Rao radioactive waste. What is the danger of radioactive waste

Removal, processing and disposal of waste from 1 to 5 hazard class

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In the 20th century, the non-stop search for the ideal source of energy seemed to be over. This source was the nuclei of atoms and the reactions taking place in them - active development began all over the world nuclear weapons and construction of nuclear power plants.

But the planet quickly faced the problem of processing and destroying nuclear waste. The energy of nuclear reactors carries a lot of dangers, as well as the waste of this industry. Until now, there is no carefully developed processing technology, while the sphere itself is actively developing. Therefore, safety depends primarily on proper disposal.

Definition

Nuclear waste contains radioactive isotopes of certain chemical elements. In Russia, according to the definition given in the Federal Law No. 170 “On the use atomic energy” (dated November 21, 1995), further use of such waste is not envisaged.

The main danger of materials lies in the radiation of gigantic doses of radiation, which has a detrimental effect on a living organism. The consequences of radioactive exposure are genetic disorders, radiation sickness and death.

Classification map

The main source of nuclear materials in Russia is the sphere of nuclear energy and military developments. All nuclear waste has three degrees of radiation, familiar to many from the course of physics:

• Alpha - radiant.
• Beta - emitting.
• Gamma - emitting.

The former are considered the most harmless, as they give a harmless level of radiation, unlike the other two. True, this does not prevent them from being included in the class of the most hazardous waste.


In general, the classification map of nuclear waste in Russia divides it into three types:

1. Solid nuclear waste. This includes a huge amount of maintenance materials in the energy sector, staff clothing, garbage that accumulates in the course of work. Such waste is burned in kilns, after which the ashes are mixed with a special cement mixture. It is poured into barrels, sealed and sent to storage. The burial is detailed below.
2. Liquid. The process of operation of nuclear reactors is impossible without the use of technological solutions. In addition, this includes water that is used to treat special suits and wash workers. Liquids are carefully evaporated, and then burial occurs. Liquid waste is often recycled and used as fuel for nuclear reactors.
3. Elements of the design of reactors, transport and means of technical control at the enterprise constitute a separate group. Their disposal is the most expensive. To date, there are two ways out: installation of the sarcophagus or dismantling with its partial decontamination and further shipment to the repository for burial.

The map of nuclear waste in Russia also defines low-level and high-level:

• Low-level waste - arise in the course of the activities of medical institutions, institutes and research centers. Here, radioactive substances are used to conduct chemical tests. The level of radiation emitted by these materials is very low. Proper disposal can turn hazardous waste into normal waste in about a few weeks, after which it can be disposed of as normal waste.
• High-level waste is spent reactor fuel and materials used in military industry to develop nuclear weapons. The fuel at the stations is a special rod with a radioactive substance. The reactor operates for approximately 12-18 months, after which the fuel must be changed. The amount of waste is simply enormous. And this figure is growing in all countries developing the field of nuclear energy. The disposal of high-level waste must take into account all the nuances in order to avoid a catastrophe for the environment and humans.

Recycling and disposal

On the this moment There are several methods for the disposal of nuclear waste. All of them have their advantages and disadvantages, but whatever one may say, they do not completely eliminate the danger of radioactive exposure.

burial

Waste disposal is the most promising method of disposal, which is especially actively used in Russia. First, the process of vitrification or "vitrification" of the waste occurs. The spent substance is calcined, after which quartz is added to the mixture, and this " liquid glass» is poured into special cylindrical steel molds. The resulting glass material is resistant to water, which reduces the possibility of radioactive elements on Wednesday.

Finished cylinders are brewed and thoroughly washed, getting rid of the slightest contamination. Then they go to storage for a very long time. The repository is arranged in geologically stable areas so that the repository is not damaged.

Geological disposal is carried out at a depth of more than 300 meters in such a way that for a long time the waste does not need further maintenance.

Burning

Part of the nuclear materials, as mentioned above, is the direct results of production, and a kind of side waste in the energy sector. These are materials exposed to radiation during production: waste paper, wood, clothing, household waste.

All this is burned in specially designed furnaces, which minimize the level of toxic substances in the atmosphere. The ash, among other wastes, is cemented.

Cementing

Disposal (one of the ways) of nuclear waste in Russia by cementing is one of the most common practices. The bottom line is to place irradiated materials and radioactive elements in special containers, which are then filled with a special solution. The composition of such a solution includes a whole cocktail of chemical elements.

As a result, it is practically unaffected external environment, which allows you to achieve an almost unlimited time. But it is worth making a reservation that such a burial is possible only for the disposal of waste of an average level of danger.

Seal

A long and fairly reliable practice aimed at burying and reducing the amount of waste. It is not applicable to the processing of basic fuel materials, but allows the processing of other low-hazard wastes. This technology uses hydraulic and pneumatic presses with low pressure force.

Reapplication

The use of radioactive material in the field of energy is not fully implemented due to the specific nature of the activity of these substances. Once exhausted, the waste still remains a potential source of energy for reactors.

AT modern world and even more so in Russia, the situation with energy resources is quite serious, and therefore the recycling of nuclear materials as fuel for reactors no longer seems unbelievable.

Today, there are methods that allow the use of spent raw materials for applications in the energy sector. Radioisotopes contained in the waste are used for food processing and as a "battery" for the operation of thermoelectric reactors.

But while the technology is still in development, and the ideal method of processing has not been found. Nevertheless, the processing and destruction of nuclear waste makes it possible to partially resolve the issue with such garbage, using it as fuel for reactors.

Unfortunately, in Russia, a similar method of getting rid of nuclear debris is practically not being developed.

Volumes

In Russia, all over the world, the volumes of nuclear waste sent for disposal amount to tens of thousands of cubic meters annually. Every year, European storage facilities receive about 45,000 cubic meters of waste, while in the United States, only one landfill in Nevada absorbs such a volume.

Nuclear waste and work related to it abroad and in Russia is the activity of specialized enterprises equipped with high-quality machinery and equipment. At the enterprises, waste is subjected to various methods of treatment described above. As a result, it is possible to reduce the volume, reduce the level of danger, and even use some waste in the energy sector as fuel for nuclear reactors.

The peaceful atom has long proved that everything is not so simple. The energy sector is developing and will continue to develop. The same can be said about the military sphere. But if we sometimes turn a blind eye to the release of other wastes, improperly disposed of nuclear waste can cause a total catastrophe for all mankind. Therefore, this issue needs to be resolved as soon as possible before it is too late.

radioactive waste

radioactive waste (RAO) - waste containing radioactive isotopes of chemical elements and having no practical value.

According to the Russian "Law on the use of atomic energy" (November 21, 1995 No. 170-FZ), radioactive waste (RW) is nuclear materials and radioactive substances, the further use of which is not expected. Under Russian law, the import of radioactive waste into the country is prohibited.

Often confused and considered synonymous with radioactive waste and spent nuclear fuel. These concepts should be distinguished. Radioactive waste is materials that are not intended to be used. Spent nuclear fuel is a fuel element containing nuclear fuel residues and many fission products, mainly 137 Cs and 90 Sr, widely used in industry, agriculture, medicine and scientific activity. Therefore, it is a valuable resource, as a result of the processing of which fresh nuclear fuel and isotope sources are obtained.

Sources of waste

Radioactive waste comes in a variety of forms with very different physical and chemical characteristics, such as the concentrations and half-lives of the radionuclides that make it up. These wastes can be generated:

• in gaseous form, such as vent emissions from facilities where radioactive materials are processed;
• in liquid form, ranging from scintillation counter solutions from research facilities to high-level liquid waste from spent fuel reprocessing;
• in solid form (contaminated consumables, glassware from hospitals, medical research facilities and radiopharmaceutical laboratories, vitrified waste from fuel processing or spent fuel from nuclear power plants when it is considered waste).

Examples of sources of radioactive waste in human activities:

Work with such substances is regulated by sanitary regulations issued by Sanepidnadzor.

• Coal . Coal contains a small number of radionuclides, such as uranium or thorium, but the content of these elements in coal is less than their average concentration in the earth's crust.

Their concentration increases in fly ash, as they practically do not burn.

However, the radioactivity of ash is also very low, it is approximately equal to the radioactivity of black shale and less than that of phosphate rocks, but it represents a known danger, since some fly ash remains in the atmosphere and is inhaled by humans. At the same time, the total volume of emissions is quite large and amounts to the equivalent of 1,000 tons of uranium in Russia and 40,000 tons worldwide.

Classification

Conditionally radioactive waste is divided into:

• low-level (divided into four classes: A, B, C and GTCC (the most dangerous);
• medium active (US legislation does not classify this type of radioactive waste as a separate class, the term is mainly used in European countries);
• highly active.

The US legislation also allocates transuranic radioactive waste. This class includes wastes contaminated with alpha-emitting transuranium radionuclides with half-lives of more than 20 years and concentrations of more than 100 nCi/g, regardless of their form or origin, excluding high-level radioactive waste. Due to the long period of decay of transuranic wastes, their disposal is more thorough than the disposal of low-level and intermediate-level wastes. Also Special attention this class of waste is distinguished because all transuranium elements are artificial and the behavior in the environment and in the human body of some of them is unique.

Below is the classification of liquid and solid radioactive waste in accordance with the "Basic Sanitary Rules for Ensuring Radiation Safety" (OSPORB 99/2010).

One of the criteria for such a classification is heat dissipation. In low-level radioactive waste, the heat release is extremely low. In medium-active ones, it is significant, but active heat removal is not required. High-level radioactive waste releases heat so much that they require active cooling.

Radioactive waste management

Initially, it was believed that a sufficient measure was the dispersion of radioactive isotopes in the environment, by analogy with production waste in other industries. At the Mayak plant, in the first years of operation, all radioactive waste was dumped into nearby water bodies. As a result, the Techa cascade of reservoirs and the Techa River itself were polluted.

Later it turned out that due to natural and biological processes, radioactive isotopes are concentrated in various subsystems of the biosphere (mainly in animals, in their organs and tissues), which increases the risks of public exposure (due to the movement of large concentrations of radioactive elements and their possible entry with food in the human body). Therefore, the attitude towards radioactive waste was changed.

1) Protection of human health. Radioactive waste is managed in such a way as to provide an acceptable level of protection of human health.

2) Environmental protection. Radioactive waste is managed in such a way as to ensure an acceptable level of environmental protection.

3) Protection beyond national borders. Radioactive waste is managed in such a way that possible consequences for human health and the environment beyond national borders are taken into account.

4) Protection of future generations. Radioactive waste is managed in such a way that the predicted health consequences for future generations do not exceed appropriate levels of consequences that are acceptable today.

5) Burden for future generations. Radioactive waste is managed in such a way as not to impose an undue burden on future generations.

6) National legal structure. Radioactive waste management is carried out within the framework of an appropriate national legal framework that provides for a clear division of responsibilities and the provision of independent regulatory functions.

7) Control over the generation of radioactive waste. The generation of radioactive waste is kept to the minimum practicable level.

8) Interdependence of radioactive waste generation and management. Due account shall be taken of the interdependencies between all stages of radioactive waste generation and management.

9) Installation safety. The safety of radioactive waste management facilities is adequately ensured throughout their lifetime.

Main stages of radioactive waste management

• At storage radioactive waste should be contained in such a way that:
  • ensured their isolation, protection and monitoring of the environment;
  • if possible, actions at subsequent stages (if they are provided) were facilitated.

In some cases, storage may be carried out primarily for technical reasons, such as storing radioactive waste containing primarily short-lived radionuclides for decay and subsequent disposal within authorized limits, or storing high-level radioactive waste prior to disposal in geological formations for the purpose of reduction of heat generation.

• Preliminary processing waste is the initial stage of waste management. It includes the collection, regulation chemical composition and decontamination and may include an interim storage period. This step is very important because in many cases the pre-treatment provides the best opportunity to separate the waste streams.

• Treatment management of radioactive waste includes operations whose purpose is to improve safety or economy by changing the characteristics of radioactive waste. Basic processing concepts: volume reduction, removal of radionuclides and composition change. Examples:
  • incineration of combustible waste or compaction of dry solid waste;
  • evaporation, filtration or ion exchange of liquid waste streams;
  • precipitation or flocculation of chemicals.

Capsule for radioactive waste

• Conditioning radioactive waste management consists of those operations in which radioactive waste is formed into a form suitable for movement, transportation, storage and disposal. These operations may include the immobilization of radioactive waste, the placement of waste in containers, and the provision of additional packaging. Common methods of immobilization include solidification of liquid radioactive waste of low and intermediate levels by incorporation into cement (cementing) or bitumen (bituminization), as well as vitrification of liquid radioactive waste. Immobilized waste, in turn, depending on the nature and concentration, can be packed in various containers, ranging from conventional 200-liter steel drums to containers with a complex design with thick walls. In many cases, processing and conditioning are carried out in close connection with each other.

• burial mainly that radioactive waste is placed in a disposal facility with appropriate security, without the intention of removing it and without providing long-term storage monitoring and maintenance. Safety is mainly achieved through concentration and containment, which involves sequestering suitably concentrated radioactive waste in a disposal facility.

Technology

Intermediate radioactive waste management

Usually in the nuclear industry, intermediate-level radioactive waste is subjected to ion exchange or other methods, the purpose of which is to concentrate radioactivity in a small volume. After processing, a much less radioactive body is completely neutralized. It is possible to use iron hydroxide as a flocculant to remove radioactive metals from aqueous solutions. After absorption of the radioisotopes by iron hydroxide, the resulting precipitate is placed in a metal drum where it is mixed with cement to form a solid mixture. For greater stability and durability, concrete is made from fly ash or furnace slag and Portland cement (as opposed to conventional concrete, which consists of Portland cement, gravel and sand).

Handling of high-level radioactive waste

Removal of low-level radioactive waste

Transportation of flasks with high-level radioactive waste by train, UK

Storage

For temporary storage of high-level radioactive waste, storage tanks for spent nuclear fuel and storage facilities with dry barrels are designed to allow short-lived isotopes to decay before further processing.

Vitrification

Long-term storage of radioactive waste requires conservation of waste in a form that will not react and break down over a long period of time. One way to achieve this state is vitrification (or vitrification). Currently in Sellafield (Great Britain) highly active PAO (purified products of the first stage of the Purex process) are mixed with sugar and then calcined. Calcination involves passing the waste through a heated rotating tube and aims to vaporize water and denitrogenize the fission products to increase the stability of the resulting vitreous mass.

Crushed glass is constantly added to the resulting substance in the induction furnace. As a result, a new substance is obtained, in which, during hardening, the waste is associated with a glass matrix. This substance in a molten state is poured into alloy steel cylinders. Cooling, the liquid solidifies, turning into glass, which is extremely resistant to water. According to the International Society of Technology, it will take about a million years for 10% of this glass to dissolve in water.

After filling, the cylinder is brewed, then washed. After being examined for external contamination, the steel cylinders are sent to underground storage facilities. This state of waste remains unchanged for many thousands of years.

The glass inside the cylinder has a smooth black surface. In the UK, all work is done using high activity chambers. Sugar is added to prevent the formation of the RuO 4 volatile substance containing radioactive ruthenium. In the West, borosilicate glass, identical in composition to pyrex, is added to the waste; in the countries of the former USSR, phosphate glass is usually used. The amount of fission products in glass must be limited, as some elements (palladium, platinum group metals, and tellurium) tend to form metallic phases separately from glass. One of the vitrification plants is located in Germany, where the waste from the activities of a small demonstration processing plant that has ceased to exist is processed.

In 1997, the 20 countries with most of the world's nuclear potential had 148,000 tons of spent fuel in storage facilities inside reactors, 59% of which were disposed of. There were 78 thousand tons of waste in external storage facilities, of which 44% was recycled. Taking into account the rate of disposal (about 12 thousand tons annually), the final elimination of waste is still quite far away.

geological burial

Searches for suitable deep final disposal sites are currently underway in several countries; it is expected that the first such storage facilities will become operational after 2010. The international research laboratory in Grimsel, Switzerland deals with issues related to radioactive waste disposal. Sweden is talking about its plans for direct disposal of spent fuel using KBS-3 technology after the Swedish parliament deemed it safe enough. Discussions are currently underway in Germany about finding a place for permanent storage of radioactive waste, residents of the village of Gorleben in the Wendland region are protesting vigorously. This place until 1990 seemed ideal for the disposal of radioactive waste due to its proximity to the borders of the former German Democratic Republic. Currently, RW is in temporary storage in Gorleben, the decision on the place of their final disposal has not yet been made. U.S. authorities chose Yucca Mountain, Nevada as the burial site, however this project met with strong opposition and became the subject of heated discussions. There is a project to create an international repository for high-level radioactive waste; Australia and Russia are proposed as possible disposal sites. However, the Australian authorities oppose such a proposal.

There are projects for the disposal of radioactive waste in the oceans, among which are disposal under the abyssal zone of the seabed, disposal in the subduction zone, as a result of which the waste will slowly sink to the earth's mantle, and disposal under a natural or artificial island. These projects have obvious merits and will allow solving the unpleasant problem of radioactive waste disposal at the international level, but, despite this, they are currently frozen due to the prohibition of maritime law. Another reason is that in Europe and North America they are seriously afraid of leakage from such a storage, which will lead to an environmental disaster. Real Opportunity no such danger has been proven; however, the bans were tightened after the dumping of radioactive waste from ships. However, in the future, countries that cannot find other solutions to this problem are seriously able to think about the creation of oceanic storage facilities for radioactive waste.

In the 1990s, several options for conveyor disposal of radioactive waste into the bowels were developed and patented. The technology was assumed to be as follows: a large-diameter starting well up to 1 km deep is drilled, a capsule loaded with radioactive waste concentrate weighing up to 10 tons is lowered inside, the capsule must self-heat and melt the earth rock in the form of a “fireball”. After the first “fireball” is deepened, the second capsule should be lowered into the same well, then the third, etc., creating a kind of conveyor.

Reuse of radioactive waste

Another use of isotopes contained in radioactive waste is their reuse. Already, cesium-137, strontium-90, technetium-99 and some other isotopes are used to irradiate food products and ensure the operation of radioisotope thermoelectric generators.

Removal of radioactive waste into space

Sending radioactive waste into space is a tempting idea, since radioactive waste is permanently removed from the environment. However, such projects have significant drawbacks, one of the most important is the possibility of a launch vehicle failure. In addition, the significant number of launches and their high cost make this proposal impractical. The matter is also complicated by the fact that international agreements on this problem have not yet been reached.

Nuclear fuel cycle

Cycle start

Waste from the front end of the nuclear fuel cycle – usually alpha-emitting waste rock from the extraction of uranium. It usually contains radium and its decay products.

The main by-product of enrichment is depleted uranium, consisting mainly of uranium-238 with less than 0.3% uranium-235. It is stored as UF 6 (waste uranium hexafluoride) and can also be converted to U 3 O 8 . In small quantities, depleted uranium finds use in applications where its extremely high density is valued, such as in the manufacture of keels of yachts and anti-tank shells. Meanwhile, several million tons of waste uranium hexafluoride have accumulated in Russia and abroad, and there are no plans for its further use in the foreseeable future. Waste uranium hexafluoride can be used (along with recycled plutonium) to create mixed oxide nuclear fuel (which may be in demand if the country builds significant quantities of fast neutron reactors) and to dilute highly enriched uranium, which was previously part of nuclear weapons. This dilution, also called depletion, means that any country or group that gets its hands on nuclear fuel will have to repeat a very expensive and complex enrichment process before it can create a weapon.

End of cycle

Substances in which the nuclear fuel cycle has come to an end (mostly spent fuel rods) contain fission products that emit beta and gamma rays. They may also contain actinides that emit alpha particles, which include uranium-234 (234 U), neptunium-237 (237 Np), plutonium-238 (238 Pu) and americium-241 (241 Am), and sometimes even sources neutrons such as californium-252 (252 Cf). These isotopes are produced in nuclear reactors.

It is important to distinguish between the processing of uranium to produce fuel and the processing of used uranium. The used fuel contains highly radioactive fission products. Many of them are neutron absorbers, thus getting the name "neutron poisons". Ultimately, their numbers increase to such an extent that, by trapping neutrons, they stop the chain reaction even when the neutron absorber rods are completely removed.

The fuel that has reached this state must be replaced with fresh, despite the still sufficient amount of uranium-235 and plutonium. Currently, in the US, used fuel is sent to storage. In other countries (in particular, in Russia, Great Britain, France and Japan), this fuel is reprocessed to remove fission products, then, after re-enrichment, it can be reused. In Russia, such fuel is called regenerated. The reprocessing process involves working with highly radioactive substances, and the fission products removed from the fuel are a concentrated form of highly radioactive waste, just like the chemicals used in reprocessing.

To close the nuclear fuel cycle, it is supposed to use fast neutron reactors, which allows processing fuel, which is a waste product of thermal neutron reactors.

On the issue of nuclear proliferation

When working with uranium and plutonium, the possibility of their use in the creation of nuclear weapons is often considered. Active nuclear reactors and stockpiles of nuclear weapons are carefully guarded. However, highly radioactive waste from nuclear reactors may contain plutonium. It is identical to the plutonium used in reactors and consists of 239 Pu (ideal for building nuclear weapons) and 240 Pu (unwanted component, highly radioactive); these two isotopes are very difficult to separate. Moreover, highly radioactive waste from reactors is full of highly radioactive fission products; however, most of them are short-lived isotopes. This means that waste disposal is possible, and after many years the fission products will decay, reducing the radioactivity of the waste and facilitating work with plutonium. Moreover, the unwanted isotope 240 Pu decays faster than 239 Pu, so the quality of weapons raw materials increases over time (despite the decrease in quantity). This causes controversy that, over time, waste storage facilities can turn into a kind of "plutonium mines", from which it will be relatively easy to extract raw materials for weapons. Against these assumptions is the fact that the half-life of 240 Pu is 6560 years, and the half-life of 239 Pu is 24110 years; Pu in a multi-isotope material will halve on its own - a typical conversion of reactor-grade plutonium to weapons-grade plutonium). Therefore, "weapon-grade plutonium mines" will become a problem, if at all, only in the very distant future.

One solution to this problem is to reuse reprocessed plutonium as fuel, such as in fast nuclear reactors. However, the very existence of nuclear fuel reprocessing plants, necessary to separate plutonium from other elements, creates an opportunity for the proliferation of nuclear weapons. In pyrometallurgical fast reactors, the resulting waste has an actinoid structure, which does not allow it to be used to create weapons.

Recycling of nuclear weapons

Waste from the processing of nuclear weapons (unlike their manufacture, which requires primary raw materials from reactor fuel), does not contain sources of beta and gamma rays, with the exception of tritium and americium. They contain much more actinides that emit alpha rays, such as plutonium-239, which undergoes a nuclear reaction in bombs, as well as some substances with high specific radioactivity, such as plutonium-238 or polonium.

In the past, beryllium and highly active alpha emitters such as polonium have been proposed as nuclear weapons in bombs. Now an alternative to polonium is plutonium-238. For reasons of national security, the detailed designs of modern bombs are not covered in the literature available to the general public.

Some models also contain (RTGs), which use plutonium-238 as a durable source of electrical power to operate the bomb's electronics.

It is possible that the fissile material of the old bomb to be replaced will contain decay products of plutonium isotopes. These include alpha emitting neptunium-236, formed from inclusions of plutonium-240, as well as some uranium-235, obtained from plutonium-239. The amount of this waste from the radioactive decay of the bomb core will be very small, and in any case they are much less dangerous (even in terms of radioactivity as such) than plutonium-239 itself.

As a result of the beta decay of plutonium-241, americium-241 is formed, an increase in the amount of americium is a bigger problem than the decay of plutonium-239 and plutonium-240, since americium is a gamma emitter (its external effect on workers increases) and an alpha emitter, capable of generating heat. Plutonium can be separated from americium in a variety of ways, including pyrometric treatment and extraction with an aqueous/organic solvent. A modified technology for the extraction of plutonium from irradiated uranium (PUREX) is also one of the possible separation methods.

In popular culture

In reality, the effect of radioactive waste is described by the effect of ionizing radiation on a substance and depends on their composition (what radioactive elements are included in the composition). Radioactive waste does not acquire any new properties, does not become more dangerous because they are waste. Their greater danger is due only to the fact that their composition is often very diverse (both qualitatively and quantitatively) and sometimes unknown, which complicates the assessment of the degree of their danger, in particular, the doses received as a result of an accident.

see also

Notes

Links

• Safety in handling radioactive waste. General provisions. NP-058-04
• Key Radionuclides and Generation Processes (unavailable link)
• Belgian Nuclear Research Center - Activities (unavailable link)
• Belgian Nuclear Research Center - Scientific Reports (unavailable link)
• International Atomic Energy Agency - Nuclear Fuel Cycle and Waste Technology Program (unavailable link)
• (unavailable link)
• Nuclear Regulatory Commission - Spent Fuel Heat Generation Calculation (unavailable link)

The disposal of radioactive waste is necessary to prevent the influence of harmful chemical elements and radioactive isotopes on environment, the environment, and, most importantly, human health.

The level of education is increasing every year, and recycling and recycling still does not capture the entire amount of incoming waste. Recycling and recycling are too slow, while the disposal of radioactive waste requires more active action.

Sources of environmental contamination with radioactive waste

The source of radioactive or can be any facility that uses or processes radioactive isotopes. It can also be organizations that produce EBPM materials, the production of which produces radioactive waste. This is an industry in the nuclear or medical sector that uses or generates radioactive materials to manufacture their products.

Such waste can be generated in different forms, and, most importantly, take on different physical and chemical characteristics. Such as the concentration and half-life of the main element constituting the radionuclides. They can form:

• When processing scintillation counters, the solution, which passes into a liquid form.
• When processing used fuel.
• During the operation of ventilation systems, releases of radioactive materials into gas in similar forms can also occur at various enterprises that deal with such substances.
• Medical supplies, consumables, laboratory glassware, radiopharmaceutical organizations, glass containers used when working with fuel for nuclear power plants can also be considered a source of contamination.
• Natural sources of radiation known as PIR can also emit radioactive contamination. The main part of such substances is nuclides (beta emitters), potassium - 40, rubidium - 87, thorium - 232, as well as uranium - 238 and their decay products emitting alpha particles.

Sanepidnadzor has issued a list of regulations for sanitary rules for working with such substances.

A small part of the radionuclides is contained even in ordinary coal, but it is so small that even the average concentration in earth's surface such elements exceeds their share. But coal ash is already equal in radioactivity to black shale, since radionuclides do not burn. During the use of coal in furnaces, only radioactive elements are released and enter the atmosphere with fly ash. Further, with the air, a person annually inhales toxic chemical elements that got there during the operation of any power plants using coal. The total of such emissions in Russia is approximately 1000 tons of uranium.

Spent elements of gas and oil products may also contain an element such as radium, the decay of such a product may depend on sulfate deposits in oil wells. As well as radon, which can be a component of water, gas or oil. The decay of radon forms solid radioisotopes, as a rule, it forms as a precipitate on the walls of the pipeline.

Propane production areas in refineries are considered the most dangerous radioactive areas, since radon and propane have the same boiling point level. Vapors, falling into the air as a precipitate, fall to the ground and infect the entire territory.

Disposal of this type of radioactive waste is practically impossible, since microscopic particles are present in the air of all cities in the country.

Medical radioactive waste also has sources of beta and gamma rays, they are divided into two classes. Nuclear diagnostic medicine uses a short-lived gamma emitter (technetium - 99th). Most of it decomposes in a fairly short period of time, after which it has no impact on the environment and is disposed of with ordinary garbage.

Classification of radioactive waste and its elements

There are three groups into which radioactive waste is divided, these are:

• low active;
• medium active;
• highly active.

The former are also divided into four classes:

• GTCC.

The last one is the most dangerous.

There is also a class of transuranic radioactive waste, it includes alpha waste emitting transuranic radionuclides with a half-life of more than 20 years. And the concentration is more than 100 nCi/g. Due to the fact that their decay period is much longer than that of conventional uranium waste, disposal is carried out more carefully.

Methods for disposal or disposal of radioactive waste

Even for safe transportation and storage, such waste must be processed and conditioned for its further transformation into more suitable forms. Protection of man and the natural environment, the most pressing issues. The disposal of radioactive waste should not cause any damage to the environment and fauna in general.

There are several types of combating nuclear substances, the choice of which depends on the level of danger of the latter.

vitrification.

The high level of activity (HLW) forces the use of vitrification as a burial method in order to give matter a solid form that will remain in this stable form for thousands of years. During the disposal of radioactive waste in Russia, borosilicate glass is used, its stable form will allow preserving any element inside such a matrix for many millennia.

Burning.

Utilization of radioactive waste using this technology cannot be complete. It is used, as a rule, to partially reduce the volume of materials that pose a threat to the environment. With this method, there is concern for the atmosphere, because unburned particles of nuclides enter the air. But, nevertheless, it is used to destroy such types of contaminated materials as:

• wood;
• waste paper;
• clothes;
• rubber;

Emissions into the atmosphere do not exceed the established norms, since such furnaces are designed and developed according to the highest standards, a modern technological process.

Seal.

This is a fairly well-known and reliable technology that allows to reduce the volume (used for the processing of MSW and other large-sized products) of low-hazard waste. The range of installations for presses of such actions is quite large and can vary from 5 tons to 1000 tons (super compactor). The compaction factor in this case can be equal to 10 or more, depending on the material being processed. In this technology, hydraulic or pneumatic presses with low pressure force are used.

Cementing.

Cementing of radioactive waste burial grounds in Russia is one of the most common types of immobilization of radioactive substances. A special liquid solution is used, which includes many chemical elements, their strength is practically not affected natural conditions, which means that their service life is almost unlimited.

The technology here is to place a contaminated object or radioactive elements in a container, then fill it with a pre-prepared solution, allow time to harden and move it to be stored in a closed area.

This technology is suitable for intermediate hazardous waste.

It has long been believed that in the near future the disposal of radioactive waste can be carried out on the Sun, according to media reports, Russia is already developing such a project. But while this is only in the plans, you need to take care of the environment and the ecology of your native land.

Radioactive waste (RW) is those substances that contain radioactive elements and cannot be reused in the future, as they have no practical value. They are formed during the extraction and processing of radioactive ore, during the operation of equipment that generates heat, and during the disposal of nuclear waste.

Types and classification of radioactive waste

By types of radioactive waste are divided:

• by state - solid, gaseous, liquid;
• by specific activity - highly active, medium activity, low activity, very low activity
• by type - deleted and special;
• according to the half-life of radionuclides - long- and short-lived;
• by elements of the nuclear type - with their presence, with their absence;
• for mining - in the processing of uranium ores, in the extraction of mineral raw materials.

This classification is also relevant for Russia, and is accepted at the international level. In general, the division into classes is not final, it needs to be harmonized with various national systems.

Released from control

There are types of radioactive waste in which there is a very low concentration of radionuclides. They practically do not pose a danger to the environment. Such substances are classified as exempt. The annual amount of exposure from them does not exceed the level of 10 μ3v.

RW management rules

Radioactive substances are divided into classes not only to determine the level of danger, but also to develop rules for handling them:

• it is necessary to ensure the protection of a person who works with radioactive waste;
• the protection of the environment from hazardous substances should be improved;
• control the process of waste disposal;
• indicate the level of exposure at each repository on the basis of documents;
• control the accumulation and use of radioactive elements;
• in case of danger, accidents must be prevented;
• in emergency cases, all consequences must be eliminated.

What is the danger of RAO

To prevent such an outcome, all enterprises using radioactive elements are obliged to apply filtration systems, control production activities, decontaminate and dispose of waste. This helps prevent an environmental disaster.

The RW hazard level depends on several factors. First of all, this is the amount of waste in the atmosphere, the power of radiation, the area of ​​the contaminated territory, the number of people who live on it. Since these substances are deadly, in the event of an accident, it is necessary to eliminate the disaster and evacuate the population from the territory. It is also important to prevent and stop the transfer of radioactive waste to other territories.

Rules for storage and transportation

An enterprise working with radioactive substances must ensure the reliable storage of waste. It involves the collection of radioactive waste, their transfer to disposal. The means and methods necessary for storage are established by documents. For them, special containers are made of rubber, paper and plastic. They are also stored in refrigerators, metal drums. Transportation of radioactive waste is carried out in special sealed containers. In transport, they must be securely fixed. Transportation can only be carried out by companies that have a special license for this.

Recycling

The choice of recycling methods depends on the characteristics of the waste. Some types of waste are shredded and compacted to optimize waste volume. It is customary to burn certain residues in a kiln. RW processing must comply with the following requirements:

• isolation of substances from water and other products;
• eliminate radiation;
• isolate the impact on raw materials and minerals;
• assess the feasibility of recycling.

Collection and removal

Collection and disposal of radioactive waste should be carried out in places where there are no non-radioactive elements. At the same time, it is necessary to take into account state of aggregation, category of waste, their properties, materials, half-life of radionuclides, potential threat of the substance. In this regard, it is necessary to develop a strategy for RW management.

For collection and removal, you need to use specialized equipment. Experts say that these operations are possible only with medium and low active substances. During the process, each step must be controlled to prevent an environmental disaster. Even a small mistake can lead to an accident, environmental pollution and the death of a huge number of people. It will take many decades to eliminate the influence of radioactive substances and restore nature.

Every production process leaves behind waste. And spheres that use the properties of radioactivity are no exception. Free circulation of nuclear waste, as a rule, is already unacceptable at the legislative level. Accordingly, they must be isolated and preserved, taking into account the characteristics of individual elements.

Sign, which is a warning about the danger of ionizing radiation of radioactive waste (radioactive waste)

Radioactive waste (RW) is a substance that contains elements that have radioactivity. Such waste has no practical significance, that is, they are unsuitable for recycling.

Note! Quite often, a synonymous concept is used -.

From the term "radioactive waste" it is worth distinguishing the concept of "spent nuclear fuel - SNF". The difference between spent nuclear fuel and radioactive waste lies in the fact that spent nuclear fuel after proper processing can be reused in the form of fresh materials for nuclear reactors.

Additional information: SNF is a collection of fuel elements, mainly consisting of fuel residues from nuclear installations and a large number of half-life products, as a rule, they are 137 Cs and 90 Sr isotopes. They are actively used in the work of scientific and medical institutions, as well as in industrial and agricultural enterprises.

In our country, there is only one organization that has the right to carry out activities for the final disposal of radioactive waste. This is the National Operator for Radioactive Waste Management (FGUP NO RAO).

The actions of this organization are regulated by the Legislation of the Russian Federation (No. 190 FZ of July 11, 2011). The law prescribes the mandatory disposal of radioactive waste produced in Russia, and also prohibits their import from abroad.

Classification

The classification of the considered type of waste includes several classes of radioactive waste and consists of:

• low-level (they can be divided into classes: A, B, C and GTCC (the most dangerous));
• medium-level (in the United States, this type of radioactive waste is not allocated to a separate class, so the concept is usually used in European countries);
• highly active radioactive waste.

Sometimes one more class of radioactive waste is isolated: transuranic. This class includes wastes characterized by the content of transuranic α-emitting radionuclides with long decay periods and extremely high values ​​of their concentrations. Due to the long half-life of these wastes, the burial is much more thorough than the isolation of low-level and medium-level radioactive waste. predict how dangerous environmental situation and the human body will be these substances, extremely problematic.

The problem of radioactive waste management

During the operation of the first enterprises using radioactive compounds, it was generally accepted that the dispersion of a certain amount of radioactive waste in areas of the environment is permissible, in contrast to the waste generated in other industrial sectors.

Thus, at the infamous Mayak enterprise, at the initial stage of its activities, all radioactive waste was discharged into the nearest water sources. Thus, there was a serious pollution of the Techa River and a number of reservoirs located on it.

Subsequently, it turned out that accumulation and concentration of hazardous radioactive waste occurs in various areas of the biosphere, and therefore their simple discharge into the environment is unacceptable. Together with contaminated food, radioactive elements enter the human body, which leads to a significant increase in the risk of exposure. Therefore, in last years various methods of RW collection, transportation and storage are being actively developed.

Disposal and recycling

Disposal of radioactive waste can occur in different ways. It depends on the RAO class to which they belong. The most primitive is the disposal of low-level and medium-level radioactive waste. We also note that according to the structure, radioactive waste is divided into short-lived substances with a short half-life and waste with a long half-life. The latter belong to the class of long-lived.

For short-lived wastes, the easiest way to dispose of them is considered to be their short-term storage on specially designed sites in sealed containers. Within a certain time, radioactive waste is neutralized, after which radioactively harmless waste can be recycled in the same way as household waste is recycled. Such waste may include, for example, materials from medical institutions (HCF). A container for short-term storage can be a standard two-hundred-liter barrel made of metal. To avoid the penetration of radioactive elements from the tank into the environment, the waste is usually filled with a bituminous or cement mixture.

The photo shows the technologies for handling radioactive waste at one of the modern enterprises in Russia

Disposal of the waste that is constantly generated at nuclear power plants is much more difficult to implement and requires the use of special methods, such as, for example, plasma processing, recently implemented at the Novovoronezh NPP. In this case, RW is subjected to transformation into substances similar to glass, which are subsequently placed in containers for the purpose of irretrievable disposal.

Such processing is absolutely safe and allows several times to reduce the amount of radioactive waste. This is facilitated by the multi-stage purification of combustion products. The process can run offline for 720 hours, with a productivity of up to 250 kg of waste per hour. At the same time, the temperature indicator in the furnace installation reaches 1800 0 C. It is believed that such a new complex will work for another 30 years.

The advantages of the plasma process of radioactive waste disposal over others, as they say, are obvious. So, there is no need to carefully sort the waste. In addition, numerous cleaning methods can reduce the release of gaseous impurities into the atmosphere.

Radioactive Contamination, Radioactive Waste Repositories in Russia

For many years, Mayak, located in the northeastern part of Russia, was a nuclear power plant, but in 1957 one of the most catastrophic nuclear accidents occurred there. As a result of the incident, up to 100 tons of hazardous RW were released into the natural environment, affecting vast territories. At the same time, the catastrophe was carefully concealed until the 1980s. For many years, waste from the station and from the polluted surrounding area was dumped into the Karachay River. This has caused pollution of the water source, so necessary for thousands of people.

"Mayak" is far from the only place in our country subject to radioactive contamination. One of the main environmental dangerous objects in the Nizhny Novgorod region is a radioactive waste disposal site, located 17 kilometers from the city of Semyonov, also commonly known as the Semyonovsky burial ground.

There is a storage facility in Siberia that has been storing nuclear waste for more than 40 years. To store radioactive materials, they use uncovered pools and containers, which already contain approximately 125,000 tons of waste.

In general, a huge number of territories have been discovered in Russia with levels of radiation exceeding the permissible norms. They even include such large cities as St. Petersburg, Moscow, Kaliningrad, etc. For example, in kindergarten near the Institute. Kurchatov in our capital, a sandbox for children with a radiation level of 612 thousand mR / h was identified. If a person were at this "safe" children's facility for 1 day, then he would be exposed to a lethal dose of radiation.

During the existence of the USSR, especially in the middle of the last century, the most dangerous radioactive waste could be dumped into the nearest ravines, so that a whole dump was formed. And with the growth of cities, new sleeping and industrial quarters were built in these infected places.

It is rather problematic to assess what is the fate of radioactive waste in the biosphere. Rains and winds actively spread pollution to all surrounding areas. Thus, in recent years, the rate at which the White Sea is polluted as a result of radioactive waste disposal has increased significantly.

Burial problems

There are two approaches to the implementation of nuclear waste storage and disposal processes today: local and regional. Disposal of radioactive waste at the site of their production is very convenient from different points of view, however, such an approach can lead to an increase in the number of hazardous disposal sites during the construction of new facilities. On the other hand, if the number of these places is strictly limited, then there will be a problem of cost and ensuring the safe transportation of waste. Indeed, regardless of whether the transportation of radioactive waste is a production process, it is worth eliminating non-existent hazard criteria. Making an uncompromising choice in this matter is quite difficult, if not impossible. In different states, this issue is solved in different ways and there is no consensus yet.

One of the main problems can be considered the definition of geological formations suitable for organizing a radioactive waste cemetery. Deep adits and mines used for the extraction of rock salt are best suited for this purpose. And also they often adapt wells in areas rich in clay and rock. High water resistance, one way or another, is one of the most important characteristics when choosing a burial site. A kind of burial ground for radioactive waste appears in the places of underground nuclear explosions. So, in the state of Nevada, USA, on a site that served as a test site for about 450 explosions, almost each of these explosions formed a repository of highly active nuclear waste buried in the rock without any technical "obstacles".

Thus, the problem of the formation of radioactive waste is extremely difficult and ambiguous. Achievements in nuclear energy, of course, bring enormous benefits to mankind, but at the same time they create a lot of trouble. And one of the main and unresolved problems today is the problem of disposal of radioactive waste.

More details about the history of the issue, as well as a modern view on the issue of nuclear waste, can be seen in the special issue of the program "Nuclear Legacy" of the TV channel "Science 2.0".