event of an unforeseen catastrophic development of a chain reaction, each reactor is provided with an emergency termination of the chain reaction, carried out by dropping special emergency rods or safety rods into the core - an emergency protection system.

Design and principle of operation

Energy release mechanism

The transformation of a substance is accompanied by the release of free energy only if the substance has a reserve of energy. The latter means that microparticles of a substance are in a state with a rest energy greater than in another possible state to which a transition exists. A spontaneous transition is always prevented by an energy barrier, to overcome which the microparticle must receive a certain amount of energy from the outside - excitation energy. The exoenergetic reaction consists in the fact that in the transformation following excitation, more energy is released than is required to excite the process. There are two ways to overcome the energy barrier: either due to the kinetic energy of colliding particles, or due to the binding energy of the joining particle.

Excitation by joining particles does not require large kinetic energy, and, therefore, does not depend on the temperature of the medium, since it occurs due to unused bonds inherent in the attractive forces of particles. But to excite reactions, the particles themselves are necessary. And if we again mean not a separate act of reaction, but the production of energy on a macroscopic scale, then this is possible only when a chain reaction occurs. The latter occurs when the particles that excite the reaction reappear as products of an exoenergetic reaction.

Design

Any nuclear reactor consists of the following parts:

Core with nuclear fuel and moderator;
Neutron reflector surrounding the core;
Chain reaction control system, including emergency protection;
Radiation protection;
Remote control system.

Physical principles of operation

Iodine pit

Main article: Iodine pit

Iodine pit - a state of a nuclear reactor after it is turned off, characterized by the accumulation of the short-lived isotope xenon. This process leads to the temporary appearance of significant negative reactivity, which, in turn, makes it impossible to bring the reactor to its design capacity within a certain period (about 1-2 days).

Classification

By purpose

According to the nature of their use, nuclear reactors are divided into:

Power reactors, intended for the production of electrical and thermal energy used in the energy sector, as well as for the desalination of sea water (desalination reactors are also classified as industrial). Such reactors are mainly used in nuclear power plants. The thermal power of modern power reactors reaches 5 GW. A separate group includes:
- Transport reactors, designed to supply energy to vehicle engines. The widest groups of applications are marine transport reactors used on submarines and various surface vessels, as well as reactors used in space technology.
Experimental reactors, intended for the study of various physical quantities, the value of which is necessary for the design and operation of nuclear reactors; The power of such reactors does not exceed several kW.
Research reactors, in which fluxes of neutrons and gamma quanta created in the core are used for research in the field of nuclear physics, solid state physics, radiation chemistry, biology, for testing materials intended to operate in intense neutron fluxes (including parts nuclear reactors) for the production of isotopes. The power of research reactors does not exceed 100 MW. The released energy is usually not used.
Industrial (weapons, isotope) reactors, used to produce isotopes used in various fields. Most widely used to produce nuclear weapons materials, such as 239 Pu. Also classified as industrial are reactors used for desalination of sea water.

Reactors are often used to solve two or more different problems, in which case they are called multi-purpose. For example, some power reactors, especially in the early days of nuclear power, were designed primarily for experimentation. Fast neutron reactors can simultaneously produce energy and produce isotopes. Industrial reactors, in addition to their main task, often generate electrical and thermal energy.

According to the neutron spectrum

Thermal (slow) neutron reactor (“thermal reactor”)
Fast neutron reactor ("fast reactor")

By fuel placement

Heterogeneous reactors, where fuel is placed discretely in the core in the form of blocks, between which there is a moderator;
Homogeneous reactors, where the fuel and moderator are a homogeneous mixture (homogeneous system).

In a heterogeneous reactor, the fuel and moderator can be spatially separated, in particular, in a cavity reactor, the moderator-reflector surrounds a cavity with fuel that does not contain a moderator. From a nuclear physical point of view, the criterion for homogeneity/heterogeneity is not the design, but the placement of fuel blocks at a distance exceeding the neutron moderation length in a given moderator. Thus, reactors with the so-called “close grid” are designed as homogeneous, although in them the fuel is usually separated from the moderator.

Nuclear fuel blocks in a heterogeneous reactor are called fuel assemblies (FA), which are located in the core at regular lattice nodes, forming cells.

By fuel type

uranium isotopes 235, 238, 233 (235 U, 238 U, 233 U)
plutonium isotope 239 (239 Pu), also isotopes 239-242 Pu in the form of a mixture with 238 U (MOX fuel)
thorium isotope 232 (232 Th) (via conversion to 233 U)

By degree of enrichment:

natural uranium
weakly enriched uranium
highly enriched uranium

By chemical composition:

metal U
UC (uranium carbide), etc.

By type of coolant

Gas, (see Graphite-gas reactor)
D 2 O (heavy water, see Heavy water nuclear reactor, CANDU)

By type of moderator

C (graphite, see Graphite-gas reactor, Graphite-water reactor)
H2O (water, see Light water reactor, Water-cooled reactor, VVER)
D 2 O (heavy water, see Heavy water nuclear reactor, CANDU)
Metal hydrides
Without moderator (see Fast reactor)

By design

By steam generation method

Reactor with external steam generator (See Water-water reactor, VVER)

IAEA classification

PWR (pressurized water reactors) - water-water reactor (pressurized water reactor);
BWR (boiling water reactor) - boiling water reactor;
FBR (fast breeder reactor) - fast breeder reactor;
GCR (gas-cooled reactor) - gas-cooled reactor;
LWGR (light water graphite reactor) - graphite-water reactor
PHWR (pressurized heavy water reactor) - heavy water reactor

The most common in the world are pressurized water (about 62%) and boiling water (20%) reactors.

Reactor materials

The materials from which reactors are built operate at high temperatures in a field of neutrons, γ quanta and fission fragments. Therefore, not all materials used in other branches of technology are suitable for reactor construction. When choosing reactor materials, their radiation resistance, chemical inertness, absorption cross section and other properties are taken into account.

Reactor materials are in contact with each other (fuel shell with coolant and nuclear fuel, fuel cassettes with coolant and moderator, etc.). Naturally, the contacting materials must be chemically inert (compatible). An example of incompatibility is uranium and hot water entering into a chemical reaction.

Burnout and reproduction of nuclear fuel

During the operation of a nuclear reactor, due to the accumulation of fission fragments in the fuel, its isotopic and chemical composition changes, and transuranic elements, mainly isotopes, are formed. The effect of fission fragments on the reactivity of a nuclear reactor is called poisoning(for radioactive fragments) and slagging(for stable isotopes).

The main reason for reactor poisoning is , which has the largest neutron absorption cross section (2.6·10 6 barn). Half-life of 135 Xe T 1/2 = 9.2 hours; The yield during division is 6-7%. The bulk of 135 Xe is formed as a result of the decay ( T 1/2 = 6.8 hours). In case of poisoning, Keff changes by 1-3%. The large absorption cross section of 135 Xe and the presence of the intermediate isotope 135 I lead to two important phenomena:

To an increase in the concentration of 135 Xe and, consequently, to a decrease in the reactivity of the reactor after it is stopped or the power is reduced (“iodine pit”), which makes short-term stops and fluctuations in output power impossible. This effect is overcome by introducing a reactivity reserve in regulatory bodies. The depth and duration of the iodine well depend on the neutron flux Ф: at Ф = 5·10 18 neutron/(cm²·sec) the duration of the iodine well is ˜ 30 hours, and the depth is 2 times greater than the stationary change in Keff caused by 135 Xe poisoning.
Due to poisoning, spatiotemporal fluctuations in the neutron flux F, and, consequently, in the reactor power, can occur. These oscillations occur at Ф > 10 18 neutrons/(cm²·sec) and large reactor sizes. Oscillation periods ˜ 10 hours.

Nuclear fission produces a large number of stable fragments, which differ in absorption cross sections compared to the absorption cross section of the fissile isotope. The concentration of fragments with a large absorption cross section reaches saturation within the first few days of reactor operation. These are mainly fuel rods of different “ages”.

The mass of loaded fuel exceeds the mass of unloaded fuel due to the “weight” of the released energy. After the reactor is shut down, first mainly due to fission by delayed neutrons, and then, after 1-2 minutes, due to β- and γ-radiation of fission fragments and transuranium elements, the release of energy in the fuel continues. If the reactor worked long enough before stopping, then 2 minutes after stopping the energy release is about 3%, after 1 hour - 1%, after a day - 0.4%, after a year - 0.05% of the initial power.

The ratio of the number of fissile Pu isotopes formed in a nuclear reactor to the amount of burnt 235 U is called conversion rate K K . The value of K K increases with decreasing enrichment and burnup. For a heavy water reactor using natural uranium, with a burnup of 10 GW day/t K K = 0.55, and with small burnups (in this case K K is called initial plutonium coefficient) K K = 0.8. If a nuclear reactor burns and produces the same isotopes (breeder reactor), then the ratio of the reproduction rate to the burnup rate is called reproduction rate K V. In nuclear reactors using thermal neutrons K V< 1, а для реакторов на быстрых нейтронах К В может достигать 1,4-1,5. Рост К В для реакторов на быстрых нейтронах объясняется главным образом тем, что, особенно в случае 239 Pu, для быстрых нейтронов g grows and A falls.

Nuclear reactor control

Control of a nuclear reactor is possible only due to the fact that during fission, some of the neutrons fly out of the fragments with a delay, which can range from several milliseconds to several minutes.

To control the reactor, absorber rods are used, introduced into the core, made of materials that strongly absorb neutrons (mainly, and some others) and/or a solution of boric acid, added to the coolant in a certain concentration (boron control). The movement of the rods is controlled by special mechanisms, drives, operating according to signals from the operator or equipment for automatic control of the neutron flux.

In case of various emergency situations, each reactor is provided with an emergency termination of the chain reaction, carried out by dropping all absorbing rods into the core - an emergency protection system.

Residual Heat

An important issue directly related to nuclear safety is decay heat. This is a specific feature of nuclear fuel, which consists in the fact that, after the cessation of the fission chain reaction and the thermal inertia usual for any energy source, the heat release in the reactor continues for a long time, which creates a number of technically complex problems.

Residual heat is a consequence of the β- and γ-decay of fission products that accumulated in the fuel during the operation of the reactor. Fission product nuclei, due to decay, transform into a more stable or completely stable state with the release of significant energy.

Although the decay heat release rate quickly decreases to values small compared to steady-state values, in high-power power reactors it is significant in absolute terms. For this reason, residual heat generation necessitates long time ensure heat removal from the reactor core after shutdown. This task requires the design of the reactor installation to include cooling systems with a reliable power supply, and also necessitates long-term (3-4 years) storage of spent nuclear fuel in storage facilities with special temperature conditions- cooling pools, which are usually located in close proximity to the reactor.

Literature

Levin V. E. Nuclear physics and nuclear reactors. 4th ed. - M.: Atomizdat, 1979.
Shukolyukov A. Yu. “Uranium. Natural nuclear reactor." “Chemistry and Life” No. 6, 1980, p. 20-24

Notes

"ZEEP - Canada's First Nuclear Reactor", Canada Science and Technology Museum.
Greshilov A. A., Egupov N. D., Matushchenko A. M. Nuclear shield. - M.: Logos, 2008. - 438 p. -

December twenty-fifth marks 70 years since the launch of the first domestic nuclear reactor F-1, created to implement the Soviet nuclear project. The reactor, built in Moscow on the territory of Laboratory No. 2 of the USSR Academy of Sciences (now the National Research Center "Kurchatov Institute"), became the starting point for the development of many peaceful nuclear directions, in which Russia occupies a leading position.

The president of the center, corresponding member, spoke in an interview with RIA Novosti special correspondent Vladimir Sychev about the significance of that event for the history of Russia and the whole world, about the importance of the state choosing the right strategic priorities for its development and about the new unique technologies developed by the Kurchatov Institute. Russian Academy Sciences Mikhail Kovalchuk.

Mikhail Valentinovich, what did the launch of the first F-1 reactor on the Eurasian continent mean for our nuclear industry, for the country?

Not only for the country, but also for the future of the whole world. This was an event whose significance is difficult to overestimate. Imagine the military-political context of that time. The Soviet Union won a great victory in May 1945. Our country bore the brunt of the battle with Nazi Germany. Towards the end of the Great Patriotic War The Soviet Union had the most combat-ready and technically equipped army. The role of the USSR in the world strengthened. With our participation, the fate of the world was decided - at conferences in Tehran, Yalta, Potsdam.

And so on August 6 and 9, 1945, the United States dropped atomic bombs on Hiroshima and Nagasaki. In fact, one country turned out to be the owner of unprecedented weapons of colossal destructive power. In fact, our victory was devalued. Until August 29, 1949 - tests of the Soviet atomic bomb at the Semipalatinsk test site - the future of our country was in question. As you know, on January 1, 1950, according to the American Trojan plan, it was planned to drop 300 nuclear and 20 thousand conventional bombs on the cities of the USSR.

Therefore, the implementation in a very short time, with incredible effort and resources, of the Soviet nuclear project, the very first stage of which was the launch of the F-1 reactor, made it possible to restore nuclear parity. Until now, the world lives without a global war only because there is a balance of power. And Russia has survived to this day as a sovereign state because then, in the most difficult times, the country’s leadership and advanced science found mutual understanding in the face of the threat facing it. For us today, those events serve as an example of how a state should choose and combine tactical and strategic priorities, including scientific and technological ones.

- What priorities are we talking about?

Tactical priorities are short-term, they support our daily lives, are aimed at the production of specific products, the creation and development of certain markets and, in fact, are industry-specific.

And strategic priorities are medium- and long-term in nature. They are not initially expected to create new products and markets, but they are the ones who ensure the creation of fundamentally new, breakthrough technologies and lead to a change in the technological structure. In fact, strategic priorities set the future.

But tactical and strategic priorities are related to each other. Although you will not solve current problems without tactical priorities, if you neglect strategic priorities, devoting forces and resources only to solving tactical problems, then the security and independence of the country and its future may be at risk. It is important to note that strategic priority, including in science, can never be chosen, figuratively speaking, at a people's meeting.

Tactical priority is actually a balance of interests of a huge number of players, market participants with their products and money. A serious, strategic priority can only be identified by a group of progressive people who look forward and see the future.

Strategic priorities always advance through struggle, overcoming environmental resistance. Their justification must be confirmed by a large number of professional examinations. Only then can a picture emerge that looks to the future.

- And the atomic project is an example of this?

I think this is the most important example. During the war, tactical priorities included, for example, the evacuation of defense enterprises to the east, the deployment of production of new types of weapons, with the help of which we won. But the start of work on atomic weapons in the United States became a real strategic challenge for our country.

And imagine what would have happened if, during the most difficult years of the war, part of our scientific community did not ring all the bells, saying that we need to create our atomic weapons, and the authorities did not support scientists and we did not begin work on this topic. Perhaps by the beginning of the 1950s, our country could have ceased to exist altogether and we would not be talking to you now.

The US nuclear weapons program was called the Manhattan Project. The first atomic bomb was detonated at a test site in New Mexico in July 1945. Outstanding world scientists, many of whom emigrated to the United States from occupied Europe, attracting enormous financial and production capabilities, 130 thousand workers and engineers - all this allowed the Americans to create an atomic bomb in just over three years.

In the USSR in the 1930s a whole series physical institutes achieved important results in the study of, as it was then called, the prospects for using intranuclear energy: Leningrad Institute of Physics and Technology, headed by Abram Ioffe, Institute of Chemical Physics, headed by Nikolai Semenov, Radium Institute, headed by Vitaly Khlopin, Lebedev Physical Institute, headed by Sergei Vavilov , KIPT in Kharkov.

Among Ioffe’s students (by the way, who once studied with Wilhelm Roentgen himself) was Igor Vasilyevich Kurchatov, who headed the nuclear physics department at LPTI in the early 1930s. In 1937, at the Radium Institute, together with Lev Mysovsky, he launched the first cyclotron in Europe, and there in 1940, Konstantin Petrzhak and Georgy Flerov discovered the phenomenon of spontaneous fission of uranium.

It was this same Georgy Flerov, a lieutenant technician (later an academician, Kurchatov’s comrade-in-arms in creating the first Soviet atomic bomb, one of the founders of the Joint Institute for Nuclear Research in Dubna) who wrote a letter from the front to Joseph Stalin in April 1942, where he spoke with almost certainty about that in the USA in full swing work began on the creation of nuclear weapons. Around the same time, the leadership of the GRU of the General Staff of the Red Army informed the USSR Academy of Sciences about foreign work on the use of atomic energy for military purposes.

But the actual beginning of the Soviet atomic project is considered to be September 28, 1942, when the State Defense Committee (GOKO) recognized the need to resume “work on studying the possibility of mastering intranuclear energy,” interrupted by the outbreak of war. The country's leadership, relying on its system of expertise, on data received through various channels, including from intelligence, assessed what the scientists were saying and made the absolutely right choice by starting work on the atomic problem.

- Why is the creation and launch of the F-1 reactor considered a key stage in our nuclear project?

The fact is that the central core of any program to create atomic weapons is the production of fissile materials and nuclear explosives. You can develop as original designs of nuclear charges as you like, but without the required amount of plutonium-239 or uranium-235, these ideas will remain ideas.

Initially, for our first atomic bomb, the option with a plutonium charge was chosen - the production of plutonium in an industrial reactor was more achievable than the production of enriched uranium, and from the point of view of time, which is very important.

But first it was necessary to build an experimental reactor or boiler, as it was called then. The first experiments showed that the materials produced by our industry, from which the reactor could be assembled, contain a lot of harmful impurities. To carry out a nuclear chain reaction, only very pure uranium is needed. Thus, the main goal was the creation of a uranium-graphite boiler as the basis for the next step - the industrial production of nuclear explosives - plutonium. The Soviet Union began its atomic program in war conditions, almost complete absence resources, with enormous human and material losses.

To create our first reactor, it was necessary to ensure geological exploration and mining of uranium, create its metallurgy from scratch, and establish the production of graphite of the highest, unprecedented quality. In addition, the necessary instruments were created. Only at the end of 1945 did they begin to produce uranium and graphite of the required quality and in sufficient volumes.

Second important direction The work involved calculating the operability of the reactor design for implementing a self-sustaining nuclear chain reaction. This was also a colossal undertaking. In the summer of 1946, a special building was built with a reactor shaft 10 meters deep, with reliable biological protection, internal and external radiation monitoring devices, remote control reactor.

Four assemblies were assembled one by one (hundreds of tons of graphite), and at the same time a building for the reactor was built. In its pit, the final fifth assembly was assembled, which on December 25, 1946 became the legendary F-1 reactor - the “Physical First”. It took only 16 months to complete this grandiose project! Since then, the Kurchatov Institute has been at the forefront of creating new reactors. And it all started with the F-1 reactor.

So the launch of F-1 was a truly epoch-making event - it was experimentally proven that our scientists can carry out a controlled self-sustaining chain reaction of uranium fission. The phrase Kurchatov said immediately after the launch of the F-1 is well known: “Atomic energy is now subordinated to the will of the Soviet people.”

This made it possible to immediately begin creating powerful industrial reactors for producing weapons-grade plutonium. After the launch of the F-1 reactor, a number of very important experiments were carried out, which made it possible to build and launch the first industrial reactor in the Southern Urals in 1948. Here are three key points in the creation of our first atomic bomb: December 25, 1946 - the launch of the experimental F-1 reactor, June 22, 1948 - the industrial reactor built in the Urals - the producer of weapons-grade plutonium "Annushka" - was brought to full power, August 29, 1949 - the explosion of our first atomic charge at the test site in Semipalatinsk.

The most important conclusion from those events is this: the creation and launch of the F-1 reactor in the most difficult conditions for the country is a demonstration of the timeliness of the country’s leadership making strategically correct decisions in the most difficult, sometimes critical conditions.
But the launch of F-1 also became the starting point for the very rapid, rapid development of nuclear science and technology, and the country’s nuclear industry. In 1957, we launched our first nuclear submarine, Leninsky Komsomol, and in 1959, the world's first nuclear icebreaker, Lenin, was put into operation. Today Russia is the owner of the world's only nuclear icebreaker fleet. It guarantees us a strategic presence in the northern latitudes, where huge reserves of oil, gas and biological resources are concentrated.

And back in 1954, Igor Vasilyevich Kurchatov launched the world's first nuclear industrial power plant in Obninsk. Today Russia, the state corporation Rosatom, is a world leader in the construction of nuclear power plants. The Kudankulam nuclear power plant in India, the Tianwan nuclear power plant in China, and the Bushehr nuclear power plant in Iran are those plants that were launched in this century. The Ostrovets station is being built in Belarus, the Paks-2 nuclear power plant is planned in Hungary, Rooppur in Bangladesh, Hanhikivi in Finland, and Akkuyu in Turkey. Rosatom's order portfolio now exceeds $300 billion. We are mastering nuclear energy in all areas - from uranium mining to design, construction of nuclear power plants, ensuring their operation, fuel supply and decommissioning (that is, throughout their entire life cycle).

- What is the role of the Kurchatov Institute here?

The Kurchatov Institute has always been the main scientific organization of our country in the atomic field. We have such a scheme, as we call it “Kurchatov Reactor Tree”. It shows how the reactors came out of the F-1 reactor different types– industrial, energy, research, transport, which are used on submarines, on nuclear icebreakers, nuclear power plants for space.

And now we can be said to be an independent think tank, providing scientific support for Rosatom projects. Practice has proven the correctness of creating such a national laboratory as the Kurchatov Institute. We have the country's most powerful nuclear physical potential. We act as not only an expert on Rosatom projects, but also as their direct scientific participant. Each nuclear power plant was developed and launched with the participation of the Kurchatov Institute.

A nuclear power plant is a technologically complex, gigantic facility. These are hundreds of systems working simultaneously. But the heart of a nuclear power unit is a nuclear reactor. Kurchatov Institute – scientific supervisor their design and installation. We calculate the parameters of these reactors, their active zones, and nuclear fuel.

After Chernobyl, an idiosyncrasy towards nuclear energy arose for some time, largely caused by a powerful information campaign. I believe that the West largely used the Chernobyl disaster to undermine the structure of the Soviet Union, which was already weakened economically and geopolitically at that time. A terrible image of our country, incapable of handling nuclear energy, was created in public opinion. I will not go into a discussion of those events now - this is a topic for a separate discussion, but in fact Chernobyl was used to deal a heavy blow to the Soviet Union. And I must say that, unfortunately, this was a success.

But after Chernobyl accident We began to actively work, including in international cooperation, on the development of new safety systems for nuclear power plants. And the new safety systems we created - the so-called melt traps - are already part of the NPP equipment; they were first installed at the Tianwan NPP in China and the Kudankulam NPP in India. Such melt traps are designed to reliably collect, contain, and prevent radioactive substances from leaving the reactor facility in the event of a severe accident.

In addition, we even calculate scenarios of almost incredible, so-called beyond design basis accidents, up to a hypothetical plane crash on the station dome or a terrorist attack.

We are also engaged in work to extend the service life of nuclear units. And we are not just studying the possibilities of this, but also putting them into practice - our specialists have developed a system for the so-called annealing of reactor vessels, as a result of which their operational characteristics are almost completely restored.

One of our main areas remains nuclear technology, its development and improvement. We are not just scientific leaders of such modern projects as NPP-2006 and VVER-TOI, but also active creators. For example, in the field of materials science, with our participation, a new grade of steel has been developed, which, with the help of nanotechnology, acquires special properties, and this will help extend the life of reactor vessels to hundreds of years.

We also have a lot of developments related to low-power nuclear power plants, relevant, for example, for the Arctic. There are huge distances, few settlements, these are mainly small villages, military bases, and large power plants are simply not needed there. What is also fundamentally important is that in this region there is a demand for installations that do not require constant maintenance over many years. The Kurchatov Institute has been working in this direction since the 1970s; we have created working prototypes of such low-power stations operating on the principle of direct energy conversion. Such reactors, by their design parameters, provide passive safety, and in addition, they can be manufactured at a factory as part of mass production and installed almost anywhere.

Today our nuclear industry is close to restoring a full-fledged system of scientific leadership organizations. How important do you think this is?

This, from my point of view, is an absolutely necessary process. Obviously, without system recovery scientific leadership New breakthroughs are impossible - neither in the nuclear field, nor in the defense industry, nor in the space sector. After all, any engineering, technological, production structure or the organization itself cannot, and should not, generate new ideas, since it is engineering and technologically mastering the scientific results transferred to it and is responsible for the high-quality, reliable production of final products. Therefore, it is essentially conservative, and this is healthy conservatism.

But anyone new principle Only science can propose and justify it - in full contact with engineers and technologists.

The Kurchatov Institute performs this function of scientific director, and we need to return to this system in other areas. The institute of general designers and chief technologists is already being revived in the military-industrial complex.

- How does the Kurchatov Institute see the ways of developing nuclear energy?

Current nuclear energy is built on reactors using so-called thermal neutrons. The main nuclear fuel for such installations is uranium-235. But in natural uranium, the share of the uranium-235 isotope is only 0.7%, the rest is almost entirely uranium-238, and in order to create fuel for nuclear power plants, it is necessary to obtain enriched uranium, in which the share of the 235 isotope would already be several percent .

By the way, domestic uranium enrichment technologies were also developed at the Kurchatov Institute under the leadership of Academician Isaac Kikoin. Our enrichment industry and isotope separation complex remain today one of the best in the world. We have a new generation of gas centrifuges on the way, and, for example, the United States closed its gas centrifuge program this year, having failed to master this technology.

So, by burning uranium-235 in thermal neutron reactors, nuclear energy almost does not use huge volumes of valuable raw materials - uranium-238. And this big problem from the point of view of efficient provision of nuclear energy with raw materials. But this problem can be solved by using fast neutron reactors, which are where uranium-238 “burns.” In addition, with the help of so-called breeder reactors, or breeders, expanded reproduction of nuclear “fuel” is possible.

There is another advantage of "fast" reactors. After all, nuclear energy leaves behind spent nuclear fuel and radioactive waste that must be buried, and there are appropriate technologies for this. However, from an environmental point of view, this is not the best option, of course.

But it is possible to create a closed nuclear fuel cycle - reprocess spent nuclear fuel, extract valuable fissile materials from it, use them to create new nuclear fuel, both for fast neutron reactors and thermal reactors, and burn dangerous radionuclides in “fast” reactors . And then we will not only solve the raw materials problem, but also come to real “green” nuclear energy in the sense of minimizing radioactive waste.

Russia is a world leader in the development of these technologies. We are now - the only country, in which industrial-level fast neutron reactors operate, these are the BN-600 and BN-800 reactors at the Beloyarsk NPP. Now one part of the experts says that the future lies only with fast neutron reactors, while the other does not agree with this. In reality, we must understand that our promising nuclear energy must be two-component, in which both types of reactors will be interconnected. This means that we must improve the existing base of our water-cooled VVER thermal neutron power reactors, since these are massive installations for the production of electricity. And at the same time bring it to high quality new level"fast" reactors, using them to "afterburn" uranium-238 and create a fuel base for thermal reactors. And together we will achieve complete harmony.

The future of energy is also associated with the use of thermonuclear reactions. And the Kurchatov Institute, as is well known, was the founder of technology in this direction.

Nuclear energy is based on the use of energy released during the fission of heavy atomic nuclei. And the basis of thermonuclear energy should be the use of energy released during the fusion of nuclei of light isotopes of hydrogen - deuterium, tritium. Moreover, fusion reactions release orders of magnitude more energy than fission reactions, and therefore thermonuclear fusion is energetically much more favorable.

Our Soviet scientists from the Kurchatov Institute proposed thermonuclear technology; back in the mid-1950s, the world's first tokamak installation (a toroidal chamber with magnetic coils) was built, in which the conditions necessary for the flow of controlled thermo nuclear fusion. Since it is impossible to obtain materials that can hold plasma heated to gigantic temperatures of tens of millions of degrees, the plasma cord in the tokamak was held by a powerful magnetic field.

But it is necessary not only to ignite the plasma, but to hold it for a certain time, so that the plasma burns, works, so that you can get at least the same amount of energy as was spent on its ignition. Therefore, now in the south of France, in Cadarache, with the active participation of Russia, including our center, an international thermonuclear ITER reactor. This is not a thermonuclear power plant, but a pilot plant, its purpose is precisely to prove this possibility of plasma operation.

In general, the ITER project is actually a transition to new principles for mastering energy and nuclear fusion processes occurring in the Sun and stars. This is difficult to evaluate using any templates. After all, at first no one thought about the economic benefits of nuclear energy, but now it is the basis of modern energy development.

The question of what kind of thermonuclear power plant there will be is a very difficult one and clearly not in the near future. But a closer possibility of using plasma technologies is already visible.

Thermonuclear fusion produces huge amount neutrons with high energy. Thanks to this, it is possible to dramatically increase the efficiency of installations operating on the principles of fission of heavy nuclei. That is, it is possible to create a hybrid reactor - for example, surround a thermonuclear neutron source with a so-called blanket, a structure containing fissile nuclei, for example in the form of liquid salts, including uranium-238. Work in this direction is already underway at the Kurchatov Institute.

With the help of molten salt reactors, it is possible to solve the resource problem of nuclear energy by using thorium-232, the reserves of which are large on Earth, and converting it into uranium-233. The attractiveness of the concept of molten salt reactors, in contrast to traditional reactors with solid fuel, lies in the possibility of changing the composition of nuclear fuel without shutting down the reactor, in addition, the accumulation of fission products in its core is eliminated. In addition, in the same installation, a thermonuclear source can be combined with a closed nuclear fuel cycle.

So, in my opinion, hybrid reactors are a realistically achievable use of thermonuclear as a source of neutrons, capable of bringing closer, so to speak, the “greening” of nuclear energy.

- Where else, in your opinion, can applications of plasma technologies be found?

In space. We are on the threshold of deep space exploration. But with the help of ships equipped only solar panels, this will be impossible to do for obvious reasons. Fundamentally different energy sources are needed. And today, as you know, a megawatt-class nuclear power plant is being created in Russia. Let me emphasize this word – energy-motive. All modern cosmonautics is, figuratively speaking, a Munchausen flight on a cannonball. That is, we launch a rocket as if we were firing from a cannon, in the sense that we cannot change the trajectory of the “core”. But for deep space exploration this is absolutely necessary.

Today, the orbit of our geostationary satellites is corrected using plasma engines installed on them, developed by the Kurchatov Institute and produced by the Kaliningrad Design Bureau Fakel. The idea of these so-called Morozov engines dates back to the 60s of the last century.

But then it is possible to create powerful electrodeless plasma rocket engines. Such engines can already be used for long-distance interplanetary flights. And the next step is a thermonuclear rocket engine based on a thermonuclear fusion installation, called an “open trap,” from which plasma will flow, creating jet thrust. With the help of such an engine it will be possible to accelerate or slow down movement and maneuver in space. This is a fundamental thing and, in essence, will lead to a paradigm shift in astronautics.

Mikhail Valentinovich, in December 2015, at a meeting with the president of the country, you proposed adopting a domestic thermonuclear program. Is there any progress in this direction?

Yes. There is a corresponding instruction from the president of the country. In addition, at the beginning of June this year, we signed agreements with Rosatom on the creation of two interdepartmental centers - a center for plasma and thermonuclear research, as well as a center for neutrino research.

We also proposed that the Russian Academy of Sciences join the projects of both centers, but, alas, we did not find understanding. But some academic institutes have expressed interest - the Institute of Physics and Technology in St. Petersburg, the Institute of Nuclear Physics in Novosibirsk are asking to be involved in this work.

Such centers are now being formed. A research program is being created for the Center for Plasma and Thermonuclear Research together with Rosatom, its concept has been formed and heard at the relevant scientific and technical councils. Now this concept has been sent to the president of the country.

You spoke about the “Kurchatov evolutionary tree” of nuclear reactors. But on the wall in the corridor near your office there is another diagram - this is a “tree” of various technologies that came out of the walls of the Kurchatov Institute. There is, for example, what is now called living systems technologies.

Few people know, but domestic molecular biology also began at the Kurchatov Institute, in its radiobiological department, created on Kurchatov’s initiative in 1958.

The fact is that in order to understand the effect of radiation on living organisms, it was necessary to know their structure at the molecular level. Kurchatov and Alexandrov, at a time when there was persecution of genetics, saved this trend in the USSR, because their opinion was always significant for the authorities. The Institute of Genetics and Selection of Industrial Microorganisms (GosNIIGenetiki) and the Institute of Molecular Genetics then emerged from the radiobiological department. Today, the sciences of living things and nanobiotechnologies are becoming a mainstream area, with more than 70 percent of all world research focusing on living objects. And our Founding Fathers were blindsided when they came out in support of work in the field of biology almost 60 years ago.

IN recent years work on nature-like technologies has become one of the calling cards of the Kurchatov Institute. Is there a contradiction here with the directions you talked about?

On the contrary, this is the logic of the development of science. As I have already said, nuclear technology and nuclear energy remain one of our priorities - these are the same tactical priorities that we talked about at the very beginning. However, today we face a new choice of strategic priority, no less tough than in the mid-1940s. It is globally connected with the sustainable development of our civilization, which is impossible without sufficient energy and resources. Moreover, we are talking not only about oil and gas: supplies of drinking water, arable land, forests, and minerals are being depleted. There is already a fierce struggle for them in the world, we see this every day. It is already obvious to many that today’s global crisis cannot be resolved within the existing paradigm of modern civilization.

What is needed is a qualitative leap, a transition to other principles, first of all, of energy production and consumption, which will drag all other areas with them. In the man-made technosphere, we use machines and mechanisms that consume enormous amounts of energy. Technical progress has disrupted the peculiar metabolism of nature, creating technologies hostile to it. These technologies, in fact, are poor copies of individual elements of natural processes and are based on a highly specialized model of science and industry technologies.

In general, such development was inevitable and natural; it became the price to pay for technical progress, for the comfort of our lives. But in the end, human influence on the world around us is already close to a critical point. But in recent decades, in the context of globalization, technological development, and in fact the destruction of resources, has involved more and more countries and regions, bringing a resource catastrophe closer.

You can continue with the previous paradigm, build more and more nuclear power plants and increase energy production, exhausting resources to the end. But there is a second way - the creation of fundamentally new technologies and systems for using energy through hybrid materials and systems based on them, that is, replacing today's final energy consumer with systems that reproduce the principles of living nature - orders of magnitude more economical and safe.

The largest supercomputers consume tens of megawatts of energy. And it is believed that the limitation of computer power will be due precisely to the lack of energy for them. But the human brain consumes only ten watts - that is, a million times less! Today, the development of science has reached such a level that it is already possible to construct such nature-like materials and systems.

A tool for creating a new nature-like technosphere is convergent nano-, bio-, information, cognitive and socio-humanitarian technologies (NBICS technologies). They became the second most important highway direction scientific development Kurchatov Institute in recent years.

- What does a specific NBICS project look like in practice?

Nanobiotechnologies have already become a new technological culture, where at the atomic level the lines between living and nonliving, organic natural world and inorganic are erased. The matter of the near future is the reproduction of systems and processes of living nature in the form of a synthetic cell, mass creation of artificial tissues and organs, additive technologies that use the natural principle of forming objects, growing them, creating them to order.

Bioenergy, devices that produce and use energy through natural metabolic processes in living systems, is also actively developing. The next step is creating artificial intelligence based on cognitive information technology and on material base nano-bio. Figuratively speaking, we plan to create a computer that would be comparable in both performance and energy consumption to our brain, based on the connection latest technologies with nature-like ones.

We have a colossal research program. Indeed, today’s national research center “Kurchatov Institute” includes six sites in Moscow, Protvina, and St. Petersburg. In the next couple of years, we will commission the world’s most powerful full-flow neutron research reactor, PIK, at our site in Gatchina, and we also plan to build the latest fourth-generation synchrotron source there.

We also add a powerful educational infrastructure to our research - not far from Gatchina, in Peterhof, the Faculty of Physics of St. Petersburg University is located, of which I am the dean. And here in Moscow, on the basis of MIPT, seven years ago we created the world’s first faculty of NBICS technologies, which every year supplies about 50 graduates to the Kurchatov Institute. We also have a whole interdisciplinary educational school curriculum, which we launched jointly with the Moscow government and in which almost 40 schools today participate.

That is, if I can put it in one phrase, the future of the Kurchatov Institute is, in fact, the creation of the future itself in it?

I would say this - creation. We have everything for this.

In 2017 Rosatomhas picked up a pace that convincingly proves that a nuclear renaissance has taken place in our country.

Moreover, our nuclear project is expanding to more and more countries interested in their development, because atomic energy is the basic generation of electricity, it is the development of science, technology, medicine, and even agriculture.

We can and should talk about this, but does everyone remember how our country became a world leader in this industry? Does everyone remember how it all began, who exactly conquered the atom, created unprecedented technologies from scratch?

To understand where and how we are moving, we must remember the beginning of the road. Analytical online magazine Geoenergetics.ru I’ve already started talking about this, but there were much more events and names of those who were pioneers of the atomic era in the USSR than described in that article.

On December 25, 1946, in Laboratory No. 2 (the future Kurchatov Institute), a controlled chain reaction began in our first nuclear reactor F-1 - the “physical first”.

From it, like from Gogol’s “Overcoat,” all our reactors grew - transport and research, “military” and completely peaceful.

Let's remember who created these technologies and how, how and by whom their evolution was ensured, and how exactly the evolution proceeded. By remembering, we will learn to understand better latest news from Rosatom, achieved level of development and prospects.

"Atomic Principles"

To begin with, let us recall the basic principles, postulates of nuclear energy, which are set not by technology, but by physical laws - eternal and constant. There are not many of them, they are easy to remember.

The basis of nuclear energy is the chain reaction of fission of the nuclei of uranium and plutonium atoms. The mass of fission fragments is less than the mass of the mother nuclei; the excess mass is converted into energy, which we use for our own purposes. The reason for the start of a chain reaction is primary free neutrons colliding with the nuclei of fissile elements on their way. Free neutrons produced during the decay of uranium or plutonium nuclei are called “secondary”. For a reaction to become a chain reaction, there must be as many or more secondary neutrons than primary ones;

Plutonium does not exist in nature, it is only formed internally nuclear reactor, therefore, the basis of nuclear energy today is uranium;

The fission chain reaction occurs only in the nuclei of the uranium isotope 235 U, the amount of which in natural ore is 0.7%, and 99.3% of the ore mass is the main uranium isotope 238 U, which does not take part in the chain reaction. Secondary neutrons produced during the fission of uranium-235 nuclei have the most different speeds, which in atomic physics means “having different energies.” The analogy is simple: if you throw a stone at a window, some of the glass fragments fly quickly, some - slowly, and it is impossible to predict exactly how each fragment will behave;

Uranium-235 nuclei fission when interacting with neutrons moving at any speed, but fast neutrons are very actively absorbed by uranium-238 nuclei, which can cause the chain reaction to stop. At the same time, uranium-238 “does not pay attention” to slow neutrons, so one of the main tasks for implementing a chain reaction is the ability to slow down secondary neutrons. Heavy or ordinary water and chemically pure graphite can be used as moderators;

In order for the chain reaction to be controllable, there must be more secondary neutrons than primary neutrons by only 2%. If there are too many secondary neutrons, the reaction grows like an avalanche and gets out of control, the extreme stage of its development is an atomic explosion. Second main task to carry out a controlled chain reaction, the multiplication factor of free neutrons should not exceed 1.02. This requires control and protection systems.

Here, in fact, are all the fundamental points. To carry out a fission chain reaction, you need more uranium-235; so that the chain reaction does not die out on its own, one or another moderator is needed; To prevent the chain reaction from becoming too violent, a control and protection system is needed. Three postulates of nuclear energy, set by the laws of nature, the laws of physics.

NII-9

The F-1 reactor was created to produce weapons-grade plutonium, its isotope 239 Pu - a substance that provides significantly greater energy at atomic explosion than uranium-235.

This isotope is formed as a result of the capture of a free neutron by uranium-238; capture reactions occur continuously, but plutonium-239, under the influence of free neutrons, can begin its own fission chain reaction. To prevent this from happening, you need to learn to determine the moment when a significant amount of plutonium-239 atoms has been produced, but its chain reaction has not yet begun.

The design of the F-1 was such that it left the possibility of literally snatching uranium blocks out of it at the right time, after which they were sent for “chemical procedures” to separate plutonium-239 from other chemicals.

In December 1947, Zinaida Ershova's group obtained 73 micrograms of plutonium-239 for the first time. This was proof that F-1 made it possible to obtain weapons-grade plutonium, which was to become the charge for our first atomic bomb. But it was obvious that this amount of plutonium-239 was too small - at least 6 kg of this formidable element was required for the charge.

Control panel of the first Russian nuclear reactor, Photo: ru.wikipedia.org

“At the end of 1945, they began to produce uranium and graphite of the required quality and in the required volumes” - we already remembered this phrase, and even began to decipher it.

The creation of an atomic reactor was only part of the huge volume of problems that had to be solved to create our first atomic bomb. In the USSR, before the start of the war, they did not have time to study all the problems associated with uranium - now they had to do this in the shortest possible time, since information from foreign intelligence that the United States was preparing new plans for the atomic bombing of our country was continuously received.

How to find uranium ores, how to organize the work of mining and processing plants, how to increase the content of uranium-235, how to isolate plutonium, how to make it into a metal, what are the properties of this metal - hundreds of questions, hundreds of problems that had to be solved from scratch.

We often hear “incredibly true” stories about Lavrentiy Beria, but the facts speak of a completely different face of the head of the Special Committee.

Zinaida Ershova, the “Russian Madame Curie,” took the initiative to create a scientific center to solve all of the above problems - Lavrenty Pavlovich “took up the trick.” On December 8, 1944, the GKO (State Defense Committee) decree “On measures to ensure the development of mining and processing of uranium ores” was issued, according to one of the points of which the creation of a uranium research institute began within the NKVD structure.

The name they gave it, of course, was one that did not mean anything: “Institute of Special Metals of the NKVD,” in which Zinaida Ershova became the head of the radiochemistry laboratory. The leadership of the new institute was entrusted to Viktor Borisovich Shevchenko, an engineer-colonel of the NKVD.

A tyrant satrap, an evil overseer of scientists? Viktor Shevchenko is a graduate of the Moscow Institute of Non-Ferrous Metals and Alloys, who worked at the same institute for two years as deputy director for scientific work, Doctor of Technical Sciences, during the war he was the chief engineer of the Norilsk copper-nickel plant. Viktor Shevchenko “pulled out” all the organizational work on creating a new research institute, but this did not stop him from being a brilliant professional metallurgist.

Was it possible in those years to separate the NKVD from the scientific work of the Special Committee? In our opinion, it is impossible.

At the end of 1945, Shevchenko organized Laboratory No. 12 at NII-9, which was entrusted with the creation of industrial production of heavy water. Max Vollmer, who had previously been director of the Institute of Physical Chemistry in Berlin, felt an unexpected desire to supervise her work.

Having learned about this decision, the professors expressed an active desire to work with him, Doctor of Sciences V.K. Beierl and G.A. Richtel.

The “Laboratory of Captured Germans” worked successfully, in 1955 the plant for the production of heavy water began to operate, and Comrade Max Vollmer returned to Berlin to lead the work of the German Academy of Sciences Democratic Republic. Here, try using this example to independently separate the NKVD and scientific work, if you wish.

Andrey Anatolyevich Bochvar

Through the efforts of Viktor Shevchenko, by the end of 1945, the construction of the first buildings of the institute was completed; December 27 is the official birthday of the High-Tech Research Institute of Inorganic Materials, VNIINM, which now bears the name of Andrei Anatolyevich Bovchar.

By mid-1946, NII-9 already had more than one and a half thousand employees, 13 laboratories, pilot production facilities in Moscow and Elektrostal, and a branch in Leningrad. Was it possible to organize such an institute at such a pace without the help of the NKVD? The question is rhetorical.

A.A. Bochvar

In 1946, Kurchatov invited the best metallurgist in the country, Andrei Anatolyevich Bochvar, to participate in the atomic project. The son of the founder of the Moscow school of metallurgy, the first doctor of this science in the Union at the age of 33, Andrei Bovchar by 1946 managed to do so much in science and in the development of the country's non-ferrous metallurgy that would be enough for two biographies.

Using his textbooks, several generations of our metallurgists prepared for work; the method of shaped casting with crystallization under pressure that he developed was in demand in aircraft construction during the war; in 1945, Andrei Anatolyevich discovered the phenomenon of superplasticity of alloys. It sounds complicated, but explaining what this discovery does is simple.

From sheets of Bochvar steel under slight pressure you can blow parts of the most complex shapes - just as glassblowers do in their workshops. No welding seams, no rivets with bolts - spheres and hemispheres, complex forms, this method is still used today.

In 1946, Bochvar was elected a full member of the Academy of Sciences - with such regalia, with such merits, he had every right to engage in “high science” and teaching work, but he responded instantly to Kurchatov’s proposal. The importance of the work and at the same time the opportunity to become the founder of the metal science of nuclear materials - a real scientist could not help but take part in our atomic project.

In 1946, Bochvar headed laboratory “B” at NII-9 - a name that is not often remembered, but its importance for our atomic project and especially for nuclear energy cannot be overestimated. The list of developments and discoveries that were made by the staff of laboratory “B” under the leadership of Andrei Bovchar is so impressive that we will not place it in this article.

If we talk about atomic and thermonuclear weapons, then let’s say briefly - without the work of Andrei Bovchar, it would have been impossible to create either one or the other.

Everything that is made from metallic plutonium is his merit, marked with two stars of the Hero of Socialist Labor and Stalin Prizes. The creation of the first industrial nuclear reactor would also have been impossible without his participation.

A-1 reactor design

The F-1 reactor was created so that scientists could verify the very possibility of carrying out a controlled fission chain reaction. F-1 did not have a cooling system; to produce plutonium, it was brought to a power of almost 4 MW, but in this mode it could operate for a matter of minutes - the reaction had to be stopped in order to cool the reactor using fans.

The F-1 did not have biological protection - it was controlled remotely, accumulating the data necessary to develop it. The experimentally measured neutron multiplication factor for F-1 turned out to be 1.00075. This, in fact, was the description of the problems that had to be solved when creating an industrial reactor.

More uranium was required - this ensured an increase in the amount of plutonium-239 produced. The reactor required biological protection to guarantee complete safety of personnel. The reactor required a cooling system so that the “half an hour of operation + several hours of fan operation” mode would disappear.

Industrial processing of uranium blocks was also needed - not on a laboratory scale, but on a factory scale. Please note that both F-1 and A-1 used natural uranium that was not enriched in the isotope-235 content. The development of enrichment technology had not yet been completed, and there was no critical need for it - the goal was to obtain plutonium-239.

Photographs, drawings, drawings of nuclear reactors not so rarely appear on the pages of the media; reactors become the “heroes” of documentaries - you, dear readers, have probably come across these images more than once.

In all of them, the reactor has a vertical arrangement - fuel assemblies and fuel rods, control and protection rods are directed from top to bottom, coolant moves from bottom to top. A simple question: if the F-1 had a horizontal design, then when and why did the vertical design appear?

This change, which now seems completely natural to us, is the “invention” of a remarkable scientist, designer, Engineer with a capital “E”, to whom we owe much of the development of nuclear energy.

Nikolai Antonovich Dollezhal, whom many encyclopedias call “an energy scientist, designer of nuclear reactors.” This, of course, is true, but this is only part of the truth - encyclopedias very famously skip the first 50 years of the life of this amazing man.

Chief designer

Nikolai Antonovich was born in 1899 in the family of railway engineer Anton Ferdinandovich Dollezhal (Czech by origin), since 1912 the family settled in Podolsk. After real school, in 1917, Nikolai entered the mechanical faculty of the Moscow Higher Technical University.

Nikolai’s father was convinced that without working with his hands, without a sense of metal, his son would not become a real engineer, so Nikolai, without interruption from his studies, worked in the depot, at the locomotive repair plant, and in his design bureau. In 1923, he received a diploma, for the next five years he worked in design organizations, in 1929-1930 he completed an internship in European countries, after which he spent a year and a half under investigation - they were looking for his connections with the Industrial Party.

They searched, but did not find, and already in 1932 Nikolai Dollezhal took the post of deputy chief engineer of OKB No. 8 of the technical department of the OGPU, in 1933 he became deputy director for the technical part of Giproazotmash and at the same time - head of the department of chemical engineering at the Leningrad Polytechnic Institute.

This is how the designer’s career progressed - Dollezhal was the chief engineer of the Bolshevik plant, Glavkhimmash, and Uralmash, which was then just under construction. Thermal power engineering, compressor engineering, chemical industry - such a range was accessible only to a specialist with a huge amount of knowledge, with the mindset of an inventor, with a “built-in” desire to improve the solutions found.

Nikolay Antonovich Dollezhal, Photo: biblioatom.ru

In 1943, the time came to show organizational skills - Nikolai Antonovich headed the Research Institute of Chemical Engineering. This research institute has become completely atypical scientific institution- under the leadership of Dollezhal, a whole complex of research and development units was formed, and even with very serious experimental and production bases.

We developed it ourselves, designed it ourselves, tested the first samples ourselves, and set it up ourselves industrial production- the “mechanism” that was required in 1946 in our atomic project. Igor Kurchatov had a good instinct for this level of specialists - it was he who invited Nikolai Dollezhal to participate in work on the design of the first industrial reactor in January 1946:

"We need to the shortest possible time create a uranium boiler for industrial use. You know how to work at the molecular level - now you have to master the atomic one"

Exactly one month was enough for Nikolai Dollezhal to fully understand what laboratory No. 2 was doing - already in February 1946, he proposed to “expand” the reactor from horizontal to vertical, and Igor Kurchatov completely agreed with the decision of the “atomic recruit."

But, as with the creation of any other complex technical equipment, scientific supervisor and designer - these are not all the specialists who ensure the development of the project.

Those of you who are associated with industrial production can easily name another specialist whose competence is necessary in such cases - the chief technologist.

It is to him that the scientific supervisor hands over the technical assignment, based on the requirements of which the technologist, together with the designer, develop each component of the complex, each of its individual mechanisms, and think through their connection into a single whole. Igor Kurchatov then, in January 1946, made a decision about who could be entrusted with such important work.

Chief technologist

This person was Vladimir Iosifovich Merkin, a 32-year-old employee of Laboratory No. 2, who, despite his age, had been the head of Sector No. 6 since 1944, where he developed one of the methods for transferring the plutonium charge of a future bomb to a supercritical state.

An explosion occurs when a certain mass of plutonium in a certain volume of a certain critical value is exceeded, for which it is enough to bring several parts of the warhead closer to each other, each of which has a mass less than the critical one. But this approach must occur at maximum speed so that the explosion occurs simultaneously throughout the entire volume of the charge.

One of possible ways- “cannon”, when two parts of a plutonium charge are literally shot towards each other using specially calculated explosions. Sector No. 6 had to solve the problem of synchronizing these two auxiliary explosions with an accuracy of 0.0001 seconds at an initial speed of flying parts of 1,500 m/s.

Why was such responsible work entrusted to Vladimir Merkin? In 1939, Merkin graduated from the Moscow Institute of Chemical Engineering, and immediately after that he became an employee of GSPI-3, where he worked on improving smoke screen systems for camouflaging Navy ships.

During the war, Vasily Iosifovich was transferred to TsKB-114, where he developed new flamethrowers for the needs of the army. The developments were successful - several types of flamethrowers were put into industrial production, played a certain role in the first years of the war, for which in 1942 Merkin was awarded the Stalin Prize of the second degree.

Director of the synthetic rubber plant V.V. Goncharov, with whom Merkin worked very closely, recommended a young talented engineer to Kurchatov in 1943. After an interview with the head of Laboratory No. 2, Merkin was demobilized from the army in a matter of days and transferred to the disposal of Igor Vasilyevich.

Like many specialists of that time, Vladimir Merkin and his employees were able to switch to solving completely new problems in a very short time.

The project of the first industrial reactor was the beginning of a long journey for Merkin - under his leadership, several more reactors were created for the production of weapons-grade plutonium, followed by projects of the first in the USSR research pressurized water reactor VVR-2, reactors for submarines and the first nuclear icebreaker"Lenin", the creation of a nuclear flying laboratory on board the Tu-95M aircraft, research into gas-cooled reactors.

But that was all later, and in 1946 Merkin became a member of the quartet “scientific director - chief technologist - general designer - metallurgist”:

Kurchatov - Merkin - Dollezhal - Bochvar

“We will cool it using running water, otherwise it is impossible to ensure the continuous operation of the reactor required by Igor Vasilyevich.” “Of course, we’ll install the compressor ourselves, but the uranium should not come into contact with water.” “I see, here is a shell alloy that will withstand heat and radiation.”

“Vladimir Iosifovich demands that water flow through the core at a speed of 2,500 tons per hour.” “It’s clear - here is an alloy that will withstand radiation, pressure and temperature and will not corrode.”

“According to the technical specifications, we will install 26 rods of the protection and control system.” “Yes, here is an alloy for technical channels.” “Igor Vasilievich gave information on biological protection, for the top, bottom and side protective layers, this alloy will be used, it weighs this much - Nikolay, calculate the design.”

“Andrey Anatolyevich, if Nikolai Antonovich calculated everything correctly, you will have to extract plutonium from 83,000 uranium blocks, calculate the processing capacity”...

At the same time, the computing equipment for solving all these problems is checkered paper, a slide rule and an adding machine. A question for those who have a developed imagination - what achievements would the groups of Kurchatov, Merkin, Bovchar and Dollezhal achieve if they had at their disposal... well, for example, the processors found in our home computers and phones?..

General diagram of the A-1 reactor, Fig.: economics.kiev.ua

Thermal power - 100 MW, core diameter and height - 9.2 m, 150 tons of uranium, 1’050 tons of graphite. The total number of uranium blocks is 83,000, 74 blocks per technological channel, of which there are 1,150 in A-1 (this was the name given to the first industrial reactor; physicists and engineers affectionately called it “Annushka”).

Let us note an important detail: the temperature of the water leaving the reactor was only 85-90 degrees.

"Lighthouse"

At the end of 1945, a place was determined where a whole complex of buildings and structures was to be built - an industrial reactor, chemical processing shops for irradiated uranium blocks, metallurgical units, premises for chemical water purification, an electrical substation, residential buildings for personnel and much more.

This place is known to everyone who is familiar with our nuclear project - next to Lake Kyzyl-Tash in the Southern Urals, in the Chelyabinsk region. Now this is the city of Ozersk and the Mayak industrial association, whose history deserves not one, but many articles.

The NKVD was appointed responsible for the construction of object 817, the parent organization being Chelyabmetallurgstroy. On November 24, 1945, the first peg was driven into the construction site, which became the start for grandiose construction, and in April 1946 the master plan was approved.

The most difficult stage was the excavation work when digging a pit for the reactor - the project was not yet completed, everything had to be clarified literally on the fly. The top-secrecy regime also had its effect - the mechanization of earthworks was minimal, almost everything had to be done manually.

In September 1946, when digging of the pit began, it was planned to have dimensions of 80 x 80 x 8 meters, and after all the clarifications, the depth was increased to 53 meters. 340 thousand cubic meters of soil almost manually, in winter period 1946-47, after 30 meters the rock layer began - a titanic work that employed 11,000 diggers.

In July 1947, concrete work was completed, and for the first time iron ore was used as a concrete filler to increase the level of biological protection.

At the same time, by order of Lavrentiy Beria, Efim Pavlovich Slavsky, the future head of the Ministry of Medium Engineering, was appointed director of the plant being created, and Vladimir Merkin was appointed chief engineer.

Efim Slavsky, who had the opportunity to directly contact Lavrentiy Beria, was able to increase the pace of work, which required expanding and expanding residential buildings - by the end of 1947, when construction and installation of equipment were underway simultaneously, 60 thousand people were working on the site.

Start

The reactor building was completed at the end of 1947, and installation began immediately. On June 1, 1948, the construction of the A-1 reactor, the construction of which required 5,000 tons of metal structures and equipment, 230 km of pipelines, 165 km of electrical cables, 5,745 units of fittings and 3,800 instruments, was completed.

The loading of the reactor with graphite and uranium began - yes, that's right, on June 1, 1948, there was no time for a break. Loading began at 08:50 on the first of June, at 23:15 on the seventh of June the last, 36th, layer of graphite was placed in its place.

At 00:30 on June 8, Igor Vasilyevich Kurchatov stood at the control panel and physically launched our first industrial nuclear reactor. The reactor began to gain power and was well regulated; by morning Kurchatov handed over the control panel to the personnel on duty, leaving an entry in the log:

“Shift supervisors! I warn you that if the water stops there will be an explosion. Therefore, the device should not be left without water under any circumstances. I.V. Kurchatov"

At a power of 10 kW, the physical characteristics of the reactor, control and protection systems were tested. Having received reports of full readiness, Kurchatov gave the order to raise the reactor power to the design level, which was reached on July 19 at 12:45.

This date is associated with the beginning of the production activities of plant 817, then the Chemical Plant named after. DI. Mendeleev", then "Enterprises p/box 21", then "Chemical Plant "Mayak" and only then - Production Association "Mayak".

Continuous round-the-clock operation of the facility began - with large and small problems that had to be solved literally on the fly. Unexpected corrosion phenomena, radiation swelling of graphite and uranium blocks, failures in the water supply of technological channels and many other incidents that were impossible to foresee.

But the plant’s personnel solved all the problems time after time, setting up, modernizing, correcting, and repairing. The plutonium produced on the A-1 became, in the hands of specialists from Yuli Khariton’s group, the warhead of our first atomic bomb, RDS-1.

Engineers and designers gained vast experience, which made it possible to build new “military” reactors. In the years cold war and the most intense work of Mayak, 10 reactors were working here simultaneously, and uranium from Seversk and Zheleznogorsk arrived here for processing.

The A-1 reactor itself, which according to the plan was supposed to operate for three years, lasted a little longer - 39 years, 13 times exceeding any guarantees; it was stopped only in 1987.

Military needs are the engine of progress

Atomic energy was conquered and mastered specifically for defensive purposes, but the scientists, designers, technologists, and engineers gathered into the huge team of the Special Project never believed that they were working only and exclusively for this purpose.

Yes, they were faced with the need to solve a very important problem; the physical survival of the country, without any stretch of the imagination, depended on the speed and accuracy of the solution. But, revealing new and new secrets of the atom, it amazing properties, our scientists have seen how useful it can become atomic energy for completely peaceful purposes.

Very little time passed - and the same people who created the most formidable, most powerful weapons began to create peaceful nuclear energy.

Igor Kurchatov became the person who carried and pushed through all power structures the idea of creating a nuclear power plant, Vladimir Merkin and Nikolai Dollezhal developed power reactors, Andrei Bovchar “invented” alloys with fantastic properties that were required for the materials of fuel rods, fuel assemblies, and reactor vessels.

We remembered only a part of those whom we rightly call the creators of our peaceful atomic project, but we also talked only about the very first steps of its development.

The topic of the next article will be a logical continuation of this one, if we take a closer look at what was not implemented at the A-1 reactor.

At the outlet of the reactor, the cooling water had a very low temperature - only 85-90 degrees; natural uranium, not enriched in the composition of the isotope-235, was used as a raw material.

How these facts are related to each other, how our nuclear scientists were able to find and implement this connection - that’s about it next time.

B. Martsinkevich

Nuclear reactor, principle of operation, operation of a nuclear reactor. Great encyclopedia of oil and gas

Story

Design and principle of operation

Energy release mechanism

Design

Physical principles of operation

Iodine pit

Classification

By nature of use

According to the neutron spectrum

By fuel placement

By fuel type

By type of coolant

By type of moderator

By design

By steam generation method

Reactor materials

Burnout and reproduction of nuclear fuel

Nuclear reactor control

Design and principle of operation

Energy release mechanism

Design

Physical principles of operation

Iodine pit

Classification

By purpose

According to the neutron spectrum

By fuel placement

By fuel type

By type of coolant

By type of moderator

By design

By steam generation method

IAEA classification

Reactor materials

Burnout and reproduction of nuclear fuel

Nuclear reactor control

Residual Heat

See also

Literature

Notes

"Atomic Principles"

NII-9

Andrey Anatolyevich Bochvar

A-1 reactor design

Chief designer

Chief technologist

"Lighthouse"

Start

Military needs are the engine of progress