OTHER METHODS OF ISOTOPE SEPARATION 9.31. In addition to the isotope separation methods described above, several others have also been tested. The ion mobility method, as the name indicates, is based on the following fact. In an electrolyte solution, two ions, chemically identical,

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THE PROBLEM OF ISOTOPE SEPARATION ON AN INDUSTRIAL SCALE INTRODUCTION10.9. By the time the Atomic Bomb Project was reorganized in December 1941, the theory of isotope separation by gaseous diffusion was well developed. Therefore, it was possible to formulate technical problems, with

Chapter XI. Electromagnetic separation of uranium isotopes INTRODUCTION 11.1. In Chapter IV we said that the possibility of separating uranium isotopes on a large scale by electromagnetic methods was predicted in late 1941 by E. A. Lawrence (University of California) and G. D. Smith

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The beginning of nuclear energy. Discovery of isotopes In the post-war years, research in nuclear physics, interrupted by the war, was resumed. In Cambridge, D. D. Thomson continued his research on positive rays, which had begun before the war. D. Thomson worked with a discharge tube, in

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SPONTANEOUS FISSION OF URANIUM NUCLEI AND THE POSSIBILITY OF A CHAIN ​​PROCESS In 1934, Italian physicist Enrico Fermi first irradiated uranium with newly discovered neutrons in the hope of increasing the mass of the original nuclei and obtaining elements with a higher atomic weight than uranium. Results

Is it true, you say, that no one needs natural uranium? Let's look at consumption.

Currently, the following types of enriched uranium are in demand in the world:

• 1. Natural uranium (0.712%). Heavy water reactors (PHWRs) such as CANDU
• 2. Weakly enriched uranium (2-3%, 4-5%). Water-graphite-zirconium, water-water-zirconium reactors, VVER, PWR, RBMK reactors
• 3. Medium enriched uranium (15-25%), Fast reactors, transport reactors (icebreakers, floating nuclear power plants) nuclear power plants
• 4. Highly enriched uranium (>50%), nuclear power plants (submarines), research reactors.

There will be an article about enrichment methods.

The raw material for enrichment is not pure metallic uranium, but uranium hexafluoride UF 6, which, due to its combination of properties, is the most suitable chemical compound for isotope enrichment. For chemists, we note that uranium fluorination occurs in a vertical plasma reactor.
Despite the abundance of enrichment methods, today only two of them are used on an industrial scale - gaseous diffusion and centrifuges. In both cases, the gas used is UF 6.

Closer to the matter of isotope separation. For any method, the efficiency of isotope separation is characterized by the separation coefficient α - the ratio of the share of the “light” isotope in the “product” to its share in the primary mixture.

For most methods, α is only slightly greater than unity, so to obtain a high isotope concentration, a single isotope separation operation must be repeated many times (cascades). For example, for the gas diffusion method α = 1.00429, for centrifuges the value strongly depends on the peripheral speed - at 250 m/s α = 1.026, at 600 m/s α = 1.233. Only with electromagnetic separation α is 10-1000 per 1 separation cycle. Comparison table according to several parameters it will be in the end.

The entire cascade of enrichment machines is always divided into stages. In the first stage of the separation cascade, the stream of the initial mixture is divided into two streams: lean (removed from the cascade) and enriched. The enriched one is fed to the 2nd stage. At the 2nd stage, the once enriched stream is subjected to separation for the second time:
the enriched flow of the 2nd stage enters the 3rd, and its depleted flow returns to the previous (1st), etc. From the last stage of the cascade, the finished product with the required concentration of a given isotope is selected.

I will briefly tell you about the main separation methods that have ever been used in the world.

Electromagnetic separation

Since the separation can be performed with uranium ions, the conversion of uranium to UF 6 is, in principle, not necessary. This method gives high purity, but low yield at high energy consumption. The substance whose isotopes need to be separated is placed in the crucible of the ion source, evaporated and ionized. Ions are drawn out of the ionization chamber by a strong electric field. The ion beam enters the vacuum separation chamber in a magnetic field H directed perpendicular to the movement of the ions. As a result, the ions move along their circles with different (depending on mass) radii of curvature. Just look at the picture and remember school lessons, where we all calculated the radius along which an electron or proton would fly in a magnetic field.

Diagram demonstrating the principle of electromagnetic separation.

The advantage of this method is the use of relatively simple technology (calutrons: CAL ifornia U university).
It was used for uranium enrichment at the Y-12 plant (USA), had 5184 separation chambers - “calutrons”, and for the first time made it possible to obtain kilogram quantities of highly enriched 235U - 80% or higher.

In the Manhattan Project, calutons were used after thermal diffusion - 7% raw material was supplied to alpha calutrons (Y-12 plant) and enriched to 15%. Weapons-grade uranium (up to 90%) was produced using beta calutrons at the Y-12 plant. Alpha and beta calutrons have nothing to do with alpha and beta particles, they are simply two “lines” of calutrons, one for preliminary enrichment, the second for final enrichment.

The method makes it possible to separate any combination of isotopes and has a very high degree divisions. Two passes are sufficient to enrich above 80% from a lean material with an initial content of less than 1%. Productivity is determined by the value of the ion current and the efficiency of ion capture - up to several grams of isotopes per day (total for all isotopes).

One of the electromagnetic separation workshops in Oak Ridge (USA)

Giant alpha calutron from the same plant

Diffusion methods

If you pass a gas consisting of two types of molecules (in our case, two isotopes) through a small hole or through a mesh consisting of a large number of small holes, it turns out that lighter gas molecules pass through in greater quantities than heavy ones. It is important to note that this phenomenon occurs only when the molecules pass through the hole without colliding in it... i.e., when the mean free path of the molecule is greater than the diameter of the hole. Accordingly, the gas passing by the grids turns out to be depleted in light molecules. Almost always there is a reverse leakage of gas through the mesh, as a result of which in reality the increase in the concentration of the light isotope (enrichment) turns out to be somewhat less.

More details under the spoiler, from the same report.

“On the state of scientific research and practical work Laboratory No. 2 for the production of uranium-235 by the diffusion method"

The greater the pressure drop across the grid, the greater the enrichment. The pressure difference is usually created by a compressor (pump) that moves gas between the grids. Such a system, consisting of grids and a compressor moving the gas, is the separation stage

We use uranium hexafluoride as gas. This is a salt that has a fairly high vapor pressure at room temperature. As for the grids, they are required that their opening diameter be less than the free path of uranium hexafluoride molecules. The latter, as is well known, is inversely proportional to gas pressure. At atmospheric pressure, the free path of molecules is approximately 1/10000 mm. Therefore, if we could make a fine mesh with holes smaller than 1/10,000 mm, we could work with gas at atmospheric pressure.

Currently, we have learned to make meshes with holes of about 5/1000 mm, i.e. 50 times greater than the free path of molecules at atmospheric pressure. Consequently, the gas pressure at which the separation of isotopes on such grids will occur must be less than 1/50 of atmospheric pressure. In practice, we assume to work at a pressure of about 0.01 atmospheres, i.e. under good vacuum conditions. Multiple gas enrichment during a continuous process can be carried out using a cascade installation consisting of a large number of stages connected in series. Calculations show that to obtain a product enriched to a concentration of 90% with a light isotope (this concentration is sufficient to produce an explosive), it is necessary to combine about 2000 such stages in a cascade. In the machine we are designing and partially manufacturing, it is expected to produce 75-100 g of uranium-235 per day. The installation will consist of approximately 80-100 “columns”, each of which will have 20-25 stages installed. The total area of ​​the grids (the area of ​​the grids determines the productivity of the entire installation) will be about 8000 m2. The total power consumed by the compressors will be 20,000 kW.

It was used as one of the first stages of enrichment. In the Manhattan Project, the K-25 plant enriched uranium from 0.86% to 7%, then the raw material was used for calutrons. In the USSR - the long-suffering D-1 plant, as well as the D-2 and D-3 plants that followed it, and so on.

Also, the “diffusion” separation method is sometimes understood as liquid diffusion - also, only in the liquid phase. The physical principle is that lighter molecules gather in a hotter area. Typically, a separation column consists of two coaxially located pipes in which different temperatures are maintained. The mixture to be separated is introduced between them. The temperature difference ΔT leads to the emergence of convective vertical flows, and a diffusion flow of isotopes is created between the surfaces of the pipes, which leads to the appearance of a difference in isotope concentrations in the cross section of the column. As a result, lighter isotopes accumulate at the hot surface of the inner tube and move upward. The thermal diffusion method allows the separation of isotopes in both gaseous and liquid phases.

In the Manhattan Project, this is the S-50 plant - it enriched natural uranium to 0.86%, i.e. increased enrichment for fifth uranium by only 1.2 times. In the USSR, work on liquid diffusion was carried out by the Radium Institute in the post-war period, but this direction did not receive any development.

Cascade of gas diffusion isotope separation machines.
Signatures on the patent - F. Simon, K. Fuchs, R. Peierls.

Aerodynamic separation

Everything you need to know about aerodynamic separation is in this picture

Injector options

Gas centrifugation

The principle of operation is separation due to centrifugal forces depending on the absolute difference in mass. During rotation (up to 1000 rps, peripheral speed - 100 - 600 m/s), heavier molecules go to the periphery, lighter ones - in the center (at the rotor). This method is currently the most productive and cheapest (based on $/EPP price).

Google is replete with schematic pictures of the centrifuge device, I’ll just give a couple of photos of what the assembled cascade looks like. In such a room, by the way, it is quite hot - the uranium hexaphosphoride there is far from being at room temperature, and the entire cascade must also be cooled.

Cascade of centrifuges from URENCO. Large, about 3 meters in height.

There are also smaller ones, about half a meter. Our domestic ones.

To understand the scale, or what a “shop from horizon to horizon” is.

Laser enrichment

The method uses uranium vapor and lasers that are precisely tuned to a specific wavelength, exciting atoms of precisely the 235th uranium. Next, ionized atoms are removed from the mixture by an electric or magnetic field.

The technology is very simple, and, generally speaking, does not require any super-complex mechanical devices such as diffusion grids or centrifuges, there is one problem.
In September 2012, Global Laser Enrichment LLC (GLE), a consortium of General Electric, Hitachi and Cameco, received a license from the US Nuclear Regulatory Commission (NRC) to build a laser separation plant with a capacity of up to 6 million SWU at the site of the existing joint venture of GE, Toshiba and Hitachi fuel fabricator in Wilmington, North Carolina. The planned enrichment is up to 8%. However, licensing was suspended due to problems with the spread of technology. Modern technologies enrichment (diffusion and centrifugation) require special equipment, so special that, generally speaking, if desired, through monitoring international contracts one can indirectly assume who is going to “quietly” (without the knowledge of the IAEA) enrich uranium or conduct work in this direction. And such monitoring is actually being carried out. If the laser enrichment method proves its simplicity and effectiveness, work on weapons-grade uranium may begin to be carried out where it is not really needed. Therefore, for now the laser method is being crushed.

Laser methods also include the molecular method, based on the fact that at infrared or ultraviolet frequencies, selective absorption of the infrared spectrum by gas 235 UF 6 occurs, which subsequently allows the use of the method of dissociation of excited molecules or chemical separation.
The relative content of U-235 can be increased by an order of magnitude already in the first stage. Thus, one pass is enough to provide sufficient uranium enrichment for nuclear reactors.

Explanation of the “molecular” method with chemical separation.

Advantages of laser enrichment:

• Electricity consumption: 20 times less than for diffusion.
• Cascading: the number of cascades (from 0.7% to 3-5% for U-235) is less than 100, compared to 150,000 centrifuges.
• The cost of the plant is significantly less.
• Environmentally friendly: less dangerous uranium metal is used instead of uranium hexafluoride.
• The need for natural uranium is 30% less.
• 30% less tailings storage (dump storage).

Comparison of performance of different methods

Uranium enrichment in Russia

• JSC "Angarsk Electrolysis Chemical Plant" (Angarsk, Irkutsk region),
• JSC "PO "Electrochemical Plant" (Zelenogorsk, Krasnoyarsk Territory),
• JSC "Ural Electrochemical Plant" (Novouralsk, Sverdlovsk region),
• JSC "Siberian Chemical Plant" (Seversk, Tomsk region).

For 2000 Enrichment capacity in Russia is distributed as follows: 40% for internal needs, 13% for processing waste dumps of foreign users, 30% for processing HEU and LEU, and 17% for external orders. All this is a peaceful atom. The production of enriched uranium for military purposes has been discontinued since 1989. By 2004 170 t (out of ~500 t) of HEU (highly enriched uranium) were processed under the HEU-LEU agreement.

That's all. Thank you for your attention.

Isotopic separation — process, in which individual isotopes of that element are isolated from a material consisting of a mixture of different isotopes of one chemical element. The separation of isotopes is always associated with significant difficulties, since isotopes, which are variations of one element that differ little in mass, chemically behave almost identically. But - the speed of some reactions differs depending on the isotope of the element, in addition, you can use the difference in their physical properties- for example, in mass. The differences in the behavior of isotopes are so small that during one stage of separation, the substance is enriched by hundredths of a percent and the separation process has to be repeated again and again - a huge number of times. The performance of such a cascade system is influenced by two factors: the degree of enrichment at each stage and the loss of the desired isotope in the waste stream.

Basic methods of isotope separation

Electromagnetic separation

Electromagnetic separation method is based on different action magnetic field into equally electrically charged particles of different masses. The machines, called calutrons, are huge mass spectrometers. Ions of the substances being separated, moving in a strong magnetic field, are twisted with radii proportional to their masses and fall into receivers, where they accumulate.

This method allows the separation of any combination of isotopes and has a very high degree of separation. Usually two passes are sufficient to obtain an enrichment degree greater than 80% from a lean substance (with an initial content of the desired isotope of less than 1%). However, electromagnetic separation is poorly suited for industrial production: most of the substances are deposited inside the calutron, so it must be periodically stopped for maintenance. Other disadvantages are high energy consumption, complexity and high cost. maintenance, low performance. The main area of ​​application of the method is the production of small quantities of pure isotopes for laboratory use.

Gas diffusion

This method uses the difference in the speed of movement of gas molecules of different masses. It is clear that it will only be suitable for substances in gaseous state. At different speeds of movement of molecules, if you force them to move through a thin tube, the faster and lighter ones will overtake the heavier ones. To do this, the tube must be so thin that the molecules move along it one by one. Thus, the key here is to produce porous membranes for separation. They must prevent leaks and withstand excess pressure.

For some light elements the degree of separation can be quite high, but for uranium it is only 1.00429 (the output stream of each stage is enriched by a factor of 1.00429). Therefore, gas diffusion enrichment enterprises are cyclopean in size, consisting of thousands of enrichment stages.

Gas centrifugation

This technology was first developed in Germany during World War II, but was not used industrially anywhere until the early 50s. If a gaseous mixture of isotopes is passed through high-speed centrifuges, the centrifugal force will separate the lighter or heavier particles into layers where they can be collected. The great advantage of centrifugation is that the separation coefficient depends on the absolute difference in mass rather than on the mass ratio. The centrifuge works equally well with both light and heavy elements. The degree of separation is proportional to the square of the ratio of the rotation speed to the speed of the molecules in the gas. Hence, it is very advisable to spin the centrifuge as quickly as possible. Typical linear speeds of rotating rotors are 250-350 m/s, and more than 600 m/s in advanced centrifuges.

Typical separation coefficient is 1.01 - 1.1. Compared to gas diffusion installations, this method has reduced energy consumption and greater ease of increasing power. Currently, gas centrifugation is the main industrial method of isotope separation in Russia.

Manufacturers of stable isotopes: The Rosatom State Corporation includes enterprises engaged in the industrial production of isotopes of medium and heavy masses, as well as isotopes of noble gases. Electromagnetic and gas centrifuge technologies are used for industrial isotope separation. These technologies make it possible to separate isotopes of almost all elements of the periodic table. The number of Rosatom State Corporation enterprises using these methods of isotope separation includes the following:

1. Federal State Unitary Enterprise "Electrokhimpribor" Plant - 209 items (electromagnetic method).
2. OJSC Production Association Electrochemical Plant produces 95 types of isotopes (gas centrifuge method).
3. OJSC "Siberian Chemical Plant" - 91 names of isotopes (gas centrifuge method).
4. FSUE "RFNC-VNIIEF" - 24 items (gas centrifuge method)

Isotopic separation- a technological process of changing the isotopic composition of a substance consisting of a mixture of different isotopes of one chemical element. From one mixture of isotopes, two mixtures are obtained at the output of the process: one with increased content the required isotope (enriched mixture), the other with a reduced one (lean mixture).

The main application of the isotope separation process is the enrichment of uranium with the isotope 235 U for the production of nuclear fuel, weapons-grade radioactive materials and other applications involving the use of radioactive substances.

Industrial work to separate isotopes is measured in separation work units (SWUs). For a certain change in the isotopic composition of a certain initial mixture, the same amount of SWU is required, regardless of the isotope separation technology.

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Subtitles

General principles

The separation of isotopes (for example, the extraction of 6 Li, 235 U,) is always associated with significant difficulties, because isotopes, which are variations of one element that differ little in mass, chemically behave almost identically. But - the speed of some reactions differs depending on the isotope of the element, in addition, you can use the difference in their physical properties - for example, in mass.

Be that as it may, the differences in the behavior of isotopes are so small that during one stage of separation, the substance is enriched by hundredths of a percent and the separation process has to be repeated again and again - a huge number of times. Technologically, this is carried out by sequentially passing the separated volume of isotopes through cells of the same type that perform the separation - cascades. To obtain the necessary separation, there can be several thousand cascades in series, and to obtain the required volume, tens and hundreds of thousands of such consecutive groups of cascades connected in parallel.

The performance of such a cascade system is influenced by two factors: the degree of enrichment at each stage and the loss of the desired isotope in the waste stream.

Let us explain the second factor. At each enrichment stage, the flow is divided into two parts - enriched and depleted in the desired isotope. Since the degree of enrichment is extremely low, the total mass of the isotope in the waste rock can easily exceed its mass in the enriched part. To avoid such loss of valuable raw materials, the depleted flow of each subsequent stage returns to the input of the previous one.

The starting material does not enter the first stage of the cascade. It is introduced into the system immediately for a certain nth stage. Thanks to this, from the first stage, material that is highly depleted in the main isotope is removed to waste.

Main isotope separation methods used

• Electromagnetic separation
• Gas diffusion
• Gas or liquid thermal diffusion
• Aerodynamic separation
• Laser isotope separation
• Chemical enrichment
• Photochemical separation

In any case, the amount of enriched material produced depends on the desired degree of enrichment and depletion of the output streams. If the source substance is available in large quantities and is cheap, then the productivity of the cascade can be increased by discarding along with the waste a large amount of unextracted useful element (for example, the production of deuterium from ordinary water). If necessary, a greater degree of isotope extraction from the raw material is achieved (for example, when enriching uranium).

Electromagnetic separation

The electromagnetic separation method is based on the equal strength of interaction between a magnetic field and equally electrically charged particles. However, with the same force, particles of different masses will behave differently. For example, the trajectory of equally charged ions moving in a magnetic field will depend on their mass. By placing traps in appropriate installation locations, the appropriate isotopes can be collected. In fact, such installations, called calutrons, are huge mass spectrometers. In them, ions of the separated substances, moving in a strong magnetic field, are twisted with radii proportional to their masses and fall into receivers, where they accumulate.

This method allows the separation of any combination of isotopes and has a very high degree of separation. Usually two passes are sufficient to obtain an enrichment degree greater than 80% from a lean substance (with an initial content of the desired isotope of less than 1%). However, electromagnetic separation is poorly suited for industrial production: most of the substances are deposited inside the calutron, so it must be periodically stopped for maintenance. Other disadvantages are high energy consumption, complexity and high cost of maintenance, and low performance. The main area of ​​application of the method is the production of small quantities of pure isotopes for laboratory use. However, during the Second World War, the Y-12 plant was built, reaching a capacity of 204 grams of 80% U-235 per day in January 1945.

Efficiency. A plant producing 50 kg of highly enriched uranium per year through electromagnetic separation ( calutron), is estimated to consume over 50 MW of electricity.

Gas diffusion

This method uses the difference in the speed of movement of gas molecules of different masses. It is clear that it will only be suitable for substances in a gaseous state.

At different speeds of movement of molecules, if you force them to move through a thin tube, the faster and lighter ones will overtake the heavier ones. To do this, the tube must be so thin that the molecules move along it one by one. Thus, the key point here is the production of porous separation membranes with typical pore sizes of tens to hundreds of nanometers. They must be leak-free, withstand high overpressure and be resistant to fluorinated environments. There were several methods for producing porous membranes, for example:

• Sintering of metal or polymer powders under such conditions that normalized gaps remain between the grains of the powder.
• Etching one metal from an alloy of two metals under certain conditions provided a porous structure.
• Electrolytic oxidation of aluminum forms a porous structure of aluminum oxide.

Membranes were usually made in the form of tubes up to several meters long. One separation cascade was assembled from several hundred tubes.

For some light elements the degree of separation can be quite high, but for uranium it is only 1.00429 (the output stream of each stage is enriched by a factor of 1.00429). To obtain high degrees of enrichment, several thousand separation cascades were sometimes connected in series. Considering that one typical industrial cascade occupied an area of ​​up to 100 m 2 or more, the gas diffusion enrichment enterprises were cyclopean in size. The relatively large pressure losses on the membranes and the size of the installations determined the enormous energy consumption of the compressors. In addition, the plant contained huge quantities of technological hexafluoride: sometimes several weeks passed from the startup of the plant to the receipt of the first product at the output, during which the hexafluoride sequentially filled the volumes of all cascades. This circumstance placed very serious demands on the reliability of the equipment, because the failure of even one cascade could cause the entire chain to stop. To minimize the damage from process stops, the cascades were equipped with automatic performance monitoring and bypass of the problematic cascade.

Thermal diffusion

In this case, again, the difference in the speed of movement of molecules is used. The lighter ones, when there is a temperature difference, tend to end up in a more heated area. The separation coefficient depends on the ratio of the difference in mass of isotopes to the total mass and is larger for light elements. Despite its simplicity, this method requires a lot of energy to create and maintain heat. At the dawn of the nuclear era, there were industrial installations based on thermal diffusion. Currently not widely used on its own, however, the idea of ​​thermal diffusion is used to increase the efficiency of gas centrifuges.

Gas centrifugation

The idea of ​​centrifugal separation began to be actively developed during the Second World War. However, difficulties in optimizing the technology delayed its development, and in Western countries a verdict was even reached about the economic futility of the method. In the USSR, the industrial introduction of centrifuge technology also began only after the industrial development of gaseous diffusion.

If a gaseous mixture of isotopes is passed through high-speed gas centrifuges, the centrifugal force will separate the lighter or heavier particles into layers where they can be collected. The great advantage of centrifugation is that the separation coefficient depends on the absolute difference in mass rather than on the mass ratio. The centrifuge works equally well with both light and heavy elements. The degree of separation is proportional to the square of the ratio of the rotation speed to the speed of the molecules in the gas. Hence, it is very advisable to spin the centrifuge as quickly as possible. Typical linear speeds of rotating rotors are 250-350 m/s, and more than 600 m/s in advanced centrifuges. The pressure difference at the centrifuge axis and at the outer wall can reach tens of thousands of times, so centrifuge cascades operate at low pressures to avoid hexafluoride condensation. To improve separation by thermal diffusion, a temperature gradient of several tens of degrees is created in centrifuges along the axis of the centrifuge.

Typical separation coefficient is 1.01 - 1.1. Compared to gas diffusion installations, this method has reduced energy consumption and greater ease of increasing power. Currently, gas centrifugation is the main industrial method for separating isotopes in Russia.

Aerodynamic separation

This method can be considered a variant of centrifugation, but instead of swirling the gas in a centrifuge, it swirls as it exits a special nozzle, where it is supplied under pressure. This technology, based on the vortex effect, has been used by South Africa and Germany.

The problems with the technology were that the radius of the nozzle was about 100 microns, while the total length of the nozzle at each industrial separation cascade amounted to hundreds and thousands of meters. This length was gained in pieces of several tens to hundreds of centimeters. In addition to the difficulties of manufacturing nozzles, there was the problem of diluent gas, such as helium. The diluent made it possible to keep uranium hexafluoride in the gaseous phase at high pressures at the inlet to the nozzles, necessary to create a high-speed flow in the nozzle. At the production output, the diluent and hexafluoride had to be separated. High pressures determined significant energy consumption.

Laser isotope separation (LSI)

Laser separation is not an independent method, but is used to improve the characteristics of electromagnetic or chemical methods divisions. The method is based on the selective ionization of one of the isotopes electromagnetic radiation(for example, laser light). The selectivity of ionization is based on the resonant (narrow-band) absorption of light by atoms; different isotopes have different radiation absorption spectra. This means that it is possible to select irradiation parameters at which atoms of a given isotope are predominantly ionized. Further ionized atoms can be separated, for example, in a magnetic field (AVLIS (English) Russian). In addition, the ionization of atoms can change the rate chemical reactions, for example, facilitating the decay of some chemical compounds(MLIS (English) Russian).

Laser separation technology has been developed since the 1970s by many countries and is considered promising, but has not yet gone beyond research work. In the 90s of the last century in the USA there was a research program for laser enrichment with electromagnetic separation at an experimental facility, but it was closed. Currently, a research program is underway in the United States at a demonstration facility of one of the options for laser enrichment with chemical separation called SILEX (English) Russian. The technology was developed in 1992 by the Australian company Silex. Since 2006, work on Silex technology has been carried out by Global Laser Enrichment LLC. A license was obtained to build a plant in Wilmington, North Carolina.

Chemical enrichment

Chemical enrichment takes advantage of differences in the rates of chemical reactions with different isotopes. It works best when separating light elements, where the difference is significant. In industrial production, reactions are used that involve two reagents in different phases (gas/liquid, liquid/solid, immiscible liquids). This makes it easy to separate rich and lean streams. Using additionally the temperature difference between the phases, it is achieved additional growth separation coefficient. Today, chemical separation is the most energy-saving technology for producing heavy water. In addition to the production of deuterium, it is used to extract 6 Li. In France and Japan, methods of chemical enrichment of uranium were developed, but they never reached industrial development.

Distillation

Distillation (distillation) uses the difference in boiling points of isotopes of different masses. Typically, the lower the mass of an atom, the lower the boiling point of this isotope. Again, this works best on light elements. Distillation is successfully used as the final stage in the production of heavy water.